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car wont boost past 16 psi

I've done a boost leak test already b/c that was my first thought of what could be wrong. No leaks anywhere. I tried two differt boost controllers and i can't get the boost past 16 psi.
any thoughts are greatly welcome.


Thanks:
TJ
 

Does the boost come on more slowly than before? I'm thinking pre-turbo exhaust leak.
 

Diego

Well-known member
Joined
Dec 9, 2007
Messages
2,132
Location
In a van down by the river, Iowa
Did it ever boost past 16psi......

Does it cut out trying to get to 16?

Is your fuel pump rewired......?
Octane your running? Chipped to compensate, if so?
 

by saying it's not boosting past 16, do you mean it hesitates and misfires after 16psi, or it physically doesn't boost more than 16psi? if it's the latter, then i'm also thinking exhaust leak or your turbo is toast /ubbthreads/images/graemlins/ooo.gif
 

NickDromez

Well-known member
Joined
Jul 2, 2010
Messages
165
Location
Berkeley, CA
does your wastegate allow you to go above 16psi?
 

H05TYL

Well-known member
Joined
Jun 9, 2007
Messages
752
Location
Wgtn, NZ
I'm going to go against the grain and say, stock bov leaking
 

The car runs perfect, it runs just like a car that's boosting 16 psi.

mods that might make a difference:
small 16g
dsm link v3
550 injectors
hks bov
97 octane

I've tried a perrin bc and a turbo xs both have the same results so i'm fairly certain that it's not the bc.
 

On my car, my turbo xs BC was cranked shut at 15 psi, aem tru boost and I can run 30 or better. I don't have any experience with a Perrin bc though...
 

RedTwo

Well-known member
Joined
Jul 16, 2008
Messages
1,917
Location
New Zealand
The turbo should just keep pumping up the pressure until it hits a release (wastegate or engine becoming atmospheric /ubbthreads/images/graemlins/banghead.gif)
I can only think of 3 sources for it not working propperly:

A) Boost controllers were both installed backwards - very unlikely.
B) Exhaust leak around one or both head/manifold/turbo connection.
C) Crack(s) in the turbo exhaust housing or in the manifold.

a) is unlikely, but if you pull off the vaccuum hose and see if it will free boost it will solve options b & c without havnig to remove anyhting
 

vtecds1

Well-known member
Joined
Jan 16, 2004
Messages
1,705
Location
Las Begas
My manifold had a couple of hairline cracks and it would take forever to spool. I would double check how your boost controller was installed. When I first got my Profec B, it kept boosting to 28lbs and I couldn't figure out why. Then I realized that I had it installed wrong.
 

I installed the perrin BC both ways just to make sure I wasn't being retarded but still nothing more than 16psi.
 

RedTwo

Well-known member
Joined
Jul 16, 2008
Messages
1,917
Location
New Zealand
If there are cracks on the top side, the manifold is probably cracked on the underside. What kind of engine speed do you hit 16psi?
 

mitsuturbo

Well-known member
Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
Quoting H05TYL:
I'm going to go against the grain and say, stock bov leaking


This is a definite possibility. You should do a bewst leek test.

Alternatively, try disconnecting all boost sources from wastegate.. see if it will go over 16psi then. (be careful, of course)
 

speedyvr4

Well-known member
Joined
Jan 1, 2006
Messages
1,245
Location
miami, fl
Mine had the same problem and it turned out to be a nice sized crack around th wastegate flapper. at first it would boost fine for a couple months, then it started getting laggier and laggier.pulled the 02 housing and saw the crack. threw a another small 1g in it and bye bye lag.
 

belize1334

Well-known member
Joined
Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
Just disconnect the wg line entirely. That will simulate MAX boost from any mbc. Roll on the throttle and see if it's any better. But be CAREFUL. If it spikes to 30 you'll wish it hadn't.
 

So i finally figured it out. The line to the boost gauge had a hole in it. When I bought this car I had to do so much crap to it b/c the guy I got it from did some really stupid stuff. Now I finally get around to raising the boost and it wont go up. Go figure, one of the things I didn't check on the car and that's the problem.

Thanks for all the help guys:
TJ
 
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