Anyone have any experience running aviation fuel in a vintage engine? My neighbors son dropped a fairly low mileage 390 from a '68 T-Bird in his truck and has been running av gas in it. Runs good, but I’m curious if there’s any adverse effects from using it.
Used to be leaded, and higher octane rating. I think most of it is low lead these days anyway, but still w/a higher octane rating than road fuels. Been a while since I worked at an airport.
Unless the engine is built to use that high octane, it’s a waste of $, not to mention the time and effort to fill up at the airport (where it’s prob. illegal to pump that into a private vehicle).
There has been a lot of discussion of Av Gas on the Boss 302 forum over the years, since those cars have such high compression engines. Naturally, people come down on both sides of the issue. My experience is that adding some 100 LL helps with detonation, but cuts down on power.
Good article on fuels here: (thanks, bosscougars)
http://www.groupk.com/tec-gas96.htm
When I could get it I ran 100 octane LL blue av gas in a 440 6 pack Superbird I had years ago. It ran like a scalded dog with no problems.
I believe LL means Low Lead when talking about aviation fuel. Yet for cars it’s a “high lead” content. Whatever, you can bet you won’t get a bad tank of av gas as it’s really highly filtered more so than gas in the tanks at stations.
Yes, the LL in 100LL stands for “low lead”. Yes, it is illegal to pump it into anything other than an aircraft. That does not mean it can’t/won’t happen.
At $4.24-$5.83 per gallon here at KTUL, I’m sure as heck not going to buy it for my car. Spendy enough filling up the airplanes!
Ive been running av-gas in my vert for almost as long as i’ve had it. My future plan is to run 50/50 av-gas / marine fuel (no ethanol). Since my vert is a weekend driver it can sit for a week or two without driving (rains every day in fl lol) No issues and Ive spoken to a couple of other classic car people at shows and they do the same.
I get mine at a sunoco station that has a specific island for av-gas and race fuel. The local airport will fill up private gas cans but they have to be metal ( I’ve heard from others in similar threads they don’t suffer from that regulation).
Motor runs great and for a street cruiser it has plenty of pep for me. 
Been using scrap Avgas in my cars for 30+ years. It is virtually identical chemically to Sunoco 102 octane gas that was available in the 1970’s. Best gas that you can get! Especially when it is free…
Aviation gas 100 LL contains about 28 grams of TEL per gallon minimum. The octane is achieved through the use of that amount of TEL, and Iso Octane which is simply refined petroleum. In other words there is no ethanol and no additives to degrade and turn sour in your tank. As such it has excellent storage properties, and can be just fine after 12 months in the can or your car’s tank. Airplanes have to operate from the Dead Sea airport in Israel up to perhaps 25000 feet for some high performance turbocharged aircraft, so the vapor properties are also excellent.
Never gassed at Petro Canada befotre this weekend. Seems they have regular (10% corn oil), mid level (5% corn oil) and for no ethanol: premium at 91 octane, AND super premium at 94 octane.
In case someone might be interested. I asked the clerk (in Gatineau) and she said all Petro Canada had 94 octane.
Ran it in my snowmobile back in the day for a radar run.
Didn’t go any faster, smelled funny. IIRC it dropped a few mph. 
That’s about what Pure / non-Ethanol gas runs around here. Spendy, for sure.
Ouch.
“Pure” stuff here is about 2.30… 
Yeah, our local stations are a bit of a rip off. Truthfully, I haven’t been by there since the end of summer to see what they are asking now, but at that time it was right about $4.25 ~ over a dollar more than what blended Premium was running.
Might go by and see what the current price is. Cougar is almost empty again. Thirsty thirsty!
OK, years of messing around with stuff and spending some time at Ethyl corp testing oil and fuel:
It is a waste of money and effort to run any more octane than you need to prevent detonation.
The higher the octane, the lower the BTUs.
You will lose power.
I realize iI am tilting at windmills and most of will not believe this since it goes against urban ledgen and anecdotal old wives tales, but research this and save.money and effort.
LB
The former engineering student in me will go along with that. Besides, the leaner you can get the mixture without detonation is where you make the most power. Run premium in mine without detonation and it runs fine.I DID have some playing around with the total advance and advance rate, but runs fine now on pump gas.
On the other hand if you really need the octane, as I do for my two Cougars, there is no replacement for good fuel. You can say what you want, high compression and good gas make more power than the opposite.
n
High compression demands high octane.
You should be able to find a chart with compression v octane.
You still do not need more octane than necessary to prevent knock.
And compression iis the best bang for the buck for HP.
Direct pay off.
LB
I’ve heard a lot here about AV fuel, but what is the difference between AV fuel and Cam 2 ?
Operationally, not much difference if both are 100 Octane.
Avgas achieves its octane with TEL and Iso Octane. Race gas achieves its octane using TEL. Race Gas is not federally regulated to meet standards of storage, low altitude or high altitude performance.
Race gas has Federal road taxes taken into consideration as part of its price. Avgas does not have road taxes in its price.
Race gas is legal to use in older motor vehicles (pre 1971 in general) originally intended for use of leaded fuels. Avgas is illegal to use in motor vehicles that are operated on public roads.