Highlander

Hello guys...
I was wondering what AFR you tune for when doing hard autox or similar...

What would be lean and rich... 1/4 miles is a different ball game.

THanks

Jon A

I tried to stay just on the rich side of 13:1. And make sure the rest of your fuel system is up to snuff if you make a lot of power. Just because your fuel pump holds up just fine on the dyno, doesn't mean it can keep up all day at the track. Ask me how I know....

Highlander

YES PLEASE DO because i tuned a z06 13:1 and it broke after the 5th turn./

JimMueller

Why would the ideal AFR be any different for a different style of racing? I always heard you should tune for ~12.7:1 on a dynojet since it doesn't factor in the correct load

Highlander

because you are pumping more power more time nad it will tend to overheat the engine and you need the cooling effect of the fuel to bring down temps....

I did it for 13.05:1 and it was at night... so on the track it should have been close to that during the day at full speed.

JimMueller

So how rich without giving up a lot of HP? I'm getting some new dynojet pulls on my rebuilt engine tomorrow. I'd like to what AFR's to strive for once I know what it's at now. I don't drag race at all - it's 100% daily driver & autox right now, but maybe some RR in the future as well.

Highlander

Well that what i was trying to find out... you will lose about 3-5hp from 13.0:1 to 12.8:1. I targeted 13.0:1 on the dyno at night so I would have around the same during the day with 100mph winds...

For the next engine and/or race i will use 12.0:1 just to be sure, no matter if i loose 10rwhp, which i will.