I've always heard the av gas is a very different hydrocarbon molecule optimized for oxygen lean enviornments and is simply not appropriate for car. I think there was something else about the lubricants that are built into auto fuel that av gas doesn't have, but I'm not recalling clearly.

 

Here's what Wikipedia says about Avgas, although I don't know the author:


Avgas properties and varieties

Avgas has a lower volatility than mogas (i.e. it does not evaporate as quickly), which can be important for high-altitude use and higher temperatures. The particular mixtures in use today are the same as when they were first developed in the 1950s and 1960s, and therefore the high-octane ratings are achieved by the addition of tetra-ethyl lead (TEL), a highly toxic substance that was phased out for car use in most countries in the 1980s. The main petroleum component used in blending avgas is alkylate, which is essentially a mixture of various isooctanes, and some refineries also use some reformate.

Avgas is currently available in several grades with differing maximum lead concentrations. Since TEL is a rather expensive additive, a minimum amount of it is typically added to the fuel to bring it up to the required octane rating so actual concentrations are often lower than the maximum.

 

When we had my blown 540 on the dyno the guy there made some comment about AV gas being to Dry? Or something like that and said use AV gas for what its ment for (Airplanes) and race fuel for automobiles

 

I have been racing cars and boats all my life, and now snowmobiles and motorcycles. If you add race gas to pump gas you can not count on the formula to add up equally by the gallon as pump gas really kills race gas. The product that I use now is Torco Accelerator. This stuff really works. I have a supercharged Yamaha Apex that pumps up to 18 LB. of boost. I am in the Rockies, so our premium pump gas is only 91 octane. I put 16 oz. to 10 gallons of 91 octane and get unbelievable performance at any elevation. It costs me less than $0.45 per gallon to convert pump gas to race gas. It is really convenient too, as I only have to carry 16 ozs with me if I am going to gas up in a remote area. I also have extemely high performance Harleys and carry Torco with me on out of town trips.
This stuff is really worth a try.
Chris

 

Well, there's two strong Votes for Torco.

 

Not sure I would recommend it, but my college chem professor was also a drag racer and told us he added moth ***** (carbon) to his fuel for added octane. I guess the trick would be measuring the octane rating after adding it in.

 

Octane boosters are pretty much a scam. I've mixed Toluene (which is an additive actually used at refineries). It blends fine and gives that race gas smell. However, much beyond 20% mix and in cold climates you might start to have a little viscosity problem . We're not kidding about Torco Accelerator, it's impressive stuff. Just wish I new how it worked, but that's apparently a trade secret. I've got better results, with less volume and cost with Torco than even with Toluene. But if you want your garage to look like Meth lab, Toluene is fun.

 

I would stay away from the toluene...If my memory serves me correctly, toluene is known to be highly carcenogenic

 

VERY. If you don't use a respirator when mixing it in, you'll become seriously lightheaded. Hence the "meth-lab" metaphor. But when you smell race gas, you are in fact smelling Toluene.

 

I got my Max Lead 2000 and added 1 pint to a full 93 octane tank. It runs a lot better. I had my timing at 26, but advanced it to 34. It pinged a little under hard acceleration, so I have since added another pint, but have not road-tested to see if that took care of it. (bad wx today.) I bought 1 gal, so including shipping, that's $11.25 per fill-up to add 1 qt. I think they might have a qty discount, but that's not too bad and it's cheaper than racing fuel. I'm sold.

 

Anybody ever try this stuff?

http://kemcoindustries.com/product_info.php?pId=61

 

Mothballs are Naphthalene (branched isomer)

Avgas has an RVP that has a smaller range than that of gasoline but it's within the range of gasoline.

The boiling points of avgas are covered by those of gasoline

The flamable range of avgas are the same as those of gasoline

The flashpoint of avgas is the same as gasoline.

Avgas is usually made of polymerized blendstock whereas gasoline has a small portion of polymeric blendstock.

 

According to Mark Borosky, Vehicle Test Engineer for Sunoco,"Of the nine octane boosters tested, none showed a significant increase, and one actually lowered the octane number of the test gasolines."Testing repeatedly showed a maximum increase in octane of 3.5 points by only two of the six street legal octane boosters when the recommended treatment rate was blended with lower base 87 octane gasoline. The best the remaining four products could muster was less than a one point increase. "While clearly no one would actually use an octane booster in a low base octane fuel, we wanted to give the manufacturers the benefit of the doubt relative to their claims of five-to-seven point increases," explained Borosky.

When tests were performed using 93 and 94 octane fuel, even the two best products from the previous tests produced a disappointing 1.5 to 2 point maximum increase. The remaining four street-legal octane boosters showed less than a .5 point increase. Those products designated for offroad use only didn't fare any better than the street-legal products. Subsequent tests where the dosage of octane booster was doubled, tripled, and even quadrupled produced only minimal improvements in octane, regardless of the base octane number of the test gas. In fact, quadrupling the treatment rate of the most powerful additive produced only a 3.5 point increase in octane when added to 93 premium, resulting in a cost of $3.25 a gallon.

An alternative path to octane euphoria is to blend gasolines of different octane levels yourself. It's easier than you may think, safe, and the results are predictable. The formula for mixing gasolines of the same type is pretty straightforward. When you mix a 50/50 blend of two unleaded fuels, simply average the two octane ratings to determine what's in the tank If you mix 94 and 100, you get 97. The same generally holds true for leaded gasolines, assuming the lead content is
nearly equal.

Blending a leaded fuel with unleaded, however, pushes the octane up a bit more than the math would suggest, due to the effect of the lead. Just a gram or two of lead blended into the unleaded fuel will raise the octane number significantly. Commercial leaded racing fuels contain anywhere from a trace to six grams of lead per gallon. If you were to mix 50 percent 110 octane leaded fuel with 100 octane unleaded, you would actually end up with an octane number around 106 to 107. Keep in mind that even the smallest amount of lead or leaded gas line with unleaded, could spell the end of your catalytic converter or oxygen sensor. The same holds true for using octane boosters intended for off-road use only. A word to the wise, check for any lead content in all the additives you might mix with your unleaded gasoline. And check with your state emissions regulations for street use.

 

OK, so what were the two street legal brands that improved 87 by 3.5 and premium by 1.5 to 2 points at recommended treatment rates?

And, is that Motor, Research or just R+M/2 octane?

IMHO, 93 + 1.5 to 2.0 = 94.5 to 95 is math which may be well worth the investment for a good number of us.

 

Was Torco "Race Fuel Concentrate" tested? All I can say is this. On crappy CA 91 Octane, I get detonation at WOT. It takes about 1.5 Gallons of Toluene (114 Octane) with 14 gallons 91 to eliminate detonation. It takes only 1 quart of Torco to achieve the same result. This may be anecdotal, but it is a real world application.