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View Full Version : Boost issues


jskateborders
09-28-2007, 01:16 AM
Ok, so heres the thing. Im a noob to turbos(kinda) but I have experience on engines. I know the basics on how a turbo works, ect ect, but wouldnt call myself an expert.
Basically my story starts with my CAS going out. I was boosting fine, replaced it, and then the issues started. The engine never misses, at all. it never breaks up. the weird thing about my timing is that its not set to oem specs. I have set sr's and various other engines to timing. Thats cake. My blacktop doesnt start with oem timing. tdc, second dot lined up when its all the way in. So I pulled it out and advanced it a tooth, and runs great. I can retard it and advance it fine like that. Thats how it was when I first did the swap. Now my CAS goes out, so I replace it. pull the valve cover off, do it all oem style, and no start. So I advance it a tooth, runs great.
Now that you have a background, my real issue is boosting. Sometimes itll boost to around 5psi, in first and second, sometimes not. It only boosts all the way in higher gears (7psi) and sometimes occasionally in second. So my first thought is boost leak. So I test it, all the way to 20psi, and no leak. I take the turbo outlet to the intake off, and theres some black shit. I wanna say carbon build up, or really really old oil. More leaning towards carbon build up. I mess around with the wheel a little bit, and absolutely no front to back movement and very barely noticable side to side movement. like not even to the wall.
Im wondering if this slight movement would be enough to do this?
Also, If my timing isnt exactly right, would the change in exhaust flow cause this issue?
It spools up perfect every time in higher gears. In fifth, It spools up nicely at 2500rpms.
Yes I searched, And im really dumbfounded.
Please help me someone!!!!

jskateborders
09-28-2007, 11:12 AM
no one has any ideas?

bshotts
09-29-2007, 12:54 AM
Try to get a compression check on all cylinders. I had myself convinced that my compression was perfect after a recent turbo/injector/MAF/ECU install, but after some time boosting and such, I kept losing alot of power and eventually could hardly build boost. After another compression check (warm engine etc), I found my #4 was very low...I pulled the spark plug and woila, oil on the plug = bad piston rings. Oil was blowing by the rings, mixing with fuel...all around bad news.

Let us know what your numbers are!

jskateborders
10-01-2007, 01:09 AM
I did a compression test. And fuck, I wish I had just kept myself in the dark. Im looking at 115, 105, 111, 102. bummer. looks like I need a bottom end rebuild. Kinda sucks. should I run a thicker oil to prevent major oil blow by until I get the money to rebuild. This is my daily.
Is there a whole oem kit that I can buy, or do I have to by everything separatley. The only thing I found as far as bearing sets go is ACL bearing set. I have no intentions of going over 350 whp with this motor ever, and I am a broke college kid. What are recomendations.

jskateborders
10-01-2007, 12:06 PM
and no black smoke. weird

jskateborders
10-01-2007, 10:31 PM
some one please flame me with some info