boosting problem...tricky one

[santa]

well heres the deal my friend has a 92 6 bolt he has a rewired pump 3inch apex-i exhaust and a 02 dump and the new cast slow-boy exhaust manifold the turbo has some slight shaft play. and a turbo xs 1 stage boost controller...has new plugs wires coil pack ....well it will not boost over 10psi no matter what.... mike (raptor) at qpr thought it might have been a broken spring in the acuator so I put my acuator on and nothing changed mine is fine... there are absolutly no boost leaks and idk it started ever since he put the 02 dump on.... but the thing is if you boost above 4000rpm. it will creep slowly up to 14psi but thats it...the exhaust housing has no cracks the flapper is intackt and working right. all I can think of is possibly that the 02 dump pipe itself is not large enough but even that doesnt really add up eather... so any bright Ideas would be great so the kids car can feel quick again. ohh its a 14b also btw.

thanks
Kevin

 

[2.4 turbo Hyped]

If the turbo has shaft play it could be "refusing" to spin any faster at that point because the oil is being sheared off of the propeller shaft inside the turbo. Im abusive to vehicles that dont cooperate so I would drive it till the turbo grenades and get a new turbo.

 

[santa]

well the turbo has slight slight play but mine has quiet a bit more than his does. and I can boost over 20 psi. so were still stuck....idk what to do. any other ideas?

 

[FastEclipseGSXT]

"a 02 dump"??? could you be a litte more descriptive on that, such as what type, or is still routing back in the exhaust, where did you get it from?...sounds like your still using the internal wastegate...from what it sounds to me is that your not building enough exhaust pressure inside the exhaust manifold to spin the turbo...if all of this started happening when you went to the new o2 housing that probably is the problem...maybe a couple pics might help us see what were looking at...i would say it could be that the flapper on the turbo isnt closing completely but you said this all started with the new o2 dump so i would ck the differences between that an the original first

 

[santa]

k its a tubular 02 housing with the external dump. its a brand new slow-boy racing cast manifold which out flows the evo manifold...anyways the dump tube looks to be crush bent alsmost but not quite so im thinking that what is happening is that tube is building up in some way and not letting the waste gate open up but it doesnt make any sense casue if that were to happen the car would creep wouldnt it? were going to try switching back to the stock 02 housing and see if that takes care of the problem.

 

[FastEclipseGSXT]

did you modify the flapper when you removed the housing, are you sure there are no exhaust leaks, and all the bolts are nice a tight, i would ck everysingle bolt, the four turbo bolts, exhs manifold bolts all o2 houseing bolts and any other possible bolt on the exhaust you can see, yea to answwer your quiestion it would build up but thats not happening sounds like a leak