Hey everyone I have a 1988 gl-10 turbo, and I can't figure out how to turn the boost up past the factory settings. I have a boost controller hooked up and I bypassed the boost solenoid. I am still gettin 4 psi. I really wanna increase it to about 10 psi if I can figure out how.. If anyone knows what i might be missin please give me a hand here. Does the ECU restrict the amount of boost or am i hookin it up wrong.

 

 

Thanx, Dave

Please read thru the results of this search to see if any of the prior topics here have already addressed your question.

 

http://usmb.ultimatesubaru.org/forum/search.php?s=&action=showresults&searchid=6225&sortby=lastpost&sortorder=descending

The ECU limits the boost at about 9 psi.. even with stock settings you should be getting more than 4psi.. wondering if your wastegate is letting pressure off early.

 

Maybe skip is around.. or corky.. they know more about these things

The low boost can be one of several things. Like said already, a faulty waste gate actuator can do this. If you have a guage installed, then you can pull off the actuator rod, and see if you can get more boost, if not, on to the next problem. The crossover pipe, between the heads. (this is the problem that I had on mine when I suffered from low boost) What can happen is the welds on the crossover (which is made up of 3 pieced) can come loose from time, and allow exhaust to leak out, you can check this by grabbing the middle of the pipe and seeing if it moves, or if when running you can hear a leak. If thats not it, then it's time for a cat-ectomy. The catalytic converter can become plugged up, slowing the exhaust flow, and hindering the turbo massively. This would be the 3 best places to check out. Lotsa luck.

These guys have hit the ol' wood holder on the cranium.

Are you certain your boost gauge is calibrated??!!

Removing the control rod from the waste gate actuator is a bit of a pain. You could first remove and plug the rubber line to it.

I have never seen one "hang open" but yours could be, thus the reasoning behind removing the control rod.

If you choose this method. You will have to some how tie, prop or make sure the waste gate "flap" is forced to stay closed. With out the rod it would be free to "flap" around as it is held closed by an internal spring in the acuator.

This internal spring that holds it closed could also be knackered.

This could let it open at an early pressure. Removing just the rubber line to it would show this.

Adam's comments on the exhaust sytem deserve checking for sure.

 

You ask

Does the ECU restrict the amount of boost

 

No that is the sole job of the waste gate, but it has the ability to increase boost via the waste gate solenoid.

The ECU will enact a fuel cut if you run over 9 psi for a period of about 3~5 seconds.

Hope this helps, please let us know.

Some of you may remember the turbo Brat that I found awhile ago and was purchased by a guy in Florida who came out here and drove it home. When he picked up the car, he couldn't figure out why there wasn't any boost, everything looked good. Upon further inspection, he noticed that one of the exhaust flanges appeared to be leaking, so he took it into an exhasut place. When they pulled the crossover pipe, the only think the was there was the shielding, so they fabricated a new crossover and the boost problem was fixed. I doubt that your's is that bad, but if there is any place where it is leak, the gas will take the lease course of resistence and go out the leak and not the turbo.