Anyone running 100LL av-gas?

[EMX5636]

I'm thinking about swapping my 12:1 440ex from a 50/50 mix of c12 and 93pump to straight 100Low Lead (LL). I have heard of ppl doing it in dirtbikes, but not sure if anyone on here has tried it. I have been told it burns better, so you may have to richen up your mixture. So, the main question is, is it worth the swap? It's cheaper by a bunch, I do mx my quad, i just don't want to blow it up. Thanks, all.

Justin W

[F-16Guy]

I've run it several times both straight and 50/50 with no problems. It may or may not have an effect on jetting for you, but I didn't notice anything significant. The only down side to running leaded fuel is the deposits. If you run a leaded fuel for a prolonged period of time, lead deposits may begin to form and foul your plug or build up in the combustion chamber. That applies to leaded race fuel too, not just 100LL. If you're running 50/50, it will probably be diluted enough that you won't have any issues. The good thing about 100LL, aside from it being cheaper, is that it's purely MON (motor octane number) rated, meaning that the rating came from actual engine testing, not the lab. The Research Octane Number (RON) is usually a bit higher than the MON, so on pump gas they average the two out to make it look like higher octane fuel than it may actually be. 100LL is no BS 100 octane running through your engine.

[GPracer2500]

One minor point of clarification: Research Octane Number is kind of a misleading label. It is not some theoretical number generated on paper by a scientist verses Motor Octane Number being generated through actual testing of fuel samples. Both MON and RON ratings are determined in the same fashion--actual laboratory testing in a special variable compression test engine. The only difference is the parameters of the test. MON is the more demanding test so MON numbers will almost always be lower than RON.

Waukesha Engine (a division of Dresser Inc.) is the only manufacture of this testing equipment. They've been doing it since the late 1920's.

Here's what the beast looks like:
http://www.waukeshaengine.com/internet/businessunits/waukesha/pages/images/cfr_f1_f2.jpg

[EMX5636]

So 100LL is probably actually a higher octane than the 112/93 50/50 mix i'm running now? I know mixing fuels isn't always exact, and the local airport is nice to you if you pay cash in a can, so to speak. I have to re-jet now anyways, so I guess I might as well swap and only do it once... Thanks,

Justin

[Wheelie]

I ran straight and 50/50 AV gas mixed for several years in my quad without any problems. It keeps detonation at bay and smells good.

Recently, however, I've been running 50/50 premium and 110. I don't notice any difference in performance between race fuel and AV gas, but my quad does seem to run a bit smoother on the race gas.