boost problems... maybe turbo's going out?

Jdizzle659 · Jul 20, 2009

So i'm tuned at 18psi and when I go WOT in 3rd gear at 40mph my boost spikes at 20psi and instantly goes down to 16psi then to 15psi then back up to 16psi then back to 15psi and so on all the way to redline and does same thing in 4th. Car feels like it is getting slower and slower. After about 75mph right when i go into 4th there is a huge loss of power... I go from 40-75mph faster than 75mph to 85mph. Way faster. Any ideas? I have 0 knock, afrs are holding right around 12 the entire time, and while spraying co2 on stock tmic- boost air temp through 3rd gear starting at 115degrees goes down to 107 by redline and 4th gear starting at 115 goes up to 135(I know temperature is rising but 135degrees still isn't that hot... maybe the turbo is just blowing really hot air by that time making me think turbo could be going out)

coyfish · Jul 20, 2009

What tune are you running. Could be many things but it doesn't seem like your turbo is going bad. Are you running the stock bpv ?? maybe boost leak . . .

Jdizzle659 · Jul 20, 2009

coyfish said:
What tune are you running. Could be many things but it doesn't seem like your turbo is going bad. Are you running the stock bpv ?? maybe boost leak . . .

custom tune @ cobb with accessport. Stock electronic boost controller is controlling the boost. Yeah i have the stock bpv but it is a new one with only 2 to 3,000 miles on it, and wouldn't it spike really high with boost leak. thanks for the response

Jdizzle659 · Jul 20, 2009

coyfish said:
What tune are you running. Could be many things but it doesn't seem like your turbo is going bad. Are you running the stock bpv ?? maybe boost leak . . .

My guess is bad tune. what's your opinion on that one?

onelsono · Jul 20, 2009

id get rid of that stock valve and see wut happens, when i put my stock valve on one time for s**** and giggles the car felt sooo slow.. runnin forge and no problems, spikes 22 and holds 20

Jdizzle659 · Jul 20, 2009

onelsono said:
id get rid of that stock valve and see wut happens, when i put my stock valve on one time for s**** and giggles the car felt sooo slow.. runnin forge and no problems, spikes 22 and holds 20

what's your opinion on the turboxs bpv? I could get one for free right now

cpolly69 · Jul 21, 2009

sounds like you've got boost oscillation - the factory system isn't really an electronic control it's just vacuum/bleed control system with a simple solenoid - it's prob you spraying the c02 throwing the ecu for a loop - when you were tuned were you spraying? you're tuning was done with the boost being regulated at 18? which is really spiking somewhere higher and leveling out at 18? - i'd try switching to a real electronic boost control or if you can't afford that go to a regular manual boost controller and getting a tune done with that

coyfish · Jul 21, 2009

Could be a bad tune but who knows. How bout getting a datalog on here when you can?

Jdizzle659 · Jul 21, 2009

cpolly69 said:
sounds like you've got boost oscillation - the factory system isn't really an electronic control it's just vacuum/bleed control system with a simple solenoid - it's prob you spraying the c02 throwing the ecu for a loop - when you were tuned were you spraying? you're tuning was done with the boost being regulated at 18? which is really spiking somewhere higher and leveling out at 18? - i'd try switching to a real electronic boost control or if you can't afford that go to a regular manual boost controller and getting a tune done with that

When I'm not spraying co2 all the conditions remain the same except the temperatures are higher. Boost is completely uneffected. I've been having this problem for months... I just thought it was the intercooler not being able to keep up. The spray is not the problem

Jdizzle659 · Jul 21, 2009

coyfish said:
Could be a bad tune but who knows. How bout getting a datalog on here when you can?

i don't know how to put datalogs on. I've always tried. can i email it to you?

cpolly69 · Jul 21, 2009

well the k04's surgeline is 18psi -after that you are just blowing hot air - so spraying to make it cooler is a cheaper way to push it past it's limits - i'd say taking it down to 17 and tuning from there would be a good idea - if you want more boost you should get a better turbo - all i can tell from what you have said is that some factor your ecu is seeing is causing the oscillation - or you have parts physically malfunctioning (vac lines that control the boost or like you said the turbo)

cpolly69 · Jul 21, 2009

Jdizzle659 said:
i don't know how to put datalogs on. I've always tried. can i email it to you?

pm sent for posting datalogs

Jdizzle659 · Jul 21, 2009

cpolly69 said:
pm sent for posting datalogs

said error and couldn't get it. thanks though

Jdizzle659 · Jul 21, 2009

cpolly69 said:
well the k04's surgeline is 18psi -after that you are just blowing hot air - so spraying to make it cooler is a cheaper way to push it past it's limits - i'd say taking it down to 17 and tuning from there would be a good idea - if you want more boost you should get a better turbo - all i can tell from what you have said is that some factor your ecu is seeing is causing the oscillation - or you have parts physically malfunctioning (vac lines that control the boost or like you said the turbo)

i just remembered that when i used to have a manual boost controller on the hoses stretched a little to get on and the clamps don't do s***. Could that be a definite possibility?

cpolly69 · Jul 21, 2009

if those are leaking you boost would be all over the place

Jdizzle659 · Jul 21, 2009

cpolly69 said:
if those are leaking you boost would be all over the place

how bad all over the place. like 5 to 16 to 7 to 14?

onelsono · Jul 21, 2009

Jdizzle659 said:
what's your opinion on the turboxs bpv? I could get one for free right now

i havent herd problems wih turbo-xs, but ive herd alot of problems with the greddy.. any good valve is better than the stocker, forge hks turbosmart, turbo-xs all seem to be good, synapps is prob the best vta vlave our for the speeds, runs perfect thats if u want a vta

MSMS3 · Jul 21, 2009

onelsono said:
i havent herd problems wih turbo-xs, but ive herd alot of problems with the greddy.. any good valve is better than the stocker, forge hks turbosmart, turbo-xs all seem to be good, synapps is prob the best vta vlave our for the speeds, runs perfect thats if u want a vta

Respectfully disagree. I'm running stock BPV with catless DP/RP and CAI for more than a year and it holds boost beautifully. But if I were to consider an aftermarket BPV, it would be the Turbosmart pure BPV. I am on stock tune and not trying to push boost above stock level, though. If I can hit 0-100 mph in 11.5 seconds and run the quarter in 13.4 -13.5 (which I do), I have no reason to go around crapping on stock BPV's.

Cpolly's advice to OP is right on target, though, especially taking boost back to about 17 psi. Look for boost leak somewhere. Post the datalogs. I don't think this has anything to do with the turbo mechanically.

coyfish · Jul 21, 2009

MSMS3 said:
Respectfully disagree. I'm running stock BPV with catless DP/RP and CAI for more than a year and it holds boost beautifully. But if I were to consider an aftermarket BPV, it would be the Turbosmart pure BPV. I am on stock tune and not trying to push boost above stock level, though. If I can hit 0-100 mph in 11.5 seconds and run the quarter in 13.4 -13.5 (which I do), I have no reason to go around crapping on stock BPV's.

Cpolly's advice to OP is right on target, though, especially taking boost back to about 17 psi. Look for boost leak somewhere. Post the datalogs. I don't think this has anything to do with the turbo mechanically.

Nothing to disagree about. The stocker is a piece of plastic. Some hold boost fine while others leak practically brand new. Nothing wrong with the valve but it is plastic (cheaper) and may leak. I installed a forge on my practically brand new car and i held 2 psi higher consistantly. Some stockers are fine and others leak but its obvious that most aftermarket bpv's are superior quality and won't leak.

Jdizzle659 · Jul 21, 2009

MSMS3 said:
Respectfully disagree. I'm running stock BPV with catless DP/RP and CAI for more than a year and it holds boost beautifully. But if I were to consider an aftermarket BPV, it would be the Turbosmart pure BPV. I am on stock tune and not trying to push boost above stock level, though. If I can hit 0-100 mph in 11.5 seconds and run the quarter in 13.4 -13.5 (which I do), I have no reason to go around crapping on stock BPV's.

Cpolly's advice to OP is right on target, though, especially taking boost back to about 17 psi. Look for boost leak somewhere. Post the datalogs. I don't think this has anything to do with the turbo mechanically.

i don't know how to post datalogs.... i've tried many times. I don't have money for retune and taking it back to 17psi, but what about using a manual one to force it to 17psi?

boost problems... maybe turbo's going out?

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