Tracing Intake Noise Rb25det

[Dale FZ1]

I'm trying to trace an odd noise happening with my RB25, noticed it over the past month occasionally.

Basically accelerating only moderate, either off-boost or 1-2psi max and an odd noise comes from the engine. Initially I put it down to the air-con cutting in, and the belt needing more tension. Checked that, same noise happens periodically.

The noise seems a bit like a sneeze and is only really audible when the windows are down. I suspected it may be a backfire (funny - it's not a violent noise or anything) but it is happening only when the car is under load, and nearly always happens accelerating away from the same intersection, heading uphill.

Any ideas where to look?

cheers

Dale

[Daniel_]

I'm not an expert or anything but it could be wastegate noise.

I find that if the car is under load but the revs are less than 3k it makes a very different noise than when above 3k.

I think this is because I still have my solenoid connected as standard so it runs lows boost until it hits about 3.5k rpm and is dumping alot of the exhaust through the wastegate instead of past the turbo.

I really should get around to rewiring the solenoid and see if the noise changes.

edit: Reread and you said off boost so I'm prob wrong but you never know

Edited January 11, 2006 by Daniel_

[Dale FZ1]

No it is definitely off-boost.

The noise really is like "CHOO" and can be felt from the driver's seat.

any other ideas?