Race Gas Vs. Premium Gas Whas the deal???
Posted September 20, 2001 - 09:33 PM
Posted September 20, 2001 - 09:39 PM
Posted September 20, 2001 - 01:03 PM
'99 WZ/YR (you choose!) with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, OEM YZ tank, IMS YZ seat.
Posted September 20, 2001 - 04:51 PM
Posted September 21, 2001 - 05:21 AM
Posted September 21, 2001 - 07:41 AM
I read that in a tech article, about the cooler engine temps, although it does make sense.
I have read several magazine articles not run race fuel in these bikes...[???]
Posted September 21, 2001 - 07:48 AM
you *CAN* see some real gains by using a good fuel (like VP C12 or MR1) and jetting it to take advantage of that fuel.
my 250F has NEVER seen pump swill and it never will.
plus, i *KNOW* i won't have any combustion problems in deep sand or mud.
Posted September 21, 2001 - 08:00 AM
Posted September 21, 2001 - 11:30 AM
Originally posted by NH Kevin:
Another side note on race fuel, it runs COOLER! The higher octane fuel has a lower flashpoint, i.e. it ignites at a lower temperature...meaning the engine also runs at a lower temperature.
Ok, let me straighten this out before it gets going for too long. The OCTANE rating of a fuel is an indication of that fuel's ability to RESIST, yes RESIST burning. The higher the OCTANE number, the MORE RESISTANT the fuel is to igniton. Why do we need this? Higher compression engines, or one's that are also timed closer to TDC, require the fuel to still be in vapor form (i.e. not auto-ignited) when the spark is delivered to the cylinder. The higher the compression, the more heat produced in the cylinder (an increase in pressure also increases the temperature). If that increase reaches the temperature of the fuel's flash point, then the fuel will auto-ignite (or detonate, as you might hear from motorheads). So, you must have a high enough octane rating to keep the fuel from igniting prior to spark delivery. If your engine is detonating under normal use, use a fuel with a higher octane rating (and therefore HIGHER flashpoint). BUT, if your engine is running fine on 93, putting 108 into it will only cause you to spend more money for your gas (speaking from a purely detonation / octane rating viewpoint). You get nothing out of it. If you really wanted to know what the performance gain possibility was, get ahold of the manufacturer of the race gas and find out what the specific internal energy is and compare that to regular gas. I think you'll find that they are almost identical.
*plink, plink* my two cents.
Posted September 21, 2001 - 02:38 PM
Originally posted by Butta:
Ok, let me straighten this out before it gets going for too long.
Butta, I'll add two more cents to this...
Using higher than needed octane can also result in less than complete combustion of the fuel (because as you say, it's a little harder to ignite), which in turn can lead to excessive carbon deposit build-up in the combustion chamber. This is a viscous cycle in that the deposits raise the compression ratio which eventually may REQUIRE the higher octane fuel to prevent detonation. A worst case scenario may involve the piston and/or valves having trouble moving freely due to this build-up.
Because the combustion may be less complete when running more octane than needed, you're also probably making less power than you could. The general idea is to use an octane level that is barely high enough to prevent detonation.
Jerry in Deltona, FL
Posted September 21, 2001 - 08:27 PM
01' WR426,YZ timing,EMP #2,#48Pilot,#100PAJ,#172 Main,BK mod,stock pipe-no baffle, open airbox,Gray-Wire Pulled,K&N Filter, throttle stop mod,CA Street Legal,Pure SuperMotard 17 in. wheels, 15/46 gears,ProTaper bars,
Posted September 21, 2001 - 08:33 PM
Now I have to find my technical instruction from other sources...!
Posted September 23, 2001 - 04:29 AM
Big difference. Knock is caused by pre-ignition, This means ignition by means other than a spark plug. As compression goes up, the chance for pre-ignition (also called auto-ignition) goes up. Octane helps eliminate this.
Due to substantial differences in formulation. nobody should expect to get a performance gain from simply pouring race fuel in their tank without rejetting.
Posted September 23, 2001 - 06:16 AM
Posted September 26, 2001 - 06:32 PM
Posted September 26, 2001 - 08:56 PM
I think you are right. For trail riding, premium pump gas should be fine. I would only suggest racing fuel if you are....well....racing!! Trail riding does not put the load and heat into an engine like racing does.
Life is too short, work hard...play hard
Sponsored by Yamaha of Cucamonga and Larry Roeseler's Stroker Fourstroke Speed Equipment
Posted September 27, 2001 - 07:32 AM
Y2K WR400FM,Answer top tree w/Accu-Trax clamp,Pro-Tapers(CR-Hi w/ EE handguards),Devol Rad. & frame guards, Guts tall soft foam w/ ballistic cover, 14/52 w/DID VM X-Ring, Kouba-T,Michelin M-12's ft.& rr.,12 oz. flywheel weight, Zip-Ty Racing Link & Shark Fin, Cycra front rotor guard and T.M. Designworks Chain guide, buffer & chain wheels. Street legal except for the non-"DOT" tires.
[This message has been edited by BlueThunder (edited September 27, 2001).]