Originally Posted by
hensleya1
1. Get a scanner. Aeroforce, ScanGauge, Torque App, etc. Scan for KR - knock retard. It happens when the computer senses the engine is pinging (the fuel is predetonating) and yanks timing to compensate. It works, but there's two limitations... first, it kills power, and second, to yank timing there must have been knock in the first place. Not good. When the piston is moving down, and the explosion is going up... the explosion wins every time. Chipping a piston means its time for a new motor.
2. Most cars have a couple degrees of KR in stock form, and that's only when they make about 6# of boost. Don't pulley down without at least a downpipe, or for a 3.4, headers and a tune. Any less is inviting a motor swap. I had KR with a downpipe and 1.9 rockers on a 3.5 pulley. Speed daddy headers are like $200. Do supporting mods first, then pulley down.
3. After headers, then pulley down to the 3.4 or 3.5 range... and get it tuned pronto. A canned tune (Intense, ZZP, etc.) will work at this point but an in-car or dyno tune would be best.
08-08-2014
