the turbo has always spun freely with no dragging when i spin it with my hand. even right after a run.

 

I would do a hump couple since it seams like a quick and cheap thing to check. Also if you dont have enough room for a hump coupler, maybe do a coupler on the intercooler as well.

Also on the launch is where the motor will torque the most making it more likely that the piping is causing the comp to hit the wheel.

 

exactly my thoughts. sometimes it does it in the burnout too which is pretty much the same hard hit as leaving. if it leaves the line fine it always runs good down the track. another thing that has happened this year is the car all of a sudden running rich down the track which i believe what's happening is the turbo is still binding up a bit causing the air flow to go down causing the VE to not be where it was tuned on and causing the rich mixture. It almost has to be in the turbo. I'm going to pull it off tonight and check everything out on it and send it out to precision and have them go through it.

 

I would send it out just yet, unless there is obvious signs of contact and damage to the wheel. i would try hump couplers first

 

took the compressor housing off tonight and there are no signs of the wheel hitting the housing. the housing looks fresh and the blade has one tiny tiny knick in it but nowhere near where it would contact the housing. shaft play is minimal to no play.

One thing I have a question on. when we got the turbo we welded the vband flange on the compressor housing for the intercooler pipe. is there any way the housing could've been warped? i do notice that it's difficult to get the compressor housing back on the turbo like it's tight and once i get it pressed on the housing won't spin easily at all to angle it the way it needs to be. i almost need to line it up before putting the backing plates/bolts on it. could that cause it to bind up the turbo or anything once tightened all the way down?

I have the billet 6768 with the "H" housing. There is supposed to be a oring between the compressor housing and the turbo isn't there?

 

very good question cause from the looks of it the turbo could have a divide housing and the manifold pipe might not be divided.

 

I guess anything can happen, but ive welded a bunch of v-band fittings on turboes and three were 6768, non of them had problems

 

How is it possible that if the wheel isn't hitting the turbo stops spooling/making boost then?

 

What does the exhaust wheel look like? Are you comfortable taking the turbo apart to inspect the shaft? The compressor housing should definitely spin freely without the bolts being snugged up at all.

 

see and it doesn't spin very free at all. it's actually even tough getting slid on the turbo. you can see drag marks on the inside of the comp housing where it sits on the turbo from where i've tried to spin it and it's so tight it's digging it up a bit. i had the downpipe off a few weeks ago and didn't notice anything but i wasn't really looking for what i am now. i'll take that off tonight and look and probably take the whole turbo apart as well.

I also just found out that the 6768 "H" housing doesn't take the oring that seals up to the turbo but when we put the turbo back together and on the dyno it was overboosting every time. we put an oring in it from another 67mm and the overboosting went right away. not sure if there is an issue there causing something.

 

if you can hear it "whistle" it really cant be the turbo binding up right? to me that can only mean boost leak because if it were binding up and not spinning it would sound flat like a na car

 

It does....in the video when the car falls on its face...no turbo sound.

 

You can still hear it even as it leaves the line. It seems like the turbo is lazy even on the launch control and as soon as it leaves it drops until the rpm starts coming up.

 

that video is the best pass of the night that i have video of. but your right the turbo spooled in the burnout great. was boosting up at first when i was up on 2step at stage but as soon as it left it went all the way back to vacuum and didn't see but 2-3psi until about 7500 and the turbo usually hits full spool around 6300-6500.

It's not that i'm not leaving off boost. for example in 3rd gear 100% throttle it will be pulling 27psi and running good. all of a sudden it just falls flat back to vacuum and the car loses all power and rpms fall off still while at 100% throttle. you can hear that the turbo is no longer whistling at all. a lot of the time it will leave good and at the top of first boost will just drop off hard.

How do i post a log up and i'll post a couple when the car is doing it.

 

your car does the samke identicle thing mine does man

i would launch at 7500 then fall back to 3500, and just past the 60' it would come alive.

i spent a day at the track with my tuner trying to solve this issue, and we never did. going from a soft cut to a medium cut helped me out a little bit, but my pump took a dump on me as well that day.

are you running boost from vss or by gear???? mine is by vss,a nd i have also debated going to s300 over my current aem box to se eif this solves my issue.

 

to me it looks like your turbo mani setup is causing this issue... from the vid the whole way down the track till late rpm you lagged.. wg placement should have been on the colector, and the pipe from the mani to the turbo is way too long..you want to stay as close to a colector as posible and keep the pipe as short as possible... our k on a 6262 and a full race mani has no issues at all makes spring boost in a split of launch control on kpro... i can say im 99% sure its your manifold

 

actually his power ramps up right before the 1-2 shift you can hear the noticable differance in it for sure.

 

Out of curiousity- do the logs show it going lean just before boost drops or rich immediately after it drops off?

 

Post the log.

Pull it up on your laptop
Press ctrl + alt + print screen
Open up paint or a similar program and paste
Save file
Post it up on here

 

This may sound odd but check the turbine exhaust housing to manifold bolting. I had a problem where my bolts where backing out and the car would build boost in a "odd fashion". Like at the start, it would build a little boost then cut out before 7K. If you tried again, it would build boost all the way to the rev limit, ok, but the car seemed a little sluggish. To fix, it I replaced the wastegate gasket, bolts, etc and now it works like a champ.

 

are these pte turbos you guys are having problems with? i know the OP has pte.

 

im on a old school pt67

the fact that he build boost in the water box, and at the line, but then it falls on its face at the launch would hint to me that its electrical thats why i asked what type of bost management he is using everyone i have seen on bbg screams out the hole making emdiate power. My cr acts just like this one builds boost in the box, and the line then launch and for some reason as the wheels start to track it falls hard then ramps back up. I wanna see this issue solved for the OP because it may help me out as well.

 

It's not a boost control issue. Even with boost control settings off in kpro and solenoid completely unhook the car will fall down to vacuum in the middle of a 100% throttle pull.

We are taking tuesday and Wednesday to redo the turbo kit back to a sidewinder location and use only one gate this time right off the collector. I believe once that is done the car will completely change. I also bough a new unmodified compressor cover and it slides on and off the turbo and spins freely unlike the housing that the vband was welded on.

 

sure hope this helps you out

im still curiouse to know what boost option you are on though???

bbg
vss
?????

 

Maybe I'm overlooking something, but it just sounds like there's not enough RPM in the launch.