The fuel controller is a haltech. I have been running the car sequential but decided to make some changes in how things where hooked up, mostly to bring the solenoids out from under the UIM, in any case I ran into things I wanted to do but didn't have parts on hand for and just hooked it up with "poor mans NS" for the time being so I can drive it.

Now its making a real loud high pitched whirring noise under boost. It sounds like a supercharger on steroids, its real dam loud. It's still boosting the same and feels very powerful but this sound is getting to me.

Its louder with more boost, more throttle and more RPM, non existant when boost is not present.

Any idea's

 

Make sure your y-pipe is tightly secured, as a loose bolt would create a place for pressured air to escape and it will sound like a whistling effect. This can be found real easily especially if your twins are blowing a little oil, as it will be smudged around that area. Also check all gaskets and IC pipe connectors as well. If you took off the LIM/TB check these places as well. The metal gasket likes to be loud if its not secure enough.

Had this issue on the y-pipe my self a while back.

 

He wouldn't be boosting normally if that was the case...

 

Does it sound like a metallic noise at all? If so then I would guess shaft play with a compressor wheel rubbing inside the housing. Its easy enough to check if you get the noise every time you boost, the rear turbo is the primary and its very simple to pull the intake pipe off the back of it.

 

The front turbo is the primary.....

 

I've had turbo's with a **** load of shaft play before that where rubbing the housings, they didn't build **** for boost.

 

in some cases that is not true. you might see a slight change in vacuum or startup idol every once in a while, but that could be all. b-leak is not always noticable.

+1 checking gaskets, i believe that could be the route cause.

 

Oops

 

it apparently was a bad check valve, I was somewhat hasty in how I set it to the "poor mans NS" and I left a check valve. If I just blow on it it seems to be fine, but blow through it with anything more than a few PSI and it wistles like one of those coaches wistles

 

You know that I knew that you knew better and just brain farted......too busy peeing in the pool ?

 

Mine did the same, it was a cracked manifold.

 

EfiniR11,

As i stated i had the same problem, normal boost and vac. But under boost you would have the whistle sound. This was apparent because of the extra pressure within the pipes. Its not a major boost leak where you say have a hole in a coupler, but one where just a small amount of air can escape and the metal gasket acts like a wrethe similar to a woodwind instrument.

 

Back from the dead.

I'm experiencing this very problem and I have replaced all the check valves and vac lines and the noise is still there!

Which gaskests in particular should I be paying attention too and how do I check for leaks?

 

+1 i can hear air rushing from the driver side

car is set for 9psi but wont go pass 0.4bar