Race gas

[David Greenburg]

I now live near a major racetrack, and attended a car show there today that was being put on in conjunction with vintage sportscar races.  Participants were allowed to drive sedately (45-55, no passing) for three laps, which suited the '60 quite well, but that is a story for another day.  On my way out, I was able to top off my tank with 10 gallons of 110 octane race gas.  The car seems to enjoy this very much; she probably hasn't tasted the good stuff in 40+ years. Other than the price, is there a downside to using this stuff?  At about twice the price of what passes for premium around here (91 octane corn juice) I'm certainly not going to run a full tank of it, but what is a good proportion to get the benefits of the high octane?  Would adding say 5 gallons every other tankful be beneficial?

[V63]

The downside is you will realize the Pump
crap they call gasoline today. You won't want to go back.

The race fuel sounds like 'purple 110' with lead. (And No alcohol!)

Straight you should notice your engine runs quieter with the lead. It's amazing.

Straight , You will be able to run at factory advance settings and consequently...lower engine temp

[wrench]

About 40 years ago, I worked at a major international airport on a contract to fix piston poppers like Zantop DC -6s and DC3 running parts for a local GM auto plant.

We used to have to drain 110LL by the drum to change fuel system components etc.

It was me and another guy. I was driving a 74 Datsun wagon and the other guy was driving a 72 Eldorado.

Both cars loved that stuff.

Of course, the distribution of the bounty was asymmetrical as my Datsun got 35 miles per gallon and I only drove a half hour back and forth to work.

The guy with the Eldorado got poor mileage and drove over an hour each way....

That eldo sucked down that juice pretty hard.

If you are gonna run a mix of that stuff, I would make sure the tune is right and check the air/fuel ratio. For both performance and economy purposes.

[fishnjim]

I don't think it's rational for one to anthropomorphize about a vehicle's appetite for fuel.

The old or period gas spec number for "premium" used to be around 103, if memory serves me, but not sure if R or M value.  I have the data somewhere.
I guess with a steady diet, it could be slightly leaned out and function quite normally.   If it's burning clean, no soot, I wouldn't worry.   
Airplanes have different fuel requirements than autos beyond the octane rating.   They have to operate at varying atmospheric pressures with altitude, etc. - lean out as required.  "No" water, so it don't freeze and plug up the carb or lines.   Freeze point is minus 40 or so.   That's why there's a visual drain tube.
Jets use "Jet A" which is closer to diesel/kerosene.   So you DO NOT want to use that in a gasoline vehicle!

[Cape Cod Fleetwood]

Sunoco "Surge" is a great race fuel, 110 octane, no ethanol. 5 gallon or 50 gallon drums,
hang on to your wallet. I mixed this in my car 75% 93 Octane, 25% Surge before I had the engine rebuilt.
With modern innerds now, I'm OK with straight pump gas. If the dealer asks you what you want the fuel for,
its for your off road dirt bikes.

There's a huge difference between AVGAS and Jet A. AVGAS for the piston Pipers, Jet A for, well, jets. Many old engines
thrive on AVGAS.

[TJ Hopland]

You also have to be aware of the legal issues.  That fuel usually doesn't have the on road state taxes applied to it so you can't legally burn it on public roads.  How would you get caught?  Easy a inspector just sees you put it in your car then sees you don't load it on a trailer when you leave.  Some states even have a whistleblower program where people can get a reward for sending in videos of misuse.   If you get caught its like many government things where they estimate how much you owe them and its up to you to prove that it was less.   

I have not heard of it at racetracks because I don't think their ability to dispense fuel is as clear as an airport but I have heard of airports that have had their fuel dispensing license threatened for selling fuel to people that were not clearly putting it in planes.   Obviously the location makes a difference but it just takes one auditor inspector sort of person to decide that its an easy target and the fun is over.   They do it a lot with diesel but there its easier to prove because off road stuff has a dye in it so they check the tank or your filters for the dye.   

[Poncholover]

2 advantages to Avgas, it typically has a 5 year shelf life so the risk of it going stale is reduced.
It also has enough lead to boost the octane of a largely full tank so much less is needed.
Of course TEL is a poison...

[David Greenburg]

It is Sunoco 110, which was the lowest octane they were serving.  They also had 112 and 114 available. The regular pumps were shut off, and there was a large Sunoco truck there that they were pumping from.  Apparently the regular pumps are not used during events, but are otherwise available during business hours and contained some other octanes, including 91 and 100. As for dispensing, they just pumped it right into my car, which was obviously not a race car.  OTOH, the guys manning the station appeared to be Sunoco employees who might travel with the truck to race events and not be paying much attention to state laws. They sure loved the car though, and took pics and asked  all the usual questions about mileage, how many bodies in the trunk etc.

[wheikkila]

The other problem is if your car has a catallactic converter the lead will kill the converter. I'm sure the cars run well on it. My old 69 Lamon's loved the stuff.
Thanks Wayne

[wrench]

I don't think it's rational for one to anthropomorphize about a vehicle's appetite for fuel...

I guess with a steady diet...

Lol, I agree.

[Dave Shepherd]

2 others things to consider  with Av  gas, different  Reed vaporization rate and fuel's specific gravity, used some of this in my former race car and it required some rejetting to run properly.

[scotth3886]

I do somewhat the same.  I go to our local VP racing fuel distributor, and although it's available to pump directly into your car, I bring 3 or so 5-gallon containers to bring home about 15 gallons of 110, which is leaded.  While the Cadillac seems to be fine on whatever pump 93 premium I feed, but my GM brand P isn't.  Even a 10% mix of the race gas is enough to control detonation on hot days running the A/C.  My brand P cars with closed chamber heads had much the same issue when new back in the early to mid 60s, but back then we had Sunoco 260 which also took care of the issue.  I have the Cadillac timing set on the edge of detonation, which still gives me 8 - 9 BTDC so it's pretty much fine the way it is. 

[bcroe]

That lead really is poison, way too much of it found on
stuff near major roadways.  For a while I found mixing
leaded premium with unleaded premium worked better
than any single grade.  For a while I used water injection.
to get engines to run right on crap gas.  But those
engines took a LOT of maintenance, and the water
injection was worse.  Engines were not designed to have
the timing set by how inferior the fuel might be. 

In the end I got rid of those high performnce 60s engines
that always needed maintenance.  I changed to the biggest
low compression late 70s V8 that would fit, along with a
really good exhaust system and a (6 speed) switch pitch
trans. The heaviest car I ever owned runs just fine on the
cheapest crap unleaded, no looking for airport fuel.  Go
100,000 mile tuneups, it is actually also my fastest car
ever, and cruising to the coast at 70 mph, it gets the SAME
19mpg as those 60s machines.  Bruce Roe

[dochawk]

I have a delusion that, someday, Bruce will manage to simultaneously defy the laws of physics and the geometry of the TH425, and show me how to get more gears and a switch pitch torque converter onto my Eldorado . . .

[bcroe]

I have a delusion that, someday, Bruce will manage to simultaneously defy the laws of physics and the geometry of the TH425, and show me how to get more gears and a switch pitch torque converter onto my Eldorado . . .

For a 72 E, just put a 66-67 Toronado trans in.  Manny's
Transmission will sell you a heavy duty rebuilt.  Bruce Roe

[fishnjim]

I'm not aware of (m)any auto catalytic convertors before clean air act of 1970, certainly not in a '60 or '61 Cadillac from the factory.   
I try to keep my feelings out of these grey areas and contentious debates but personally, I think you're wasting money for very little improvement and more risk.   I see this a lot in this "sport".   People have their pet ways and do things to their cars in the name of preservation, originality, or whatever and espouse the benefits without proof or much knowledge of what is going on.   Once an engineer, always an engineer.
You can read about the evolution of gasoline and a lot of those things will clear up.   It had more to do with refining practices.

ps: I don't always agree with the EPA on things, and they're just doing what the law provides, until it becomes political.   TEL was a bona fide octane booster and was marketed to do all sorts of engine miracles so it would be widely adopted without regard to the risks.   I think that's somewhat folly and myths persist.  There are other ways to mitigate engine knock.   There are plenty of "plumbophobes" out there, even when it's not in a form that poses much of a risk, like brass, etc.  And it's nearly impossible to eliminate Pb completely in some things even if they claim zero lead. 
The same political hysteria applies to the climate now.   Go buy a Lyriq and be a "good" citizen.   ha, HA, HAAA!

[Cadillac Jack 82]

I typically use regular pump 91 for the 55 but my 67 (Buick) loves the 100 octane they sell at a Loves Truck Stop off of the I-10 near Maricopa.  It was 7.99 but they've since raised it to 9.99.  160 bucks for 16 gallons hurts but good lord....that engine is so so so smooth now.

["Cadillac Kid" Greg Surfas 15364]

Hey,
The good part about them permanently closing our local drag strip is no more VP-MS109 at $16.50 per gallon. at 10.5:1I can run all day using 93 octane Chevron.
Greg Surfas

[Technician!]

www.pure-gas.org is your friend.

[dochawk]

For a 72 E, just put a 66-67 Toronado trans in.  Manny's
Transmission will sell you a heavy duty rebuilt.  Bruce Roe

But that's just another TH425, isn't it?

I'm thinking of more gears--a modern 8-10, but I'd settle for 4, and particularly an overdrive or three, changing the drive ratio and using the switch pitch to make up for it.

Hey, I said it was delusional!



I suppose the real solution is a '68-'70 Deville convertible, where I could just use a modern transmission, or a 4L80 . . .