[NA3Turbo]

I've been having a problem with my Greddy kit loosing boost at higher RPM's, yet im not sure if i have a boost leak or the Starion intercooler is just not sufficient enough.

I'm currently running 15psi(hi) and 6psi(low) on a dual stage Turbo XS manual boost controller. Boost holds well at 6psi up until redline, but when under load on 15, it hits 15lbs for a second or two then drops down to about 9-10 psi.

I've checked all of my hoses(which are clamped with t-bolt clamps) to the intercooler as well as the clamps on my pressure lines to the turbo,wastegate, and boost controller.

I havent ever had a problem with a BOV leaking and i dont believe my HKS is, but im sure its a possibility. Anyone have any ideas?

 

[Hammerhead]

I'm sure you've thought of this, but are you sure that you're not just spiking to 15 lbs? Its a common problem. Have you maintained a steady 15 lbs of boost prior to now?

 

[NA3Turbo]

yes, i have maintained a steady 15lbs prior to about 2 weeks ago when this started happening.

the only thing i can think of now is that

a) the intercooler is not sufficient and/or something hit it causing a crack which would lose boost pressure...
b) my boost controller is a p.o.s

 

[Hammerhead]

For myself, I am maintaining 14 lbs constant pressure @ WOT with a very obvious and whistling leak. My first guess would be the MBC.

You would more than likely hear the leak at your boost levels.

 

[NA3Turbo]

the only thing i can hear at WOT is my exhaust(open straight pipe all the way back) and intake sucking in air to the turbo.

ill try out a friends boost controller and see how his does.

i may end up just buying all brand new couplers and replace them. maybe one is cracked that i can not see.

 

[Sid]

my rx7 had similar problem at one point, it was a tiny crack in the turbo outlet coupler. it was so small that I couldnt see it untill I took the hose clamp off and saw the split. about 1/4" long and totally sealed looking when the clamp was on...

 

[urban]

alot of wastegates have problems holding high boost if they are not ment to. like your 8psi greddy wastegate,it is reaching its limits.i used a Helper Spring to help the wastegate stay closed.

 

[NA3Turbo]

where did you get your helper spring?

 

[urban]

you make one, just attach it so it helps hold the wastegate shut.