Impreza WRX STi possible turbo problem?

[mack]

Just after a bit of advice on behalf of my brother-in-law.
He's got his Subaru Impreza WRX STi advertised at the moment and has just rung asking advice about an unusual noise that's just started.
I've not listened to the car myself but,basically,he's said that there's a 'hissing' noise as soon as the turbo kicks in. He's not noticed any loss of power and the car seems to drive as normal.
Any ideas whether this could be the start of turbo problems or is it to do with dump valves,etc? (excuse my ignorance,I've had no dealings with these type of cars)
Unfortunately,I've not been able to look at it myself,as he doesn't live near me,so I'm just trying to point him in the right direction
The car is a 2004 model with 27000 miles on it.
Any help greatfully received
Thanks
mack

Edited by mack on Wednesday 30th May 03:44

[GravelBen]

I'd probably be checking pipes first of all - could be a split in an intercooler pipe or something.

[mack]

Cheers Ben,I'll tell him to have a good look round there first (it's frustrating 'cos I can't see the car myself and I'm not familiar with the setup on these cars!)
I would have thought any problem would have caused a loss of power though?

Edited by mack on Wednesday 30th May 09:32

[GravelBen]

mack said:

I would have thought any problem would have caused a loss of power though?

I would think so too, but I guess if its a very small split/hole there may not actually be much air getting through it, just a small amount going fast enough to make the noise. Could be wrong but IMO its always worth checking the cheap, simple things first.

[stevieb]

mack said:

Just after a bit of advice on behalf of my brother-in-law.
He's got his Subaru Impreza WRX STi advertised at the moment and has just rung asking advice about an unusual noise that's just started.
I've not listened to the car myself but,basically,he's said that there's a 'hissing' noise as soon as the turbo kicks in. He's not noticed any loss of power and the car seems to drive as normal.
Any ideas whether this could be the start of turbo problems or is it to do with dump valves,etc? (excuse my ignorance,I've had no dealings with these type of cars)
Unfortunately,I've not been able to look at it myself,as he doesn't live near me,so I'm just trying to point him in the right direction
The car is a 2004 model with 27000 miles on it.
Any help greatfully received
Thanks
mack

Edited by mack on Wednesday 30th May 03:44

I have had the same problem on my 2004 WRX done 50k miles. I had a hissing sound and then when revs pickup to 4000rpm it stopped. it was caused by the OEM dumpvalve not closing fully. I endedup removing it for a spare i got hold of and it solved the problem but a general clean should solve it.

If not it could be a split hose somewhere. could be any part of the induction system from intercooler, pips that connect it to the airbox etc.

[mack]

Thanks for the replies.
Yeah,I thought it could possibly be dump valve related, but,I'll get him to check all the pipework over as well

[MrFlibbles]

Has it got one of those dodgy manual bleed valves?