Scotsman

iTrader: (3)

Hi chaps

I posted a while back about a problem with a screaming noise coming from the engine when on high boost map (nothing on low map).

https://www.scoobynet.com/general-te...ise-track.html

and

https://www.scoobynet.com/general-te...hen-boost.html

We thought it was down to the blades in the turbo touching the casing when on the higher boost, but we've swapped the turbo out and the noise is still there

We though it might be the back box as with the back window open it sort of sounded like it could be coming from the back - though with the windows up it sounds like it's coming from behind the dash.

We've swapped the backbox over too and the noise is still there. I'm running a straight through centre pipe and a prodrive sports-cat downpipe.

We're now thinking that it could be the up-pipe - it's an Sti cat-less up-pipe and perhaps something has been dislodged/bent within it during the session at Knockhill (when this started) - and that perhaps something inside is causing the noise/vibration (a bit like holding a piece of beach grass between your thumbs and blowing on it). Could that be a possible?

Numpty question, but when on a higher boost, does that increase in pressure continue through the entire system - i.e. when exiting through the exhaust manifold and up-pipe?



As I said, on low map the noise doesn't happen (duel ecutek map by AndyF) - it only happens when on the higher map (more pressure?) and at full throttle.

Any other thoughts on what it could be?

Cheers
Richard.

e6tony

iTrader: (1)

it sounds like a gasket or pipe letting go under high pressure there mate,goodluck finding it though!!

i had a similar problem which turned out to be a very slight blow from the up-pipe gasket under high boost!!

hope this helps

Scotsman

iTrader: (3)

Thanks Tony - I agree, it really has proved to be a pain to find the source.

The Sti up-pipe has a heat shield so we can't get a good look from the outside - but I think if the pipe was cracked then it would blow even under the low map boost. I've got the car booked in for a couple weeks time, when they are taking the up-pipe out and having a good look inside - also replace the gaskets at the same time. It really is such a loud noise though - everyone who's heard it thinks it's the turbo blades touching metal - but we know it's not now.

I'm tempted to put it on a rolling road next, so we can perhaps trace the noise when the car is on full boost/throttle.

Cheers
Richard.

Scotsman

iTrader: (3)

Ended up being a knackered gasket before the up-pipe. All quiet now