Who here can help resolve a boost issue? 3rd gen, stock twins
06-09-09, 03:37 PM
#1
Full Member
Thread Starter
iTrader: (1)
Join Date: Apr 2008
Location: Denver, CO
Posts: 120
Likes: 0
Received 0 Likes
on
0 Posts
Who here can help resolve a boost issue? 3rd gen, stock twins
Is there anyone local that knows a lot about the sequential twin vacuum routing? My lines were simplified by another shop (Rotorsports Racing in NC) and it worked great originally. Then it was stolen last fall, and ever since I got it back, it's never worked the same. I tried calling and emailing Rotorsports to get a diagram, or any info at all on how my car was setup, but unfortunately I never heard back.
So here's the problem. Basically, my car boosts perfectly as long as I don't get into the secondary turbo...so I can't rev it past 4500 or so. Once the secondary kicks in, it kills the primary, so to speak. As an example, here's what an on-ramp pull feels like...
2nd Gear, full throttle: Primary boosts to 8 PSI. Pulls hard, feels normal. Secondary comes on at 4500 RPM, switches over just fine, stays at 10 PSI. Feels great, just like it should be.
3rd Gear, full throttle: Since I'm shifting, I put the clutch in and let the RPMs drop back down. When I get back on the gas, I can feel and see that it's not boosting as high as before. It's almost like I can feel it slowly slipping into less and less boost.
4th Gear, full throttle: Shift again, get back on gas, around 5000 RPM. With both turbos on, I get only 5 PSI of boost, and the car struggles to go anywhere. Feels terrible.
And every time after that, I get NO boost at all from the primary turbo. You just hear this massive whoosh noise in place of the turbo spool. My guess is the wastegate is locking open for some reason. If I let it wind out to the point where the secondary comes on, it's the same as the last run, it boosts to 5 PSI (or less, sometimes it only boosts to 3 PSI) and feels terrible. I have no clue where to even start diagnosing this. I've already made the decision to start saving for a single turbo kit, but I would like to fix this first so I can actually drive the car and enjoy it.
Would have posted this in the 3rd gen section, but I don't know much about the turbo controls, so I figured I'd see if anyone around here can come take a look at it for me in person and explain
So here's the problem. Basically, my car boosts perfectly as long as I don't get into the secondary turbo...so I can't rev it past 4500 or so. Once the secondary kicks in, it kills the primary, so to speak. As an example, here's what an on-ramp pull feels like...
2nd Gear, full throttle: Primary boosts to 8 PSI. Pulls hard, feels normal. Secondary comes on at 4500 RPM, switches over just fine, stays at 10 PSI. Feels great, just like it should be.
3rd Gear, full throttle: Since I'm shifting, I put the clutch in and let the RPMs drop back down. When I get back on the gas, I can feel and see that it's not boosting as high as before. It's almost like I can feel it slowly slipping into less and less boost.
4th Gear, full throttle: Shift again, get back on gas, around 5000 RPM. With both turbos on, I get only 5 PSI of boost, and the car struggles to go anywhere. Feels terrible.
And every time after that, I get NO boost at all from the primary turbo. You just hear this massive whoosh noise in place of the turbo spool. My guess is the wastegate is locking open for some reason. If I let it wind out to the point where the secondary comes on, it's the same as the last run, it boosts to 5 PSI (or less, sometimes it only boosts to 3 PSI) and feels terrible. I have no clue where to even start diagnosing this. I've already made the decision to start saving for a single turbo kit, but I would like to fix this first so I can actually drive the car and enjoy it.
Would have posted this in the 3rd gen section, but I don't know much about the turbo controls, so I figured I'd see if anyone around here can come take a look at it for me in person and explain
Thread
Thread Starter
Forum
Replies
Last Post