Thread: Tuning for a 3.5" pulley upgrade

Originally Posted by SnowFlake

When you say "PE knock" do you mean KR as soon as you enter PE at partial throttle? Or do you mean just WOT?
These cars do weird things sometimes. I was tuning an N/A Gp a few weeks ago and the car had KR everywhere. He then did a full maintenance work up, added headers and 1 step colder plugs along with a new 180 t-stat. We were figuring it would handle a ton more timing... we were wrong. It still knocked badly.

Went through the whole shpeal looking for false KR and all that and came up with nothing. In the end all I could do was send him on his way with a 12.8 AFR at about 19 degrees of timing. It made no sense at all especially considering I was getting away with 30 degrees of timing on my aunts NA GT that has no mods at all.

KR as soon as I enter PE, and anytime in PE. That leads one to believe PE AFR is too rich, but I am already leaner than stock by 0.4. To sum it up, I'm seeing about one degree of KR for every PSI of boost. My car is your friends car's bastard child.

BTW, I was having a lot of sub-PE KR in the summertime, until I switched IFRs. Then, after you looked at my file, you put it back to stock. Somehow its been working very well sub-PE with the same settings that were killing me in the summer.

Machines can be wierd.

Thanks for the help.

Originally Posted by mechguy

KR as soon as I enter PE, and anytime in PE. That leads one to believe PE AFR is too rich, but I am already leaner than stock by 0.4. To sum it up, I'm seeing about one degree of KR for every PSI of boost. My car is your friends car's bastard child.

BTW, I was having a lot of sub-PE KR in the summertime, until I switched IFRs. Then, after you looked at my file, you put it back to stock. Somehow its been working very well sub-PE with the same settings that were killing me in the summer.

Machines can be wierd.

Thanks for the help.

Your base PE was a little too high for your mods. I wouldnt run higher than 12.0 base PE on a 3.5 pulley unless it was cammed. Lol.