Upgrade to enjoy this feature!
Vital MX fantasy is free to play, but Premium users receive great benefits. Premium benefits include:
- View and download rider stats
- Pick trends
- Create a private league
- And more!
Only $10 for all 2026 SX, MX, and SMX series.
" Re: 100ll Avgas Ok to run?
Real info on Race Gas/Av Gas...
My experience comes from 7 years as the western states representative for 76 Race Fuel, Unocals 40 hours Advanced Products course, Working personally with Tim Wusz (senior performance products Rep for Unocal, Tim was responsible for Unocals race fuel development for 30+ years). I have also met and discussed fuels/motors with just about every engine builder in every facet of racing in the western United States. I also conducted Educational Seminars at the Fred L. Hartley Institute in Brea in which we would invite Engine Builders for a tour of Unocals testing facilities and do live octane tests on any gasoline they would choose to bring to the seminar. Included in the training we would demonstrate live tests how Distillation curve, Reid Vapor Pressure, Specific Gravity, Octane Rating, F;ashpoint, etc are conducted and the importance of these numbers. Some of you will remember me from contingency with my 76 Racing Gasoline hospitality trailer in the 1990's.
Through the 50's, 60's, 70's and 80's Av gas was the base product used for most racing "gasoline". VP, f&L, Turbo Blue, and Trick all used AV gas as the base product. They would buy a tanker (8000 gallons of Av Gas) than add other hydrocarbons/TetraEthylLead (TEL) to the base, drive around the block stopping and accelerating the truck/trailer until they felt the product was mixed well. Obviously this was not science, but it worked for most racers only because most racers use a higher rated octane than they actually need.
In the mid to late 1990's VP graduated to buying there own base product and do there blending of products in a much better fashion. Turbo Blue and Trick have since been bought Sunoco and are blended by Sonoco. Trick was purchased by Phillips 66 and has continued to be blended by Phillips 66.
The only two companies I am aware of who "cracked" there own base product is Sunoco and 76. And as we all know, 76 race fuel is no longer available, leaving only one true manufacturer of Racing Gasoline....Sunoco.
AV Gas has a MOR (motor octane rating) of 96, R+M/2 rating of 100, and ROM (Research Octane Rating) of 106.
AV Gas is lighter than racing gasoline thus more fuel/larger jetting is required. Jetted correctly you should not experience a lean burn at WOT.
I would not use AV Gas as a cleaner. The amount of TEL (2 grams/gallon) and other hydrocarbons makes it extremely carcinogenic. Same goes for all other racing gasolines.
Shelf life is NOT better. The reason pump gas won't last as long is because street gas has extremely lightend hydrocarbons to help your car start and idle. Racing Gasoline does not have these light end hydrocarbons needed for idle and starting, hence the reason race motors start and idle poorly.
Av Gas is NOT designed for low RPM motors. AV Gas is designed to not detonate/preignite causing detination. This would be the same design as race fuel. If you compare the "distillation curve" of AV Gas to Race Gas, you will find they are almost identical. The "distillation curve" controls the speed of burn across the combustion chamber.
You will only "spit" gas out the exhaust pipes if you run to rich or include a supercharger/turbocharger on your engine and "overdrive" the blower. Example would be the bitchin flames you see at the starting line of a drag race on normally aspirated engines and the long flames you see on all "blown" engines.
The LEAD (TEL) added to AV Gas is to increase the octane rating only. All heads these days have harden valve seats. There is no need for lubrication of the valve seats. All engines have come with harden seats since the late 60's.
AV Gas is not formulated for High Altitude. and will have very little, if not any performance differences vs racing gasoline. On the other hand, commercial grade fuels (87, 89, 92) will definitely enhance your performance due to the commercial fuel being oxygenated. The Oxygen enhancers added to commercial fuel is only for California Smog laws.
Advancing timing on your motor will definitely help with AV Gas and Race Gas due to its slow burn characteristics. On the other hand, be careful if your running commercial grade gasoline, more timing can cause detonation/preignition quit quickly.
AV Gas does not go BAD faster. It is extremely consistent. The MOR is only 96, whereas Sunoco Purple or VP C12 is 104. A rating of 96 is good for up to 10:1 on Steel heads and 12:1 on Aluminum heads with water cooling. Air cooled motors run much hotter.
Buying a higher octane for a $20-50K motor is the cheapest insurance available.
Remember this...OCTANE is a measure of a fuels ability to resist detonation/preignition. The higher the Octane number, the slower the fuel burns. Technically speaking 87 Octane fuel will develop more power than 118 Octane fuel. With this said, you should see gains in throttle response and HP by mixing commercial fuel and AV Gas/Race Gas. You now have some light end Hydrocarbons for throttle response and heavy hydrocarbons/TEL for detonation resistance.
Bottom line... use the most consistent fuel you can find and create horsepower by moving as much air as possible though the combustion chamber.
I have no reason to be bias here as I have moved on to much greener pastures. See you on the race course.
Good Luck,
Steve Poole "
Most places, you just walk up to the counter, pay for how many gallons you want and they just walk with you to the back of the pumper truck and fill up your can. We were filling up 55 gallon drums every 3 weeks for a while.
About the use of the fuel..... we ran a group of bikes 125's and 250's, 3 amateur and 2 experts for over 4 years on 100LL and every one of us has a lot of plastic trophies to show for it and not one nuked 2 stroke engine.... Ever. That being said, I run race gas now.
Ride safe
The Shop
Luxon 4-Post Bar Mounts
$189.95 - $239.95
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Free shipping: VITALMX
Even the Japanese Yamaha factory riders used it when they tested here once the fuel they shipped from Japan or USA ( they sometimes showed up with VP or Sonoco) was used up.
I have seen Would superbike and GP teams use it here back in the day when they had to.
Race fuels are better now days but 100/110LL is streets ahead of Pump and way better to run in a two stroke. I think we worked out engine life was halved on unleaded compared to Leaded, back in the day we had a big old bunch of crank bearing wear on Unleaded that was put down to detonation. We ran a sensor under the spark plug and it counted the detonation and from memory the count was at double the detonation.
Leaded fuel sales is so tightly controlled now in Australia you have to have a log book to show how and when you used the fuel you bought! and basically the only guys allowed to use it in competition are vintage bike competitors LOL
AV gas works fine at any RPM as long as the bike has been rejetted for it.
( which has already been said but you don't believe them)
we started using av gas in our race bikes 30 years ago long before race gas could be bought in a can...
Pit Row
It contains NO ETHANOL.
ethanol is what is screwing up your carbs, gumming up the bowls, and turning into a gel in your gas tank.
Post a reply to: AV gas in a 2 stroke?