I don't have the figures in front of me but but if I remember correctly the
100LL
av. gas octane is about the same as the 92 M*R/2 pump gas. The ratings for
the two different. Pump gas is rated by taking the Motor rating and the
research
rating and averaging the two. Aviation gas just uses the higher rating. Are
you sure
you need 100+ octane? If doesn't ping or knock on pump gas higher octane
will not help you HP. If you do need the higher octane I would use the pump
gas
and add 10% Toluene (124 Research octane if I remember correctly) from a
paint
supply house. The higher the octane generally speaking the energy in the
fuel goes
down and you have to burn more of it to get the same HP.
Compression Octane Number Brake Thermal Efficiency
Ratio Requirement ( Full Throttle )
5:1 72 -
6:1 81 25 %
7:1 87 28 %
8:1 92 30 %
9:1 96 32 %
10:1 100 33 %
11:1 104 34 %
12:1 108 35 %
Avgas is less dense than most racing gasolines. Instead of weighing about
6.l to 6.3
pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per
gallon. The racer
must compensate for this by changing to richer [larger] jets in the
carburetor when
changing from racing gasolines to Avgas.
Check out:
http://agassiz.cas.und.nodak.edu/~nordlie/cars/gasoline.html
http://www.cs.ruu.nl/wais/html/na-dir/autos/gasoline-faq/part3.html
http://www.tgill.com/racefaq.htm#faq5
Monty Getz wrote:
> Doug I saw your address in a question answer thing I came across while
> looking for info on 100LL. When You were talking about avgas harming
> motors, did you mean the old 130LL or the 100LL? I need a high octane
> fuel for a weekend race truck, and 100LL is a lot less than pump 92, and
> a octane booster to bring it up another 4-7 points. Is 100LL going to
> hurt my motor? I don't have any emission controls, and laws don't apply.
> I would like to stay away from racing fuels, the cost here in Canada are
> outrages and it's about a 4 hr. drive to the nearest supplier, was 2.5
> hr but they went out of business. Is 100LL even better than the 92 with
> super 104+ additive, or just a waste of money? 92 plus the booster cost
> $0.81 a L and 100LL is only $0.73 a L Thanks for your time I hope you
> can help me.
> Monty Getz
|