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Old 04-09-2006, 12:52 PM   #1
06EvoKiller
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Member#: 99550
Join Date: Oct 2005
Chapter/Region: South East
Location: St. Peterburg ,FL
Vehicle:
2006 2.5L wrx gt35r

Default Having trouble raising boost...

The car is a 2.5L wrx with a cat-less 3inch turbo back exhaust and an intake.

We put the cobb stage 2 reflash on the car with the accessport and the car would only peak 13psi and fall off to 9 psi.

Last night we unplugged the stock boost control solenoid, and hooked up a Hallman manual boost controller. No matter how much we turn the boost controller up, the car will peak at 15-16psi, and fall off to 10-11psi.

We put a wideband on the car and its hitting a high of 10.3:1 and falling off to 9.9:1 and maybe lower, im not sure if the innovative even reads that low. These wideband numbers were pulled with the boost controller turned all the way up. (15-16psi falling off to 11-10psi)

The owner put an aftermarket blow off valve on the car and sold his stock one, then later got rid of the aftermarket BOV to a person with a 2002 wrx and put the stock 2002 bov on the car. and thats what it has now.

My question is...do the stock 2002 BOV's on these cars leak badly? Could our reason for not being able to up the boost be that the bov is leaking all the boost out? Or is there some other reason, like some sort of electrical/ecu crap that is limiting it.

remember the stock boost control solenoid is no longer connected to the wastegate. and we did a boost leak check that showed no leaks.

all boost figures were read straight off the accessport display

I could try to shorten the wastegate arm or some other solutions but it seems like those are just bandaids to a problem i want to fix the correct way.
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Last edited by 06EvoKiller; 04-09-2006 at 02:06 PM.
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Old 04-09-2006, 02:31 PM   #2
Payback
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Member#: 41328
Join Date: Aug 2003
Chapter/Region: SWIC
Location: Tucson, AZ
Vehicle:
2003 WRX Sedan
SOLD - 2/07

Default

Was the boost OK before the turbo-back install and Stage 2 reflash? Did you remove the intercooler for the install?

I don't know if or what the difference is in the recirc valve, but you might have a leak in the intercooler hoses somewhere. Did you make sure all the hoses are tightened down?
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Old 04-09-2006, 06:51 PM   #3
-Kevlar-
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reconnect the stock BS and try to run the HWG.
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Old 04-09-2006, 07:05 PM   #4
06EvoKiller
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Member#: 99550
Join Date: Oct 2005
Chapter/Region: South East
Location: St. Peterburg ,FL
Vehicle:
2006 2.5L wrx gt35r

Default

Quote:
Originally Posted by Payback
Was the boost OK before the turbo-back install and Stage 2 reflash? Did you remove the intercooler for the install?

I don't know if or what the difference is in the recirc valve, but you might have a leak in the intercooler hoses somewhere. Did you make sure all the hoses are tightened down?
the car did not have a boost gauge before this. there are no leaks in the intercooler piping, we did a boost leak test. The only thing that MIGHT be leaking is if the blow off valve is being pushed open from turning the boost up, im just not sure how much boost the stock 2002 bov holds before it starts to leak. i have no clue, but i could not hear air leaking from it durring the boost leak test. The stock bov is recirculated. The intercooler was not removed.

Quote:
Originally Posted by wrxblubayou
reconnect the stock BS and try to run the HWG.
How could that make it boost more than the manual boost controller cranked all the way down. The stock BS just bleeds air off the wastegate signal back into the intake.


but anyways.... here is an update

following up on this...

we were doing all our testing pulls in 3rd gear. It looks like with the boost controller cranked all the way up, the boost acts like this...

1st gear: 12psi peak falling to 8ish
2nd gear: 13psi peak falling to 9psi
3rd gear: 16psi falling to 11psi
4th gear: 18psi peak falling to 12ish psi
5th gear:18psi falling off to 15psi

rolling into 4th gear will spike a pretty large spike of boost, and hit fuel cut. so the boost went back down to where it was spiking 16psi in 4th.

Is there an obvious reason that im overlooking as to why this is happening? or is this just how terrible the stock turbo is?

The boost controller is hooked up from the compressor cover nipple of the turbo, to the wastegate, should i take the boost source from somewhere in the intake manifold maybe? to get a more consistant pressure signal?

Cobb claims that its normal to spike then lose 4-5psi by the end of the gear, but how do you get the car to hit the same amount of boost in each gear?

Last edited by 06EvoKiller; 04-09-2006 at 07:17 PM.
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Old 04-09-2006, 07:16 PM   #5
Payback
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Join Date: Aug 2003
Chapter/Region: SWIC
Location: Tucson, AZ
Vehicle:
2003 WRX Sedan
SOLD - 2/07

Default

Stock valve is supposed to hold up to about 20. You can carefully remove the gasket, use very fine sandpaper, and sand off the flange on the intercooler and recirc valve. Best thing to do would be to replace the gasket at the same time. Mine had some kind of glue or something on the intercooler side that held it on. I wasn't experiencing what you are, but at WOT full boost in 4th and 5th, my boost would have a seizure. The needle would flutter back and forth at an amazing speed going back and forth about a psi or two. After replacing the gasket and cleaning off the surfaces, it is better, but not cured.

It also sounds like you are running very, very rich. Are the numbers above at WOT or just regular driving or the extreme between both? I would also take off the MBC. You are not hitting the right boost and that's a problem. But adding a MBC to counteract that is not the best idea. Give Cobb a call first thing in the morning. They can help you try to find the root cause so you can fix that. I've had good experiences when calling them.
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Old 04-09-2006, 07:22 PM   #6
06EvoKiller
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Member#: 99550
Join Date: Oct 2005
Chapter/Region: South East
Location: St. Peterburg ,FL
Vehicle:
2006 2.5L wrx gt35r

Default

Quote:
Originally Posted by Payback
Stock valve is supposed to hold up to about 20. You can carefully remove the gasket, use very fine sandpaper, and sand off the flange on the intercooler and recirc valve. Best thing to do would be to replace the gasket at the same time. Mine had some kind of glue or something on the intercooler side that held it on. I wasn't experiencing what you are, but at WOT full boost in 4th and 5th, my boost would have a seizure. The needle would flutter back and forth at an amazing speed going back and forth about a psi or two. After replacing the gasket and cleaning off the surfaces, it is better, but not cured.

It also sounds like you are running very, very rich. Are the numbers above at WOT or just regular driving or the extreme between both? I would also take off the MBC. You are not hitting the right boost and that's a problem. But adding a MBC to counteract that is not the best idea. Give Cobb a call first thing in the morning. They can help you try to find the root cause so you can fix that. I've had good experiences when calling them.
when i say the bov might be leaking, i dont mean from around the flange, i mean that it might be getting pushed open, as in the pressure from inside the pipe is greater than the pressure keeping the bov closed, and it opens and leaks boost out through the recirc tube. i know there are no leaks at the flange area because we did a boost leak test. im not certain there is any leak at all anymore to tell you the truth. nothing was found in the boost leak test.

the car is rediculously rich! 10.3 dropping to 9.9? thats rediculous. that was at WOT. The reason we put the MBC on is because the cobb reflash was not boosting high enough, there were no leaks, and the wideband said super rich.

I will call cobb in the morning.
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Old 04-09-2006, 08:46 PM   #7
Payback
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Member#: 41328
Join Date: Aug 2003
Chapter/Region: SWIC
Location: Tucson, AZ
Vehicle:
2003 WRX Sedan
SOLD - 2/07

Default

Sorry I couldn't be more help. Good luck and let us know how it turns out.
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Old 04-11-2006, 11:49 AM   #8
-Kevlar-
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Default

what psi are you trying to see??
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