100LL has less tetraethyl lead than 80 avgas. Hence the name 100LL

Been running 100LL for the last 10yrs in my boats , no detenation problem whatsoever, the marvel mystery oil is a good idea.. That $2.00 a gallon you can get it for is a great price .. I pay $2.50 Tom

Brad, the 100LL would be a good idea. You shouldn't have to change anything, the engine will likely make more power than with 93 Octane.

How about mixing with 93? We sometimes keep the boat at a private airport(my Father in laws). We will top off with 100LL, last year at $1.85 a gallon, and I always figured it was good for a safety margin. What do you guys think?

Plus it smells good too!

Brad I use a lot of 100 LL it is much better than 93. I add about 1/2 pint of 2 cycle oil to 20 gal.
LOY

Hate to be on a different side of the issue, however...

1) Octane be damned...burn rate is what it is all about. Check out http://www.factorypro.com/tech/fuel_..._vs_power.html

2) This topic was aired out very well on the APBA site. Various gas companies had great web pages explaining why NOT to burn avgas in autos, boats etc. but i can't remember the links. I'm sure someone will.

3) Putting oil in avgas undoes the octane rating gain (diesel fuel is about 40) and makes a slow burning fuel burn slower. As the article says, you want the fastest burning fuel you can get without knock. The higher the octane rating the slower the burn.

4) The energy in a gallon of fuel has nothing to do with the octane rating. Harnessing the maximum amount of energy for the fuel you are burning with ignition and valve timing is what it is about.

Ted

Ted, for reference Brad Perry's engine is a blown 800 plus horsepower application. Your information is correct for milder engine combinations.