A/F RATIO WITH THE PREDATOR?????????????????????
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TECH Apprentice
Joined: Apr 2003
Posts: 315
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From: Katy, Tx
A/F RATIO WITH THE PREDATOR????????????????????? ANYONE HAVE ANY OPINONS ON WHERE I SHOULD SET MY A/F RATIO AT WITH THE PREDATOR??? WHICH IS BETTER TO BE RICH OR LEAN??
THANKS ALREADY
THANKS ALREADY
Re: A/F RATIO WITH THE PREDATOR????????????????????? How are you checking it? You need to go to a dyno with a wideband - that is the only accurate means of knowing where you are. You should run around 12.7:1 for a safe ratio. Richer is safer than leaner.
Re: A/F RATIO WITH THE PREDATOR????????????????????? No, not in absolute terms. Peak HP comes at a mixture
of about 12.5:1 - 12.8:1 which is well richer than
the 14.7:1 stoichemetric (ideal chemical) air:fuel mix.
In closed loop the car will center around stoich. The
important thing is what happens when you leave closed
loop into WOT operation. Here there are multiple things
at play - the basic fuel vs airflow map, power enrichment,
safety modes that might grossly over-enrich the mixture.
When people say they gained power from leaning the car
out, they meant that they made it leaner than its previous
programming. If the car were programmed to hit (say) 12.4:1
at WOT from the factory and they tweaked it back to 12.8:1
they might have squeezed another 5-10HP out of it. Tweak it
some more, to 13.2:1 and you might give back those ponies
and pick up some knock too.
Arbitrarily adjusting the engine lean is probably the worst
guess to make. Worse on some years (late) than others (early).
of about 12.5:1 - 12.8:1 which is well richer than
the 14.7:1 stoichemetric (ideal chemical) air:fuel mix.
In closed loop the car will center around stoich. The
important thing is what happens when you leave closed
loop into WOT operation. Here there are multiple things
at play - the basic fuel vs airflow map, power enrichment,
safety modes that might grossly over-enrich the mixture.
When people say they gained power from leaning the car
out, they meant that they made it leaner than its previous
programming. If the car were programmed to hit (say) 12.4:1
at WOT from the factory and they tweaked it back to 12.8:1
they might have squeezed another 5-10HP out of it. Tweak it
some more, to 13.2:1 and you might give back those ponies
and pick up some knock too.
Arbitrarily adjusting the engine lean is probably the worst
guess to make. Worse on some years (late) than others (early).
