DDP

Just like the title says there is a fluttering sound on boost. It seems that the car hesitates a little during this flutter. Sometimes its there, sometimes it isn't. It's at both part throttle and WOT. I thought it could have been a torn divertor valve and I replaced that. Didn't change a thing. Please don't tell me turbo...

Eyal 951

its the turbo. compressor surge.
EDIT: under boost, not shift? don't ask me!

DDP

On boost. Not during shifting.

Tom M'Guinn

Check your I/C pipe connections -- when they get loose, they can let boost out, causing funny noises and an overly-rich hesitation.

DDP

Will do, thanks Tom.

When it is the acutual turbo having problems, they are silent correct? Even when a turbo is on the verge of throwing itself apart it doesn't make a sound. Is this correct?

shortyboy

bad cycling valve, or blow off valve?

Skunk Workz

You can have surge under boost....if it's a badly matched or dying one. Then it runs smoothly at first when you floor it and the boost builds,then hesitates/stutters as the rpm rises ,and then back to smooth again at high rpm... Most turbo's I've heard on the brink of imminent brutal death gives off a high-pitched whine,much louder/higher pitch than the normal whistle most turbos give off...

jimbo1111

Make sure that your not running lean. When the mixture leans out the turbo sound winey and sputters at part throttle. This could also be a bad tps.

mroberts

Are you losing boost ?

I got funny noises when my recirc valve hose was loose and it was blowing off around the clamp.

Do you have an A/F gauge ?

sweanders

That is usually a "whoosching" noise, seen it many times while dynoing 951's where the intercooler pipes are not on tight enough.

DDP

Well it is not the divertor valve as I have replaced that. It is also not an intake leak. I think it may be running lean. I set the boost on the car when it had exhaust leaks and now I have fixed those leaks so its gotta be running lean. I'll slap a boost gauge in there and see whats its running. Thanks.