octane

white eagle · #1 Fri, July 31st, 2009, 09:50 AM

is there any problem associated with running higher (110)octane fuel in your truck
there is a station that has 110 race fuel that I want to try

maybe a mix of 93 and 2-3 gals of the high stuff

408F150 · #2 Fri, July 31st, 2009, 08:32 PM

There's no risk of running higher than normal octane (assuming it isn't packed full of cheap additives) as far as I've heard, however our engines aren't efficient enough to see any benefit from it unless you're driving around in heat so high you're getting premature detonations (pinging). Higher octane's only benefit in most engines is it takes a higher temperature to ignite the fuel so it allows higher compression pistons and more aggressive cams to be used. I've put aviation fuel which is I think 108(?) in my quad that is engineered to run on 91 and saw only a slight difference, and that's in an engine with much higher compression than my truck. Could be wrong but that's just what I've experienced first hand

***Power Hungry*** · #3 Sun, August 2nd, 2009, 02:12 AM

Like 408 said, unless you're running high compression or forced induction, there's not much benefit to running anything over about 95 octane. Higher octane doesn't make more power on a low compression engine, it just resists detonation/preignition.

Another thing to keep in mind is that high octane fuels such as aviation fuels are "drier" than normal automotive grade fuels. This can possibly result in advanced wear of the exhaust valves. This used to be a much bigger problem years ago with cars designed to run leaded fuels, but even today's vehicles which run hardened exhaust seats and alloy valves can still see accelerated wear due to the lack of lubricant additives in aviation fuels. Even many motorcycle manufacturers do not recommend running these types of fuels in 2-stroke engines due to the lack of lubrication on the rod bearings, rings, and piston/cylinder surfaces.

This is a very interesting article on fuel octane and is worth the read if you have about 30-40 minutes to kill. (I read kinda slow, too.) http://www.turborx7.com/fuel.htm It even has a section on octane, performance, and tuning. I hope it's useful.

Take care.