ok so I've got this fluttering/rattling/whistle noise that's becoming a real mystery and a pain in the ****. 99% sure its not a boost leak. (Car is stock standard other than powerFC)

We thought for a while it was pinging, and it sounds VERY similar to pinging, but its happening to low in the rev range (starts at about 3000rpm) and when I took 5 degrees out of the timing it still did it (and according to hitman there's no way it can ping with 5' out of the timing).

So it could be a dying Turbo - but then again its actually starting at 3000rpm, noise goes away seemingly when the turbo overlap happens then comes back on full boost with the second turbo. ie. noise happens on both turbos so unlikely to be dying turbos (since they pretty much operate independently and its not Formula 1 quality so the exact same prob couldn't happen to both turbos at exact same time).

So now we're thinking its either:

A: Control flap in the Y-Pipe
B: somewhere in the air intake
C: somewhere in the exhaust (cat converter??) .. and my gf said she could hear really loudly in her car behind, over her exhaust and radio

Anyone experience any noise like this before?

To clarify it sounds just like 'crickets' or 'cicadas' making there noise at night, but a longer drawn out version (instead of 'crick crick circk...")

Or as my mechanic said it sounds very similar to pinging but less violent than pinging.

very bloody frustrating - i'm tempted to get it on a dyno just so I can replicate the sound and listen from the outside to see where the noise is coming from exactly ...

 

bump!

anyone?

 

You might try capturing a sound bite of it to post on the forum for others to hear.

 

I had the same problem. Turned out one of my turbos was not seated correctly. Happened when I picked up my car after having a new block installed.

Mine sounded like a whistle that would start out low and get higher in pitch when I accelerated.

Hope this helps.

Super77

 

Yeah, perhaps it's a loose connection. The metal gasket can sing like a reed as the air escapes by it.

Dave

 

What is the appropriate fix for this? New gaskets? How can you diagnose which gasket? (Y-Pipe, Manifold?)

 

If its stock, then it has the stock accordian hose connectors to and from the IC. You have to sqeeze them a bunch to spot a slit in the hose, or better yet, get some aftermarket kit to replace those accordian hoses since they expand noticably with boost.

Tim

 

It's hard to believe that brand new car has "problems".

 

I'm sorry but his is clearly not the issue discussed here.

 

What is the peak knock value in the Commander? Post a log with a Datalogit logging "Advance" only. Then we can look at your timing and knock sensor curves.

 

Pics of said FD please.

 

I'll go for a drive after work and log peak knock onthe commander. Not sure how that will help locate the failing gasket/seal. I don't have the capability of logging knock / rpm or time.

 

It's even harder to mistake a 7 year old vehicle for a brand new car.

Dave

 

Well I took it as a whistling type noise that was mainly under boost. I just had a clamp come off my silicon hose going into the IC. Under boost it would make a fluttering/whistling type noise, worth a shot since we don't really know what the noise his car is making.

Tim