The Dodge Challenger Message Board

If there is 10 gallons of 91 Octane fuel in a tank, and one added 5 gallons of 100 octane AV gas, what would the resultant octane be?

could be about 94 octane give or take 1 octane, you have alot of chemistry involved,due to the effect that both fuels are not made the same

Thanks Drew, is there an algebraic formula or something to get the base figure.

yea i hate math,i got seth the safety engineer on that

drewcrane wrote:could be about 94 octane give or take 1 octane, you have alot of chemistry involved,due to the effect that both fuels are not made the same

It feels like you are spot on,drewcrane: 2/3*91+1/3*100=94
(This formula seems to be working. At least, I do not have any better suggestion.)

That seems to be correct Chris/Drew, thanks.

The airport is conveniently located between my home and town. As part of the weekly trip in for supplies I decided to stop and buy 5 gallons of AV100 for my "off road dirt bike".

I'll mix it up and see how it works.

Jon wrote: I'll mix it up and see how it works.

Not a hint of pinging with this ratio. In fact I added 6 gallons of 91 octane to top off the tank at the end of the test session, along with adding 2 degrees advance. Again no detonation.

I plan to add 2 more degrees initial advance (16) and settle the ratio to about 20% Avgas to 91 Pump Fuel, and see if that's what we can live with.

Of interest, the idle went down a little bit after mixing the brew. It was very humid today though so I may wait till the weather normalizes before resetting the fuel/air mixture.

The Oder is quite noticeable. I wonder what the people following me thought. Guess you would have to be involved with aircraft to know the smell.