a/f ratio info.

["estorhok" <estorhok@domain.elided>]

For those of you lucky enough to be able to tune your car with a REAL
exhaust a/f meter- some generalities:

cruise- try running as close to 14.6 as you can.  or perhaps a bit lean of
that for fuel economy.

idle- if you need to pass a standard, run as lean as you can and still get
it to run smoothly, but 14.6 is a good start.

wide open- max power *usually* comes around 12 to 12.5:1.  The funny thing
is the fuel by itself only gives you about 5% or so.  The big benefit is the
ability to run a far more aggressive spark than at 14.6 (where it would
likely knock much earlier).

While an O2 sensor will do a pretty good job, if you were to build a real
race car, and needed every single hp, and mpg you can, a real a/f meter is
invaluable.  If you are willing to spend $3400, I can tell you where to get
a REAL good one....  or $10k for the best (a little overkill...).  A good
dyno shop should have one- either one like an exhaust sniffer or a real
exhaust mounted one.

Enough of my dribble.
Eric Storhok
Ann Arbor, MI

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