[Robevo]

If you have a MAF then you can not run VTA . You need to recirculate you venting. That is a way it designed the evo set up with MAF sensor in place.
Its not a BOV cutting , that is your actual engine ECU. It sense the disturbance in the air flow (hence no recurculate) and cutting the engine.
There is no spring or anything will help on that. Either you get a new BOV not VTA or as I said before get that valve to recirculate.

Rob

 

[Robevo]

I think its an easier route to get a recirc new bov for thje car

 

[Robevo]

VTA is fine, don't listen to those people.

What spring are you running now? I have the same thing, Tial 50mm VTA. You'll want a -9psi spring. -12 is way too stiff and the valve won't even open at full boost...you'll get some crazy off throttle surge.

You're getting a little surge (fluttering) because the BOV is staying closed, like it's supposed to, and your turbo is basically spooling too fast at part throttle, flowing more air than the engine can take in. Either adjust your right foot, or adjust your MIVEC and wastegate duty cycles a little so it doesn't spool so fast at part throttle.

There will always be part throttle situations with high load/low rpm when you can't avoid that light surge, but you can minimize it by tweaking the above mentioned tables.

please do not give out false information's. VTA and the stock EVo MAF set up doesn't work right.

You need to get rid of the MAF to have the VTA bov set up work right .

I dont know who is this guy, but you can ask all respectable tuners and engine builders. They all say the same. I tried the VTA Once in the 4G63T engine and once in the 4B11T. wont work right,.
Now i have VTA , but i have no MAF anymore.


Rob

 

[Robevo]

from some tuners for you ( there is a difference between a MAF and the MAP sensor... )

"For anyone who's wondering why VTA BOVs don't work worth a crap on our cars, our fuel is metered from the MAF. The MAF signal tells the ECU how much air the motor is getting and it uses that to calculate how much fuel it should be putting in. The stock BOV (which is really a compressor bypass valve, not a BOV) recirculates the air back to the intake so the MAF readings are still correct. When you install a VTA valve it lets air out after its been measured by the MAF so the ECU dumps way too much fuel into the motor, which is why it runs like crap."

"concern would be the fact the temp sensor on the maf is now reading charge air temps rather than intake air temps. Charge air temps are a good bit higher than intake temps in most situations."


as you know the ETS guys respond this :
"I wouldn't recommend it. We have had customers have good luck with the 50/50 setup, but the straight VTA seems to always have a problem. I wouldn't recommend it unless running speed density.

Thanks,

Michael"


i am not entirely sure why you think you know better then these guys. Because you tried and you think its working? Some peole actually test and work more cars then one. Others actully even race them, all those do not recomend VTA with MAF sensor in the evo.

Actually i dont really care what you think , i am posting more towards those who try to decide what to do.
Everybody do what ever they want they own car, so i will leave it like that.
Everybody here is an adult and can decide what direction they would like to take.


Cheers Rob

this is my engine bay and i am running MAP sensor that is why i can run VTA. AS you see there is no MAF sensor in the car

 

[Robevo]

Ok i understand what your showing me there. But when your just say, driving on the highway around 80. Is when i get my flutter. I'm right there with you at WOT. I have no problems there.

Wide open throttle the BOV is NOT working it is suppose to be closed.
The BOV works when you lift throttle, basically releases the extra pressure.
You cant tune cars for BOV valve. That is nonsense.

 

[Robevo]

Thanks for all the help guys. I didnt mean to start a pissing match but hey its helping me in the long run so thanks! Im not going to do anything with it until i can find out what its going to cost me to go back to recirc.

this is not a pissing match. I dont get angry at all, So i hope that is true for everyone. End of the day we all want the same so yes we need heated debate to get and move forward.
I just share what i think , and if someone can provide me a great fact to make his point valid, i'll take it.

But until , just because "i said", it is not working in my library... LOL
It takes a lot more then that.

ROb

 

[Robevo]

MAF is a primary sensor in this case, what the ECU reads and follows. That is why the VTA cars with stock set up has an issue being bucking and so on so forth. The all well know issues.( the last 10+ years in the EVo world).
I think at this point we start going in circles , with nothing really proven me wrong So i will let it be.

Cheers Rob

as people say , "the little knowledge is the most dangerous", which probably apply's for me too in this case. LOL

 

[Robevo]

I'm quite aware of the differences between a MAF sensor and a MAP sensor. So you do know that our cars have both sensors as a stock setup, correct?

hm... i sense some sarcasm here and high horse at a same time... :clap:

But still very hollow...:yay:

one last quote's from me here to leave the discussion ...
--------------------------------------
"CBRD:
ive found that some cars are more sensitive than others.

we run a tial 50mm on our 05 MR with the utec and 35R, and have had no stalling problems at idle.... also with a turbonetics raptor valve before...

if you adjust the bov, you can get the car to run "well" or "decent" but obviously as stated, MAF should be recirculated.

cheers

cb"
-------------------------------------------

"ETS:
I wouldn't recommend it. We have had customers have good luck with the 50/50 setup, but the straight VTA seems to always have a problem. I wouldn't recommend it unless running speed density.

Thanks,

Michael"
__________----------------------------------------------------------------


"Malibujack:

No drawthrough equipped MAF car will run correctly with a VTA Blowoff valve, you will have to recirculate it.. There is no fix for it other than removng it or recirculating it.. Even those who claim not to have problems are in reality deluded, their car still has problems, only they don't understand what they are."
"I run a blowthrough MAF, it removed a very problematic stock MAF, and being able to VTA is a side effect of the coversion as the ford MAF sensor is integrated into my intercooler pipe AFTER the BOV.

I still run a stock ECU, and still have stock drivability, so it has very little to do with tricking the ECU or anything like that.

However doing this conversion just so you can VTA is a COLLOSSAL waste of money and time, as the stock MAF is capable of pretty decent numbers.

I have clearly had some issues with my MAF early on, and was probably one of the first, if not the first to have successfully used on on a USDM Evo. \

So Cliff Notes:

1) If you run a speed density setup (either using a MAFTPRO or a standalone EMS) or blowthrough MAF conversion where the sensor is AFTER the BOV, then you can VTA with no Ill effects.

2) Doing this conversion is expensive, and probably not a wise thing to invest in unless you need it

3) VTA on a stock MAF results in performance and drivability problems.. PERIOD, you can adjust a BOV to stay closed at idle and it won't stall at idle.. But if you vent at very low throttle, it will stall, it will shift rich, and potentially cause other issues. Those who think their not actually somehow hurting their car's drivability or performance by doing that are deluded."

good read :
http://forums.evolutionm.net/evo-en...-mass-air-conversion-vta-100-no-problems.html
------------------------------------------------------------------------------------------

"
Originally Posted by BakaUnchi
Lets clear up some MASSIVE mis conceptions here.

VTA BOV on MAF cars WILL affect the tune / Car

Bov's are not just open when you let off the throttle from WOT
Bov's are open quite a bit while cruising, and in part throttle situations.
Bov's Tend to open @ idle quite a bit

Any time you are venting metered air out of a maf system the car will try to compensate just like if you had a boost leak . @idle it will open and mess with fuel trims and idle quality. At Cruise it will do the same thing.

Subarus have fuel trims and the LAST of the 4 affects WOT fueling directly
Bov's make the car think it is rich (cause the air went bye bye) so the ECU says time to lean out that area. It leans it out whatever % it feels and continues to do so until it feels the afr in that area is ok. This area is typically highway cruise speed/airflow.

A bov VTA can cause up to 15% NEGATIVE fuel trims so now your WOT Fueling is -15% and that + WOT in just about any TUNED/Stock car will blow it the **** up. It may take a week or 3 to get that bad but i can tell you it WILL. Some BOV are better than others about it some are not.

This is FACT not fiction, i have seen it on hundreds of Subarus and Evos and other cars. Anyone who tells you differently has no idea how it works. The OEM's use maf for reliability and the ability to drive in massively changing environments without a retune. The cars ECU's are DESIGNED to have a Recirculated valve. Unless you swap to SD or pull some trickery and know how to prevent WOT fueling changes please please please for the love of god KEEP YOUR BOV RECIRC

This has been a PSA from Jon"
-----------------------------------------------------------------------------------------------------------------------



This comes Form UK,:

"quote "There are a number of issues to consider when using a VTA or blanking off the OE recirc valve.
VTA (and recirc) DV's come in a range of opening pressure settings. Whether high or low pressure, with a VTA there can be issues.

1 - Overfueling due to excessive venting to atmosphere
2 - Stalling the turbo
3 - MAF revertions and System volume
4 - Repressurisation time
5 - High pressure damage


Looking at the issues one at a time,

1 - Overfueling due to excessive venting to atmosphere

If you run a standard pressure vent to atmosphere dump valve (BOV, VTA, Atmo DV) with a mass air flow monitoring ECU such as the OE Subaru, then you can have problems when the DV opens under cruise conditions. The DV allows air to escape from the system during the high vacuum conditions during cruise, The reason for this is the signal side of the DV is subject to vacuum and the flow side is subject to slight boost pressure (the difference across the throttle valve) If this exceeds the spring pressure then the valve starts to vent.
This airflow has been monitored by the ECU and fuel is added accordingly, the result is too much fuel for the air being consumed by the engine.
Best case - You just waste fuel but who cares when you get that 'pschhhht' you've always wanted
Worst case - You cause bore wash, increase oil consumption and reduce engine life.


2 - Stalling the turbo

The term turbo stall refers to stalling the airflow across the compressor blades, not physically stalling the rotor (common misconception)
This is a case of what happens if you don't use any DV or use a valve with too strong a spring.
When you lift off the throttle on full boost, the compressed air has no where to go and blasts back across the blades giving that (lovely ) sharp 'cacho' or WRC chirp as some call it. Very taxing for the turbo, all this backwards flow.
Best case - Runs forever (TD series generally tougher than VF series)
Worst case - Shatters compressor wheel or thrust bearing fails


3 - MAF revertions and system volume

This is not such an issue with a TMIC but when FMIC's are used the system volume is so large that when the throttle is brought back from power (boost) to cruise, if a strong spring DV is used (strong enough to eliminate issue 1 ) then you can get a sudden pulse of pressurised air back out of the MAF, this is measured as an airflow (the meter can't differentiate) and the engine overfuels giving a hicup/jolt
Best case - Slightly jerky drive as you come off throttle
Worst case - Very jerky !


4 - Repressurisation time

This is where the stiff spring DV or running without DV scores a point. The system holds more pressure between gearshifts as the DV isn't venting it. Boost recovery in the next gear is improved (slightly)
Best case - Improved response after a gearshift
Worst case - Issues 2 and 3 above.


5 - High pressure damage

If you use no DV or a high pressure DV spring then when the turbo is spinning at high speed and the throttle valve is snapped shut, there is a pressure pulse in the system
which can be high enough to damage the intercooler etc.
Best case - At boost below 1.5 bar you will probably be ok
Worst case - Bigger turbo's/ higher boost may pop hoses off or 'balloon' the intercooler core.

Options ?

A light pressure recirc valve (just like std) overcomes all of the above issues but sounds a bit boring

Sequential dump valve. At light pressure it recircs, at high pressure lift off it still goes Pssshhht

You pays your money, you takes your chances.

Andy" end quote"


aaaaand we can go on and on... LOL

 

[Robevo]

You would have a more credit in this situation if you have a proven tune and racing history which means your tune and work was put it up for test
Racing teams "not weekend wariors" are the best place to test your product street and occasional track use will NEVER prove a 100% reilability of your tune,period.

Those guys who said a BIG no for MAF with VTA , has countles tuned cars and racing history. With the X too. I do race my X since day one in 2008 early springs. Fact many company's test and tryed they first product on my car...
So you are not exactly talking to someone from your locals.

Those people you say you don't care what they say , they do put down something on the table, and your comment on them more then ignorant.
This attituide will not fly neither in the tuning world or the racing.

I could have post seriuos race tuners opinion on this but would be really useless since most of you never heard of them. They do not tune personal cars. I hope you do understand the difference of they knowlidge in the tuning. About the X. Fact one of them is coming to visit me next month or february, who tunes cars and his OWN racing history is more then stellar. Like won the WRC 2011 rally Catalunia rally grupe N with his own evo. Which he tunes and also he does his own suspension work.
By the way this is the guy who helped and designeds the R4 suspension for the evos for Ralliart...
Now I am sorry if I give them credit over your testing and opinion, wheter is a X or the 4G63T.

There is a hard and long head of you with these attitude.

Be safe

Rob

 

[Robevo]

Oh by the way you didn't show Any evidence yet, besides I say so , and useless video.
If you will show some hard evidence over what the leading evo and race tuners have, then you are talking. But you will still lacking is proving your theory since it was not put into test yet.
You see even dyno tunes can fail in racing when you put them in use. Ask me how I know...

 

[Robevo]

What that map has to do with the VTA discussion here?


Tephra mades changes in the ECU etc. ( he is very good with that), so other people use his maps for different reasons.

This thread/case for the car wouldnt go to LIMP mode with VTA, and you can use that for your X, if you want to run a car without warning codes and ecu safe modes- actions /like limp mode to save the engine/, since the codes are disabled to have a VTA bov - valve, trhough the ECU tune...
Other words you take out the safety fetures in the ECU, to having a VTA valve run "properly" . It does change the fact is not good for the car? No, only thing it does , the car will not recognize the problem, in my mind.
Since they are not there anymore after the retune , and it was a reason why need it to be taken out in a first place. I am sure you get where i am going with this.


http://www.evoxforums.com/forums/showthread.php?t=18264


press on .

Rob

 

[Robevo]

The X is a smarte design and using boit maf and map sensor. But the primery is a MAF whic the ecu use for calculate the airflow. This graph if I am right shows how you calculate how they work together in diffenent condition.
I am also not a tuner, so I can be off here.
I talk to couple tuners and they al said the same about the VTA.
And they told me this about the two sensor too.

 

[Robevo]

I think I said everything already. This is going I circles.
I trust in 10+ year tuning and race toner , so you can say what evet you want. By the wat the older evos used MAP too.
Hm I think this is the end of my end here.
There is nothing more to say here specially if some one that right with that much experience ... LOL

Rob

 

[Robevo]

Those guys I talked to has an expetional tuning back ground so as racing. I personally doesn't ever heard of you neither kniw who you are.
So you have to understand my point of view. The reason I do not get involved it tuning just listen they opinion , I do not have a money neither a time or the will to having failures. They all have done that and they all learn from it. So I don't need to.
You talking about those guys like "who they are to tell me"..
Well they knwolidge is way beyond your at least for a next couple of years based onthe experince only by the amount of evop and yes evox they tune and tuned. As we talking here most of them is on a test day and tweaking cars. Thye are not find on forums.
But if you want see how they work , I would be happy to intruduce to them. I think it would be a very bebefical for you. They are usually super nice and not kocky people.

After that you can have your personal opinion from them.
It was a convesation for sure but as isadi it is nothing more to say.

I said what personally tuners told me years in building evo race cars. Those tuners are tunning high hp rally cros EU and hill climb - track and rally cars. Since evo 1.
As much as probabaly you donnt like ti I will give them a credit on this.

Good luck in your endevours
Rob


Ps: if you interested to see things and how things been done and where , just let me know and we can cook up something