booboo782

A/F gets progressively leaner in lower gears starting with third gear. It goes 11.7 A/F in fifth & fourth gear, 12.2 in third, 12.5 in 2nd & 1st gears. No boost-by-gear yet just for tuning purposes, same boost settings in all gears. And it is hitting the same boost column in all gears. Everything else is the same.

This is the first time I noticed this. Probably because I have only ever tuned/paid attention to fourth gear (1 to 1 gearing ratio).

I started fiddling with the fuel gear corrections and got things looking more consistent across the gears, but question is: should I have? Is this normal? What are your guys' experience with this. Thanks.

theYBLEGAL

Tuning system?

With neptune, I lean 5th, and richen 1st a tad. Same effect as you, inverse way.

With crome on same hardware, engine, no gear correction.

Each system is different. Its OK to some, if variation is not huge

boosted94gsr

I use Neptune and had to add some fuel trim in 1st and 2nd to even out my afrs too.

blackeg

i always thought this was a normal thing that the stock ecu does. with the gearing so high in 1st and 2nd there is much less load on the motor. that said, i also use neptune and add a bit more fuel in 1st and 2nd with the gear correction. i feel i can never get the fuel correction for 5th gear to remove fuel very well..

VegasInvasion

didn't you guys watch bill nye as a kid?
velocity and load are exchanged depending on the pulley ratio.
3rd gear spins at a higher velocity than 4th gear, so it needs less force, therefore less fuel.
You can add more fuel, but it'll be in the exhaust before it starts burning.

blackeg

i occasionally make my students watch bill nye video clips. you would think at 15 and 16 years old they would have no interest but they love it

B and B

iTrader: (3)

Mr. Wizard was more my era

booboo782

You said that 3rd gear NEEDS less fuel. So if I'm showing slightly leaner conditions in 1st, 2nd & 3rd vs 4th & 5th, don't worry about it is what you are saying? No gear modifier necessary?

Thanks guys, y'all have been informational gold to me over the years. You just have no idea... almost as good as Bill Nye.