So if you remember, I was having some issues and didnt really know what happened. I was cruising one day, about 25mph, and could hear a noise. It sounded like a rock was stuck in the brakes so I figured it would just work its way out. Then I slowed to about 5mph to cross some train tracks. The noise got louder and it almost sounded as if the exhaust was somehow dragging on the ground. Then about 5 feet off the train tracks, my wheels locked up and I couldnt move. Couldnt even push it out of the street.

Got it towed home, and jacked it up. Drained the tranny and t-case fluid to see if there was metal shavings or chunks in there. Nothing. So then I disconnected the driveshaft from the rear diff and the back wheels still wouldnt turn. The fronts turn so Im guessing that the front is ok. I drained the gear oil from the rear diff and only about 6 drops of oil came out lol. It looked like chocolate syrup as well. So then I drained the ATF fluid and all looked good. I went out to start removing the rear diff so we could figure out what happened. Thats when I noticed this........

http://i675.photobucket.com/albums/vv120/hauser0995/GOPR0017.jpg


I dont think thats supposed to be like that lol

Hole-y crap!

I guess that's the gear oil's escape tunnel...

Shitty.

So now what? The front diff pins and rear diff pins both back out?

Did you notice an absurd amount of gear oil in your driveway or at work?

That's an amazingly clean hole for having fluid leaked out of it!

I'd bet that fluid's been gone for more than a few miles. It'll take a while with no oil before the diff actually locks up.

holy crapoli! thats a decent hole you got there...

Holy shiat!!!! Wtf happened?!?!?!

Yikes! Do you launch alot or anything?

duct tape ... get her done ...
But wow that is an amazingly clean hole - no traces of jizz anywhere!

Ugh.

Try to get it covered under warranty.

If that doesn't work, I have an extra rear diff. Let me know.

Hole-y crap!

I guess that's the gear oil's escape tunnel...
That is what I was thinking lol
Shitty.

So now what? The front diff pins and rear diff pins both back out?

Did you notice an absurd amount of gear oil in your driveway or at work?
Not sure what now. I have to remove the diff thats for sure. No fluid under the car whatsoever
That's an amazingly clean hole for having fluid leaked out of it!

I'd bet that fluid's been gone for more than a few miles. It'll take a while with no oil before the diff actually locks up.
:+1:
holy crapoli! thats a decent hole you got there...
:duh:
Holy shiat!!!! Wtf happened?!?!?!
:tumbleweed:
Yikes! Do you launch alot or anything?
I used to. But I havent launched in a while
duct tape ... get her done ...
But wow that is an amazingly clean hole - no traces of jizz anywhere!

Yeah there is nothing under there lol.

Has anyone removed the rear diff? I need some help in doing this. I think the only thing I really need to know is how to get the axles out of the diff. I dont see any bolts or anything and Im too worried about breaking more shit by prying on them too much.


Ugh.

Try to get it covered under warranty.

If that doesn't work, I have an extra rear diff. Let me know.
How am I supposed to get it there? Besides, the dealershit in Boise dont cover anything. They fucking suck

I would think the axels should just pop out. Usually you need to use a big flat head screw driver and wedge it right between where the axel meets the diff. Obviously the wheel side needs to be free'ed up so when it pops out it has somewhere to go.

P.S- You've done a fair amount of 1/4 mile right? How many launches would you estimate you've had? How many miles ago did you change your rear diff fluid? And was it the diaqueen or whatever the OEM fluid is?

Well I guess Ill give it a shot. I still have to unbolt the axle from the hub but with one person, I think its going to be a bitch

Sounds like somthing from the ur hit ur diff, comp loss, file ins claim and pay ded and be out.

Sorry to hear this brother, but look on the bright side, you can get a built replacement! :innocent:

Almost looks like it had a small piece of metal wedge itself from the inside between the housing and the open diff and busted it from the inside out. It looks to be a 1/2" inward from the bearing, is that little lip you can see (on the left hand side of the photo) the bearing?

Removing the cover / housing should not be too bad, just have to work off the oil seal first. The cover should come off without removing the diff, it should sit in there still. The bearing is not fixed in the housing, it just rides on a hardened seat. It's a roller pin, so maybe one of the rollers busted and slipped out? Probably still in there..........

http://img405.imageshack.us/img405/1038/diffw.jpg

Yeah it maybe still in there. Im going to drop it anyway, it will make things easier. From what I can see/tell from under the car, it really doesnt seem that bad to take out. I just dont have a pry bar to get the axles out of the diff. I wonder if there is any aftermarket anythings that can be done to these. So far all I have seen is upgraded axles

Im going to try and have the dealership cover this. My warranty is still in effect so Im curious to see what happens

What worries me is I've heard this quoted a few times now by dealerships as "A known problem" has anyone else heard this and what the actual problem is the Mitsu knows of?

That sucks man, such bad luck. That rear diff picture makes it look like a very complicated rear diff lol.

OT post - Is the 60,000mile/5 year powertrain warranty transferable between owners? IDK if that's the actual mileage and timeline, but it's something like that. JW, cause that looks EXPENSIVE and i'm the third owner of my evo so idk if it is.

damn Joey! Fingers crossed for you on the warrenty

What worries me is I've heard this quoted a few times now by dealerships as "A known problem" has anyone else heard this and what the actual problem is the Mitsu knows of?

Yeah and if its a known issue, where the fuck is the recall. I just hope they cover my shit

That sucks man, such bad luck. That rear diff picture makes it look like a very complicated rear diff lol.

OT post - Is the 60,000mile/5 year powertrain warranty transferable between owners? IDK if that's the actual mileage and timeline, but it's something like that. JW, cause that looks EXPENSIVE and i'm the third owner of my evo so idk if it is.

I would assume that its transferable but not sure. But yes, the warranty is 5 year/60000 miles
damn Joey! Fingers crossed for you on the warrenty

Thanks homie

sorry for your lost joey.

Thanks dude. lets just see what the dealership says

Thanks dude. lets just see what the dealership says
what are symptoms, when did they actually started with your car??

What dealer are you going to? You could always go to the same one I managed to grab a new T case and $25.00 petty cash from (with my FP Black setup on). They were a bunch of morons.
Best of luck though, sorry to hear.

that sucks! sorry, put back to stock, trade in for new lesbaru forestmuncher

what are symptoms, when did they actually started with your car??
Nothing really. The car just locked up and I couldnt move it at all

What dealer are you going to? You could always go to the same one I managed to grab a new T case and $25.00 petty cash from (with my FP Black setup on). They were a bunch of morons.
Best of luck though, sorry to hear.
Im going to the new one in Boise. Who did you go to? Im not going to chance going any further than Boise. If they dont fix it, then Ill just do it myself
that sucks! sorry, put back to stock, trade in for new lesbaru forestmuncher
haha. Not going to happen. I have too much fun with this car to give it up. But with that said, if the right price came along, I would sell

sorry about the rear dif

Im going to the new one in Boise. Who did you go to? Im not going to chance going any further than Boise. If they dont fix it, then Ill just do it myself


I went to the one in Ogden. Ken Garff I think it was.

Got the car towed to the dealership last night. Wish me luck fellas

Best of luck Joey! Keep us posted

good luck man! I just read this thread bc I'm at the stealership getting my transfer case, rear diff & acd/ayc fluids changed -- managed to get them down to $200 for everything, not too bad .. over-priced? yes, but I don't have to do it myself. It probably would have taken half a day for me -- and my free time is non-existent as-is. Plus, I don't own a fluid pump, so this is all a matter of convenience.

Anyway, Good luck with the Rear Diff and let us know how it works out at the Dealership, if they cover it under warranty!

^^^will do. It wont be inspected till tomorrow so I guess we will see. Im going to try and get those fluids done for free while its there. I drained the tranny and tcase before I took it there. If they have to drive it for whatever reason, then they have to fill it lol

^^^will do. It wont be inspected till tomorrow so I guess we will see. Im going to try and get those fluids done for free while its there. I drained the tranny and tcase before I took it there. If they have to drive it for whatever reason, then they have to fill it lol

hahah, well, make sure they know it's empty! They may just try to drive it!!

If they fill it, I'm sure they will charge you for it too

Yeah I already warned them that there is no fluid. If they charge me, then they charge me. That just means I dont have to do it. But Im going to see if they will just do it and not make me pay for it. im a pretty good talker when it comes to things so we will see

sub'd. curious to see what they have to say...

good luck mate.

Getting answers today

^^^will do. It wont be inspected till tomorrow so I guess we will see. Im going to try and get those fluids done for free while its there. I drained the tranny and tcase before I took it there. If they have to drive it for whatever reason, then they have to fill it lol

Not sure if emptying them was a good idea...now they can claim that it was empty all along and that's why it blew. :/

I guess they could but the reason that its empty is because there is a hole in the case haha. Either way, Ill find out what the deal is

good luck buddy >

thanks man

good luck

Car wasnt looked at yesterday or today. Now they wont get to it till Tuesday :wallbash:

Thats some standup customer service.

Not sure if emptying them was a good idea...now they can claim that it was empty all along and that's why it blew. :/

^ whos posting as testdummy?

Dino

Sud for results.

Good luck joey, and my condolences for your rear diff

Dinololz 10-4 good luck for Tuesday mate.

Im upset that the car has been there for 2 whole days, open to close, and hasnt even been touched yet

Any word as to what is breaking to causing the diff failure to see if a upgrade could be made to prevent it. If it is a case issue I wonder if if replacing the driveshaft bushings and the rear diff mounts may help?

That might help but who knows. I would like for a solution though, I dont want to go through this again.

Im upset that the car has been there for 2 whole days, open to close, and hasnt even been touched yet


It is warranty work which does not pay well. They will not be in any big rush to get to it if they have private pay customers booked up.

Oh man waiting on the response cause my rear diff is jacked up too. This will decide if I go to the stealership or not...

I should find out today but Ill let everyone know

Hope you get good news man.

edit: although considering the circumstances I'm not sure how any new will be good. So I should have said hope you don't have to pay for it.

I'm interested to hear what went wrong.

GL dood. I hope its good news

NEWS FLASH:

Warranty is VOID lol. They looked at it and did what they were supposed to do. Then some dude that walked through said he recognized the car. The dealership asked where from and the guy told them that I was the 2010 SCCA IMS racing champion lol. At that point, they found some vids and wabam! So I have the car back in my possession and will start the tear down again. Lesson learned: Dont post videos of you racing. I wasnt the one that posted it but that does not matter. Fuck it

So now what?

Let me know if you need that diff I have.

Yeah. Right now Im still deciding on what to do. Ill get back to you when I have a solid plan

Sorry about the warranty, sort of expected it though. Seems odd that some guy would recognize your car at the dealer though. Most at the dealerships I go to seem to be clueless. They really did a vid search?!!! WTF!!

Damn, I'm sorry for you joey. Wrong place wrong time type of thing

Its probably why they didn't look at it for so long

They voided his warranty due to the huge radiator lol

yeah haha. the guy was like, man thats a big ass radiator haha

What's a "AMS" radiator? Got asked that one a few times.

Joey- I landed a rear diff on ebay with <5k miles for 1300 not long ago. Swapping it takes a whopping 20 minutes of your life. Definitely don't pay labor.

Or make Justin help you. :neener:

There's a few diff's on ebay right now with low-ish miles for like 1100-1300. I just bought one with 20k on it for $800 shipped :-) Mine took a dump too. Don't really know the cause yet, just started hearing a terrible clunking while turning and drained the oil and it looked like metal soup....

Wow that's messed up, was the guy an employee or just another customer that walked in?

What's a "AMS" radiator? Got asked that one a few times.

Joey- I landed a rear diff on ebay with <5k miles for 1300 not long ago. Swapping it takes a whopping 20 minutes of your life. Definitely don't pay labor.
Good lookin out. Ill be keeping an eye out
Or make Justin help you. :neener:
oh hes going to help haha. I will be doing the diff real soon, just have to get the car in the garage
There's a few diff's on ebay right now with low-ish miles for like 1100-1300. I just bought one with 20k on it for $800 shipped :-) Mine took a dump too. Don't really know the cause yet, just started hearing a terrible clunking while turning and drained the oil and it looked like metal soup....
nice pick up. Ill most likely hold out till I can get a good deal like that
Wow that's messed up, was the guy an employee or just another customer that walked in?

Not sure. They guy wouldnt tell me

What's a "AMS" radiator? Got asked that one a few times.

Joey- I landed a rear diff on ebay with <5k miles for 1300 not long ago. Swapping it takes a whopping 20 minutes of your life. Definitely don't pay labor.

Is it really that easy to swap the rear diff? I plan on doing it but my mechanic said I needed to go to the dealer afterwards to bleed the awc pumps.

You will need to bleed the ACD/AYC pump after you disconnect the lines, at least it's a good idea to. You need the Mut3 to do it.

Hardest part of the rear diff is dealing with the cv axles, need to pry them off (which is a bitch, I used a huge screwdriver and it took awhile). Other than that its very easy, a few bolts........helps to have an extra hand or one of those tranny cradle things.

Ahh ok will I be able to drive it to the dealership safetly without causing damage? Also any idea how much it runs to bleed the acd/ayc pump?

For a long time I left my car alone and did not get to have much fun with it since everything I do or didn't do people would tell the dealer. Had several people claim sightings of me at the local drag strip even. That was a pretty easy myth to bust tho by the fact i am not even sure where it is since I have never been there. Now that i killed my power train warranty i do not have to worry about the dealer seeing what i do and such. much more fun.

The job calls for 9 hours of labor. You can bleed the lines with a MUT3, manual pump bleeder, or if you know anyone who has a Modis scan tool with the latest updates it can do activate the bleeder pump.

Ahh ok will I be able to drive it to the dealership safetly without causing damage? Also any idea how much it runs to bleed the acd/ayc pump?

Some fluid will come out, try and minimize fluid loss with the lines dangling. I put little vinyl caps I had on the ends, but just keeping them up in the air (tie them up) would probably work. If the fluid in the res goes down below the line, fill it so it's between the min/max lines (DO NOT OVERFILL IT). Should be able to make it to the dealer ok, try and drive slow to avoid alot of diff clutch activation.

There will be air in the system on the trip to the dealer, the pump activates on ignition ON and tries to build accumulator pressure. It shouldn't be some huge problem for one quick trip.

A guy at the dealer told me that if I wanted to bleed it, it would be real simple. He said turn the key to on and turn the wheel all the way to the right. That will bleed the right line and then do the opposite and that would do the other line. He has an X as well and did this himself (he says). Any truth to this at all?

^^thanks a lot! :thumbup:

No, it's absurd. He is mistaken. I can go in depth on how the system works. You need the Mut3 program to give you constant pressure for around 5 minutes. You also have to turn the wheels as described in the service manual, but that is during the Mut3 tool's program where it builds pressure and the turning actuates the directional valves. You then need the tool to measure WSS readings to see if the system is working correctly. You need the dealer tool to ensure no air in the system after a line break, period.

See this thread for more info:

http://www.evoxforums.com/forums/showthread.php?t=51452

If the MUT3 wasn't like $3K I'd just go buy one (started to before but not quite that baller), then cut the dealer out all togther.

the forum should buy one and rent it out to people

They would have to charge basically the price to own for a deposit but not a terrible idea.

I would rather have a vendor get them at cost (which I would hope would be a lot cheaper) and sell them.

sucks that this happened joey. Is anyone working on aftermarket solutions to strengthen the rear diff? Is swapping the the RS diff or 9 diff a real possibility (and easy to do?)

Hollywood, I know you're dabbling in this area, any info?

I thought there were ppl already doing this (8/9 diff swaps)?

sucks that this happened joey. Is anyone working on aftermarket solutions to strengthen the rear diff? Is swapping the the RS diff or 9 diff a real possibility (and easy to do?)

Hollywood, I know you're dabbling in this area, any info?

Joey's will be looked at by Jack's to determine what actually failed, and if it is something that may be a weak point.

I thought there were ppl already doing this (8/9 diff swaps)?

Been a few but you lose part of your AWC when you do it.

oh

Yeah, the 8/9 diff swap is a huge huge job that seems almost impossible. You can get a Cusco or such Torsen diff to replace the open diff for the Evo X, it's a drop in replacement. You would have to completely disconnect the hydraulic lines and plug them up and not use the AYC clutches at all (i.e. dead weight).

Evoscan supports the diff bleeding stuff on older models, Hamish is also on this forum. We talked with him on another thread about supporting it in the future, he said it was fairly easy for him to do. I think he's waiting to see if there is enough desire in the Evo X community to do it............it would mean no more Mut3 and dealer for these situations.

what about the X RS diff from japan? Doesn't that drop in easier than an 8/9 swap?

Not sure about an X RS diff from Japan. It's S-AYC so unless there are different mounting positions, etc, I guess it would be ok? What is the difference between that and a USDM X AYC?

the RS in japan has no AYC, its a mechanical diff IIRC. I think you swap the diff and have to change the controller chips as well

Yeah, sounds like a Torsen or Viscous diff in the back. Cusco sells quite a few, I hear it's a must for drifting, etc. Anyone can drop one in but the effect on the S-AWC might be bad- as in the whole system would throw codes and you would loose the ACD as well.

It would probably explode if you kept the AYC attached and operation with a Torsen diff. The AYC is designed to divert power from an open diff in one direction (left clutch brakes the right wheel) so the whole system would be backwards. You would be sending power to the wheel that is slipping, and who knows if the Torsen would burn out or the clutches would fry.

Why get rid of AYC, its the best torque vectoring system ever, it's what makes the X the X. Joey, doesn't it make a difference in the "stuff" you do?

the RS in japan has no AYC, its a mechanical diff IIRC. I think you swap the diff and have to change the controller chips as well

Don't they sell RSs in Canada? Might be cheaper to get the part if they do.

Any updates?

The rear diff should arrive at Jacks Transmissions tomorrow. Ill have an update soon

You want me to check up on it?

IMO, the AYC gets in the way 50% of the time, and saves my ass 50% of the time. Kinda on the fence about it.

hi, recently i have encountered a problem, that is when i engage first gear and gas a little, it move a bit forward then sometimes it might vibrates seriously like the gearbox to the differential, if i move forward a little and shifting to 2nd gear then i can eliminate this problem. This happen in normal, sport and SS mode.

i m not sure whether it is due to the clutch or the differential. pls shed me some lights.

You want me to check up on it?

If you could yeah. That would be great. Thanks homie

Ok. I will pop in there and see if he has any progress on it today

Sweet. It should arrive today so I doubt he will make any headway on it today. maybe pop in tomorrow if u could

will do

thanks homie

word. im probably going to pick up some trans fluid while im there anyway

Why get rid of AYC, its the best torque vectoring system ever, it's what makes the X the X. Joey, doesn't it make a difference in the "stuff" you do?

For motorsport, they are rubbish. Same goes for the front diff, again rubbish when you have a decent amount of mumbo and you are on the circuit.

For motorsport, they are rubbish. Same goes for the front diff, again rubbish when you have a decent amount of mumbo and you are on the circuit.


So why spend so much to even buy the car, when the stuff you are paying so much for sucks? A better platform would surely be better starting place if that is your take.

So why spend so much to even buy the car, when the stuff you are paying so much for sucks? A better platform would surely be better starting place if that is your take.

Exactly. This is a rally bred system designed for many uses, the track is one of them. I would disagree that it is "rubbish" on the track, but it confounds me that people use the Evo for such specific uses when it was designed to be a swiss army knife. Get a dedicated track car (hint: not a sedan) with slicks if want the ultimate track car.

Back on topic, I was looking at my rear diff today and wondering how to plumb a cooler for either the gear oil side or the ATF side (not the actuation, just the clutch paks). I've read in Britain in hard autocrossing, the AYC on the Evo 9 and earlier would loose hydraulic pressure and bust the pistons inside the diff. Seems like it's somewhat related to the heat involved, so cooling this diff might be a good autoX idea.

IMO, the AYC gets in the way 50% of the time, and saves my ass 50% of the time. Kinda on the fence about it.

How does ayc get in your way??

How does ayc get in your way??

My guess is hes talking about ASC and that would be throttle cut...

No smith I'm not talking about ASC. :rolleyes:

The AYC in the rear is rubbish guys. For motorsport, as in circuit racing.... it's rubbish!

It's great for a road car, no doubts there. It lets most big hairy palmed rock apes with no talent feel like they are Carlos Sainz or Sébastien Loeb. Not bad for a weekend hack around the track but for serious motorsport they are rubbish and yes the Evo X is not a race car, but the Evo X RS is. Thats the one Mitsubishi Build specifically for motorsport, it comes with the right diffs in it to begin with (sans fancy diff centres) it has no ABS an no A/C. It has no Recaro seats, no Stereo, the rear bumper bar reo is 900g lighter ( In another life I worked with these cars in a motorsport application, so I could bang on about the RS for hours ) etc etc.

The X RS has a mechanical (helical) front and rear diff, there is no hydraulic transfer style rear diff anywhere to be seen, why do you think that is? Why do you think Mitsubishi have plated LSD centres for both front and rear diffs with no torque transfer mechanisms?

In all the WRC cars of past, none of them ran AYC's in competition.

As for why they are rubbish in a circuit racing application, once you have some decent bushing, decent suspension, decent tyres (I'm talking motorsport 'weapons grade' stuff, not the fast road car stuff most of you run) and the right circuit, the AYC will try to kill you!

When the car is seriously loaded up through a corner, high G, high speed the rear will start pig rooting, and it's then it becomes pretty easy to turn the car around and back it into a wall. The AYC will fight with itself and as for the front Helical diff, thats rubbish too. Once you start upping the Power and Torque of the car you'll be spinning up an inside wheel to buggery. Drop the Transfer, whack in a supertraction, adjust the preloads and you'll wonder why you didnt do this sooner, as you watch the lap times plummet!

I can see your point in an absolute dry track monster with 500 HP, there you have professional or near professional drivers making decisions that do not require an artificial yaw moment. They are their own yaw moment, you could say.

But that assumes the system has not been tailored for the application either. In other threads, I have theorized that the system is not much good beyond around 350whp and tuners would need to re-calibrate to get results. Since no one tunes it, the power and physics are designed for a 300hp road car and nothing else. I would love to get my hands on a controller that could do the AYC. The physics are hardcore from all the JSAE papers I have read, it's no picnic to tune.

As far as WRC is concerned, they ran AYC on eveything up to the Evo 6 when it was officially banned in 2001. Mitsu claimed it was extremely hard for their techs and crew to tune them for each individual driver. Tommi's world championship cars all had AYC.

The Evo X RS has no active systems because:

1) They are banned in most motorsports
2) Mitsu will not help tune the AYC nor do they have any intention of supporting others that could do it
3) It's lighter and less complex
4) The ACD / AYC stock system is only capable of handling around 350hp and 350 tq at the wheels before they system begins to slip too much to be any good

Various racers around the world run AYC and it has yielded some good results. Nurburgring 24, Time Attack, etc. There are a few racers here that use it and it works for them.

I can see your point in an absolute dry track monster with 500 HP, there you have professional or near professional drivers making decisions that do not require an artificial yaw moment. They are their own yaw moment, you could say.

But that assumes the system has not been tailored for the application either. In other threads, I have theorized that the system is not much good beyond around 350whp and tuners would need to re-calibrate to get results. Since no one tunes it, the power and physics are designed for a 300hp road car and nothing else. I would love to get my hands on a controller that could do the AYC. The physics are hardcore from all the JSAE papers I have read, it's no picnic to tune.

As far as WRC is concerned, they ran AYC on eveything up to the Evo 6 when it was officially banned in 2001. Mitsu claimed it was extremely hard for their techs and crew to tune them for each individual driver. Tommi's world championship cars all had AYC.

The Evo X RS has no active systems because:

1) They are banned in most motorsports
2) Mitsu will not help tune the AYC nor do they have any intention of supporting others that could do it
3) It's lighter and less complex
4) The ACD / AYC stock system is only capable of handling around 350hp and 350 tq at the wheels before they system begins to slip too much to be any good

Various racers around the world run AYC and it has yielded some good results. Nurburgring 24, Time Attack, etc. There are a few racers here that use it and it works for them.

Okay lets go 4 for 4.

Yes, the rear mech diff is lighter and less complex.
Yes, the AYC torque transfer diffs are made of glass and can't handle any real power. (and they hate being launched)
Yes Mitsubishi have no inclination in tuning AYC diffs when they have made a supertraction LSD plated diff centres!
Yes they are banned in most motorsport, like ABS brakes is too.

I don't think you are helping your case there...

You can bang on about AYC rear diffs as much as you like. I've had the exposure with using them in a motorsport application, not just writing theory. AYC is rubbish for motorsport and thats that. :neener:

For what it's worth, in the 12hr with the IX and X's, they run a standard motor, standard turbo and 98 (close to your 93) AND they have to run less boost than factory as per CAMS rulings. (CAMS - Confederation of Australian Motorsport - is the governing body for that particular race series) so the output power isn't going to be much more than around 350Hp anyway. In that series there was both RS IX and GSR Evo IX's with AYC's and we wiped the floor with them. What do you make of that?

From building circuit racing cars, just by removing the AYC rear diff with no other changes we've seen improvements in lap times, again I'm not talking time attack high HP cars, I'm talking club level, late model Evos.

In the X the AYC is pretty much going to be a pain in the ass for a LOT of people right about now, as the timing is right. When a new car comes out it takes a while for the aftermarket upgrades to be built, fitted and tuned and it's usually within 2-3 years that a large majority of people start fitting bigger turbos and breaking things. I've seen this time and time again when I was working at Team Mitsubishi Ralliart with the VIII and then the IX and now the X. Nothing ever changes. It's only now with people modding their X's and making decent torque that they are going to start killing their AYC diffs and thats something you wouldnt do with a mech rear with a supertraction centre.

Again, it's only in a motorsport application or big HP application that the AYC is rubbish. Mate, I'm not making this shit up. Ralliart themselves when they built the RS models from 7 onwards split the road and race car production. The Evo 9 is a classic example. The GSR IX has a 6 speed gearbox made of glass and an AYC rear diff. ( although you blokes stateside got the GT which is half GSR half RS) The IX GSR was great for road usage and fuel economy with the 6 speed and for hairy palmed rock apes the AYC can catch them when they have a 'moment'. So why did Mitsubishi make the IX RS with a 5 speed and mechanical diffs?

As for your precious AYC, there is another issue with it. No parts! If the thing dies, your up for a large amount of cash and since most Evo owners modify there cars to the extent they do, they sure as shit arent going to be able to claim warranty on it. (some will get lucky of course) Where as the Mech rear diff has a complete parts list available for it. If you want the crown wheel and pinion, you can buy it. If you just need the carrier bearings, well you can buy them too. Everything in the mech rear diff is cataloged, but not so for the AYC rear diff. It's a non-servicable item, like the TC-SST gearbox.

Lastly dont for one second start telling me about Gravel Rally Cars you've only read about... That'll really get my goat.

I'm not sure what we are arguing about, I can agree with you the AYC / ACD system is not supported in motorsports since the late nineties when they banned the technology. I have read quite a bit on the AYC development and they did run it in various races throughout the world championship years with good results. I've been to countless rally races with older Evo's that do great with AYC, especially on combo tarmac / dirt stages.

The problem with running AYC / ACD in motorsports now is the lack of control professional racers have over the system. Your CAMS cars are extremely lightweight and running heavy race tires, correct? That's already enough to kill the AYC's effectiveness since it is calibrated on a physics model for a car that is, well, not that race car!

I wish they supported the ability of AYC / ACD to be programmed and offered the ability to upgrade it for more power- don't you agree then it would make some kind of a difference? This is one of the most elegant systems ever designed and if it could have the support it deserves, it would work better than any torsen dirt oval track or clanky mech LSD.

Too bad WRC killed it before the technology could get going. I still say it has a benefit in most motorsports and is used widely outside the hardcore venues you have experience in.

If I told you I could program the ACD and AYC and custom tailor it to your race car, would you give it another chance?

Nope, Production cars are heavy with only a small percentage of weight removed. As for heavy tyres... What do you mean by that? Maybe a Yokohama AO50 or a Dunlop DZO3G dependent on compound. I'm still not gettin how they can be any heavier of lighter than anything else.

What would you say if I told you the ACD is already done. As for AYC diffs, they still arent strong enough and there are no parts availble. So that isn't going to work.

All in all I get what you are saying, but for race cars in my experience it's not worth it. As for a supertraction diff, I hardly think it represents something you would see in a dirty old speedway car. It's not a torsen either. ;)

Just to be clear, are you guys talking about rally racing or track racing (sebring, laguna seca) that the AYC and and the stock diff's suck for?

And I'm just wondering, if AYC and our diffs suck so bad, how does gates evo 10 do so well and smoke the shit out of other cars on the time attack circuit?

Where can us people in the states get the RS diff's?

have you had a chance to stop by Jacks?

i can today. but he isnt open for another 20 minutes

thanks man. Hopefully it got there lol

Just to be clear, are you guys talking about rally racing or track racing (sebring, laguna seca) that the AYC and and the stock diff's suck for?

And I'm just wondering, if AYC and our diffs suck so bad, how does gates evo 10 do so well and smoke the shit out of other cars on the time attack circuit?

Where can us people in the states get the RS diff's?

Sorry to hijack this thread a little, but we are talking about the ability for the ACD / AYC to be used in serious motorsports. McCoy has real experience in professionally racing the X and other Evo's, and used to work for Ralliart.

Don't want to put words in his mouth but he is contending the ACD/ AYC is an unsupported system for real motorsports and can't handle just slightly more than stock power. There is an Australia production series (kind of like a group N for circuit/endurance type racing) and they don't mod the cars much for stock. He claims X's with the ACD/AYC are slower then cars fitted with Supertraction diffs, which are Ralliart diffs. They are 1, 1.5, or 2 way spider gear plate clutch diffs for front, center, and rear. I believe they are somewhat mechanically adjustable.

There is also a prediction that ACD/AYC will not be produced anymore, meaning the 11 or whatever comes next is going to abandon it. There is a prediction that AYC's and ACD's will start to break around now in the States, since 3 years is the magic number (for harsh motorsports use).

It's a good opinion coming from a professional source, you got to respect it.

Since we have so many racers, even on this forum, using ACD/AYC and getting good results with no problems............time will tell, but getting interested in these systems, learning how to mod them, and understanding the physics is the only way to go, I think we have been lazy about this in the States in general.

This is what we have to do in this order:

1) Crack the ACD and AYC programming and learn how to tune it
2) Copy the Brits and learn how to upgrade the hydraulic pump assembly (source bigger accumulators, learn how to rebuild them, etc)
3) Get places like Sheps to rebuild the rear diff and transfer case
4) One up everyone and invent new clutch paks and internal upgrades for the diffs. They are wet clutches, so this isn't rocket science. Think of what SSP has done for upgraded clutches in the SST, etc.). If Mitsu won't support parts, then we have to source and make them ourselves.

Either that or we get failures and people will abandon the system for Torsen and plate type LSD's. It's a common thing in Europe, Japan, and now we know Australia too.

Ok, so he has all the new parts, and its ready to put back to together, he is just waiting on the new diff shell and to do the foam molding for shipping. But it looks really nice

Ok, so he has all the new parts, and its ready to put back to together, he is just waiting on the new diff shell and to do the foam molding for shipping. But it looks really nice

really? that was freakin quick! Thanks for lookin out dude.

Did you see what failed by any chance? Where the parts all fuckered up?

No problem

He didn't have any old parts there. You will have a brand new diff.

I forgot to ask if he knew specifically what had failed.

No smith I'm not talking about ASC. :rolleyes:

The AYC in the rear is rubbish guys. For motorsport, as in circuit racing.... it's rubbish!

It's great for a road car, no doubts there. It lets most big hairy palmed rock apes with no talent feel like they are Carlos Sainz or Sébastien Loeb. Not bad for a weekend hack around the track but for serious motorsport they are rubbish and yes the Evo X is not a race car, but the Evo X RS is. Thats the one Mitsubishi Build specifically for motorsport, it comes with the right diffs in it to begin with (sans fancy diff centres) it has no ABS an no A/C. It has no Recaro seats, no Stereo, the rear bumper bar reo is 900g lighter ( In another life I worked with these cars in a motorsport application, so I could bang on about the RS for hours ) etc etc.

The X RS has a mechanical (helical) front and rear diff, there is no hydraulic transfer style rear diff anywhere to be seen, why do you think that is? Why do you think Mitsubishi have plated LSD centres for both front and rear diffs with no torque transfer mechanisms?

In all the WRC cars of past, none of them ran AYC's in competition.

As for why they are rubbish in a circuit racing application, once you have some decent bushing, decent suspension, decent tyres (I'm talking motorsport 'weapons grade' stuff, not the fast road car stuff most of you run) and the right circuit, the AYC will try to kill you!

When the car is seriously loaded up through a corner, high G, high speed the rear will start pig rooting, and it's then it becomes pretty easy to turn the car around and back it into a wall. The AYC will fight with itself and as for the front Helical diff, thats rubbish too. Once you start upping the Power and Torque of the car you'll be spinning up an inside wheel to buggery. Drop the Transfer, whack in a supertraction, adjust the preloads and you'll wonder why you didnt do this sooner, as you watch the lap times plummet!


Let me get this straight...

The RS is for racing.

It has no AYC. AYC is banned in motor sports. Yet you imply that the RS is missing the AYC "Because Racecar". You imply that it is faster without it.

Why do you think it's banned in motorsports? Because it makes them slower?

Golden, it's not me saying the AYC is banned, for the life of me I don't know where disco bicky got that from...

My point is the AYC diff is weaksauce and has no replacements parts? Pretty harsh to cough up $3,500 for a rear diff everytime you kill it.

Golden, to give you an example of running costs, let just say that with Gravel Rally you treat some items as consumables that circuit car guys just dont break. Take drive shafts for instance. Everyone one runing IX's in world PRC (production Rally Championships) are using VII drive shafts because they are stronger, and even then it's a case of replacing them after a big event. Because of the environment they compete in the drive shafts just flog out.

As for what you can run, you have homologation issues too. Why would you want to run a GSR with a rear AYC when you can run a lighter RS with mech diffs that ralliart make a supertraction diff centre for? Being Homolgated and with the rules set out it means you don't have much choice in what you can run. Take the brakes for instance, if you are going to run in the group N leg of a WRC round you will be paying 25K for Brembo Group N brakes... you dont get a choice. It's not like you can fit whatever you want, you simply have to run the Group N homolgated part, even if it costs an arm an a leg.

Now the IX GSR was homologated (so was the VIII MR for what it's worth) as well as the RS. But why would you want to run the 6 speed box and AYC rear diff (you can run and AYC diff in Group N by the way, it IS NOT banned) when you could run the RS with it's infinitely stronger 5 speed and proper diffs.

I'm not saying rules in motorsport make sense, far from it. I'm saying as a pricing exercise and the overall strength of what Mitsubishi made as a road car, why would you run the road car in motorsport when mitsubishi made a car tailord to the environment of motorsport with stronger, more relible and rebuildable parts available.

As far as the X goes, both GSR and RS were homologated, meaning you could run both. Same goes for IX and VIII MR. I'm not sure where this rubbish about AYC's being banned in motorsport came from as FIA dont state that at all. For what it's worth, check out page 11 of this document, it's the homologation papers for the X. http://www.ralliart.co.jp/GRN/homologation/data/N5718-10_LancerEvo10.pdf

I hope that clears up a few things guys, again I'm not making this shit up. It's what I've been involved with for a long time and for better or for worse it's what everyone is doing. All the guys you see on the podium in PRC and Group N are all running the RS variant. Different Turbos, different and lighter body parts, different gearboxes, diffs, interior, less loom and basic wiring etc etc

Golden, it's not me saying the AYC is banned, for the life of me I don't know where disco bicky got that from...



My bad on the date, thought it was 2001.

WRC officially banned rear in 2006, center in 2010, that's where all this tech comes from so when I say banned, I mean in WRC. They banned because of "costs" but the word on the street was no one but Mitsu even had a working program, so the French (and other forces of evil) pushed to limit the influence of the technology. Whats more is they killed anything but a mechanical LSD, no hydraulic fluid or magnets or anything whatsoever.

I'll have to comb through old late nineties stuff on active diffs with regards to the Mitsu championship Evo's, there are a lot of references to some drivers liking it and others hating it.

Group N it is legal, any time attack I know of, most SCCA stuff, etc.

What's a bicky?

Good synopsis:

"As of 2006, active front and rear differentials, which used electronic control units to vary locking characteristics, were no longer allowed in competition, and this was followed by a ban on active centre diffs in 2010. The system now allowed consists of front and rear mechanical differentials, with a manually operated centre clutch to disengage the rear prop shaft (for use when the driver operates the handbrake to initiate turn-in).

Rule 5.2b of the regulations also bans the use of viscous or hybrid viscous-plate differentials, stating: “Mechanical limited-slip differential means any system which works purely mechanically, ie without the help of a hydraulic or electric system. A viscous clutch is not considered to be a mechanical system.” The result of this ruling is that a car must be set up at a compromise for a rally distance, with differential settings capable of dealing with a wide range of surfaces.

Mechanical differentials are still adjustable by the drivers, but only to a limited extent. On most units the pre-load can be loosened or tightened manually between stages. But any more meaningful adjustments can only be made in the Service Park. There are rumours, however, that some teams have found ways of exploiting the central clutch to vary power distribution from front to rear, but no official comment has been forthcoming."

http://www.ret-monitor.com/articles/1712/wrc-rally-transmissions/

http://www.wrc.com/news/features-archive/wrc-explained-differentials/?fid=1595&page=891

http://www.crash.net/world+rally/news/113913/1/panizzi_new_active_differential_helps_a_lot.html

...And I'm just wondering, if AYC and our diffs suck so bad, how does gates evo 10 do so well and smoke the shit out of other cars on the time attack circuit?

Where can us people in the states get the RS diff's?

Still wondering about these?

... He claims X's with the ACD/AYC are slower then cars fitted with Supertraction diffs, which are Ralliart diffs.

Do you mean the regular from the dealer (US) 08+ Ralliart diffs?

Do you mean the regular from the dealer (US) 08+ Ralliart diffs?


No, I don't mean Ralliart Diff's as in the Lancer Ralliart, I mean like this: http://www.ralliart.com/GRN/instruction/manual/RA166619K1.pdf

No, I don't mean Ralliart Diff's as in the Lancer Ralliart, I mean like this: http://www.ralliart.com/GRN/instruction/manual/RA166619K1.pdf


Please explain to me how a mechanical LSD can be faster than a E diff. The mechanical diff is reactive where the E diff is proactive.

It's not a question of speed, especially when the AYC is looking into the future with it's telemetry prediction capability (what Mitsu calls feed-forward).

It's a question of two things:

1) Strength of components and maintainability
2) Adjust-ability / program-ability

The AYC and ACD have neither of those things, so professional racers (payed to race, factory, sponsored professionals) are not going to take a chance on it.

Mitsu supported the system until 2001, then sporadically until 2006, since then all diffs point to Supertraction Ralliart (the company, not the model) diffs for competition.

Supertraction is just a plate LSD, it is like comparing a Space Shuttle (AYC) to a Model T (plate clutch).

Ban and death of active differentials makes Disco sad.................

No problem

He didn't have any old parts there. You will have a brand new diff.

I forgot to ask if he knew specifically what had failed.


:(

Let us know if you do find out ever.

Will do.

Please explain to me how a mechanical LSD can be faster than a E diff. The mechanical diff is reactive where the E diff is proactive.

It's not like a Torsen per say which is 'reactive' in the true sense of the word.

With a plated LSD you have adjustable ramp angles on the, you can adjust the preload for what you require, it's the ramp on the diff that dramatically change the behavior of the car under accel and decel, for a Gravel Rally car you'd want the hard diff, for circuit racing you'd want soft. Remember the diff is 'preloaded'...

I don't know how much exposure you have you had with plated differentials, but just look at any Evo currently running in Gravel and Tarmac Rally that is for sale in Australia, New Zealand, England, Ireland, Scotland, Italy, Greece, Russia ( I may as well just say Europe and be done with it) and you'll find they have replaced the standard diffs with most cars running the Ralliart supertraction.

I don't know of any successful Rally Car that is an Evo IX or X currently running on the world stage that doesn't have a supertraction. Even time attack cars run supertractions, in the case of Sierra Sierra it's a supertraction front diff. Tarmac Rally Cars run them to. They are a dead set benefit to any/all motorsport disciplines.

The reasons why you would want front and rear supertraction diffs in a fast and powerful motorsport car is:



Stronger - Will support Power and Torque that the current stock diffs won't support.
Re-buildable - There are no parts available for an AYC rear as an example, not so for supertractions, parts-a-kimbo.
Adjustable - You've got what you've got with the current setup, not so with supertractions as they are adjustable.
Quicker Acting - Preloads and ramp angles have a lot to do with that, you can shove vectoring up your arse as it won't support serious Torque.
Stable - The standard front helical diff gets 'overun' on the track, you spin up an inside wheel with any evo x that is making power. A supertraction in the front will remove that from happening, it's just that simple.


Now for the bad news, while replacing the AYC rear in the VII, VIII and IX is doable by changing the drive shafts, the carrier, the carrier brackets and diff centre over from an AYC to RS styled mech rear, you cannot do the same for the X in the rear. Well, you 'can' really, you could buy everything the RS has and swap it all over, but the S-AWC wil hate you, especially the control units for ABS and ASC.

So you cannot currently get a rear mechanical RS style diff to suit the Evo X GSR with AYC period, which means currently you cannot have the supertraction centre either. If some massively talented individual can tell me how to do it, or point me towards the direction of someone that can do it then let me know as I'd buy the technology right here and now. Not empty words, I mean it.

So luck CT9A platform owners can have the good diffs, but for Evo X owners we can only fit the front supertraction centre.

That in itself isn't a bad thing, and the good news is, its just a direct swap! all you need to do is buy a supertraction (which are dear as poison btw) buy the transfer overhaul kit (yes, one DOES exist) and buy some additional bearings that will be needed for the job. Pull the transfer out, adjust the preloads and ramps, whack it back in and let the good times roll.

I reckon with a mid to high powered Evo X around a circuit a supertraction would be good for one tenth around every corner... No, I am not kidding.

Say hello to some PB's

Note: If you've fitted one and your car now clunks around the carpark under low speed, you've wound the diff up to much, it doesn't need to be like that. Also of note is that you will need to re-learn how to drive the car, it will behave very differently. You'll find the car will pull you out wide coming out of corners under accel, it's something the helical won't do so you won't like it at first, not at least until you see the time sheets your are putting down at your favorite circuit.

It's not like a Torsen per say which is 'reactive' in the true sense of the word.

With a plated LSD you have adjustable ramp angles on the, you can adjust the preload for what you require, it's the ramp on the diff that dramatically change the behavior of the car under accel and decel, for a Gravel Rally car you'd want the hard diff, for circuit racing you'd want soft. Remember the diff is 'preloaded'...

I don't know how much exposure you have you had with plated differentials, but just look at any Evo currently running in Gravel and Tarmac Rally that is for sale in Australia, New Zealand, England, Ireland, Scotland, Italy, Greece, Russia ( I may as well just say Europe and be done with it) and you'll find they have replaced the standard diffs with most cars running the Ralliart supertraction.

I don't know of any successful Rally Car that is an Evo IX or X currently running on the world stage that doesn't have a supertraction. Even time attack cars run supertractions, in the case of Sierra Sierra it's a supertraction front diff. Tarmac Rally Cars run them to. They are a dead set benefit to any/all motorsport disciplines.

The reasons why you would want front and rear supertraction diffs in a fast and powerful motorsport car is:



Stronger - Will support Power and Torque that the current stock diffs won't support.
Re-buildable - There are no parts available for an AYC rear as an example, not so for supertractions, parts-a-kimbo.
Adjustable - You've got what you've got with the current setup, not so with supertractions as they are adjustable.
Quicker Acting - Preloads and ramp angles have a lot to do with that, you can shove vectoring up your arse as it won't support serious Torque.
Stable - The standard front helical diff gets 'overun' on the track, you spin up an inside wheel with any evo x that is making power. A supertraction in the front will remove that from happening, it's just that simple.


Now for the bad news, while replacing the AYC rear in the VII, VIII and IX is doable by changing the drive shafts, the carrier, the carrier brackets and diff centre over from an AYC to RS styled mech rear, you cannot do the same for the X in the rear. Well, you 'can' really, you could buy everything the RS has and swap it all over, but the S-AWC wil hate you, especially the control units for ABS and ASC.

So you cannot currently get a rear mechanical RS style diff to suit the Evo X GSR with AYC period, which means currently you cannot have the supertraction centre either. If some massively talented individual can tell me how to do it, or point me towards the direction of someone that can do it then let me know as I'd buy the technology right here and now. Not empty words, I mean it.

So luck CT9A platform owners can have the good diffs, but for Evo X owners we can only fit the front supertraction centre.

That in itself isn't a bad thing, and the good news is, its just a direct swap! all you need to do is buy a supertraction (which are dear as poison btw) buy the transfer overhaul kit (yes, one DOES exist) and buy some additional bearings that will be needed for the job. Pull the transfer out, adjust the preloads and ramps, whack it back in and let the good times roll.

I reckon with a mid to high powered Evo X around a circuit a supertraction would be good for one tenth around every corner... No, I am not kidding.

Say hello to some PB's

Note: If you've fitted one and your car now clunks around the carpark under low speed, you've wound the diff up to much, it doesn't need to be like that. Also of note is that you will need to re-learn how to drive the car, it will behave very differently. You'll find the car will pull you out wide coming out of corners under accel, it's something the helical won't do so you won't like it at first, not at least until you see the time sheets your are putting down at your favorite circuit.

:+1: I really enjoy reading these posts, just thought I'd let you know. Some very good info, so keep them coming

Very informative, but never will i be serious enough about racing my X to ever do anything like that. I'll stick with changing fluids ever 15,000, as opposed to changing all he said LOL.

I may just be out of the loop but what does, "dear as poison" mean??

I may just be out of the loop but what does, "dear as poison" mean??

It means it's expensive :$::$::$:

It's like saying "this is the shit" in kangaroo-speak.

Unless your getting paid to race and you head an international factory sponsored race team and your james bond (like McCoy is), then stick to AYC and ACD. It's the ultimate system for the street and track, even for semi-professional privateers. Even guys like Jeremy and Gates run AYC and ACD because they can afford to replace and rebuild every few years. Hopefully we will have more support for these systems in the near future through our American ingenuity, then we can laugh at the Australians while we torque vector their faces off.

It doesn't matter that they are laughing at us right now because Australians laughing sound like Kangaroos mating.

Do you and your AYC diff need some time alone with some mood music?

Seriously man... Until you drive with both on a track maybe you should remain impartial.

Even guys like Jeremy and Gates run AYC and ACD because they can afford to replace and rebuild every few years.

Ryan Gates got rid of his AYC years ago. He told me it was a night and day difference in control at his higher power level at the time.

All the fast 7/8/9 track guys in Euro land get rid of the AYC. Smart ones get rid of it before it breaks or gets too unpredictable for their power level.

Alot of the local fast Autox guys that used to own 8's and 9's but now own 10's are starting to ask me how to get rid of the AYC and go to a normal rear diff.

White Papers and Real World usage rarely are the same.

<load human ai>
<run human ai>

Will someone explain to robot what AYC does that is inferior?

</end transmission>

McCoy, is the Cusco 1.5 way an AYC diff, or is it a mechanical diff?

Just wondering cause that's the diff that Gates is using in the rear.

McCoy, is the Cusco 1.5 way an AYC diff, or is it a mechanical diff?

Just wondering cause that's the diff that Gates is using in the rear.

Gates is not using AYC. See my post above.

thank you very much for all the information.

I've also understood from day 1 that the AYC is only effective to certain power levels. As nobody does offer ways to beef it up and to reprogram it to respond and react properly for given power levels then I don't find it surprising that most/all motorsport teams prefer the proven reliability of a normal diff.

In theory though the AYC does have a potential that exceeds what a normal diff can accomplish, just need someone with nice $$ pockets to invest in both optomizing the technology and learning to fully utilize it.

thank you very much for all the information.

I've also understood from day 1 that the AYC is only effective to certain power levels. As nobody does offer ways to beef it up and to reprogram it to respond and react properly for given power levels then I don't find it surprising that most/all motorsport teams prefer the proven reliability of a normal diff.

In theory though the AYC does have a potential that exceeds what a normal diff can accomplish, just need someone with nice $$ pockets to invest in both optomizing the technology and learning to fully utilize it.

:+1: Maybe that is what is going on w/ Gate's new project?? Hmm...

Gates is not using AYC. See my post above.

Dohhh, I didn't put 2 and 2 together.

Well I guess my question would now be is the cusco 1.5 way a hydralic diff or mechanical diff?

Thanks Bryan

I think the issue with AYC is that you can't tune it depending on your power levels. i.e. If you are putting down 700 HP, running very sticky tires, using lots of downforce, running very high friction brakes and taking corners at very high speeds, you may not like the stock values.

I think the issue with AYC is that you can't tune it depending on your power levels. i.e. If you are putting down 700 HP, running very sticky tires, using lots of downforce, running very high friction brakes and taking corners at very high speeds, you may not like the stock values.

Technically you can on the 7/8/9.

Although the AYC diff wouldn't last long at 700whp/sticky tires/etc.

Dohhh, I didn't put 2 and 2 together.

Well I guess my question would now be is the cusco 1.5 way a hydralic diff or mechanical diff?

Thanks Bryan

Cusco is a Torsen mechanical diff. The Cusco's, like most torsen diffs, can be ordered in different 1 / 1.5 / or 2 way.

Supertraction Ralliart is a clutch plate limited slip. Most racers prefer the supertraction because they are adjustable (still means opening the diff and getting at it somehow) for preload. Expect noise out of these on the street, it's a strictly racing setup.

Torsen and plate clutch diffs work so completely differently they would yield completely different results - Torsen is looking to send power to the wheel with most traction all the time, so it is "active" in that sense. The plate clutches just limit slip, but the benefit is they are adjustable.

It's still $$ either way. They both deserve their own diff housing, as McCoy said, rather than just plopping them into a dissconnected AYC diff. I can't even find any price for the center supertraction (would fit inside the tranny), do they come with a custom transfer case?

And yes, I listen to Barry White with my AYC all the time.

http://www.rhdjapan.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/54273/Image/Normal/Image1.jpg

http://www.rhdjapan.com/ralliart-super-traction-front-lsd-cz4a-evox-54189

Supertraction center diff

That's the front diff, no? Remember, the front diff is in the Transfer case and the center diff is in the transmission (transaxle).

Umm, don't know for sure

Yeah, this is hard to believe but:

The center diff (actually open diff) sits inside the Transmission (transaxle) on either a manual or SST.

It transfers power via a complex set of gears and tubes through the Transfer Case.

The front diff sits inside the Transfer Case.

I'm working on a diagram of this, it is really very interesting.

Well my rear diff blew up and I just had to get a new one, I am now running ~600WHP and I bought a used (works fine right now) rear diff with 20k miles on it. I hope it lasts awhile, it'll be hard but I'm not gonna launch it on this rear diff. So I really want to know, what options does someone have if they are at my power levels and want to not worry about their diff. I already have a built trans and built transfer case from shep, and now the differential is the weak point. I mostly DD/weekend warrior the car, but I wanna be able to take it to the road course / drag strip every now and then and not have to worry about it. Ideally, someone who specializes in drivetrain components would step up and develop some parts to beef up the stock AYC trans. But I guess some people are switching from the X rear diff to the 8/9 rear diff without the AYC. So really, what options do I have and what do you knowledgeable folks think would be best?

Anything that disables the AYC will throw codes and generally be a pain electronically. Read 20 posts back in this thread, we have been discussing alternatives. Quite a few drop in torsen and plate clutch options.

A USDM 8/9 diff swap is supposedly very hard to do- different mounting points, drivehshafts, etc.

What failed on your diff?

That is the front diff, as I said in a previous post, you cannot get a supertraction front diff for the rear of an Evo X GSR with an AYC working at present. Currently you are stuck with running the AYC. I've got that same issue at the moment with our Time Attack car. Cusco isnt an option for me personally.

Anyone with a high powered car, lets say 400+whp who does circuit racing would beneft the most from a front supertraction, you'll be a heap quicker.

As for the the front diff and fitting it, you have to dissasemble the transfer first then you'll need a transfer overhaul kit and some bearings to make it all work. I'm about to fit one to a car in a fortnight, would it be easier for me to take pictures and show you blokes that way?

Note: Mitsubishi (Ralliart) do NOT make a supertraction diff for the SS-T gearbox, it's manual only.

So what is the magic number hp/tq for a DD that hits a road course a couple times a year and the strip about once a month? Is there a magic number at all??

That is the front diff, as I said in a previous post, you cannot get a supertraction front diff for the rear of an Evo X GSR with an AYC working at present. Currently you are stuck with running the AYC. I've got that same issue at the moment with our Time Attack car. Cusco isnt an option for me personally.

Anyone with a high powered car, lets say 400+whp who does circuit racing would beneft the most from a front supertraction, you'll be a heap quicker.

As for the the front diff and fitting it, you have to dissasemble the transfer first then you'll need a transfer overhaul kit and some bearings to make it all work. I'm about to fit one to a car in a fortnight, would it be easier for me to take pictures and show you blokes that way?

Note: Mitsubishi (Ralliart) do NOT make a supertraction diff for the SS-T gearbox, it's manual only.

Yes, pictures please

picture would be awesome!

Anything that disables the AYC will throw codes and generally be a pain electronically. Read 20 posts back in this thread, we have been discussing alternatives. Quite a few drop in torsen and plate clutch options.

A USDM 8/9 diff swap is supposedly very hard to do- different mounting points, drivehshafts, etc.

What failed on your diff?

I'm not sure yet, I heard a terrible clunking whenever I turned at low speeds from the rear and so I drained the oil and it was very metallic....looked like Mercury. Haven't torn it apart yet but there's nothing visually wrong with the housing as far as I can tell.

well if someone wants to put super tractions left/right and centre on mine I will happily go through the S-AWC code to get "it working" on a GSR...

So what is the magic number hp/tq for a DD that hits a road course a couple times a year and the strip about once a month? Is there a magic number at all??

Has not been determined yet. S-AYC is built to be much stronger than previous AYC's, so stories of everything failing overseas don't really count here.

If you change fluids every 15k (or even more often) for track, the clutches should be fine for a long, long time. Even 10-15 HPDE per year is all good.

Jeremy is running AYC, he;s a good benchmark for dedicated racers. Will SSP do the same thing that they did with the SST and offer upgraded clutch paks???? I think there would be a big market.

Tephra, Golden, Bryan, can we read those SAWC roms and ID them? We could be the world leaders in active diff technology while everyone else is using archaic clanky diffs............

Tephra, Golden, Bryan, can we read those SAWC roms and ID them? We could be the world leaders in active diff technology while everyone else is using archaic clanky diffs............

You can do it with the 7/8/9. It's on a seperate ACD/AYC ECU and you currently need to build a wire harness to attach straight to the ACD/AYC ECU to pull and flash the ROM.

Would just need to figure out how to do it on the 10/RA. Which I would imagine wouldn't be very hard since the road is traveled already. Btw, it's *REALLY* easy to make the car handle like dogcrap and/or handle *VERY* dangerously when modding these tables.

The Evo 7/8/9 AYC/ACD tables look something like this:

http://norcalmotorsports.org/users/bryan/mods/EVO/tech/evo8_ACD_AYC_tables.gif

Wow, that is much easier than I imagined. I knew steering angle was the key sensor, not lateral G. Everything I read in the older papers says the physics are tricky with AYC, and the benefit you get from the vectoring effect is a very tight margin. ACD dosen't seem to be too complicated, but it would also have a detrimental effect if not considered in the AYC tuning.

I can certainly realize the danger involved. From what I read in olden WRC days and when they did road racing factory efforts in Japan they had a hell of a time with the technicians setting up the AYC with each driver.

Good to hear the the ACD / AYC tuning is potentially the low lying fruit. Jeremy or Kris, can you make the clutches? I know rogerrally in the UK may be able to upgrade the Accumulator.

well thanks to sba I already have a copy of an X ACD ROM... he also gave me a hint on how to read my ROM if necessary.

i just havn't been bothered to find tables and whatnot for it yet...

Urgh... Getting back to real world reality after discograndfathers ramblings.

This video clearly shows where the Helical front diff falls over, check the 42 sec and 1:17 sec mark closely.

http://www.youtube.com/watch?v=YarCzf0NOp4

Even with only 450whp it's just too much for the front diff, that's why you get the pitching of the car, the steering wheel tugging in the drivers hands and the familiar woo woo woo sound, like it's bogging down where it's actually struggling for grip.

If you look at a typical circuit with 10-12 croners, out of those you may have 4-5 corners where this is more pronounced, that will be based on vehicle speed, the bank of the corner, the degree of the turn, the surface itself, the gear selected etc. All of those are contributing factors, that's why some corners are worse than others. It's the time lost without clean and crisp grip resulting in a loss of acceleration, so you lose around 2 or 3 tenths for every one of those trouble corners, multiply that 4 or 5 times a lap and all of the sudden you've lost a tonne of time. With the plated LSD in the front you'll eliminate all drama going on, and thus be much quicker.

I'd suggest that throwing $5,000 or more on that next power upgrade you have planned which 'may' get you maybe 1 second quicker around your favorite track, will not only be about the same overall price as a front diff upgrade done properly, but it puts more stress in the entire driveline, introduces more heat to areas that already have enough, and overall makes the car tired quicker. So maybe start thinking diffs.

While a diff isn't sexy like a Turbo is, and you don't see it under the engine bay, for me it's where the smart money is. And with the fair amount of blokes in the US (so it seems) that have 400+whp that do track days with their daily driven car, I'd suggest that this line of thinking should be taken into consideration.

As for the rear, I think the best solution would be to fit up and RS rear end with all the trimmings and then fix the electrical gremlins from there, that is the logical step. PITA, yes absolutely but it'll work in a motorsport or high horsepower environment.

Can't believe I read this whole thread... and I don't even have my X anymore.

As for the the front diff and fitting it, you have to dissasemble the transfer first then you'll need a transfer overhaul kit and some bearings to make it all work. I'm about to fit one to a car in a fortnight, would it be easier for me to take pictures and show you blokes that way?


We'd love to see pics. We also got a professional Australian to English interpreter on standby. Fortnight = two weeks.

Joey, How's that diff? lol

Joey, How's that diff? lol

It should be on the way back to him

I havent heard anything back yet. Been too busy to try and contact anyone

You can do it with the 7/8/9. It's on a seperate ACD/AYC ECU and you currently need to build a wire harness to attach straight to the ACD/AYC ECU to pull and flash the ROM.

Would just need to figure out how to do it on the 10/RA. Which I would imagine wouldn't be very hard since the road is traveled already. Btw, it's *REALLY* easy to make the car handle like dogcrap and/or handle *VERY* dangerously when modding these tables.

The Evo 7/8/9 AYC/ACD tables look something like this:

http://norcalmotorsports.org/users/bryan/mods/EVO/tech/evo8_ACD_AYC_tables.gif

Bryan, can you explain me, if you have time, these tables? I understand what are them for and all the parameters but I'm very confused about the numbers inside...ACD tables for tarmac and snow are the same, AYC proportioning table is till worse..

Bryan, can you explain me, if you have time, these tables? I understand what are them for and all the parameters but I'm very confused about the numbers inside...ACD tables for tarmac and snow are the same, AYC proportioning table is till worse..

In simple terms, it's all lockup %. How that is changed depends on input factors.

The ACD is a straight lockup %.

The AYC is showing % of torque to the outside wheel, so depending on which way your turning, this table must control torque % to either AYC clutch. If not, there maybe another table for "inside wheel torque" but I doubt it. It starts at 50%, which is the default "open" state for the diff, meaning no clutch pak operation. The value can go to 100% (all to the outside wheel, full lockup of RH clutch) or 0% (nada to the outside wheel, full lockup of LH clutch) depending on the situation.

That table controls the two proportioning valves in the pump. There must be another table controlling the directional vavle, which is a simple ON/OFF valve that controls if the pressure is going to the right or left clutch pak. It's probably not too important for tuning purposes.

Those ACD %'s look already modified in those tables.

There are more tables then what I posted.

ACD TPS v Speed Accel (TPS x Speed x lockup %)
ACD TPS v Speed Decel (TPS x Speed x lockup %)
ACD Lockup % Accel (Front-Rear Delta x Speed x %)
ACD Lockup % Decel (Front-Rear Delta x Speed x %)
ACD Steering Angle v Speed Accel (Steering angle x Speed x %)
ACD Steering Angle v Speed Decel (Steering angle x Speed x %)

AYC Prop (Steering angle x Speed x Outside Wheel %)

And some others.

Yup, I was wondering how wheel speed sensor data would be integrated, there is the front rear delta.

Any which way you slice it, ACD is basically how aggressive you want it to govern the delta between front and rear.

I'll make the argument AYC would make the biggest difference and be a great tool for dialing in understeer and oversteer. Trick is to come up with a way of translating a few physics based equations outlined in the JSAE papers (checking to see if they line up logically with stock settings) and understanding the relationship between the ACD settings and the AYC.

If the read some of those FQ-400 reviews I think Mitsu UK might have run into the "overpowering" the system problem or at least running outside of the stock parameters. Quite a few reviews point to hard understeer and that it doesn't "handle" as well as lower power Evo's. Maybe that was due to other issues.

Programming, like torque vectoring isnt going to be the solution to the problem for having diffs blow up though, you might get a benefit for the guy pushing maybe 20% more power over stock, but that will be about at useful as it gets.

Have you ever pulled apart an AYC rear diff? The crown wheel and pinion is of a good size but the cones and pins are tiny. The unit itself would need reprogramming, that I dont doubt, but it would need a serious upgrade in the hardware itself.

Programming, like torque vectoring isnt going to be the solution to the problem for having diffs blow up though, you might get a benefit for the guy pushing maybe 20% more power over stock, but that will be about at useful as it gets.

Have you ever pulled apart an AYC rear diff? The crown wheel and pinion is of a good size but the cones and pins are tiny. The unit itself would need reprogramming, that I dont doubt, but it would need a serious upgrade in the hardware itself.

Yup exactly. It's a 100% fact that the AYC diffs are much weaker then the mechanical diffs. Even with the Evo 10.

Which goes back to my statement that the Euro track guys usually end up replacing the rear AYC diff with the Mechanical ones, some before it breaks, some after.

Yup, some of the gears and gear pins in the AYC rear diff are tiny, near the crown wheel and pinion on the opposite side to the clutch packs.

http://i1131.photobucket.com/albums/m546/RoadTrackRally/aycweakness.jpg

This cutaway image shows the area I'm talking about, as you can see the crown wheel is decent, but those smaller gears in front of it are not, nor are the pins that hold them.

You cant expect those gears to hold a mountain of power before they let go, I've seen the gear teeth sheer off and not due to a lubrication issue, due to pure torque. The clutches themselves are only good for so much too, thing is there are no replacement clutch packs for them yet. Then of corse you get the AYC rear squawk and that is metal particles caught up in bewteen the clutch discs, and while you can bleed the fluid and flush it out, if there is particles in there you are only delaying the inevitable.

So what you have in an AYC diff is something that is very good at what it does for the Evo X in standard or close to standard trim. It's good for amatuers keeping them on the black stuff (essentially making them better drivers than they are ), but it's not anywhere near good enough for motorsport and big Hp application.

And Bryan is right, the rest of the world is awake to the fact the AYC isn't all encompasing and brilliant. I'm not sure why a few on here seem to think it's the best route to follow.

So what is the best alternative then? What is the strongest option out there that we have

An RS rear end would be the best option, thing is right now it doesnt talk to the S-AWC and ABS modules.

We already know an RS evo X rear will bolt up to a GSR without any issue as far as fitment goes. Fact is it was made for it, so there isn't any harder than just bolting it up. IF we could could use the ROM from the RS ACD computer and flash that over the X GSR ACD, we may have better success with that. A few 'key' people are looking into that at present.

Joey, once I have a rock soild solution, you'll know about it.

yeh I reckon it will work.

I just don't know what ASC or ABS will do..

*maybe* nothing :)

I don't think you'll know until we try. ;)

I do think that would be the right part though. I do know of another solution that is being developed locally at the moment. It's a twin LSD with a Torque tube between the two diffs. It's being designed to fit into the standard AYC housing and I reckon that'll be a good thing. It comes from the same people that are the only ones to do a plated style LSD diff for the front on SST equipped cars. So these blokes know what they are doing, so joey that is another alternative, but it's still in developement currently.

Active differentials make average drivers better, but they do not make professionals better. It's like ABS or traction control, if your Senna or Rohrl this is unnecessary.

It's disheartening to see the problems in the S-AYC have to do with the exact area they beefed up on compared to the old AYC. Even with uprated clutches and cooling sounds like this is just an overpowering point.

I tired to calculate max torque in another thread based off info in white papers but the math made strange sense, suggesting the clutches could hold huge amounts before being overcome. It's really a question of answering the simple question of how much torque the AYC can hold and for how long. Joey lasted 3 years autocrossing (which I cannot imagine a higher load on the diff in any other type of racing). How much did you race Joey?

has Joey actually pulled apart his rear carrier to see what broke and how?

Discograndfather, try Tarmac Rally. It's very hard on the diffs.

You may have heard of Targa Tasmania, well this is the prologue to the event. This is the 'easy' stuff: http://www.youtube.com/watch?v=32khCTnqYXw

This is just a few moments from last years Targa in an Evo X SST

http://www.youtube.com/watch?v=THKqREGoV0Q

For what it's worth discochick, the weakest link in that car isn't the weight, it isnt the SST gearbox, it isnt the power or the brakes, it's the diff's both front and rear.

I don't think you'll know until we try. ;)

I do think that would be the right part though. I do know of another solution that is being developed locally at the moment. It's a twin LSD with a Torque tube between the two diffs. It's being designed to fit into the standard AYC housing and I reckon that'll be a good thing. It comes from the same people that are the only ones to do a plated style LSD diff for the front on SST equipped cars. So these blokes know what they are doing, so joey that is another alternative, but it's still in developement currently.

Thanks for that info man. Hopefully this will be a great upgrade that wont require selling a kidney to purchase lol

Active differentials make average drivers better, but they do not make professionals better. It's like ABS or traction control, if your Senna or Rohrl this is unnecessary.

It's disheartening to see the problems in the S-AYC have to do with the exact area they beefed up on compared to the old AYC. Even with uprated clutches and cooling sounds like this is just an overpowering point.

I tired to calculate max torque in another thread based off info in white papers but the math made strange sense, suggesting the clutches could hold huge amounts before being overcome. It's really a question of answering the simple question of how much torque the AYC can hold and for how long. Joey lasted 3 years autocrossing (which I cannot imagine a higher load on the diff in any other type of racing). How much did you race Joey?

The first year I didnt race autox but like 3 times. But I took it to the drag strip often. Launched the hell out of it on a daily basis lol. Then the 2nd year I went all year long and still.......launched the shit out of it. Then this year I only went a few times and then started doing some small time attack. All of that mixed in with some daily driving and some spirited driving as well.
has Joey actually pulled apart his rear carrier to see what broke and how?

Joey has not. But I should be getting info back on what it was that failed real soon. I will chime back in when I know what it was

Thanks to razorlab and Disco for answering my questions

Launched the ell hout of it ... Well, at least you are honest. hehe

Yeah, that wouldnt have done you or your diff any favors, that's for sure.

McCoy, it's a pleasure to read your posts. Subscribed.

dont encourage him! :)

Keep us posted, joey.

Launched the ell hout of it ... Well, at least you are honest. hehe

Yeah, that wouldnt have done you or your diff any favors, that's for sure.

Yeah haha. I wont be launching any more though. there is no point

Keep us posted, joey.

will do sir

Yeah haha. I wont be launching any more though. there is no point



will do sir

There is definitely a point in launching. It's fun! And it makes you win on the strip! BTW Joey, why kind of power mods are you running? Just curious as to what kind of power you were putting down when this happened, and while you were launching the car.

There is definitely a point in launching. It's fun! And it makes you win on the strip!

Yeah I know haha. I will probably still launch it. I like having someone new in my car when launching. The looks they give are priceless

So guys, is this failure more attributed to the repeated launching w/ decently high tq, or just a power issue?
E.G. if I have a 700whp car, but only 450wtq and I don't launch it ever, will my diff be an issue? I figure even if I go to a 1/4 track, I'll soft launch and just go for trap speed

From what I have been hearing, there arent many rear diff failures. Its been the center diff pins that have been shitting out. But like I said, thats just hear say

So guys, is this failure more attributed to the repeated launching w/ decently high tq, or just a power issue?
E.G. if I have a 700whp car, but only 450wtq and I don't launch it ever, will my diff be an issue? I figure even if I go to a 1/4 track, I'll soft launch and just go for trap speed

Trap speed tells all. Check out this vid of me vs my boss. I beat him by over a second, but we trapped the same. So realistically, our cars are similarly quick from a roll. I ran a 1.6 60ft and he had slow reaction time, but you get the gist. If you're running for trap speed so you can estimate power there is no need to launch it. But if you really want to win (I really wanted to beat my boss) then launch the piss out of it!

http://www.youtube.com/watch?v=XjbTjLZwsiA

From what I have been hearing, there arent many rear diff failures. Its been the center diff pins that have been shitting out. But like I said, thats just hear say

Honestly you have the first rear-diff failure that I've heard of, as a result I'm not *too* worried about mine. There are always exceptions to the rule.

Ive heard of one more. There is a dude that lives in Boise and his shit out as well. I cant remember what his failer for though. LSD or some shit


Nice launch dude

Ive heard of one more. There is a dude that lives in Boise and his shit out as well. I cant remember what his failer for though. LSD or some shit


Nice launch dude


Are you over 380 or so WTQ? Your mod list can still remain a mystery just curious b/c I know you have launched your car probably like over 100 times from what I've picked up in threads here or there.

I got tune and it was at 377. Not sure what its at now. Shit is always changing and what not. But yeah, I have launched mnore than I can count lol

dont encourage him! :)

Shush you or I wont let you play with my MUT3! :neener:

So guys, is this failure more attributed to the repeated launching w/ decently high tq, or just a power issue?
E.G. if I have a 700whp car, but only 450wtq and I don't launch it ever, will my diff be an issue? I figure even if I go to a 1/4 track, I'll soft launch and just go for trap speed

I would suggest that Launching (although hilarious and not to mention fun) is destructive in an AWD car, I would suggest that's why you see so many threads about clutches on the Evo X forums and other threads about Transfers, Pins, knocking holes in casings etc. In Australia we don't have half the issues you blokes do, but that's because there is a stronger circuit culture here than drag strip, it's only a small percentage of Evo owners talking their car to the drags here. Most have their Evo as a daily driven car that is dual purpose for club level motorsport like gymkhana, hill climbs and circuit racing or what we call sprints, usually 5-8 lap of a race track. Then of course we have amateur and professional motorsport no different to any other country there.

Launching an AWD car is hard on the gear because the Torque isn't translated into wheel spin like it is on a RWD V8 mustang/corvette styled car. Evo's generally have sticky tyres and the AWD system is a good one, so with plenty of Grip and no wheelspin.... well you don't have to be a genius to work out what it going to happen... all that torque has to go somewhere, and it does. It's that torque eats the material on your clutch disc, its Torque that kills Transfers, its Torque that strips gears, snaps uni joints, cracks casings, tears gearboxes to bits and chews up and spits out diffs.

Yes, there is a Torque limit on different parts of the car, but it's the brutal application of that massive force applied in a Launch that will soon see good times go bad. Take your clutch for instance... If you've ever launched your car and then had the all too familiar smell of burnt monkeys stink up the cabin, that right there is a tell tail sign that you've just damaged a part of your clutch assembly, probably spotting up your flywheel and reducing your clutch disc(s) lifespan. So then you upgrade the clutch, so you stop killing that. Hey that's fine, but that doesnt mean your car is producing and more or less Torque, so again when you Launch it, it finds the weekest link. In some cases it's the pins letting go resulting in air cooling of the gearbox casing!

Our own time attack car has never been launched, has used decent fluids and we haven't seen half the issues some of you blokes have, and the car has literally done dozens of track days. Take a look here at our build thread about half way down the first post when we finally changed the OEM factory clutch. http://www.evoxforums.com/forums/showthread.php?t=54404

I wonder what is the mod on the differential and transfer case in AMS GTR that has 1300hp???

GTR dosen't have a transfer case. It's transmisson is in the rear and houses the PDK (twin clutch) gearbox, a mechanical rear diff (clutch plate) and a GKN magnetically actuated wet multi-clutch pak that diverts power to the front via a separate driveshaft. It's all one unit.

Nothing of it has anything to do with the Evo's system.

It doesn't have torque vectoring between the rear wheels and is completely passive, so McCoy is taking it to dinner and a movie next week.

http://img411.imageshack.us/img411/300/nissangr6trans002.jpg

I've heard of a lot more than two people's diffs blow up....Mine blew up. I have launched it about 10 times I'd say. I got a new stock one but I won't be launching it. I too would like to know if it seems to be launching tearing things up or just too much power/torque? Because right now no one offers upgrades. I hope someone steps up and starts offering upgrades to the rear diff for our cars.

I've heard of a lot more than two people's diffs blow up....Mine blew up. I have launched it about 10 times I'd say. I got a new stock one but I won't be launching it. I too would like to know if it seems to be launching tearing things up or just too much power/torque? Because right now no one offers upgrades. I hope someone steps up and starts offering upgrades to the rear diff for our cars.

I think the point is launching is bad for everything and is really only justified on a drag strip in competition. As McCoy stated, it's not a good idea in an AWD car. Torque has to go somewhere, and it ain't going to be wheelspin. Roll out a couple of feet and save your driveline, the AWD really makes up for that tenth of a second where your feathering the gas instead of dropping the clutch at 7k rpms.

It really is some kind of cultural fallacy for Americans that we have to burn out at every stoplight. I can respect anyone who seriously races but the Evo has never struck me as a purposeful drag car.

I've heard of a lot more than two people's diffs blow up....Mine blew up. I have launched it about 10 times I'd say. I got a new stock one but I won't be launching it. I too would like to know if it seems to be launching tearing things up or just too much power/torque? Because right now no one offers upgrades. I hope someone steps up and starts offering upgrades to the rear diff for our cars.

not sure how much power it can handle with launching, but Ryan Gates uses the Cusco 1.5 way LSD in the rear, and he has over 700 whp.

so there is an upgrade :)

History really does repeat itself. When the Evos first came out in the USA everyone and their mom where fragging tcases. From, you guessed it, launching.

The tcase got beefed up over the years and now the kids are finding another weak point when living their lives a quarter mile at a time.

Who says experience isn't everything?

I would suggest that Launching (although hilarious and not to mention fun) is destructive in an AWD car, I would suggest that's why you see so many threads about clutches on the Evo X forums and other threads about Transfers, Pins, knocking holes in casings etc. In Australia we don't have half the issues you blokes do, but that's because there is a stronger circuit culture here than drag strip, it's only a small percentage of Evo owners talking their car to the drags here. Most have their Evo as a daily driven car that is dual purpose for club level motorsport like gymkhana, hill climbs and circuit racing or what we call sprints, usually 5-8 lap of a race track. Then of course we have amateur and professional motorsport no different to any other country there.

Launching an AWD car is hard on the gear because the Torque isn't translated into wheel spin like it is on a RWD V8 mustang/corvette styled car. Evo's generally have sticky tyres and the AWD system is a good one, so with plenty of Grip and no wheelspin.... well you don't have to be a genius to work out what it going to happen... all that torque has to go somewhere, and it does. It's that torque eats the material on your clutch disc, its Torque that kills Transfers, its Torque that strips gears, snaps uni joints, cracks casings, tears gearboxes to bits and chews up and spits out diffs.

Yes, there is a Torque limit on different parts of the car, but it's the brutal application of that massive force applied in a Launch that will soon see good times go bad. Take your clutch for instance... If you've ever launched your car and then had the all too familiar smell of burnt monkeys stink up the cabin, that right there is a tell tail sign that you've just damaged a part of your clutch assembly, probably spotting up your flywheel and reducing your clutch disc(s) lifespan. So then you upgrade the clutch, so you stop killing that. Hey that's fine, but that doesnt mean your car is producing and more or less Torque, so again when you Launch it, it finds the weekest link. In some cases it's the pins letting go resulting in air cooling of the gearbox casing!

Our own time attack car has never been launched, has used decent fluids and we haven't seen half the issues some of you blokes have, and the car has literally done dozens of track days. Take a look here at our build thread about half way down the first post when we finally changed the OEM factory clutch. http://www.evoxforums.com/forums/showthread.php?t=54404


Post of the century. People don't seem to get this. This should be a sticky at the top of every subforum and on the front page of the website.

Does anyone know how the AYC actually works? I don't see any electrical connectors/sensors coming from the rear diff which makes me think that the AYC is controlled entirely by whatever fluid control system is in there.

And according to the maps bryan posted the ACD/AYC ECU appears controlled by: speed, throttle, steering angle, and g-force measurements.

So it would seem that replacing the rear diff with a mechanical one shouldn't affect any ECU ACD/AYC readings or control.

Does anyone know how the AYC actually works? I don't see any electrical connectors/sensors coming from the rear diff which makes me think that the AYC is controlled entirely by whatever fluid control system is in there.

And according to the maps bryan posted the ACD/AYC ECU appears controlled by: speed, throttle, steering angle, and g-force measurements.

So it would seem that replacing the rear diff with a mechanical one shouldn't affect any ECU ACD/AYC readings or control.

The diff is controlled hydraulically via the AYC/ACD pump (located behind the passenger tire). Look at that and you will see plenty of electrical connections and valves, and then hydraulic hard lines running the transfer case and rear diff. And yes, replacing the rear diff with a mechanical one will completely negate the AYC control. There are plenty of threads in the drivetrain sub forum to explain all of this. :deadhorse:

I want to ditch the AYC; my only concern is the ECU going nuts if I do. So I wonder if the controls on the pump then check for feedback when they control the fluid to the AYC. If they don't give a rats ass, then plugging the lines shouldn't matter when I replace the diff w/o AYC.

I want to ditch the AYC; my only concern is the ECU going nuts if I do. So I wonder if the controls on the pump then check for feedback when they control the fluid to the AYC. If they don't give a rats ass, then plugging the lines shouldn't matter when I replace the diff w/o AYC.

My guess is the worst thing to happen would be you'd get the 4WD service lights. There may be a way to disable that with ecuflash or something like that. As some others posted up above, there are people out there that went with mechanical diffs. You may want to contact them.

I want to ditch the AYC; my only concern is the ECU going nuts if I do. So I wonder if the controls on the pump then check for feedback when they control the fluid to the AYC. If they don't give a rats ass, then plugging the lines shouldn't matter when I replace the diff w/o AYC.

The wheel speed sensors control how the AYC pump disperses its fluid

Ah that's good to know. If they just tell the pump to flow x-amount and y-amount, then they probably don't check flow control. I think my next step should be to look at all the AYC/ACD error codes to see if I can figure out what the trigger is.

There is no "flow" control or any pressure transducer measuring the individual circuits. There are three circuits, ACD, AYC RH and AYC LH. There is a single transducer on the pump that monitors total system pressure and abnormal fluctuations in pressure, both of which trigger codes. So that sensor would lead to codes if you plug the two AYC lines.

Then there is wheel speed sensor data, represented in the "Delta" tables. Those will trigger codes when the AYC pump energizes, yet there is no effect on wheel speeds.

The AYC is controlled by two proportioning valves that operate from 0-4v, which control pressure to the two lines. They also are controlled by a directional valve, which chooses which way to send the power (right or left clutch). This is just a transfer switch, on 12v and off 0v.

Other than disabling some software parameter (which may or may not exist, it does work for the Evo X RS AWC-ECU) just plugging and going will get you to loose the entire system to codes. ACD would be non-functional in a service AWD condition.

But this is all moot, if you get rid of the AYC (which is not feasible or desirable for a road car) then you would probably just get a Motec or Gems ACD controller. Of course this is expensive and not road legal in the US because of non-OBD2.

Are you fixed up yet? Did you ever find what caused the problem or what failed/broke?

I should hear back by Friday. FML

I broke my rear diff two times. In both case it was the same problem.
Please see below photos.

http://img208.imageshack.us/img208/8601/aycweakness.jpg
http://img24.imageshack.us/img24/7430/0104w.jpg

On last photo 4 pinions have broken tops.

So are you just buying new duffs or replacing the pinions? What are you doing that you have gone through 2 of them already?


On a side note, my diff is back to me but I can't install it yet. Just had surgery on my wrist this morning so I am limited to doing next to nothing for a few days

Somebody, do you have any pics of the rear diff w/ AYC component separated or a picture of just the pumpkin open with the LSD+AYC in it?

I picked up a cusco RS rear diff that's AYC compatible and I was hoping to find some pictures of what I should expect when I crack the rear diff housing open.

Oh and any tips you have on issues that might arise when I do this work would be helpful too, thanks :)

I'll see if I can pull out some of the parts and take pics, I have an rear diff apart. Only problem I had was pulling the stupid oil seal off the housing, I didn't take my time and damaged it. There is also a very thin viton O-ring that seals the housing to the center casing, it's fragile. Everything else slid right off. The casing I worked off with a rubber mallet, took some time.

I did not separate the ring from the actual diff yet, don't know the torque. Outer bolts on the casing seemed around 35lbs. Mitsu does have a universal bolt torque table in the manual. Does Cusco have any instructions? Do you need to plug the AYC connections?

Attached is a high def cutaway.

Cusco gives you nothing but a sticker XD Thanks for the info.

I shouldn't have to plug the AYC lines since it's supposed to be for AYC model Evos. I'll let you know how it goes when I install it. I'm just happy tephra has the app to assist in bleeding the lines so I don't have to go to mitsu.

^But it's a torsen diff, right? Theoretically that would blow up the AYC with the lines attached, always wondered what it would do actually.

BTW the AYC clutch paks side should not need to be touched, it's got it's own case cover. Really complex bearing that separates the AYC clutches from the torque transfer gears and diff. Journal bearing on the inside and ball bearing on the outside, was a complete PITA to press from the housing.

It should be fully compatible...SHOULD be. Evodave did the install and left AYC in with no problem. I pm'd him for more info but didn't get a response unfortunately. I also asked Ryan Gates about his diff, but he wasn't sure what model AMS put in (MZ or RS).

On another note, I also got a hold of an evo x member who completely replaced his rear diff with an evo VIII/IX one and is using stock ECUs. If you ditch the AYC completely, it looks like you have to dump the ACD as well. He plugged up all the lines off the pump. No error codes, but he hasn't done too much driving yet. I'm wondering if you can actually keep the ACD since you'd only need to plug the lines from the pump to the AYC, but who knows if some crazy pressure differences would make the ECU go nuts.

I guess the technical concern would be that a torsen diff sends power to the wheel that has more grip, meaning resistance to turning. An open diff (it's an open planetary style stock) sends power to the wheel that is slipping. The right clutch pak pushes power to the left rear wheel, and the left clutch pak pushes power to the right rear wheel. It's basically a brake.

What happens when the clutch pushes power to one of the wheels are runs into a ton of resistance?

The physics might still work, IDK. Problem is I don't think wheel speed differences are governed electronically with the AYC, it's all mechanical. The table that governs the AYC works off steering angle and speed.

Keep us updated Seg, very interested to see the results. If you need any help......

I have a spare 08 diff for sale. Let me know if you need it.

So are you just buying new duffs or replacing the pinions? What are you doing that you have gone through 2 of them already?


On a side note, my diff is back to me but I can't install it yet. Just had surgery on my wrist this morning so I am limited to doing next to nothing for a few days

First time it was at 27k miles. It was on track, but before I had very much autox and sprints with a lot of launches (I think it was 60+). In my service they changed only broken pinions, pinions which were used were not new condition. Second time I think a problem was because pinions condition was used. And now I try to find new pinions.

My mechanic said that in evo ix this pinion more stronger than evo x.

so where can i get upgraded differentiate for my MR?

so where can i get upgraded differentiate for my MR?

I got mine from Speed Element.

So diff went in today. Getting it out wasn't an issue. Just had to unbolt some arms and braces to be able to move the half-shafts out of the way.

So once the entire housing is out, you need to unbolt the differential side to reveal the stock diff unit.

Pic of the new diff out of the box:
http://i217.photobucket.com/albums/cc62/Segfault00/Evo%20X/photo1-1.jpg

Pic of the housing with old diff:
http://i217.photobucket.com/albums/cc62/Segfault00/Evo%20X/photo2.jpg

You essentially just pull off the old diff, take off that main outside gear piece, and bolt it onto the new one. You'll also need to add side-bearings (top piece on the second pic)to the top of the new diff. You should buy new side bearings but can reuse the old ones if you can get them off w/o damaging. If you go that route, you better be really good and careful. Thankfully Mert at GST was able to save my butt there.

http://i217.photobucket.com/albums/cc62/Segfault00/Evo%20X/photo3-1.jpg

Once all bolted together, you just slide the new gear right into place and reverse the process you did to get everything back together. Put 75w140 SVG in the diff and refill the AYC with ATF SPIII. Then bleed the AYC (Thanks Tephra!).

So initially there was some binding sounds as I took the car out. As I broke it in using figure 8s and circles the sound steadily decreased. Now it just has that sound at very low speed turning. It just needs some more breaking in most likely.

Initial impressions are that it does add in some better exit rotation. I haven't done any full testing yet, but I'll update when I get a chance to take it for a fun run. Next auto-x isn't until 01/29 so I won't know really how much it's helped until then.

thank you for the info segfault

Nice, for some reason I thought the Cusco's where Torsen. It's a plate clutch LSD. Is yours an RS or MZ?

Still think Torsen would blow it all up, but since the Cusco is a plate LSD it makes me question if a Torsen is even available.

Do you think the AYC activates any differently now?

It's the RS model. The MZ model isn't AYC compatible. I think the AYC activates the same as before but the diff does more lockup first. I haven't pushed the car yet though.

2 segfault: Thank you, it's very important information.

FYI looked over all available front, rear, and center diffs available for the X and found out the only Torsen diffs are available for the front diff. Stock is torsen, so is the Quaife ATB front diff which is the only torsen aftermarket diff available.

Cusco, Ralliart, and Carbonetics front, center, and rear diffs are all plate LSD's. Still think any application of a torsen in the center and rear diffs would be antithetical to the nature of the ACD and AYC clutches.

I thought I had heard of a rear torsen diff that required you to disconnect the AYC pump. Maybe it was just a dream.

2 disco godfather: What do you think about cusco front diff (http://www.amsperformance.com/cart/cusco-mitsubishi-lancer-evolution-x-front-1.5-way-lsd-type-rs-w-ayc-5-speed-only.html)?
Why it's not suitable?

2 segfault: How is your setup? Everything is okay? I think I will do the same setup. Maybe with front diff.

The front diff on our cars is a Torsen. It's fine for around town and it seems to be ok track wise for most weekend warriors. It doesn't seem to bite as smoothly as I would prefer. It's been said it is also very weak, and tends to grenade under extreme stress easily.

The Cusco seems fine to me, some people use it. My Neighbor with an Evo 8 has had a cusco rear for years now. Gates uses a Cusco.

I would only go to the trouble of getting a plate LSD for a front diff if there was a problem with my Transfer case. When a decent source of upgraded ring and pinions comes out or if you have a serious problem with the T-Case then killing two birds with one stone seems logical.

There is also Ralliart Supertraction and Quaife ATB (this is torsen) for the front. Plate clutch will always be preferred bu hardcore racers because they are rebuild-able and somewhat adjustable.

Looks to me like the casting had high porosity in that area and it cracked right off. There's no reason for a cast part to have a little hole like that. It should be a huge crack before a piece falls off. Looks brittle as an egg shell.

This thread is so full of win!

2 discogodfather: Is Ralliart Supertraction front diff with plate clutch?

Hey Disco, are there any good options for getting rid of the SAWC system like center and rear dif. Or is that just over the top expensive?

Hey Disco, are there any good options for getting rid of the SAWC system like center and rear dif. Or is that just over the top expensive?

could be cheap depending on what is found in the s-awc tables. if its possible to just disable the system by zeroing out some or all the tables or reflashing it with a rom from a RS that would be awesome.

why would you want to get rid of the centre diff?

You can try removing the pump and plugging the holes if you want to ditch that stuff. Not sure why you'd want to.

why would you want to get rid of the centre diff?

SAWC Pump failed and from what i gather there is no way to get it replaced on powertrain warranty, so i figured now may be a good time, if the price is right, to go to mechanical diffs that won't break because it's cold outside.

Hey Disco, are there any good options for getting rid of the SAWC system like center and rear dif. Or is that just over the top expensive?

It's going to be very hard and costly. To do it right you would need to:

1) Complete RS rear end (similar diff to the 8/9 USDM) including driveshafts
2) Ralliart AU sourced Supertraction center diff (plate LSD)
3) Completely remove the pump

The Supertraction is $2000+ alone, and is the only replacement center available, and it only works on the 5mt. Sourcing the RS rear end would be JDM stuff, very expensive and hard to find.

You could go another route, but it's more half-assed. Get the Supertraction center and some kind of replacement rear diff (plate LSD from Supertraction, Cusco, Etc), then plug the two line inlets and remove the pump. The AYC clutches and torque transfer gears are still there, but they would be "free wheeling". The clutches would be dead weight, just sitting there without a point.

Probably lots of codes and electronic headaches. Never have done any of this myself.

That's a lot more than I had hoped for.... Oh well, looks like I will be getting another pump that will fail in 3 years. Fucking mistu...

how has it failed?

what sort of driving do you do?

how many km's?
how often did you change the fluid?

etc?

It's a cold weather thing... a lot of people here in Canada have had them fail. I'm no slouch but I don't bag it. I have 48000km on it have had the fluids changed twice in diff tranny and t case. Take a look at this thread, http://www.evoxforums.com/forums/showthread.php?t=58221

I keep thinking that the solution for the cold weather pump problems in insanely cold temps is to paint the pump with some kind of thermal coating paint, really thick.

The pump housing is made out of pot-metal like aluminum and every pump I see coming out of cold temps is corroded to hell, all white aluminum oxide. I wish I could test the theory. What harm could painting it do? I know a British shop that, when they retrofit older pumps, paint the bodies, solenoids, accumulator, and motor.

If you look at Ralliart Italy's part list on Group N cars they have all these shields for the pump (if you choose to retain ACD), so these types of splash / snow shields might work great to help. The pump is really hanging out there, lots of places for snow to get in and sit. Maybe just wrapping the whole thing in a thermal shield (like those turbo hoodies) would help too.