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Author Topic:   AVGAS??
J3
Dirt Maniac

Total posts: 188
posted February 18, 2005 07:10 PM  
Can someone help me out here. Have a 351W with a few bells and whistles. 11:1 compression. Did some checking on several things and have been told that I need to run 100 octane. I can get 110 octane racing fuel, but that cost over 5 bucks a gallon. I could mix 50/50 with 91 octane to cut that cost some, however, AVGAS is 100 octane and only cost 2.25 a gallon. Cost wise, that would be much better than pure 110 or 50/50 mix with 110 and 91. Are there any advantages to using AVGAS and more importantly are there any disadvantages to using AVGAS?

AtomicPunk
Dirt Maniac

Total posts: 130
posted February 18, 2005 09:00 PM  
at 11:1 I would think you need alittle higher octane than 100. Anyway, a lot of guys run Avgas with no apparent problems. My engine guy about had a cardiac when I ran Avgas one week when I couldn't get any 110. He said avgas is designed to burn at high altitudes (like 30,000 feet) and is too "dry" to be used in car engines. Just passing on what I been told.

77k
Dirt Maniac

Total posts: 174
posted February 19, 2005 12:16 AM  
I have run it for years. It is not much higer than prem unleaded and you can always add a little trans fluid to it for top end lube.

marrs
Dirt Full Roller

Total posts: 29
posted February 19, 2005 11:32 AM  
back when we ran avgas we added marvel mystery oil dont know any ratio just poured a little in the cell never had major problems associated to the fuel now we pay $4.15/gal for VP .

backofpack
Dirt Maniac

Total posts: 102
posted February 19, 2005 12:51 PM  
4oz to 10 gallon but it will still show more wear to the valve guides than racing fuel good luck

wrenchturner10
Dirt Forum Racer

Total posts: 80
posted February 19, 2005 03:40 PM  
We were going to run avgas but I read in one of the racing mags that avgas has additives to burn at a high altitude and would cause problems at low altitudes, take it for whats it's worth.

J3
Dirt Maniac

Total posts: 188
posted February 19, 2005 09:51 PM  
Why do you need to add trans fluid or marvels mystery oil?

hobby10k
Dirt Freak

Total posts: 226
posted February 19, 2005 11:52 PM  
it always ran hotter when we ran avegas

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stockcar5
Dirt Forum Champ
Total posts: 578
posted February 20, 2005 08:08 AM  
also remember that av gas it rated differently than race gas/pump gas. 100 octane av gas is about the same as 93 octane pump gas.

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rico 08
Dirt Forum Champ
Total posts: 1139
posted February 20, 2005 09:33 AM  
There's alot of articles on why not to run avgas,maybe the racing fuel people are funding them?..I for one like it,if you're in between 93 octane requirement and racing fuel then go for it....
one more thing...i wouldn't pay too much attention to the it's only made for 30,000 feet,they don't haul them up to that altitude and then start 'em
when they take off they really load the engines,if they only had enuf octane for 30,000 feet they would not last very long.......

backofpack
Dirt Maniac

Total posts: 102
posted February 20, 2005 10:43 AM  
avgas doesnt have the oil in it for car engines there for you need to add oil to lube the valve train we ran a couple times without it valae got to sticking had to rework the heads nothing wrong with avgas we just prefer racing fuel to eliminale the potintal problem

racin78p
Dirt Freak

Total posts: 333
posted February 23, 2005 01:33 PM  
I gotta go with Rico on this. Maybe racin' fuel companies are trying to stray everyone away from the local airports. I do know that av gas has "stuff" in it that keeps it from freezing up at altitudes. Plus av gas is tested for purity. Don't want to take you piper cub up and some water in it blips your power a little? Not.

Alcohol doesn't have oil or lubricating ingredients in it either. Ever saw a mod or late model crew blast the carb on the race car with WD-40? Alcohol dries the heck out of it. Gotta lube the parts up, man.

Regular gas doesn't have any significant oiling capabilities to really be concerned with. Racing gas has more lead (which helps produce more power/keeps engine cooler).

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racin78p
if it ain't fun, then don't run

Speedway65
Dirt Freak

Total posts: 344
posted February 23, 2005 01:56 PM  
I always heard av gas was designed for low rpm piston powered engines not engines that crank up to about 7000rpm.We used it for a couple of years without problems with some sort of oil additive.We use a mix of race gas and premium pump gas now just because our new engine builder recomends it.

backofpack
Dirt Maniac

Total posts: 102
posted February 23, 2005 02:49 PM  
i do know a lot of drag racers use it because it is goverment regulated its always 100 oct where racing fuel is not consistent makes there times fluxuate

DAYTONA392005
Dirt Roller

Total posts: 9
posted February 23, 2005 06:06 PM  
we run it alot what we always did is add 1/2 quart lucas fuel treatment to 55 gollon barrel of avgas NEVER had a problem,heat was within range,made plenty of power.

power steering fluid also acts as an octane booster when added to any fuel(so be careful here)

nothing wrong with running avgas at all, unless you are a racing fuel salesperson

PEDDLER
Dirt Freak

Total posts: 446
posted February 24, 2005 07:01 PM  
3 oz Marvel Oil plus 3 oz Octane Booster per 5 gal.

Pickel
Dirt Forum Champ
Total posts: 784
posted February 24, 2005 07:14 PM  
I ran it all last year with no problems what so ever.

I talked with the local FBO (airport fuel owner), he told me that the fuel is just LEADED fuel and is guaranteed to be 100 octane, but can be as much at 110 octane.

The only problem he mentioned is that if you leave it stored for a long period of time the lead will settle to the bottom of the jug or fuel cell.

b4racing
Dirt Forum Champ
Total posts: 626
posted February 25, 2005 08:34 AM  
go to parkercarbs.com he has all the different kinds of av fuel and tells about them. There is different kinds you need to see what color you are buying! Some is as low as 87 octane. Bobby

J3
Dirt Maniac

Total posts: 188
posted February 25, 2005 01:03 PM  
Not true anymore. Their used to be several grade, the only ones left now are 100/130 and LL100.

quote:
Originally posted by b4racing:
go to parkercarbs.com he has all the different kinds of av fuel and tells about them. There is different kinds you need to see what color you are buying! Some is as low as 87 octane. Bobby


    

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