High Octane Fuel

[bm77164]

100ll

ok... I have a PG turbo M8...was thinking about mixing some 100ll 50/50...Not sure what the airport here will say...i know you cant drive out there to get it...its a towered field...I gas a cessna there once in a while when i rent it, so maybe ill just grab a couple gas cans and try waking up to it... one question tho..my m8 runs ok an 91 will i need to retune it with the 100ll and if so will the avgas cause it to run lean or rich....thanks for the help guys

 

[jim]

I built a graph based on industry numbers. Premium non-ethanol mixed with av gas ratios. As for jetting for avgas...loaded question. You have to jet for the octane...keep the pistons cool enough to not detonate under a long pull. Whenever I have run avgas, I jet as normal. Technically, avgas has a lower density and thus you should richen up to keep the same air/fuel ratio. However, av gas seems to work really well against detonation in the two stroke motor so I've never had to change the jetting when I add it. Actually had a buddy who's motor was getting hot and going rich on longer pulls...added some av gas and it cleaned it up on long pulls. My guess is it cooled the pipe down a bit and kept it from getting as hot...kept it cooler and leaner. My experience...but every sled will be different. How's that for a non-answer? Lesson I ever learned was it balances out when you find the right octane and it much less finicky. Had the same issues with too much octane. Keep it hot enough to burn the charge...not so hot to burn the pistons.

 

[wasatchcomm]

ok... I have a PG turbo M8...was thinking about mixing some 100ll 50/50...Not sure what the airport here will say...i know you cant drive out there to get it...its a towered field...I gas a cessna there once in a while when i rent it, so maybe ill just grab a couple gas cans and try waking up to it... one question tho..my m8 runs ok an 91 will i need to retune it with the 100ll and if so will the avgas cause it to run lean or rich....thanks for the help guys

depending on you elevation you ride, your target boost you want to run, and your kits features, will determine what you need to do for fuel/octane.
pump gas kit usually means stock injectors/fuel system only.. which means you can only run so much fuel through your stock setup.

you dont want/need to run more octane than you setup needs.