SOHC_MShue

Hey guys i'm having trouble with my turbo sustaining the amount of boost i'd like. I'm running a wrx internally wastegated turbo on my y8. I have the turboxs boost controller turned up to 8psi, but after about 5000-5500rpms it will drop down to 6psi. The only reason i think this may be the boost controller is because i got it from my friend and coincidentally his car did the same exact thing. It would drop from 8psi to 6psi after vtec on his b18c with a saab t3 and external tial wastegate with I think a 6.5psi spring.

nonvtecD

Those WRX turbos are small aren't they, maybe it can't sustain power up top?

MachAF

on a stock wrx the boost bleeds off in the high rpms. turbo it really small.

J337_UNIT

its possible it couldbe the turbo but i doubt it... there have been many cases where a MBC causes boost to fluctuate along the rpm band

91civicDXdude

bypass the MBC and see if it still does it

ShaunRR

Subaru does use fairly small turbos to counteract the turbo lag inherent to a single turbo system running off of two cylinder banks.

EKB18BPR3

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91civicDXdude &raquo;</TD></TR><TR><TD CLASS="quote">bypass the MBC and see if it still does it</TD></TR></TABLE>

im always trying to learn (on honda-tech)...what is MBC? thanx!

ShaunRR

I think its Manual Boost Controller. Refers to ones like the gated type.

SOHC_MShue

well if I bypassed the mbc then it would just run 5 or 6 psi and stay there. Thats what it did before i put the boost controller on. I'm more leaning towards the fact that my internal wastegate is cracked open even when i'm not under boost because my spool up time is extremely slow. I'm having a shitload of trouble mounting the wastegate actuator...espescially because of how I had to have the turbo clocked and the fact that one of the mounting holes on the turbo is stripped.

95GSRTT

so w/o the boost controller your boost goes down about 3 psi? I just tried that out today with my car. Gave my boost controller to a buddy since I was going to install my profec b, and so I just put the compressor inlet to the wastegate. Lost about 2 psi that way. Makes me think the boost controller was taking a crap and leaking.

sporkcrx

I'm not sure with turbo's, but I know with chargers when vtec hits the boost drops. If it does the same for turbos then that would explain your buddies problem, and it might even do the same thing on your sohc (if it's vtec)

But again, I'm not positive this happens with turbos.

SOHC_MShue

yea i'm running a d16y8 so it has vtec.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95GSRTT &raquo;</TD></TR><TR><TD CLASS="quote">so w/o the boost controller your boost goes down about 3 psi? I just tried that out today with my car. Gave my boost controller to a buddy since I was going to install my profec b, and so I just put the compressor inlet to the wastegate. Lost about 2 psi that way. Makes me think the boost controller was taking a crap and leaking.</TD></TR></TABLE>

without the boost controller it just stays at 6psi where it should be. with the boost controller set at 8 it drops down to 5.5 or 6psi after vtec.

bsixteen

my friend his wrx is having the same problem. his boost would drop at higher rpms. i don't know many wrx owners nor am i on a wrx forum so i don't know how consistant this is. good luck.

95GSRTT

sounds like the boost controller is leaking. Go make a home depot one and then try it out.

SOHC_MShue

well i don't think its the turbo itself because while fiddling around with the wastegate I accidentally set it so that it would run like 13psi. When it did this the boost didn't drop at all and it would just shoot on up.

SOHC_MShue

bump anybody else had trouble with a turboxs boost controller not working?

SOHC_MShue

alright well now i'm positive its the wastegate sticking open prematurely. I removed the vacuum line from my wastegate actuator so it wouldn't regulate my boost at all. It still only boosted 6-7 psi so i know what it is now.