I was previously tuned with a gt35r on the stock motor 400whp@27psi. Car ran fine no issues.

Now im tuned for a gt35r, 264 cams, valvesprings, and an upgraded clutch 450whp@28psi.

I seem to be getting compressor surge at low throttle, low RPMs. It sounds like an extended Blow-off valve flutter and lasts for a few seconds after letting off the throttle. The tuner said it's normal and i should drive in higher RPMs.

Is this a problem? or simply something to live with when you go big turbo

 

I've had a similar issue, but I always had cams. What bov are you using? Does it vent partially or fully to the atmosphere? What size hotside is on your turbo?

 

Using stock bpv no vta at all.. I got the valve crushed to hold more boost, i think this is my problem. Basically the spring tension is to strong at partial throttle and doesnt open quick enough which cause flutter dump not surge.. This is pretty much what I got out of the research I did. I ordered the Cobb Bpv to see if this well help solve the issue.

And it is a 3586

 

Gotcha. My car still does it, cosworth mx1 cams, turbosmart diverter valve with full recirc. and a 63 hotside. Going to a bigger hotside now to see if that eliminates it.

 

Just Updating I just got the Cobb bpv and it helped the flutter tremendously. I see hear it sometimes in fourth or fifth but not nearly as bad at all and the sound is completely controllable. I might try adjust the spring more to see if I can completely eliminate the flutter but I don't think I can 100% with my ams ram air I heard you hear the flutter through the intake. Also the cold weather change has a pretty decent impact on the fluttering aswell.

 

Mine does it primarily in 4th and 5th as well. What AR hotside do you have?

 

http://www.atpturbo.com/mm5/merchant...gory_Code=VEVO

Here is all the info on the turbo I have. I really wish I could figure a way to 100% eliminate the sound

 

"Turbine Housing A/R 0.94 or 0.73 "

Not sure which one you got?

 

This is BOV flutter, not compressor surge.

 

Is their anyway to completely eliminate this? I can loosen the spring on my valve more but I don't want to go to loose on the spring. It only does it in high gears which I heaR tends to happen with the bov flutter

 

There are a variety of things than can contribute to this. I would loosen up the diverter as far as you can as long as it doesnt compromise holding your boost pressure. Quickest and easiest thing you can do to potentially get rid of it.

 

Thanks for such quick responses I will try loosening the spring more the sound is pretty much gone i guess it's trial error from here

 

Let me know what you results are when you get done... I'm curious.

 

Well i just blew a rod the other day. Gotta love dealing with this cars back with the tuner i need a new block