Is there any formula for comparing different AFRs to fuel consumption? Our Lemons/Chump Camaro runs right now high 10/low 11 AFR at WOT. It's a little rich but it runs cool and has plenty of power. We need about 15 more mins of run time per stint to cut out a pit stop on a typical 10-hr Saturday session. Right now we're burning 8.5 gallons/hr. So my question is, if we were to lean it out to say mid 11s, call it .5 points on the AFR meter, what might that gain us fuel consumption wise?
Air to fuel ratio is the ratio of fuel and air. Multiply your air used at the engine speeds you're running (function of displacement and RPM) by your ratio and you get a rough idea of your fuel consumption rate.
Another way of looking at it is percentage. If you lean it out 5%, you'll run about 5% longer on the same amount of fuel.
Bryce
Nashco wrote: Another way of looking at it is percentage. If you lean it out 5%, you'll run about 5% longer on the same amount of fuel.
Thanks, I wasn't sure if it was linear like that.
Nashco wrote: Another way of looking at it is percentage. If you lean it out 5%, you should run about 5% longer on the same amount of fuel. Bryce
FYP.
Should.
One other interesting note- assuming the car can survive running 5% leaner, you should make a little more power up to about 12.5:1.
Should, and would, yes. But SBC's are horrible at this style of racing. Running them rich has seemed to help the longevity a little. 11.5 is as lean as I'd want to go.
ross2004 wrote: Is there any formula for comparing different AFRs to fuel consumption?
Not really. Change the AFR and see if duty cycle under a given vehicle load changes.
I gained fuel economy by going from 13:1 to 12:1 because the engine was happier there and needed less fuel to make the same amount of power. It's not always intuitive.
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