Birdley42008

Also I am getting the sewing machine whine associated with compressor surge, the bov will relieve pressure but the turbo will still surge? I am thinking of taking that kids advice and taking out the damn spring.

B16Drag

Time to buy the real deal... HMT style!

Another thing is where is mounted on your charge pipe, aka how close to the turbo/intercooler...

WTF

basicly you need to rig the spring so that if you watch your valve while idle, it should open slightly running and shut as soon as you open the throttle a little

after i cut 2 coils out of the spring that came with mine it would open to easy, then i shimmed it a little by packing tinfoin in around the base, then it worked perfect with my holset @ 20psi

i cut my spring and welded it back together so it looked almost like it was never cut besides the blob of weld, i didnt want it to bind so i wanted to keep the flat top and bottom, theres even a picture of the spring in my bmw turbo thread somewhere here

Birdley42008

Yeah, that is how my bov seemed to function

Birdley42008

Same post under sponsor area:
BOV is operational, spring had to be cut, I still get a whine from compressor surge in 3rd and 4th and 5th gear as soon as I hit 10psi and past it. Whine is loudest in 3rd gear @ 14psi.

Any Ideas?

Would the addition of an elbow and a filter cause the whine?

Scott-EP

If your foot is in the throttle, then that's not compressor surge. Compressor surge is when the pressurized air has no where to go, so it stops the turbo from spinning

Birdley42008

Wrong, that is what a lot of people assume. Honest to god compressor surge will occur under load aswell as when letting off.

Here is the greatest two examples, of compressor surge under load. And no my turbo has zero shaft play and was brand new.


http://uk.youtube.com/watch?v=nCj6Spwl1CU Skyline Compressor Surge Underload

Mine is no where near that I just get alittle whine past 10psi.

http://www.youtube.com/watch?v=RIC4MOq5w9s Grand National Compressor Surge Underload again.

Again mine is no where near this one either.

It just goes to show true compressor surge can happen under load while in boost.

Scott-EP

That's from pushing the turbo too far. At 10-15 psi I doubt you are maxing out any turbo. If you are getting that, my BOV isn't your problem.

Your problem could be a restrictive filter. Have you tried running it without one?

Birdley42008

Oh I know your bov is operating 100% now and I have no problems with it anymore.

Im just trouble shooting the surge.

Scott-EP

oh, try running it without a filter. i had that problem once. it was very similar