Odd boost behavior on modified WRX
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Odd boost behavior on modified WRX
Hello all,
I'm trying to help a friend diagnose some problems on his WRX. He bought it already modified and doesn't know much about modified turbo cars so he needs some serious help. I know a little about turbocharged cars but not too much specifically geared towards WRX's!
Anyway, he's got a Blitz FM FMIC, VF22, full upgraded exhaust, Blitz boost controller with 3 stage boost presets (not sure on the model, SB, SD??), full upgraded IC piping and other miscellanous bits.
The problem is the boost will quickly build up to about 15psi (when it is on the stage 1 boost preset) and then quickly drop down several psi (like drop to 8-10 psi or so) then go back up. What could be causing this problem?
Any help is greatly appreciated.
thanks,
allen
I'm trying to help a friend diagnose some problems on his WRX. He bought it already modified and doesn't know much about modified turbo cars so he needs some serious help. I know a little about turbocharged cars but not too much specifically geared towards WRX's!
Anyway, he's got a Blitz FM FMIC, VF22, full upgraded exhaust, Blitz boost controller with 3 stage boost presets (not sure on the model, SB, SD??), full upgraded IC piping and other miscellanous bits.
The problem is the boost will quickly build up to about 15psi (when it is on the stage 1 boost preset) and then quickly drop down several psi (like drop to 8-10 psi or so) then go back up. What could be causing this problem?
Any help is greatly appreciated.
thanks,
allen
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sounds like there is a problem maybe with the boost controller or maybe one of the lines has a leak in it or my last guess would be to check the blowoff, anything after that im not really sure, but start with the boost controller that can make it do that
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From: Longing for my ol' white '02 WRX :(
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I would check the gain settings, along with what the dropoff is from the warning/limit. If the gain is too high boost will spike quickly and then drop off. This will be especially drastic if the warning correction is too large and you get, I'd guess, a rapid surging sensation.
On my Blitz Spec-R the gain is 18, and I use a set around 50, warning of 110kPa and a small drop of about 2 set points. This keeps boost from spiking quickly past 110, but when I do hit 110 it backs off slowly to resist surging.
jason
On my Blitz Spec-R the gain is 18, and I use a set around 50, warning of 110kPa and a small drop of about 2 set points. This keeps boost from spiking quickly past 110, but when I do hit 110 it backs off slowly to resist surging.
jason
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Jason,
Thanks for the reply, I think your on to something. Can you explain to me the "gain" function. What actually does it control and how can it make the boost "spike quickly". He did mention that when he first bought the car it would build boost more slowly and would feel much faster while it was building up to the 15psi. Now, he says it seems to shoot up to 15 psi (or so) and not be as fast when it gets there.
Thanks again, much appreciated,
allen
Thanks for the reply, I think your on to something. Can you explain to me the "gain" function. What actually does it control and how can it make the boost "spike quickly". He did mention that when he first bought the car it would build boost more slowly and would feel much faster while it was building up to the 15psi. Now, he says it seems to shoot up to 15 psi (or so) and not be as fast when it gets there.
Thanks again, much appreciated,
allen
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