When I let off the gas suddenly I get what I am guessing is the sound of the BOV opening up. I've also read here about turbo flutter but I don't know what that is. It is pretty loud and I don't like it. It happens at almost any boost PSI. I never got that sound when I was stock even at max boost of 10 PSI. Is this normal? I'm only seeing 15 PSI max boost with this Trifecta upgrade which sounds low. Do you think I should pull the BOV and see if something is damaged?

 

I am willing to bet your bypass valve is stuck...especially if you are getting noticeable flutter at low boost...it sucks that you are having so much trouble with trifecta...I am very happy with what it did to my car...and 15 psi is too low...you should easily see 20+ psi and feel the car put you in your seat at 50 MPH when you floor it.

pull the bypass valve and reseat the spring and boot

there is some pictures in my "how to replace bpv spring" how to..
https://www.chevyhhr.net/forums/how-tutorial-library-21/how-bypass-valve-spring-replacement-43763/

 

Thanks Badass. So that is flutter I am hearing? I'll look into the BOV later today. I'm also fighting a P2227 code. Hopefully I will hear something back from Trifecta on Tuesday about that. In hindsight, with only 40K on the car, the factory turbo upgrade would have been smarter. Then all these issues popping up would have been the dealers problem, not mine.

 

Unfortunately the boot wasn't stuck and the spring looked fine. I was hoping that was the smoking gun. I'm going to order a spring set like I've seen here. Maybe this spring is just worn out.

 

If you've got the money, just buy the forge bypass valve...I paid $100 used on the cobalt forum...I think they are around $150 or so new....they are all aluminum or stainless(can't remember which). they completely eliminate the rubber boot....

And the code is related to the bypass valve being stuck if I remember correctly

 

And the flutter is air going back through the turbo instead of out the bpv...that's probably where the code is coming from

 

Forge part# is FMDVK04S.

Got mine April 2012 from Modern Performance Racing Products.
$110 new plus shipping.
No problems and no codes with it.

 

You must have bought it a while ago. I ordered just ordered mine but found it was $144 plus shipping

 

Good advice. Just ordered one today.

 

I installed the Forge Bypass Valve. Sorry to say there was no change.