What is the difference if any?
Matt

I'd say start with THIS and go find the comparable info for whatever AVGAS you're considering.

And I'm 99% sure there will be differences...

Sunoco 260 GT is an oxygenated (E10) fuel.
https://www.sunocoracefuels.com/fuel/260-gt
There's not really enough info to accurately draw a distillation curve but the three points show much flatter - typical of racing fuels.

100LL Av Gas is a low lead fuel with distilation curve closer to pump gas.
BP had more distillation points for their 100LL, so that fills out the picture a little better.

Lot's of differences.

One is leaded one is not.

One has no ethanol and one has lot's of ethanol, more than the normal 10% to help get to 98-100 octane.

Like mentioned one is oxygenated and one is not.

One costs way less than the other.

And more.

100 LL is designed to be used in low compression motors, under 10 to 1 ratio, low RPM motors (under 3000 RPM) and it is designed to have a shelf life of 18 months the last time I check about that. It is used in turbo charged aircraft motors also but they are less than 8.5 to 1 comp. ratio to start with also
The specific gravity is usually right at 690 also, pump gas is more. My message is you will need to tune your motor, jetting, timing and spark plug heat range also, to run it and you may still have parts longevity issues
It is way better than your standard pump swill but I have never use the Sunoco 260 fuel your asking about so I can't give you a good reply about that, sorry

FWIW I run VP's 100 or 101 oxy unleaded and love it at 12.1.1 compression in my street car THUMPER...........

I run 100ll in my 383 dart. I can’t tell you the differences in the fuel but I have ran about 60 gallons through my car with no problems so far, no corrosion or lead buildup on valves or plugs, and it hasn’t messed with my o2 sensor either.
But cab is right, your jetting is going to be different and maybe need timing adjustment, I’m one range colder than factory on the plugs, 38* timing locked, and the jetting needed to be leaner than 50/50 mix of pump gas and cam 2.... now if I could get my cruise afr right I’ll be golden!

Our local dragstrip has been selling 100LL for race fuel for more than 20 years at least. He gets it in 7500 gallon semi loads at a time. I have filled my plane with it a few times here lately. The track owner has been building engines for 50 years he told me and owned the track for 40 years.
He also told me that 100 aviation octane is closer to 110 car octane? He must sell quite a bit to have that much on hand. Not sure what he sells it for to the racers?

I guess my 15.5 to 1 461" SB2.2 should be broke then. I buy 55 gallons at a time, and add a bottle of either Turbo 108+ or a brand called Race Gas Concentrate. It's about .04 slow in the 1/8 versus Q16, so I would say it's a good value. 4.79 best in the 1/8 with Av-GAs, and a 1.05 60'...

I don't know where this idea came from about Avgas being for low compression, low rpm, but its common. It may come from some confusion on the different rating methods and labelling. In the US, octane for road gas is the average of the motor octane and the research octane tests. Whereas octane for Avgas is given as lean mixture and rich mixture tests.

But comparison is relatively straight forward. The first or only number on Avgas is the lean mixture octane. Shell states "Avgas is measured on Lean Mixture (similar to MON)" and the second number represents octane tested under rich mixture conditions.

So 100/130 as well as 100LL are roughly comparible to a road gas with MON of 100. In other words, 100LL has a MON roughly comparible to a race fuel with 100 MON.

Interestingly, there's a new grade of 94UL Avgas being tried out. It's supposed to be based on the 100LL but with no TEL and has a Lean mixture or Motor Octane of 94. This is intended for lower compression aircraft that used to run lower octane Avgas that now is difficult or impossible to obtain.

In fact 100LL is required for high compression and supercharged aviation engines, whereas a lower octane fuel is all that the majority of prop planes need. But a lot of companies like Shell aren't making the other grades anymore.

https://www.shell.com/business-customers/aviation/aviation-fuel/avgas.html
https://flycorvair.net/2015/08/26/compression-ratios-fuels-and-power-output/
https://en.wikipedia.org/wiki/Avgas#100LL

As far as what has happened to avgas with the demise of the large airline a majority of the large aviation freight haulers switching to either jet engines or turbine powered aircraft is the old low octane avgas went bye-bye many years ago.
I owned and flew a 1960 Comanche 250 that had the engine switch to a newer 1965 260 HP 540 C.I. opposed flat six cylinder air cooled Lycoming engine after the original engine blew a oil line in flight damaging that motor before I bought that plane in 1991. Both of those motors had 8.5 to 1 compression ratio The 250 HP motor was limited to 2550 RPM and the newer higher HP 260 motor was limited to 2700 RPM max.
I flew that airplane around 900 hours and it required 100 LL, I learned on the second flight to lean it out some before flying it, not take of at full rich , leaving Bullhead, AZ airport to return home to Hesperia, CA It foul out the both spark plugs on one cylinder shortly after take off scaring me a lot
I had bought and used aviation fuel in several of my race cars back when I could still buy 130/145 and later to 115/130 Av gas at the local airports. I stop using it when I found pits on all the exhaust valves in my 415 M.W. stocker motor in the mid 1970s
Their are two major manufactures of piston aircraft motors being used in todays small aircraft, Textron Lycoming and Continental.
Both of the Piper airplanes I owned and flew required 100 LL as the fuel in them per the operator hand book, most Continental powered aircraft require 85 octane which hasn't been available for sale at most airports in the U.S since around 1995 or earlier
A lot of those Continental powered airplane owners have apply for and received permission from the FAA to use automotive gas in them after doing some modification to meet the FAA specs to get permission from them to use it.
Some of those owners and pilots still buy the 100 LL to use in their airplanes and they had to learn to lean the motors out properly to safely operate and fly them with that fuel
100 LL has a lot longer shelf life than any of todays pump gas or race gas, but it has it limitations.
That is my main message, be careful of what fuel you use and watch the plugs and tune the motor to the fuel your using just like I had to do when I switched to E85 in my current bracket motor with 14.8 to compression ratio

I agree with Mark...been running it for years but was alittle reluctant to run it in my 14.4to1 588.ran the same if not faster than C12 and was hardly any difference on Q16 after tunning for fuel change.1OZ of octane boost with MMT to 5gals of AV and good to GO!!!!

How much is AV Gas now?

The new motor is going to be 12.5:1 and that's what fuel I'm using.

Check with your local airport for their price per gallon
The last 100 LL I bought 4 or 5yrs ago for one my cars that isn't driven on the street yet was around $4.90 a gallon locally
The E85 I buy for my bracket car is close to $3.25 a gallon, the motor uses around 30% more E85 than gasoline per run so it is close to a wash on the total cost per run other than the E95 is a lot more consistent on the ET at the track That motor is close to 15 to 1 compression ratio so I wouldn't run straight 100 LL in it, EVER

I am in the middle of a 9 straight days of flying, so I have bought fuel almost everyday this past week. I have paid as low as 4.30 gallon, 5.20 per gallon and 6.80 for full service at one airport!! Some has minimums, the more you buy the cheaper it is. 5 or 10 gallons is a minimum order I would think? Every airport is different. I have been flying lot's of cross country flights.
Last night. Under Bravo airspace.




Earlier this week, my Wife and I flew to Rough River Ky after dinner one night. Got there at sunset and flew home in the dark. Love flying at night, so smooth and safer because you can see other planes easier.

Filling her with the good stuff!

Been IFR training in this plane hard, try to fly twice a week with my CFI.

Good luck on the IFR training. That rating will add so much utility to your flying. My beech Bonanza and a couple of my cars.

More ..

Flying down the Outer Banks of North Carolina....

Very nice!! Great cars and plane!!
I have been wanting to get one of my E bodys down to the hanger. I have high wing plane= room for a car! It is getting stored there this winter and been wanting a photo opp too. LOL

Nice deal you have there!! A year ago I would have never guessed I would be flying my own plane. Been flying it since April this year for a friend and bought it in July when I updated the panel.