Question about oem ECU

Black kNight

ok
thanks alot
but how to read the A/F ratio !! I mean what is the correct ratio for Turbo cars and NA cars it have to be ??

MikeGTO

Well I'm no expert but people generally need a wideband O2 sensor to measure the A/F ratio accurately. This is what dyno shops use for measuring A/F ratio during dyno runs.

For NA cars, and these are just approximations based on what I remember about LS1 V8s, they typically run about 12.0:1 at full throttle with factory tune & settings. This will vary some based on engine type and how the factory tune is programmed. Aftermarket tuning will usually lean this out some to make more power, somewhere in the range of 12.8:1 is usually considered a pretty good target to make good power while still being safe for a NA engine.

I don't have any real experience with turbos, but in general, turbo cars and supercharged cars will be tuned a little bit richer than NA cars, since the higher cylinder pressures with the turbo make it more prone to knock. Just throwing a number out there, but I would think a turbo or supercharged car would probably be tuned somewhere around 12.0 :1, and I wouldn't feel very safe leaning it out more than that.