racing916

I have been buying race fuel from my local speed shop or at the track for years now and when I called today the price of 110 Leaded was $9.00 a gallon. I am assuming it's the same up at Watkins Glen, if not more.

I always hear you can buy low lead aviation fuel for cheap, so I went down to my local private airport and paid $5.20 a gallon for the fuel. Just an FYI, saved me over $100 bucks. Here is a link to see if you have an airport near buy that sells high octane fuel. http://www.airnav.com/fuel/

Steve

Veloce Raptor

7.75 at Watkins Glen yesterday.

racing916

$7.75?? Seriously, I am shocked. It will be up to $9 when the Porsche clash comes to town

Veloce Raptor

I was surprised too, since it is $9 at Texas World Speedway.

mark kibort

What does your engine config look like that it needs 110 octane? High compression?

a lot of folks with street BMWs and porsche go to the race track and buy high octane gas to help what they think will give them more power.

winders

From another forum:

We asked Sunoco's Wurth about using aviation fuel in an automobile engine. He was emphatic when he said, "Don't do it. Even though Sunoco is a major producer of aviation fuel, this fuel is specifically blended for aircraft engines. Aircraft operate under very different conditions than automobiles, and the fuel requirements are quite different as well. Aircraft engines generally.... run within a very narrow rpm range. There's no need for transient throttle response in an airplane because after the pilot does the initial engine run-up, the throttle is set in one position and the rpm doesn't normally change until landing. Also, airplanes fly where the air is cold and thin, and the atmospheric pressure is low. These are not even close to the conditions your street machine will see on the ground. Also, since most piston-driven aircraft cruise at 3,000 rpm or so, the burn rate of aviation gas is much too slow for any high performance automotive applications."

Scott

racing916

Mark,

I don't usually run just 110 octane, I mix it with 93 to get above 100 octane and save my wallet. My engine builder said it was fine to mix the two. I usually mix them 1 to 1. My motor is a high compression motor that needs above 93 to work properly, not a street car.

racing916

[QUOTE=winders;8552305]From another forum:

We asked Sunoco's Wurth about using aviation fuel in an automobile engine. He was emphatic when he said, "Don't do it. Even though Sunoco is a major producer of aviation fuel, this fuel is specifically blended for aircraft engines. Aircraft operate under very different conditions than automobiles, and the fuel requirements are quite different as well. Aircraft engines generally.... run within a very narrow rpm range. There's no need for transient throttle response in an airplane because after the pilot does the initial engine run-up, the throttle is set in one position and the rpm doesn't normally change until landing. Also, airplanes fly where the air is cold and thin, and the atmospheric pressure is low. These are not even close to the conditions your street machine will see on the ground. Also, since most piston-driven aircraft cruise at 3,000 rpm or so, the burn rate of aviation gas is much too slow for any high performance automotive applications."


Ohh ****.. Thanks Scott! so I am out a few bucks, disregard my first post . In my gut I knew it was probably to good to be true and I should suck it up. Many motocross and drag race guys use it here so I assumed it would be ok. I did some reading after your post, and every post I found was "burnt pistons" etc, etc... Thanks for the post you probably just saved my motor. Off to buy real race gas now!!

Bri Bro

E85 has over 100 octane rating but you need to bump up your injector duty cycle (Carb jets) by 25-30%. Costs less then regular unleaded but with the 25% increase in fuel consumption, that is a little misleading. Still way less then 7-9 dollars a gallon.

mark kibort

why would you have to bump injector duty cycle? to keep the ideal mixture for power of this slightly differnet fuel?

can it provide more power since you need less air per unit volume?

mark kibort

That's the idea behind high octane, to slow the burn rate. I dont think the air temp and pressure have much to do with it, as its all about mass flow and most have turbochargers which drive the temps way up too.

Ive heard of many racers using Aviation fuel with no issues. I wonder what the problems are and what they do to the blends to make them different. It is known that they have lead, but that might not be an issue for race engines

I think we need some credible testimonials and another opinion brefore tossing out the Av-gas option.

People always are tossing in race fuel into their street cars like they think its ging to make them go faster. they fail to understand that race gas, if you dont tune around it, will actually make less HP. with all the modern knock sensors, its a feble waste to put even anything above regular in your street car.(unless you are tracking it) Ive used 89 octane for the tahoe and BMW for 10 years with no issues, or pinging. Ill admit, when gas was cheaper, i put a tank of premium in one time. I still dont know why. the marketing power was STRONG!!!

Mark

mark kibort

so, I dont think AV gas is really any differnt. we have heard about lot of old wives stories of burnt pistons, etc, but is this fact or fiction?
AV gas is near the same as Race fuel, without some of the additives that you might find in race gas.

Here are some comments from someone that knows more about this than I do. However, there are lots of guys using AV gas successfuly, with no issues.

enjoy:

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,
Poole

winders

No, it is not. Please get your facts straight. The higher the octane rating of a fuel, the less likely it is to detonate prematurely (before spark). In other words, the higher the octane rating the more resistance there is to knocking.

Why do I bother??

Scott

racing916

Here is what I found, that has made me decide not to use AVGas. This and Scott's post.

"Avgas is less dense than most racing gasolines. Instead of weighing about 6.1 to 6.3 pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per gallon. The racer must compensate for this by changing to richer (larger) jets in the carburetor when changing from racing gasoline to avgas.

The other major difference is octane quality. Avgas is short on octane compared to most racing gasolines. Many racing engines with "quick" spark advance curves or with no centrifugal advance have more spark advance at low rpm than avgas and some racing gasolines can handle. The result is detonation, especially during caution periods in circle track racing because all of the spark advance is "in", rpm is low, and part throttle air fuel ratios are too lean for the operating conditions. If the driver does not "work" the throttle back and forth, pistons can be "burned" which melts away part of the aluminum piston material. Inadequate octane quality is one of the quickest ways to destroy an engine. Pistons can be severely damaged during one acceleration where detonation is present and the racer may not know what is happening until it is too late.

For maximum performance and power from a racing engine, racing gasoline will normally provide better performance than avgas. Avgas can be a good gasoline for some applications, but since most racers do not know the octane requirement of their engines, they would be better off with a "real" racing gasoline that will give them the overall resistance to detonation that they need to protect their investment. If someone has spent from $15,000 to $50,000 or more on their racing engine, it is foolish to cut corners on gasoline be sure you have a gasoline with adequate octane quality."

333pg333

Disregarding whether or not you should in fact run as low an octane as possible to achieve your desired outcome, your desired outcome might change with higher octane simply because it allows you to run higher boost or c/r which in turn gives greater power or response....sometimes you can do both of course.

With E85 you generally need to run larger injectors and fpr + often extra fuel pumps to run ~25% more fuel needed to achieve the correct afrs. In turn it allows you to run some seriously high boost pressure.