S40: 1998 T4 Turbo "wooshing" under Boost

[bar72]

hi all, as the title says, the T4's developed a mad whooshing like noise [sounds like a gradual wheelspin in the wet?] when turbo is on full spool [4,500rpm, foot floored].

no decrease in performance at all, i fitted a pipercross panel filter recently & removed all soundproofing from stock airbox.

is this what i'm hearing or has a leak developed?

this isn't turbo chatter that you get when you drop accelerator quick just as turbo's starting to spool with a stock airbox with the soundproofing removed [small psssht!]

it's proper loud

middle exhaust to backbox joint is leaking badly at the minute too, would you hear turbo through that?

thanks

[Baffler]

Originally Posted by bar72

removed all soundproofing from stock airbox.

There's your answer. When accelerating lightly have you noticed a little turbo whistle too?

Also, double check the rubber hoses from the wastegate actuator, recirculation valve and boost control solenoid.

[malteser]

That is what happens when you take off the sound proofing and stick a piper cross filter in mine did too. Its even worse if you stick a cone on like I've done

[bar72]

Originally Posted by Baffler

There's your answer. When accelerating lightly have you noticed a little turbo whistle too?

Also, double check the rubber hoses from the wastegate actuator, recirculation valve and boost control solenoid.

tnx Baffler, there is a whistle, quite loud, a lot louder than before i put Pipercross filter in, will give hoses a check anyways

Originally Posted by malteser

That is what happens when you take off the sound proofing and stick a piper cross filter in mine did too. Its even worse if you stick a cone on like I've done

thank fcuk for that malteser, thought the turbo was away, does sound mental now though.

thanks to both of you for clearing that up

[gmain1967]

Put a cone on and it's like Darth Vader sucking a rat through a straw, with a cold!!!

[andyv40turbo]

Ive got a light pressure turbo and a cone is going on soon.... think ill get any woosh? sure saves me pennies instead of buying a blow off valve and turning up my pressure!

[Volvoline]

Woosh is only pronounced when you suddenly let go of the throttle... At least with me.

Stock box with KN panel. 12T Turbo

[bar72]

right, i've noticed the wastegate chatter has vanished when i drop the throttle quickly now? to satisfy my curiosity, i remove the pipercross panel filter and put the stock one back in, the noise is still there now and i'm getting no chatter, i was last week, even with the soundproofing removed and the stock panel filter.

i've checked all the hoses going into the turbo and traced back and can't find no splits in them, not that are visible anyway, any ideas would be appreciated

i'll try and get a video up later of it..

[bar72]

here's the best i can do with my phone, but you can hear the air rushing out from it:

http://www.youtube.com/watch?v=laDXu8lLFIs

[malteser]

Sounds about right to me. When you take that foam out it makes that noise. Mine did the same if not more you will notice the re cirk vale much more.

Danny