I have a weird issue that's popped up on my 08 SS (GM tune, 5-speed). When I'm in first gear, at around 2000RPMs, and have a light load on the engine and back off quickly, I'll get compressor surge. It doesn't happen any other time, I have no check engine lights, and it's runs fine otherwise. If you accelerate harder in first it doesn't do it, and if you shift below 2 grand it doesn't do it, just at that magical number, which also happens to be about where you let off when you're pulling forward in slow-moving traffic.

I hooked a vacuum pump up to the bypass valve hose and it's working fine, I checked the vacuum reservoir and it's fine, and just for fun I also bypassed the vacuum reservoir and it ran the same. It idles fine at 20inHg and builds 20psi, so I don't think it's a vaccuum leak.

I'm thinking maybe the bypass valve (the part near the red circle):


Any help would be greatly appreciated. Thanks, Ian

 

It could very well be the bypass valve at fault, only one way to fully test that theory is to replace the valve,
Or you could vacuum test the ports if you have a vacuum test gauge and ensure those spring clamps are still tight

 

Also...That engine is way too clean.

 

A nice Husky 3/8 ratchet, there !

 

TOTALLY NORMAL.... No problems....Seriously. Your hearing flutter, that is ONLY a problem when it happens at full boost.

 

I wish my engine bay was that clean! Mine looks pretty nice but nothing like that, that's just a picture I found on the Googles.

Anyway, I replaced the valve and it seems to be better, though I can still hear it happen every once in a while. I never noticed it until after I ran some Seafoam through the vacuum port (yellow circle in the above picture) about two months ago. Though, this was probably the third or fourth time I've Seafoamed and it never affected anything before.

I'm probably just being paranoid. Maybe a Trifecta tune will solve my problem?

 

Good way to justify a tune!!