Why am I boosting at 12?, Still stock, thought max at stock was 10... Options

[Green_MachToy]

I had a stud in the Exhaust manifold break at the head. In repairing it, my car is now pushing 12 pounds. I still have the stock ecu, no boost controller (until tomorrow), no FCD (stock max is 9.7). Now to give you a few more specifics: A friend of mine put a plastic t in my lines to trick the wastegate into allowing more boost. This caused me to reach 10 (probably 9.7, but meter isn't that detailed). In doing the repair I took the t out. I also found that my Cat was bad and took it out as well (it will cost me $300 to fix later). Replaced a crush gaskit after the stock down pipe to the 3" exhaust. Got everything together at approx 0130, and took it for a test drive. Found a couple of vacuum lines had worked themselves off of the stock BOV. Fixed those, and off again. Ran at stock 7 pounds of boost. Placed the t back in, ran at 10. Next day...got in the car got on it to pass a car...14! Took the t out, down to 12! It does seem to creep. When I hit the gas, it will jump to about 8-10, then steadily walk up to 12 as the rpm's increase. Did my wastegate go bad? I was thinking the increased flow in the exhaust from having no cat may have been the problem but it ran stock the night I did everything. Any ideas?

This post has been edited by Green_MachToy: Dec 5, 2005 - 8:34 AM

[lagos]

the car has a system for controlling boost. if you have an CEL codes, or low grade gas, or some other issue going on, the car will limit the amount of boost it makes. so thats probably why you were getting less boost.

stock boost for a 3rd gen 3sgte is between 12-16psi. so anything you get between there is considered normal. if you get less then that, then your car is going into low boost mode because of some issue the ecu found. make sure you run the highest octain gas you can buy too.

what did you do about the wiring harness. did you have to have anything rewired or did it all just plug and play ? i always wondered if there was any wiring that needed to be done with a 3rd gen motor

This post has been edited by lagos: Dec 5, 2005 - 1:24 PM