1979-1993 & 94 Conv [Subscribe to Daily Digest] |
AsCT89spg said there is tons of info on the performance bb. A couple basic improvements are free.
The first thing you should do is set your base boost to between 5 and 6psi. Nearly every old 900t will have a weakened wastegate controller spring that can be compestated for by shortening the rod. Tee in a calibrated boost gauge to a vac/boost line from the intake(with a long enough hose to reach into the cabin. Unplug the APC solenoid(up by the coil) to limit the engine to base boost. Test drive at wide open and my bet is you will only see 3-4psi boost. Shorten the wastegate control rod until base boost is 5-6psi. Plug in the APC solenoid and you will notice much faster spool up and boost performance.
Fill car with 93-94 octane gas if available. Make sure NGKbcp7es plugs are gapped to 0.024" and cap, rotor and wires are OEM and fresh.
Then unscrew the APC computer from the driver side fender liner. Take the box apart and you will see a printed circuit board with 3 holes for potentiometer access. Don't touch the one marked k for knock sensor. Turn the pot marked "f" (max boost)about 90 degrees clockwise. Then bump the pot marked "p" about 30 degrees clockwise. Then test drive the car. If your boost overruns before settling down about 1/4-1/3 into red, you turned "p" a bit too far. Readjust "p" so that it doesn't overrun by bumping it back counterclockwise a bit.
You can turn "f" up until the knock sensor intrudes at sustained max boost.
to go beyond this, you can add a 3.0 fpr and start playing with timing retard to reduce knock sensor intrusion.
posted by 216.75.9...
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