Alright guys, I run a motorcycle dyno but havent ever tweaked on cars. My buddy has a 03 6.0 chevy with a magnacharger on it and were trying to get it to run right. He just installed the tune that magnacharger gave him and honestly its junk. I hooked up my wideband to his truck and took it for a drive. Under load AFR drops to 11.5-1 or so with it at wide open throttle and continues to richen up as rpms increase till redline. Cruising along AFR is spot on around 14.9 or so, but the second you get on it, it drops to under 12. So basically my question is, what is a good AFR you guys shoot for on blown trucks? BTW, it's pulling around 5 psi at WOT.

 

Sounds like the tune is pretty spot on. AFR should be below 12:1 and most run 11.4-11.7:1 when WOT.

 

yeah your just used to a motorcycle which wieghs as much as an axel on the truck. At 5000+ lbs, what trever1t is saying is pretty much spot on. There's definitely room for discussion and debate all the way up to 12.25:1 under 7lbs of boost, but most will agree that boost means 11.7:1 is nice. 12:1 is probably fine, but no reason to push it, you have no room for error.

 

They have to run that rich to protect the motor from detonation.....11.5 is nice and safe...

 

I run 11.5 on 7.5 psi

 

i shoot for 11.2-11.5. seems like much under 11.0 and missfires start. i have tried going as high as lower 12's and didn't gain much if any hp.

 

If i run my setup at anything under 11.5(no meth now) I can feel the seat of the pants difference by raising to 11.8. I get nothing after 11.8. That's just the butt dyno. I can feel the bog if I go richer than 11.4. Again, this is the butt dyno and my 11.x. Which could be a point or 2 different than someone else's.

 

Even though I run a boosted Hemi, mine likes to run on the lean side. The best track times I've had, have been with my a/f's between 12.5 and 12.8. Anything below that, I'm just using the unburn't fuel for additional cooling. You have to remember that I'm stuck with the stock PCM and no help from Dodge with aftermarket tuning.

 

mine was tuned @ 13.0 WOT, no knock, kinda had no choice as we were out of injector

 

yeah but you know...bad bad bad.