Avgas

[SPEC]

Master is right on this one.  (He is lots of times, I just don't let him know) 



Don't let it go to your head

[fabr]

Too late!!!!

[Punkur67]

Im not too worried about paying the extra for fuel.
 

[Admin]

Im not too worried about paying the extra for fuel.

Must be nice to be 25 and have your deep pockets in this economic depression...

[fabr]

That's not the point.

[Yummi]

As a percentage of the total weekend adventure, including toy costs / depreciation, etc, my fuel costs are close to nill.  Raising nill by 50% still results in nill. 

[fabr]

If you start from scratch I would suggest going with a setup that is happy with pump gas.Otherwise run in it what it is built  for.SIMPLE

[BDKW1]

While modern cars may not need lead for the valves, the current crop of MX thumpers have serious valve life problems that are really helped out but a little lead. I have run a 50/50 mix of avgas and super unleaded in My 2 smokers for years. Their rings really like the stuff.

This came up recently on another web site and here is what someone in the business had to say.

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

[Admin]

Interesting read BDKW1, i thought avgas was only for airplanes from what i have read in the last 4 pages or so, i got a few buddys who use to pour that shit in there street cars, and they always seem to run....

[fabr]

It's interesting how the info given ignores the new unleaded race fuels.IMO that was very good outdated info.

[Admin]

please explain outdated, isnt avgas the same it has always been?

[fabr]

I don't disagree with 95% of the article. But there are a couple of inaccuracied that cast a shadow on the rest.One glaring misstatement is that ALL engines have had hardened valve seats since the late 60's. Ain't so. It states that all racing fuel has lead.Ain't so. It has some other innacuracies also. But IMO the only statement that is made about AV gaas that means a thing is this:"Av Gas is NOT designed for low RPM motors." That is why it is not a good choice for engines that require throttle response.Simple as that if for no other reason.