high octane jetting

[JACK STRAW]

do you have to re jet if you go from 93 octane to an additive that puts it around 104 octane?

[Stickman400]

No, but there's no point in having that high of octane if you don't have a high compression piston in it. And honestly most of that octane booster is crap and doesn't bump the octane by more than 1 point. There is 1 brand that is proven to but I don't think it's available in a store or gas station.

[2001400exrida]

Yeah, there's no reason to put high octane into a stock motor, they don't need it and won't benefit from it. If you want benefits, buy a race fuel. VP and Sunoco both make 91 and 93 octane race fuel. Many times i see people say oh you don't need race fuel because it won't do you any good, but the truth is, you can run 93 octane VP fuel that is a performance fuel and you will see performance gains. Is it worth the price tag? probably not, but I know many guys who run pump gas motors and they run the VP 91 or 93 octane and swear by it.

octane boosters aren't good for much. There are some good quality fuel additives like blendzall gold and some of the klotz stuff that actually has lead and castor oil in it for better engine lubrication. I personally run 100LL from my local airport on my 13:1

[Stickman400]

I wouldn't mind trying some of that 93 octane Sunoco or VP. I run 93 but it's just the local County Market Express gas station 93.

[2001400exrida]

^^yeah, the good thing about the race fuel is that it doesn't have ethanol. The main reason i get the 100LL from the airport is because it's only $5.00 a gal. and it is low lead and zero ethanol.

[ish416]

Anything under 11:1 is pointless running anything higher than 93 octane. That said, on hot days, a bit higher octane wouldn't hurt. Also, try to make sure you are running ethanol free 93.



^^yeah, the good thing about the race fuel is that it doesn't have ethanol. The main reason i get the 100LL from the airport is because it's only $5.00 a gal. and it is low lead and zero ethanol.


100LL is good stuff. Only downside is that it burns out the packing in your muffler faster than regular pump gas. Also, people asking questions about why your fuel is blue is always funny.

[400man]

why is ethanol bad on small engines??

[ish416]

why is ethanol bad on small engines??

It's not really. It's just bad on some rubber and plastics and is also very water absorbent.

Ethanol requires about 35% more fuel to create the same power as gasoline. Finding ethanol free gas means that per drop, you have more power, better fuel economy and it will last longer in a fuel can or in your gas tank.

Also, ethanol blends can very greatly week to week so the consistency of the fuel can change quite often. In my case, every time I purchased fuel I would usually have to play the carb to get things dialed in. This was never needed on regular or AV fuel.

[2001400exrida]

Ethanol is not bad for the motors, the problem is that it doesn't store well and is not as stable/consistant as the 100LL.

while e85 is not generally as effecient in vehicles, when you setup these sport atv's to run ethanol is can provide the same and sometimes more power than unleaded fuel. afterall it is 85% alcohol.

i personally cannot find any fuel stations around here that don't have ethanol, which is another reason i go to the airport.

[ish416]

while e85 is not generally as effecient in vehicles, when you setup these sport atv's to run ethanol is can provide the same and sometimes more power than unleaded fuel. afterall it is 85% alcohol.


The only reason you can make more power with E85 over regular fuel is because it burns cooler than gasoline. That allows for increased compression and timing, that is what makes more power, not the fuel.

Just wanting to clarify that.