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Discussion Starter #1
At the local airport they are selling 100 L/L Gasoline for 1.89. Do the "L's" stand for Lead? Also, if they do, can I run this in my 351 C? The motor has pretty high Compression. Thanks a lot.

Jeff Given
 

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I remember a post on av fuel a couple of months back and there were some serious drawbacks to the stuff. My memory isn`t what it was but I thought one of the problems was that it had additives to keep it from freezing at altitude that can be harmful in a car motor. A couple of gallons in your tank will probably be OK but I don`t think that you will want to run the stuff straight.You might be able to search the archives and find that post as it was fairly extensive.
 

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I've run tons of AV-Gas.

The "LL" stands for low lead... but, it's still 4-5 grams per gallon, which is quite high by automotive standards.

Av-Gas is a more precise fuel than auto gas. It is also blended so it doesn't vaporize quite as easily as pump fuel... (you don't want a vapor-lock at 10,000ft!) All this really means, is if you are running straight Av-Gas, cold weather starting might be a little more difficult. Personally, I don't keep snow tires for the mustang, so it doesn't matter.
But, any problems of this sort associated with running straight av-gas disappear when it is blended with automotive pump fuel.

My tow vehicle likes to ping with a load, so whenever I take the mustang anywhere, I dump in 5 gallons of av-gas with each fill up. It cures all problems.

I've also run it in the mustang quite a bit. It's heads don't have hardened seats, so I figured the lead would do them some good. It has no problem with Av-gas... even straight.

I've got eight 5-gallon gas cans, and take them to the airport in the back of my Pontiac Parisienne. They allow me to back up to the pump and fill them all. They like moving as much fuel as possible. It keeps their stock fresh.

It also works great in those old shovelhead Harleys.


It's by FAR the best, along with being a very cost effective octane booster. I highly recommend it. They guy at the airport said they sell quite a bit of fuel to musclecar and dirt track guys.

2-5 gallons with each fillup should do ya'.

Good Luck!
 

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Hey Mike wasn`t there some type of funky additive in Av gas that made it harmful to auto motors? Xylene, Tolulene or some chemical compound that made the stuff extra nasty, I tried to dig out that archived post with no luck. I am sure a blend of the stuff would not hurt. I run 115 race gas in my car but at $4.00 gal If av gas is ok the savings could be substantial.
 

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Avgas is a FANTASTIC fuel...

I agree with what N2O Mike says, with the exception of cold weather starting.

After about 2500 hours of flying all kinds of piston engines in all kinds of cold weather, I'll say avgas works great in the winter. Most carbed aviation engines have such crappy intake manifolding AND updraft carburetors you'd never believe these damn things would even run! But, after a few shots of the primer(and this only primes a couple of cylinders), which is basically what you'd get out of a few pumps of the accelerator on a Holley, they're ready to run. No choke, either!

The fuel injected engines do even better..

As far as not wanting to boil off at altitude, that's true as well. We can use avgas in the jet I fly now, but only up to 18000 feet and with all fuel boost pumps running just to keep it from vapor locking.

The only concern I would have about runnung avgas in a car engine is lead buildup in the combustion chambers. And that's not enough to make me not use it!

Greg P

OK, techno-nerd session is over!:lol:
 

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I've run tons of the stuff with no problems. The ONLY drawback is that the lead in it can coat catalytic converters and oxygen sensors. As long as your engine is not an EFI smogger, go for it!

I HAVE heard of people with oxygen sensors and no converters running leaded fuels with no problems. Most just blended a couple gallons per tankful, and just do it on occasion. Others have stated that the sensors can be removed and cleaned with carburetor cleaner.

Good Luck!
 

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Ive been an aircraft mechanic all of my adult life and I can tell you this...You have NEVER seen a thicker layer of crap built up in a combustion chamber than that of an engine that has run 100LL all its life.
 

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Yes Bossman, I can see that. Aircraft engines have some very inefficient manifolding and loaf along at fairly low rpms for the most part. I can see how they would get "carbon'd up". Leaded fuel will produce more deposits than unleaded as well.

FYI, anytime I've had the heads off of the mustang, the tops of the pistons and the combustion chambers have been very clean. (I don't do a lot of putting around)
I also just run av-gas and race gas on occasion. It usually drinks 93 octane unleaded. It doesn't really seem to run any different with straight 93, a mix, or straight av-gas. However, my buddy's Chevelle (higher compression) really likes the stuff.


My tow vehicle (84' 4cyl ranger... 5-speed, 4.10 rear) really likes it! It gets worked REALLY hard pulling the mustang on a dolly and all the racing stuff in the back. I need a full sized truck! I never knew a 4cyl ranger could get 10mpg.


Good Luck!
 

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Mike, check the classifieds.
 

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I have run pure Av gas in my race car with no problems other than running leaner & hotter temps, all I did was jet richer. A few of my roundy round buddies have switched to it & burned a piston or two, but they didnt rejet. For some reason it burns extremly dry. The race fuels have additives that cool combustion chambers, av gas doesnt. I would not hesitate to run it again if I was running gas. Alky is fuel of choice now. More consistant, cooler temps. more torque,cheaper than race gas, not as sensitive to weather & jet changes etc etc.
 

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Discussion Starter #12
Quite embarrasing?
Well, this is my combo.
351 C Torker intake, 750 Holley VS
Comp Cams .564"I/.589"E 246/256
4v Quench heads Approx 11:1 CR.
cast bottom end, yet balanced.
I will not run the stuff unless I get the 4.11 rear. I want to go all out at the drag strip, and anhilate my friends Camaro (the same car taht made me build the Cleveland). I just dont even want it to be close...

So now should I use it? If so, how much?

Thanks a lot!!

Jeff Given
 

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If it's trusted in airplanes, it can't be all that bad for your engine.


I would have zero hesitation in blending a few gallons in with every tankful. My ranger runs WFO, sometimes 1/4 tank at a time without letting off with 5 gallons per tank. No problems. I've run it straight in the mustang with no problems.

I would not hesitate blending it with pump fuel. It is a great octane booster for old musclecars.

Good Luck!
 

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I say USE IT! Beat the cr*p out of that POS camaro...

As a side note, if you ask around some of the smaller airports, you'll find them using avgas in almost every gas powered piece of equipment in the place, and Jet-A in all the diesel powered stuff. Most have had zero trouble with this.

For the airport operator, it is cheaper to burn avgas at cost than pay 34 cents per gallon tax on regular fuel.
 

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I use to run AV gas when I lived in Texas and raced at Little River Academy Dragway and on the street for a couple years even in the winter. I did have to jet up for best ETs over using pump gas. I would carry a bunch of 5 gal fuel jugs (some borrowed from friends) in the back of the Mustang and would have to carry them around betwwen 2 buildings to the back to fill. In Texas when it's 105 degrees out and 90% or more humidity, things get mighty hot under the hood and where pump gas would occasionally vapor lock on my Mustang, the AV gas and even the AV gas/pump gas mixture never did. I didn't notice any harder to start than normal conditions during the winter even when using pure AV gas. It was cheap and I loved the smell so I would run it all the time even when just putting to and from work during the week. I would use it again if I could find some here and not hesitate either. I don't know what the average/normal price per gallon is anymore but I hope it's still affordable.
 

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I have not see Av fuel for sale, but a local gas station sells racing fuel. I have not had a chance to ask them what the octane/PPG is yet. I was thinking of going down and getting some for our 2 cycle motorcycles (they love the high octane
) and I was thinking of mixing a few gallons in with pump gas. Would there be any problems with this on a every day driver? What about if I ran the race gas straight, no mix? I did try a octane booster once, and I could feel the extra power and the extra $$$ in my wallet! (improved MPG quite a bit)
Later-
Matt
 

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Discussion Starter #17
ok I guess Race Day I will be running Av gas...Now the qusetion is, How much? And how much do I advance the timing with it? Is this going to be a noticeable gain? I think the Camaro has seen its last day being #1


Jeff Given
 

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FYI but 100L/L is some of the lower octane av gas, you can run stuff like 120-130 just run less of it. It makes a great octane booster and sure gets rid of detonation


P.S. Me and my friends even played around with running nitromethane and methanol mixed with pump gas, makes a big difference but you do hagve to jet richer
 

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100LL is by far the most common. You can mix 3-5 gallons in with a tank of pump fuel and not have to worry about changing anything. 50/50 would should also be fine.

From the sounds of things, 100% might like the carb to be jetted up a size or two.

The extra octane will allow you to experiment with ignition advance. If you've got a higher compression ratio, this could produce quite a bit of extra power.

Good Luck!
 
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