Exhaust whistle?

[Lonicus]

Hi Guys,

Just had a new 2.75" Beaudesert exhaust fitted. I noticed that the sound was a little deeper than the stock exhaust and thought it to be normal for the 2.75".

Today though, I noticed that when I back off the accelerator there's a very distinct whistle coming from under the car, towards the front. It sounds like air being sucked in and only happens when I back off.

Could it be a leaking join in the exhaust?

Cheers

[MudRunnerTD]

It's not Spool on your turbo? Is it a different sound to that?

[Lonicus]

Not sure mate, very high pitched and only on back off.

Had a look and listen just then and can't pinpoint the sound. If I stand at the back it sounds like it's coming from the front and if I stand at the front it sounds like it's coming from the back. Possibly a little louder at the back though.

[Sir Roofy]

if its a bolt on job maybe just needs nipping up
or theres a pin hole in the welded joins
you are sure its not just turbo spool up

[Lonicus]

It may well be turbo spool up, just never noticed it before. Boost and EGT are all fine, power is good so probably just me not knowing what is normal and what's not

I'll go see the guys who did the exhaust and dyno on Monday and see what they say.

Cheers guys.

[Alitis007]

Start the car and with the help of some one block the exhaust with a rag for a few seconds, if you don't hear any fluttery noises from the exhaust gasses escaping its definitely just your turbo slowing down. Its sort of sounds like when you hum and whistle thru a tube yeh??

[threedogs]

You'll need someone to give it a slight rev while you have your head under the bonnet, only way I found my exhaust noise. mine more like a "pitchoo" sound

[ashleylipus]

definitely your turbo mate.. same thing with my rd28. because these diesels aren't fitted with any kind of blow off valve like those rice burners, the un-used boost pressure when you back off the accelerator cant go forwards so it goes backwards back threw the turbo and slows the turbine down and that noise is a byproduct of that process.

[Lonicus]

Just went and tested a couple of things, blocked the exhaust for a few secs, no sounds of leaking plenty of pressure. No whistle when backing off if there's little to zero boost. Only when boost builds is there a whistle when backing off. On very minimal boost there's a tiny whistle for a split second just before engine hits idle speed.

So, good call and thanks guys, looks like it's just turbo whistle and I now know what that sounds like

Cheers

[threedogs]

Now if you'll have a guide to exhaust noise, drive by guages and keep ears open, my new exhaust cracked at auto trans mount{common} and right behind the turbo