Racing Fuel vs Aviation Fuel

[Jerry]

We were having a discussion yesterday about the differences between racing fuel 100 octane and aviation fuel 100 octane. A web site we found said that the additives in Aviation fuel would hurt a car. This sounds strange to me unless they are taking about a modern car. The low lead aviation seems like it would work well for an old race car. Can anyone explain this?

Jerry

 

[Billm]

I don't know the answer but I do know that they discourage the use of car gas in aviation since car fuels have a problem at high altitudes, essentially "vapor-lock" at normal temperatures (which av-fuels are formulated to minimize) so I would guess that the converse would make it harder to start in a car?
BillM

 

[Jerry]

Here is a link that refers to street vechiles and smog equipment that race cars dont have.

Jerry



Motor Trend: 100 octane aviation "AV" gas is usually cheaper that 100 octane race gas. What is the difference between race gas and AV gas?
Rockett Brand: Aviation gasoline with an octane quality of 100 is often cheaper than 100 unleaded, thus it may look attractive to performance enthusiasts. First and foremost, 100 octane Aviation fuel contains tetraethyl lead (TEL); since 1996 it has been illegal to use leaded gasoline in a licensed street vehicle and you can be fined us to $25,000 for using it. Plus, leaded gasoline will damage the oxygen sensor(s) and catalytic converter(s) found in modern vehicles.
Aviation fuel is designed for low speed aircraft engines that run at 2700 to 2800 RPM at 10,000 feet altitude. Aviation fuel often contains hydrocarbons that are detrimental to the performance of a high-horsepower street car.
There are two grades of 100 octane aviation gasoline. One is identified as 100LL and is blue in color. The other is 100/130 and is green in color. The second number (130) shown for the green fuel is a measurement using a supercharged octane test engine. Although this 130 octane number is higher, it is achieved from an entirely different test and rating system than octane numbers determined with normally aspirated engines. For comparison, Rockett Brand 111 octane tests out at over 160 octane using the supercharged aviation method that indicates Rockett Brand 111 has a significant advantage in anti-knock ability over 100/130 aviation gasoline.


Read more: https://www.motortrend.com/roadtests/tuners/112_0606_sf_high_octane_fuel/viewall.html#ixzz23XYQlWox

 

[dougie]

I know a lot of my racing associates that use av-gas in their race cars and have for years with no ill effects. It's about half the price of the Sunoco 110 leaded that I use. I just can't bring myself to use it......

 

[BuggerAll]

I know that here in Maryland you can't buy avgas unless you have an airplane to put it in. Don't know about other states. So my H prod limited prep Midget gets a straight diet of Sunoco 110 octane race fuel. Over the course of a weekend that's about $40 worth (less than 5 gallons at about $9/gal) to cover qualifying, the short Satruday race we run (usually about 20 to 24 miles) and the Sunday feature race of 40 miles -

 

[Jerry]

I think we can get the fuel without an airplane. One of our drivers has a hanger on the airport and the airport is so small, the pump is self service only. We may go through 40 gallons over a weekend, so I was trying to save some money.

Jerry

 

[BuggerAll]

Maybe I should go for 6 or 7 gallons on a weekend. Ran out on the cooloff lap after winning at NJMP this past weekend. How embarrassing - would have been more embarrassing if I had run out before the checker.

 

[mike_h]

I used to run it in my Spitfire, 11:1 compression, with out any problems. The local airport upgraded their pumps and now you need a code to unlock them so I'm stuck paying track prices. The engine looked clean during a rebuild. I don't think it did any harm and it did free up a ton of money for the beer fund.

mike