New K04 setup help...... Low boost, N75 advise, and whinning turbo

[A4Rollin]

I have currently put in a new motor that was entirely rebuilt (AWM) and GIAC chipped K04 setup. Engine is broken in already, and the turbo has 700 miles on it.

I tuned it yesterday (since the motor needed to break in for 600 miles) and having low boost issues as well as a "whinning" turbo. The tuner also mentioned I need a new N75 valve. Ive checked for leaks and found nothing after I clamped a few hoses. Im guessing this is why im spiking at 7psi and not 20-21??
- What N75 valve should I buy for this setup and where could you point me to purchase?
- Are we now flirting with the conversation of running a N75 or bypassing to a MBC? Even tho the software should be fine and a EBC is not necessary with this setup.

As far as the whinning turbo, when full boost hits, the turbo "whines" pretty loud. Hard to explain. Ive had a K04 before and I know this is not the sound it should make.
- Could this also be caused by a faulty N75 valve?
- Or are we talking about sending back the turbo to Borg under warranty? No damage to fins, etc.

Thanks for any comments and suggestions guys!

[elpriebo]

When I first got my stage 3 setup I had low boost which was cause by the n75 valve. Check the hose both from the turbo to the n75 and to the wastegate actuator. If there's any leak in those hoses or if the n75 is bad you will run off the max boost your waste gate actuator is set to. Try running a hose directly from your turbo to the waste gate actuator. If it still runs at 7 psi then it's more then likely your n75.

[elpriebo]

And is the whine your talking about sound like a LOUD dentist drill? If so then your compressor wheel is possibly rubbing on the compressor housing which is caused by shaft play. What brand is the ko4? If you installed a cold air intake or just a cone filter in placement of the air filter box, it will definitely make the whine ALOT LOUDER which is normal! Big ass turbo diesel trucks make the same noise, but it's making an irritating dentist drill noise, then you have a problem

[elpriebo]

Sorry didn't see you said it was borg warner

[A4Rollin]

Still up in the air about what N75 would work well with a K04 setup.... J?

[A4Rollin]

Morning bump for some N75 help...

[nick91]

if i was you i would run a mbc, just bypass n75 leaving it plugged in electronically. i run this on my k03 and have 0 problems. if you dont want the mbc route run the stock h version of the n75 the race valve is crap and alot of tunes dont get along with it. (i assume you have a boost guage) tweak the mbc little by little till you get the desired boost you plan on running