Thread: Pulley drop time?

Originally Posted by jman44

I have a 99 gp gtp coupe. has speed daddy headers, no cat, magna flow mufflers, roller rockers. My question is what can i safely drop to on my s/c and run kr free?

I'd guess you can go with a 3.4 without KR but like the others mentioned a scan gauge would be smart. I'm assuming you have an intake also right? I'm running a 3.3 with similar mods except for a mild cam and a little bowl porting on the heads. I have an Aeroforce and have not shown any KR. I've got a 3.2 on the way and will keep an eye out for knock.

Originally Posted by tms8582

I'd guess you can go with a 3.4 without KR but like the others mentioned a scan gauge would be smart. I'm assuming you have an intake also right? I'm running a 3.3 with similar mods except for a mild cam and a little bowl porting on the heads. I have an Aeroforce and have not shown any KR. I've got a 3.2 on the way and will keep an eye out for knock.

Factory programmed PCM or something else?

Originally Posted by Elite6

Factory programmed PCM or something else?

I was running a factory tune without any KR but I did have my buddy change the fans to come on sooner. That's one area where the factory tune really sucks imo. The fans don't come on until 220... Now I have an intense tune with raised shift points. Both tunes showed zero KR. I can't say the Intense tune made a huge difference except for the higher shift points. In fact I think I'll even raise the shift points higher because the motor really pulls over 6000. I think the balanced crank, Xtreme cam and 105 springs can really handle some RPM's. Right now the car shifts at 6300 and I will change that to 6500. I'm going to give the 3.2 a try and maybe increase the WOT timing a little too and keep a close eye out for KR. he original poster talked about rockers... I assume he meant 1.9 rockers? If so I's guess he will be good with headers and rockers and a 3.4.