Done all the time in racing though.

Mike

> From: Angus Gordon <agordon@BRIGHT.NET>
> Reply-To: Angus Gordon <agordon@BRIGHT.NET>
> Date: Wed, 2 Jan 2002 08:58:07 -0500
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: B. Bobs day at the dyno and the importance of fuel air ratio
> update
>
> John,
>        I believe there are enough differences between the aviation and
> automotive applications that EGT (exhaust gas temperature) is not a valid
> method of setting the mixture on a car engine. Remember that in an aircraft
> EGT is only a valid measurement for leaning purposes when compared to peak
> EGT for that specific power setting. That works fine in an aircraft, where
> you can set the power, lean to determine peak EGT in the leanest cylinder,
> then set the mixture relative to that cylinder's peak EGT. I don't know how
> you could accomplish that with the constantly changing power on the road.
>
> As to burning valves, many piston aircraft engines are designed to run at
> peak EGT or on the lean side of peak EGT in cruise. Exhaust gas temperature
> is used as a relative measurement again, not an absolute in these cases.
> The only limitations I know of in terms of specific EGT, are for
> turbocharged engines, where TIT (turbine inlet temperature) becomes a
> factor. Even in the waterboxer I think there'd have to be some other
> ingredient to burn a valve, i.e. incorrect valve lash, overheating etc.
>
> But, if someone wants the very best in EGT instrumentation (and CHT on the
> same gauge) here it is -
>
> http://www.insightavionics.com/pages/602.html
>
>
> John Rodgers wrote:
>> I've been away from aviation for quite a number of  years but I remember
>> using the EGT gages as a guide to manually setting  the fuel air mixture
>> during various flight regimes for best performance. On those aircraft with
>> engines equipped with an EGT probe mounted in each exhaust stack just
>> outside the cylinder head, it was possible to  select through each
>> cylinder and determine which cylinder was running the leanest. The leanest
>> running cylinder then became the guide cylinder by which the mixture for
>> the engine was set. That way one avoided burning up a valve or worse,
>> burning up the engine. By watching the EGT gage, for any given throttle
>> setting (manifold pressure setting) the mixture could be set for Rich Best
>> Power, Peak Power, or Lean Best Power...
>
>
>
> Angus
>
>
> ================================
> Angus Gordon                       '89 Carat
> NW Ohio                            '86 Syncro
>