Overboost on stock turbo

[JohnnyLightning86]

Hey guys,
I have a stock T1 on my 86 Laser with non-intercooled log intake and have been having a fairly bad overboost problem that I can't seem to get lowered no matter what I do. I had it hooked up to the stock solenoid, but it would still hit cutout nearly everytime. So I hooked up a grainger and have it turned to as low as possible and it is still overboosting. The vaccum seems to be fine without any leaks as I have completely redone the lines. But I absolutely cannot floor it at all. Even at half-throttle it seems to be pushing 10 to 12 psi - which is definitely not good on a log intake with a stock calibration.

BTW - the turbo is a TU unit with a 2.5" SV and full 2.5" exhaust. Could it possibly something to do with the wastegate.

Any ideas?

Thanks,

[4cefedomni]

make sure the engine is COLD and reach back to the turbo and try to move the swing valve it could be siezed shut causing you to overboost

[inmyshadow]

that or the wastegate's rod came off.

Or?

On my 87 shadow es 2.2TI, there was a vacuum line to the wastegate with a tee in the line to something else. Well tee melted to the swingvalve leaving the car with no boost control. I was lucky since I new all this new found power was right.

[turbovanman²]

Sounds like the can is weak. Hook up your wastegate can to manifold vacuum. Go for a drive, if you hit overboost, you can is junk. If you stay around 4 ish psi, you have control issues-ie vacuum routing, computer, solenoid etc.

[puppet]

Guys, a weak WG can = low boost or no boost.

[turbovanman²]

Guys, a weak WG can = low boost or no boost.


Hahhaa, my bad, I always get that mixed up. :(

[turbo xtc]

check for operation of the s/v i had to bend my lever that the actuator goes to when i put my 2.5 in because it got bent when i was jockying the motor around putting it in what type of laser do you have a xe,xt or plain jane