5psi Boost??

[Spooled85gn]

Houston, we have a problem. After converting to 87 setup the car runs superb, except for the fact that max boost is 5psi. We've checked vacuum lines, everything was correct. Checked for vacuum/boost leaks, nothing. Here's a list of things done, or upgraded.
Comp Cam/Valve springs/Timing chain set
Chromeoly pushrods
Chromeoly piston rings
1" upper plenum spacer plate
009 Injectors
Walbro 340
EGR tower removed, and plugged
Heads slightly ported
Intake slightly ported
MAF Translator
LT1 3" maf
Underdrive pulleys (crank, alt)
AC delete pulley
Stock head gaskets w/head studs
stock headers/crossover
exhaust housing has 2.5" header collector welded in for fender well dump..

What could possibly be wrong?????

 

[TurboDave]

Last time I had a problem like that, it was a loose hose clamp on one of the intercooler hoses somewherre between the turbo and the throttle body.

Just forgot to tighten it.

If there were a faulty hookup on the boost lines from the turbo to the wastegate actuator, it would manifest its self in one of two ways. Either boost at the base spring rate (10-12#), or overboost like crazy.

 

[jshilli1]

Boost Guage?

Are you using an aftermarket boost guage or the stock guage ?

 

[Spooled85gn]

Autometer Ultra lite 2" 30lb vac/20 lb boost

 

[azgn]

ASSume you have the wastegate actuator arm hooked up to the downpipe (wastegate)?

 

[Spooled85gn]

Yes, and I even drove the thing up to ANS. He saw nothing wrong with a visual inspection.. Though he didnt get too involved..

 

[Spooled85gn]

This is so weird ANS looked at Vacuum routing and said its fine.. All IC piping looked good. We swapped out intercoolers last night. And true'd up the Exhaust housing. Figured maybe some rust pitting could be problematic for this problem.. maybe now the puck will be more square to the exhaust housing.. this is too weird.. I know the car's capable of low 12's but not on 5psi.

 

[azgn]

pull the downpipe and make sure the wastegate is covering the hole or just wire the wastegate shut and try it (don't get carried away if the boost takes off......)

 

[Spooled85gn]

I have a Fenderwell dump mod'd stock exhaust housing on there until I figure this thing out.. That way I can see whats going on.. Though I cant get too close to this for the unburned fuel that flames out on decel. It looks to be covering it just fine. Answer me this though, how perfect must it close off? It looks perfect now, but Im just curious if this could be the problem.. There was rust pitting on that surface so we took it to the belt sander. From what I found out by asking around thats the best way to take care of it quickly..

 

[strikeeagle]

Too much fuel.

Exhaust leaks before the turbo.

Wastegate not sealing.

Screwed up controls.

Weak wastegate actuator.

Dinged turbo.

Probably one or more of those.

But which???

 

[Spooled85gn]

WE HAVE LIFT OFF!!!!!!!!!!!!!!!!!!!!!
WELL IT WAS ONE OF 3 THINGS
NOT COMPLETELY FLUSH WGATE PUCK
THE LINE TO THE BOOST SOLENOID ON THE INCORRECT NIPPLE
BAD INTERCOOLER

THIS IS ONE OF THE WORLDS GREATEST SECRETS AND NO ONE WILL KNOW.. BUT WE'RE ALL GIDDY ON THIS END.. 15PSI AND IT BURNS THE TIRES 60FT OUT..... GD!!!!

 

[Spooled85gn]

THANKS TO ALL WHO REPLIED WITH GREAT IDEAS. YOU GUYS ROCK.. THIS HAS BEEN ANOTHER SUCCESSFUL BUICK TECH FIX...