air-fuel ratio to temp

Jonathan R. Lusky lusky at
Tue May 9 14:49:28 GMT 1995

David Cooley writes:
> If you wanted to monitor every cyl, an O2 sensor has almost instantaneous
> response once it is up to temp.  The sensors "switch" from lean to rich and
> back again quite a few times a second as the mixture changes.  This would
> give you the ability to tune individual cylinders on the fly.

Here's my two cents....  I run an O2 sensor in each collector.  I run
thermocouples in each port.  The variance in EGT gives you a good
picture of cylinder balance, and then the O2 sensor tells you what
the actual A/F is if you are running near stoich.  However, O2 sensors
are only good for tuning near stoich, so they'll only help you at idle
and low-medium load.  For WOT, just keep the EGT safe and keep an eye on
each individual temp to make sure you don't have one heading to the
moon.  As far as the idea of doing closed loop at WOT from EGT, it'd be
a neat experiment...

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Ack, just say no!

Jonathan R. Lusky                        lusky at                 (615) 726-8700
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68 Camaro Convertible - 350 / TH350  \_/ 80 Toyota Celica - 20R / 5spd

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