Will I benefit from 100LL?

[kswayze]

My 02' has a fresh Wiseco Pro-Lite top end, head shaved 0.020, timing plate set to +4. Both cylinders are testing at about 150 LBS compression and I want to know if 100LL will be better then just premium??? I found a small airport locally that sells it for $3.99 so that is not even that much more then premium. Let me know what you guys/gals think.

[Fullthrottle02]

here is a good write up comparing the 2. personally i would stick to fuels designed for your intended purpose. If your banshee happen to sprout wings though,be my guest.

 

Im sure there are plenty of people on here that have used it with no issues at all, I just dont care to take the chance.

 

Click

[firebanshee]

You would see no benifit from switching fuels,your motor doesn't need race fuel.You don't need race fuel till about 160.

[kswayze]

Thank you for the input and I will just keep using what has worked for years. I was just not sure because I have seen people claim that you need race fuel for 150 pounds but if I dont, I wont use it.

[GrMeyer]

If your wanting added insurance, you can just at one gal of 100ll to 4gal of premium. It will slightly bring up the oct. for 4 gals of 91. it would bring it up to 92.8. For 93 it would bring it up to 94.4

 

I run 3 gal of 100ll and 2 gal of 91 on 155psi. The only reason why I do this is because I dont like Arizona fuel. And just having the added insurance is safe on my books.. Fire knows his shit and alot of other people do on here as well.

[AKheathen]

you should be fine with 93. what the discussions on 100ll is all about is av vs. race fuels. guys can say what they want out of speculation, but when you have tha octane requirements to run it, av is just about some of the est you can put in there. federal regulations for purity/consistancy are just about the opposite of race fuels, since any aircraft you put it in is gauranteed to have peoples' lifes on the line, and race fuels, they just care about tax and shit, so quality depends solely on the manufacturer. avgas does atomize really nicely goin to the higher elevations as well, which makes it a great choice for mountain ridin, but with any higher oct. fuel, you need the octane/timing requirements, or you will actually loose power

[GrMeyer]

you should be fine with 93. what the discussions on 100ll is all about is av vs. race fuels. guys can say what they want out of speculation, but when you have tha octane requirements to run it, av is just about some of the est you can put in there. federal regulations for purity/consistancy are just about the opposite of race fuels, since any aircraft you put it in is gauranteed to have peoples' lifes on the line, and race fuels, they just care about tax and shit, so quality depends solely on the manufacturer. avgas does atomize really nicely goin to the higher elevations as well, which makes it a great choice for mountain ridin, but with any higher oct. fuel, you need the octane/timing requirements, or you will actually loose power

 

Well play'ed Sir...

[jayzx10r]

The Quick Answer To your Question:

If you are not experiencing pre-ignition, you don't need to run higher octane.

The truth of the matter is the lower octane you can run the more power your engine makes, limiting this statement solely to a fuel choice parameter. Octane is resistance to ignition so unless you need it because of high compression, poor combustion design, or some other reason that is making the fuel ignite early, just run premium.

 

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Me, I use 100LL at a 50/50 mix with pump premium because I have 165lbs compression ASL. I've easily burned through 300 gallons of this mix and my piston, rings, cylinder all look great so far.

 

I've mixed a gallon of 100LL to 3 pump premium for 8 years in my YZ250 and finally got around to changing the piston out. Looked perfect and to tell you the truth, I would have been comfortable just re-ringing it...but since I had a complete kit I just did the whole enchilada.

 

Maybe it's the result of using the Yamaha 2R, but I can't see a bit of harm running AVGAS. 2-strokes love lead and 100LL is proven in my book.

 

One has to think the article posted by the Union 76 rep back in 1995 may have it's conclusion based on the fact that "race" fuel is a gravy commodity that earns the company 4x the profit margin. AVGAS is the cleanest fuel manufactured....period.

One of the tests done mandates they pour fuel on a stainless steel plate and there be absolutely no residue after evaporation.

 

A side bonus: AVGAS has a shelf life of a year while standard fuel has a 5 week shelf life recommendation.

 

My $0.02

Jay in SanD.

Edited June 5, 2010 by jayzx750