Leaning fuel tables upfront

[Whiterock1]

Knowing that the Predator makes power in the '06 Corvette by leaning out the AFR a bit, if I went to the Fuel Tables, without logging data, and simply adjusted them say -5%--keeping in mind I'm at high altitude, wouldn't that improve performance in a safe manner? Or is it necessary to log the long term fuel trims before making an adjustment? GM runs the AFR at a low ratio, and your adjustment is a sealevel calculation--and conservative, so wouldn't this simple mod upfront make sense? Sorry if it's a dumb question, but I'm new to this, as I said, and am interested in better throttle response.

Mike

[mikel]

Knowing that the Predator makes power in the '06 Corvette by leaning out the AFR a bit, if I went to the Fuel Tables, without logging data, and simply adjusted them say -5%--keeping in mind I'm at high altitude, wouldn't that improve performance in a safe manner? Or is it necessary to log the long term fuel trims before making an adjustment? GM runs the AFR at a low ratio, and your adjustment is a sealevel calculation--and conservative, so wouldn't this simple mod upfront make sense? Sorry if it's a dumb question, but I'm new to this, as I said, and am interested in better throttle response.

Mike

Making changes to the injector slope without knowing where the LTFTs are at is not a good idea.
Going negative on the injector slope would cause the injectors to spray more fuel with each pulse, making the car richer. At altitude, you have less O2 available meaning the car is likely already a bit rich. You would only be making it worse and kill power at the same time.

Go ahead and do some logging so you at least have an idea where you are at before you go start modifying the tune.

Thanks

[Whiterock1]

Probably a good idea. So you + the injector slope to lean and - to richen? I guess that makes sense when you consider a steep slope means more 'something' at any given point.

[mikel]

Going (-) tells the PCM that you have smaller injectors, going (+) tells the PCM you have larger injectors.
If the PCM thinks the injectors are smaller than they are, it will telll them to spray more fuel with each pulse, and the opposite if it thinks the injectors are larger, so that the A/F ratio will be unchanged.
However, you would be doing these changes with the same size injectors which will cause the A/F to change.

Thanks