This is interesting
I notice that running 96 octane on my 10:1 race engine I get slight
detonation at various revs under full throttle, and retarding the ignition
does not fix it. However, changing to 100% avgas removes all pinging, but
even with the engine advanced a few degrees more, is noticably slower
(repeated stop watch tests). I guess this is to do with the carbs being set
to a mixture more suited to the lower octane fuel.
Greg
----- Original Message -----
From: Jarrid Gross <JGross@econolite.com>
To: Christopher Albers <Christopher.Albers@bubbs.biola.edu>;
<alpines@autox.team.net>
Sent: Wednesday, 23 August 2000 13:42
Subject: RE: Dieseling revisited
> Chris wrote,
>
> >Well, I fixed my dieseling problem, but what an expensive solution!
> >
> >I purchased 5 gallons of 110 octane leaded racing fuel and mixed it
> >with about 4 gallons of 92 octane unleaded. Poof! No more dieseling.
> >Now all I need to do is figure out what mixture ratio will keep it
> >fixed for the least amount of $. At $4.50/gal it's no small price to
> >pay unless I get it in 55 gal drums, then it gets knocked down to
> >$3.90/gal!
>
> You might try to make your own.
> Tolulene (a high VOC additive, which is commonly used as octane boost)
> WAS available for about $4usd a gallon from most hardware stores.
> Tolulene has a specified octane rating of 130.
> Mixed 1 in 10 with 92 pump gas, should yield about 96 octane, with an
> overall
> cost of less than $2usd per gallon.
>
> >Oh, yeah, and I've noticed quite a bit more pep to the motor. Love
> >that benefit.
>
> You sure?
> Racing fuel doesnt pack significanly more energy into a gallon of fuel.
> It does however allow for higher compressions, and ignition advance
> before detonation occurs, which CAN add horsepower when compared to
> the same engine with lower compression and less timing.
>
> Also, racing fuel tends to have a different specific gravity and
> stoichiometric point that shifts max power towards the rich side of the
> air fuel table.
> In order to take advantage of this, the engine must be re-jetted.
> Even still most would agree that getting 10% more power out of racing
> fuel would very optimistic.
>
> Can you feel 10 more HP?
>
>
> Jarrid Gross
>
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