I have a high frequent sound from my secondary turbo at boost above 3500rpm.
I have checked the pipes from the y-pipe to the intercooler, and no metal chips or that much oil. I guess the turbo is ok, and I therefore think it's a leak somewhere. A bad seal at the air inlet side, maybe?

The boost sound is normal below 3500 rpm when the primary turbo is boosting alone.
Boost levels are fine through the whole rev band.

Any suggestions?

 

Have you checked the couplers to verify if there are any small splits? The one at the Y-pipe to the crossover pipe always seems to get oily and eventually split and leak boost. Also check that the crossover pipe isn't split. Take it off and examine the underside. Over time and heat cycles, the plastic crossover pipe can split.

If running the stock intercooler, remove it and inspect the bottom inlet of the IC and the inlet piping. Those break over time and heat cycles as well.

 

Thanks for the reply!

I have a v-mount.
Gonna check the couplers and the crossover pipe.

 

Check the hard secondary intake pipe going down to the rear turbo inlet. I recently had a faint whistle sound and discovered one of the two 10mm nuts a little loose. There is also a gasket there.
Nice looking engine bay BTW.

 

I have checked the crossover pipe, the hard pipe to the secondary turbo, and everything seems ok. The nut on the secondary turbo's compression side is still there.



Here's a video clip of the bad sound.
http://macen.nullnet.com/film/bad_no...dary_turbo.avi (13MB)

 

Hm, when I take a look at my picture of the hard pipe connected to the turbo, I can see that the 10mm nut holding the y-pipe looks loose. What do you guys think?

 

Problem solved. It was indeed a loose nut on the y-pipe to the secondary turbo. :-)

 

I want to thank the op for this. It helped me with the same problem.

 

I'm glad to hear that. The new nuts are still there after I put som loctite on them.

 

you should have told me Calvin. I had the same problem about 6 months ago. All is good now