Plug life is cut by about 1/2 on 100LL and O2 sensor response gets

slower

when poisoned with lead (which is not a problem for monitoring

mixture).  I

get about  150 hours on plugs with mixed use of 100LL and auto fuel.
Straight auto gives about 250 hours plug life.  Never tried a

constant diet

of 100LL so don't know what would happen.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

Tracy, please tell us more about your experience with avgas versus
mogas.  I'm very concerned about a turbocharged auto engine needing 93
octane unleaded, running avgas in a pinch.  Others say that the O2
sensor will plate over in short order (1-2 hours?) and stop working,
leaving the engines to run in open loop mode.  They also say the only
way to remove the lead from the O2 sensor is to replace it or run a
propane torch over it for 15 minutes or so.  Neither of these has been
your experience?  How many times have you had to use avgas when you
couldn't get mogas?  I'm concerned that ANYtime I'm away from home or
relatives areas that I'll wind up having to use 100LL. I have a 25
gallon tank Mustang II.  Good info about the plugs, too.  They are a
pain to get to, but changing them is certainly easier than changing the
O2 sensor!

Thanks,
AI Nut

Not much to tell beyond what I said above.  As far as the fear of going open
loop when the O2 sensor gets lead poisoning, my advice is DON'T use a closed
loop EFI system using an O2 sensor in an airplane.  I use an O2 sensor only
to monitor mixture, not for feedback to the EC2 controller.   I've used
100LL on one or more legs on virtually every long cross country trip.  It is
not uncommon to find that mogas airports are out of that fuel.

Plugs hard to get to?  Put a higher priority on maintainability when
designing your installation :-)

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

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