Highlander

Is it too lean that it will break?

TA Dreaming

is that your AFR with that YS trim blower? yeah your gonna destroy something if thats with the blower. get it lower to like 12:1 and be safe. you may give up some power, but wouldnt you rather have your engine survive?

chuck

I am at 12.7:1 with my NA motor, and feel that is close to the edge.

Highlander

no this is on a z06 stock motor.

TA Dreaming

if the car is untouched program wise and the engine has no mods. then yes your fine. bolt ons like exhaust and intake are also ok.

Highlander

exactly.. the car is a header ls6.. .no intake allowed... car was tuned to 13.05:1 AFR...

it broke 2 pistons.. melted... no 5 and 7. broke a complete peice off the crown!!

the valves on those 2 pistons (intake) had like a scratching in there that looked like a asterisk but the size of the valve... 5 scratches each....

I dont know. to me it looked like over rev... rev limiter hitted at 6800 and the thing blew apart.

I run my pops z06 at 13.6:1 and i have run other cars that lean and had NO problems at all.

TA Dreaming

wow thats bad. not sure what could have gone wrong. maybe too much advance in higher temps. theres a lot more to tuning the LS1s then AFR. but thats a big part. you should have been ok with that AFR, but im not sure what the rest of the program looks like or if thats even what caused it. sorry to hear your problems

Highlander

Nahh... i've done it before... and i never had any problems.. the driver is really a bad driver...

anyways... Yes there was a lot more to it than that... i set up correctly the IAT tables and all the different tables to account for harsh environments.. STILL.... it broke...

Anyways we shall see now.

JordonMusser

way too lean. The pistons will get too hot, and poof.

Highlander

on a stock car?

JimMueller

I was inquiring on this on a couple of forums as well. The few responses I got said they would feel most comfortable with the AFR no higher than 12.7:1 on endurance racing.

TA Dreaming

just how long was the car running? i was assuming you meant a simple road course school where your out there for like 30 minutes with instructors and all that fun stuff.

LT4Firehawk

Stock on a Z06 should be around 12.6:1 on the top end, and I wouldn't run it any leaner than that for roadcourse use. You are always better off sacrificing power for reliability on a car that sees roadcourse use. In even a 15 minute track session your coolant and oil temps will increase dramatically over what they run on the street, which will lead to knock/detonation a lot easier. As that happens, you definitely don't want to be lean. I holed a piston in a 944 Turbo from being too lean at the track. Car ran fine on the street, but halfway through it's first track session it holed a piston.