Well, this weekend I thought I would perfect my launch on my Evo! After getting my failsafe changed up and letting me use launch control without going off I thought I would give her a rip!
Well the first time I did it on Friday night I took traction control off and everything pushed the clutch in, put it in first- and romped on the gas... Well with my set up I haven't launched it much to perfect it and get the best place for launch control and with how big my turbo is we set launch control at 7000rpm to start.
As I hammered my foot down on the throttle I watched anxiously as the rpms rapidly accelerated to 7000rpm and proceed to bounce right there. After about 1-2 seconds I let loose of all 400ish ponies I was on and she took off- but once again she completely bogged down like it always had done in the past, but it felt better and I could tell that this time it wasn't the failsafe going off- it was the lack of power to keep the tires spinning and boost rolling in before she bogged down!
So I started thinking about it, and I had an idea: maybe if I romped on the accelerator and let it go a little longer before I let it loose I could build some boost (Looking at my boost gauge it always appeared to be a '0' when I launched).
Well I picked up my girlfriend took her out to lunch and went to a safe place to practice a launch. As I sat there with her I took all traction control off once again, pressed in the clutch, pushed it into gear, wiped the nervous sweat off my brow and proceed to hammer down once more! Well sure as shit I was right! I watched the little needle proceed all the way up to 7000rpm to be sure it was behaving, then quickly switched my gaze to my boost gauge. I watched for what seemed like a quick second and all of a sudden a magical thing started happening- the gauge started reading off boost! 1, 2, 3, then 4lbs of boost started appearing in the tiny digital numbers. As the gauge hit 4lbs I couldn't hold back any more I was so excited so I dropped the clutch! Well for a split second I was amazed, I thought for sure everything was going perfect and I wasn't going to bog down at all! Then it happened... BOOM!
I went about 10ft then I proceeded to coast a little ways down the road.. As I let go of the throttle in disbelief I started running scenarios in my head- Did I just blow my clutch apart? Is there a new fancy window in my block? Did I leave my transmission 20 feet behind me? I was horrified! When I finally stopped I hoped out and looked underneath my car and saw a huge puddle of oil pooling up on the ground coming from my rear differential! I was so disappointing. I never even thought of something like this happening! I tried looking underneath my car at it to see the damage but I couldn't see anything as the car was too low.
After a while I thought that I should walk back to the place of launch up a ways and see if I could see anything of significance up there- well I found half of my plug to my rear diff. So I thought well maybe I just put too much pressure on it and it blew out with all the oil. (More of a hope rather than a guess). I also found a trail of oil about 1 1/2' wide by 10' long!
Well after a long process of getting a trailer and getting the car home I finally got underneath and saw the damage:








Well now that I know I have to replace/fix my rear diff... What do you guys recommend? I want to be able to launch my Evo at the drag strip still, but I am terrified of this happening again! I've heard of people doing a 8/9 swap, maybe that's a good idea? Or just getting a used one and putting better bushings and things in it? Or trying to send it to Jack's Transmissions to see if the can fix it still? Their ad says they can do it even if it is cracked, although I think I completely snapped mine in half!
Well the first time I did it on Friday night I took traction control off and everything pushed the clutch in, put it in first- and romped on the gas... Well with my set up I haven't launched it much to perfect it and get the best place for launch control and with how big my turbo is we set launch control at 7000rpm to start.
As I hammered my foot down on the throttle I watched anxiously as the rpms rapidly accelerated to 7000rpm and proceed to bounce right there. After about 1-2 seconds I let loose of all 400ish ponies I was on and she took off- but once again she completely bogged down like it always had done in the past, but it felt better and I could tell that this time it wasn't the failsafe going off- it was the lack of power to keep the tires spinning and boost rolling in before she bogged down!
So I started thinking about it, and I had an idea: maybe if I romped on the accelerator and let it go a little longer before I let it loose I could build some boost (Looking at my boost gauge it always appeared to be a '0' when I launched).
Well I picked up my girlfriend took her out to lunch and went to a safe place to practice a launch. As I sat there with her I took all traction control off once again, pressed in the clutch, pushed it into gear, wiped the nervous sweat off my brow and proceed to hammer down once more! Well sure as shit I was right! I watched the little needle proceed all the way up to 7000rpm to be sure it was behaving, then quickly switched my gaze to my boost gauge. I watched for what seemed like a quick second and all of a sudden a magical thing started happening- the gauge started reading off boost! 1, 2, 3, then 4lbs of boost started appearing in the tiny digital numbers. As the gauge hit 4lbs I couldn't hold back any more I was so excited so I dropped the clutch! Well for a split second I was amazed, I thought for sure everything was going perfect and I wasn't going to bog down at all! Then it happened... BOOM!
I went about 10ft then I proceeded to coast a little ways down the road.. As I let go of the throttle in disbelief I started running scenarios in my head- Did I just blow my clutch apart? Is there a new fancy window in my block? Did I leave my transmission 20 feet behind me? I was horrified! When I finally stopped I hoped out and looked underneath my car and saw a huge puddle of oil pooling up on the ground coming from my rear differential! I was so disappointing. I never even thought of something like this happening! I tried looking underneath my car at it to see the damage but I couldn't see anything as the car was too low.
After a while I thought that I should walk back to the place of launch up a ways and see if I could see anything of significance up there- well I found half of my plug to my rear diff. So I thought well maybe I just put too much pressure on it and it blew out with all the oil. (More of a hope rather than a guess). I also found a trail of oil about 1 1/2' wide by 10' long!
Well after a long process of getting a trailer and getting the car home I finally got underneath and saw the damage:








Well now that I know I have to replace/fix my rear diff... What do you guys recommend? I want to be able to launch my Evo at the drag strip still, but I am terrified of this happening again! I've heard of people doing a 8/9 swap, maybe that's a good idea? Or just getting a used one and putting better bushings and things in it? Or trying to send it to Jack's Transmissions to see if the can fix it still? Their ad says they can do it even if it is cracked, although I think I completely snapped mine in half!