EJ20G Boost Pressure

PeeJay · Post by **PeeJay** » Sun Oct 22, 2006 3:41 pm

It's time to get this engine of mine boosting right!

For some reason it limits itself to about 8-10 psi. I don't know what factory is but this seems a bit small. I've tried swaping all the solenoids and stuff from another car but it didn't do anything. I could hear the boost control solenoid working so I don't think it's that. Taking the pipe off the wastegate results in fuel cut at about 16psi.

I just tried swapping my ecu (93 Legacy GT) with another (96 WRX) and it seems to have a bit more power, but the boost is still the same! Once the engine cools down I'll try taking the pipe off the wastegate with the new ecu and see if it still cuts (it didn't in the other car - 23psi can't be good!)

I'm getting error code 24 which is the bypass air control solenoid, but I don't suppose that has much to do with it?

PeeJay · Post by **PeeJay** » Sun Oct 22, 2006 4:03 pm

Ok, fuel cut with the wrx ecu is at 18psi.

tim_81coupe · Post by **tim_81coupe** » Sun Oct 22, 2006 5:06 pm

10-11psi is stock. The BAC won't have anything to do with the boost pressure, it's the device the ECU uses to control idle. You've probably noticed your idle fluctuating, the check engine light coming on after a few seconds of idle or a near stall after returning to idle. These are usually the first symptoms of a faulty BAC.

16-18psi is all you'd want to ask of the stock turbo / intercooler setup. Personally I prefer aftermarket boost controllers to stock, although many people have had good success running the stock controller. Jaycar do a controller PCB that allows you to customise the stock controller, and an aftermarket ECU such as a PFC allows good boost control.

PeeJay · Post by **PeeJay** » Mon Oct 23, 2006 5:52 pm

Ahh well there you go! I've got a air/water intercooler but the water is not hooked up yet so I'll hold off on the boost controller.

Check engine light never comes on, but idle does sometimes vary by just enough to hear it, but it's still smooth so I'll just ignore that for now as well.