Folks,

I'm running the 90mm pulley on my Kraftwerks Rotrex-equipped '99 HPDE car. She's hitting just shy of 7 pounds boost at WOT and about 6800 rpm, and I'm seeing around 10.8 AFR. I'm making some changes that require a re-tune--removing the gutted MAF and adding a sealed cold air duct. Should/could I have it leaned out just a bit at WOT?

Thanks,

poormxdad

 

there's no reason to run that rich. Us turbo folks like to target 11.8:1. S/C setups can get away with slightly leaner. I'd be targeting ~12:1; no leaner.

 

I'm at a solid 11.5 AFR from 4k-7k. My car has seen over 20 track days at 8-12 lbs boost pressure(Rotrex c30-74 with 80mm pulley). I'd be more concerned with your timing map honestly..

 

Your post reads like you're talking about my particular timing map?

 

Sorry for the confusion. I was only trying to stress the relative importance of a solid ignition map. There's no magic AFR target to follow, I run something that makes good power but below 12:1

 

No worries. I asked the question because there has to be a compromise between using richness to help cool the motor, and having too much fuel contaminating the oil.