Leaded fuel is OK to run on no catalytic cars! Race GAS :)

[PrOxLaMuS©]

Looking for extra power? Ever heard of Race Gas?!!

"Race Gas" is just really really high octane fuel, which burns more efficiently, and slower to provide addition power, and a smoother running engine.

But RACE gas is EXPENSIVE, sometimes $7.00 a gallon!

Why not aviation fuel?

Airports sell 100 LL everywhere and it's blue! Damn cheap too!

Airports sell the following...

80/87 RED

100LL BLUE

100/130 GREEN

Jet YELLOW (DO NOT USE!) Karocine (spelling?)

Per gallons from $2.75-$3.75

Now, anyone can go to an airport and BRING YOUR OWN CONTAINER and buy some gas and fill it up. It is illegal to run "race gas" or high octane gas in vehicles running on the street, only for race and track.

Now there are 2 diff. kinds of basic automotive fuels, aside from jet fuel, diesal, etc.

Leaded and Unleaded. What's the difference? Is it safe to use?

------------------------------

"The Unites States and most other countries switched from leaded to unleaded

fuel years ago. The lead additive, tetraethyllead, retarded "preignition"

in gasoline engines. Preignition causes engines to run rough, and to not

shut off when the key is turned off. The suppression of preignition is

measured by the gasoline's "octane rating". A good high-octane gasoline

allows a standard engine to run smoothly. Leaded gasoline also protected

some older car engines from wearing down by covering soft engine parts with

lead-containing material.

Facts:

* Lead in fuel serves as a lubricant, raises the octane rating and serves as a cushion for the valve/seat interface.

* Most STC's, e.g. Peterson, for use of auto gas (mogas) in a certificated engine exclude the use of auto gas during the run-in and break-in process.

Discussion: Aircraft piston engine valve seats, especially the exhaust, operate at much higher temperatures than automotive, motorcycle or other altitude challenged motors. Elevated temperatures present three challenges to the design requirements for exhaust valve seats, 1) the oxidation resistance of the material must stand up to the harsh environment created by exhaust gases, 2) the coefficient of expansion for the material must be close enough to aluminum so that the seat does not fall out, and 3) the material must resist micro welding to the valve face when the valve closes on the seat. These three requirements severely limit the number of candidate materials from which to choose. A common characteristic of all of the candidates, however, is that they have a high nickel content, a material that forms a spongy oxide on the surface at elevated temperatures.

In the early days of air-cooled aircraft engine design, it was discovered that the spongy oxide absorbs lead that is left behind from the combustion of leaded fuel. The oxide matrix filled with lead forms a layer that not only cushions the valve face when it closes on the seat but also serves as a high temperature lubricant so the seat and valve face do not weld together. When the nickel oxide layer is not filled with lead, premature wear of the seat is a high probability. It is extremely important to have lead present in the combustion chamber during the initial hours of operation if the design life of the cylinder is to be realized. This is especially true for higher compression ratio or turbocharged engines. Once the lead/oxide layer has been created during run-in and break-in, it will maintain itself reasonably well even if auto gas is burned for several fill-ups. Based on experience, ECi strongly recommends the use of leaded fuel at least every few tanks so that the lead/oxide layer is maintained. The higher the compression ratio, the more important the use of leaded fuel becomes.

On the other hand, lower compression engines are plagued by lead compound build-ups in the valve guides that can lead to valve sticking. The 80-87 fuel these engines were designed to use is not universally available, and some of the available 80-87 fuel has zero lead content. The original version of this fuel had up to .5 ml/gal of tetraethyl lead, which was just about right for these engines. The 2 ml/gal of tetraethyl lead in 100LL fuel is a real challenge for engines like the C-85, O-200 or O-235.

Auto gas (mogas) has greater variables for chemistry, vapor pressure, contaminants, etc. which change with locale and season. It is not a source controlled product such as aviation gas. The adverse effects for aircraft piston engines that can be attributed to auto gas are well documented by gasoline companies and ECi as well as the engine manufacturers caution all owner operators to use auto gas only with full knowledge of the problems, appropriate care and consideration of possible limits to warranty.

Anyway besides a bunch of facts from various sources.....

it is OK to use on cars with no-cat's... but it must be used SAFELY and without harm.

I have no responsibility for the actions or consequences resulting in using leaded fuel.

But i figured maybe people would want to know a cheaper alternative, and the basics of what type of fuel can a vehicle run.

[Bambikiller240]

Kerosene is how it's spelled.

People (at least people in the know) have been using or mixing Aviation Gas for use in automobiles since at least the 1960's.

The main question is, Does your engine need, and can it really use the higher octane rating to achieve anything other than emptying your wallet a a quicker rate? If your race engine does, you probably have enough $$$ and are too busy to bother with the added hassle of lugging containers around to airports on race weekends.

[Z Kid]

And if your car is not pinging on stock fuel, then race gas with its higher octane/flash point is only going to slow your car down. And not sure about the rules in the US, but if you are caught using avgas on the street, god help you because the fines are huge in SA. As well as the fact that avgas is very hydroscopic, and when left in the tank will turn milky, rust your tank and block everything between the tank and the engine.

Chris

[speedyblue]

Methanol is very Hydroscopic. Aviation fuel is petrolium based and will mix with water about as well as normal fuel.

[Z Kid]

And given that some fuels now are up to 10 percent ethanol, its pretty hydroscopic anyhow. I am just going from what we saw after we had problems with running some suspect avgas through a race car with a metal tank.

[jmortensen]

I've been running 50/50 100 octane low lead Av gas and 91 octane and been having good results. Also had good results mixing Trick 112 octane leaded and super from the pump, and also have run tolulene and xylene and super from the pump.

All were mixed for ~95 octane. It felt the best on the 112/91 octane mix, but I never did any back to back testing.

If you don't NEED the octane, you're wasting time and money IMO.

[SuperDave]

I've been running 50/50 100 octane low lead Av gas and 91 octane and been having good results. Also had good results mixing Trick 112 octane leaded and super from the pump, and also have run tolulene and xylene and super from the pump.

All were mixed for ~95 octane. It felt the best on the 112/91 octane mix, but I never did any back to back testing.

If you don't NEED the octane, you're wasting time and money IMO.

What was your recipe for 112/91 and also super with tolulene and/or xylene? Is the low-lead still available where you are? I was told today that you can no longer get leaded fuel at the race track.

[Bambikiller240]

Is the low-lead still available where you are? I was told today that you can no longer get leaded fuel at the race track.

The post indicated low lead AV gas (as in Aviation gas). It's still available.

[PrOxLaMuS©]

yep.. any airport with a re-fueling station

[jmortensen]

What was your recipe for 112/91 and also super with tolulene and/or xylene? Is the low-lead still available where you are? I was told today that you can no longer get leaded fuel at the race track.

Just do the math. It was 5 gallons gas to 1 gallon (114 octane) tolulene = 95.33333 octane. AVgas is 50/50 since it is only 100 octane. Xylene is 118 octane but I mixed it like Tolulene, and I think I went 4 to one on the 112 leaded race gas. Look into home made octane boosters if you want to run the xylene or tolulene. You need to add some ATF and mineral spirits. Recipes are easy to find on the net.

[Mike]

Ah, I remember back in 1988 and 1989 when I was working for my grandfather. He owned an airplane fuel business in San Diego. I had just graduated from Highschool and he asked me to come run his business for a summer. It was a great job with many fringe benefits.... One of the benefits was Avgas at COST! That entire summer I ran my '71 240z on 100/130 (green).

My engine never ran better! The pinging went away along with stuttering off the line. Idling was absolutely smooth and I noticed that my tailpipe was no longer black... it was a light-grey.

Anyway, it was really nice that I could pull up to the truck and fill the car whenever I needed. The special permission to run my car on the tarmack was also a thrill! Talk about your 0-60 tests... I think I played with that every day....

I was later told that my '71 was designed to run on leaded fuel at a higher octane that what we can buy now. While the 100/130 was a bit overboard, the car did very well and could handle the extra combustion due to the higher compression engine. I also found out later that hardened valve seats are desired in these engines to accomodate for the lack of lead.

I later attempted to purchase Avgas for my car (from a local Oregon shop) but was turned away. Apparently they can't sell this fuel for your car because the government didn't get their CUT on the taxes. There is no safety reason why you can't pump Avgas directly to a car. Most Avgas trucks utilize a "static line" which is connected to an airplane. The static line is used to prevent grounding sparks transferred from the plane to the truck. When fueling an airplane it's advisable to reduce the quantity of sparks for obvious reasons. The risk of a spark from an automobile is a lot less of an issue.

So, the reason why you can't pull up to the Avgas truck is simply due to the government. They seem to always be there holding out a hand..... filthy beggers.

I suggest you find a good "friend" in your local Avgas guy.

Oh yea, don't use Jet-A on a gasoline engine. It'll damage your car. However, it will work GREAT on that diesel engine! My grandfather used to fill up his diesel Buick with that stuff and it ran a lot better!

[Mike]

I have no responsibility for the actions or consequences resulting in using leaded fuel.

What?! Now you rained on my parade. I was gonna go run cat-wizz in my car because I thought it had a high-octane rating. After it blew up (and attracted all of the neighborhood cats), I was planning on making you responsible for my actions. Besides, everything on a forum like this must be 100% accurate right? :pirate:

Just playin...