Turbo troubleshooting help
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Joined: Dec 2004
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From: slocala
Turbo troubleshooting help Need some help from the turbo experts
here is my problem
Built 346 8.5 compression, Tial 44mm WG, Manual boost controller mounted in the cabin. Speedinc cam, 317 heads, methanol, 93 octane. Its a stalled auto, vig 3200 (still from my supercharger setup)
yesterday's dyno only made 370 on same 10lbs of boost that we got 450 on a couple weeks ago. (dynojet)
16* of timing
Manual boost controller turned all the way as far as it would turn and still only 10lbs---Does that mean I need a bigger wastegate spring? The spring in it is yellow and its big so I am guessing a 8.7lb spring based on the tial site.
Unhooked exhaust still didnt change anything (only made like 3 more hp) so I assume the backpressure on the turbo is not too bad.
Car sounds fine (full oil pressure, fuel pressure good, no dipstick blowouts)
Turbo sounds fine........just does not make power?
Any ideas please......I am ready to put a bullet in the car and burn it.
we played around with the tune, added timing etc, nothing helped. maybe something wrong with turbo?
Can't be boost leak or we wouldnt see 10lbs correct?
I've seen as high as 15lbs on the street once when the vacuum hose that runs to the compressor popped off
At the track last week it trapped only 113mph and couldnt build any boost off the line.....the footbrake wouldnt hold.
here is my problem
Built 346 8.5 compression, Tial 44mm WG, Manual boost controller mounted in the cabin. Speedinc cam, 317 heads, methanol, 93 octane. Its a stalled auto, vig 3200 (still from my supercharger setup)
yesterday's dyno only made 370 on same 10lbs of boost that we got 450 on a couple weeks ago. (dynojet)
16* of timing
Manual boost controller turned all the way as far as it would turn and still only 10lbs---Does that mean I need a bigger wastegate spring? The spring in it is yellow and its big so I am guessing a 8.7lb spring based on the tial site.
Unhooked exhaust still didnt change anything (only made like 3 more hp) so I assume the backpressure on the turbo is not too bad.
Car sounds fine (full oil pressure, fuel pressure good, no dipstick blowouts)
Turbo sounds fine........just does not make power?
Any ideas please......I am ready to put a bullet in the car and burn it.
we played around with the tune, added timing etc, nothing helped. maybe something wrong with turbo?
Can't be boost leak or we wouldnt see 10lbs correct?
I've seen as high as 15lbs on the street once when the vacuum hose that runs to the compressor popped off
At the track last week it trapped only 113mph and couldnt build any boost off the line.....the footbrake wouldnt hold.
Last edited by Dbluegoat; May 27, 2007 at 12:08 PM.
Teching In
Joined: May 2007
Posts: 34
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From: J-actionville
What is the wideband saying it is doing?
Did you upgrade the fuel system?
Does is build boost really slow? Like maybe the turbo is limiting the equation?
I don't have any idea, just throwing some stuff out there.
Did you upgrade the fuel system?
Does is build boost really slow? Like maybe the turbo is limiting the equation?
I don't have any idea, just throwing some stuff out there.
Thread Starter
10 Second Club
Joined: Dec 2004
Posts: 405
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From: slocala
Originally Posted by ss53mech
What is the wideband saying it is doing?
Did you upgrade the fuel system?
Does is build boost really slow? Like maybe the turbo is limiting the equation?
I don't have any idea, just throwing some stuff out there.
Did you upgrade the fuel system?
Does is build boost really slow? Like maybe the turbo is limiting the equation?
I don't have any idea, just throwing some stuff out there.
doesn't seem to build it slow, hard for me though cause this is my first turbo experience.
Yes full fuel system, magnafuel pro 525 pump, aeromotive reg., 60lb injectors, fuel pressure is really good and fueling should handle plenty of power
I'm still thinking boost leak. My theory is that the turbo is flowing enough to support the leak and the boost you are seeing. However, the exhaust backpressure would be through the roof, killing power, if this is the case. Also, once you find the problem DO NOT use the same MBC setting on the street that you use on the dynojet. Typically you have to crank a manual boost controller higher on a non-load dyno to maintain pressure. Once back on the street it will overboost. Good luck finding the problem, and try not to get too depressed about it in the meantime.
