vettenuts

iTrader: (4)

I have been looking at a number of dyno tunes that people have posted both here and at corvetteforum.com and find that many tuners are setting up the car on the dyno with a 13:1 or slightly higher AFR while on the dyno. When I had my car tuned by a very knowledgable tuner, he set up my car in the low "12:1 ish" area telling me that the car would lean out approximately 0.4 on the street compared to the dyno such that I would end up near 12.6:1 which is where I wanted to be.

Does anyone know why some of these tuners are setting cars up at 13:1 or leaner on the dyno and then sending them out the door? I am somewhat confused on this whole thing and there seems to be a lot of conflicting information. I know my car would have pulled bigger numbers if it were a bit leaner as I saw bigger numbers during the tuning process prior to the final setup. But I also don't want to damage my car on the street either.

Patrick G

iTrader: (14)

Lean is mean. Many cars with AFR heads run best between 13.5 and 14.0 on the track, therefore dyno tuners are setting them around 13.0 on the Dynojet. My car made the same power at 14.0 and 13.5 on the dyno, then lost power at 13.0. We kept it at 13.0 (for the street) and called it good.