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copterzach
08-21-2006, 09:13 PM
I am wanting to know about running AV gas. I know that it is 100 octane low lead, but want to know about adding lead additive. I had a thread in just jets, but did not get much of an answer. My engine is 10.5 to 1. I have acess to it for free. Let me know.

DMOORE
08-21-2006, 10:03 PM
Your going to be better off running a race fuel rather than AV gas. Av gas is designed to burn a bit slower than most high performance motors are " set up for". I remember seeing an article in one of the rot rod mags awhile back comparing AV gas against a few different race fuels. Don't recall the exact details of the story, but the race fuels won hands down. They are also easier to get and cheaper.
Darrell.

kanedog
08-21-2006, 10:13 PM
Im assuming this is in your boat.
I run avgas in my 540 blown boat motor,. Have not had a problem for 2 years,. I love it.
this may not be the same for others but it works for me!
I did put in my friends v10 dodge pu and it plugged his catalytic converters. that sucked.
boat=good
truck=bad

Sleek-Jet
08-22-2006, 09:48 AM
Your going to be better off running a race fuel rather than AV gas. Av gas is designed to burn a bit slower than most high performance motors are " set up for". I remember seeing an article in one of the rot rod mags awhile back comparing AV gas against a few different race fuels. Don't recall the exact details of the story, but the race fuels won hands down. They are also easier to get and cheaper.
Darrell.
Easier to get??? I can leave my house and have a tank full of avgas bought and paid for in under 20 minutes at the local airport.
To purchase any race fuel around here, I have to go down to the track, on only certain days, and then pay out the ass for it... (not that avgas is a bargain these days...)
To answer the original question, avgas contains Tetraethyl lead (TEL), about half as much as the old 100/130 aviation gasoline (thus the Low Lead title). It's only manufactured at one plant in the world, located in England. It's added during the refinemant process.
Without the lead, 100LL has an octane rating of about 96 or so, slightly better than premium auto gas.
So, are you asking if can add more lead to the fuel, or just wondering about what's in Avgas???

don johnson
08-22-2006, 10:04 AM
All I run is 100% Av Gas with Marvel. With Av at virtually the same price as premium, why not. The Marvel does wonders for the motor as well. When I went thru my motors last year we did not have to restrip the blowers and Littlefield made note that they can always tell a motor that runs Av Gas and Marvel by how good a shape the blower is in...
fyi, I am running twin GT 572 CI blower motors at 11 lbs of boost. I have spoken to many reputable engine builders and they encourage the use of Av Gas with Marvel. Especially as opposed to pump gas.
One other side benefit of Av Gas is it never goes bad....

Keith E. Sayre
08-22-2006, 10:11 AM
I agree with everything that "Don Johnson" just said. Granted, real race gas
is also a great alternative but a very expensive one. I've used Avgas for
about 15 years with no problems related to fuel at all. I run a blown 588 incher and at times have put 14 lbs through it with 8 to 1's. It doesn't go
bad over time either.
Copterzach: where are you planning on getting this extra "tetraethyl lead"
from? I'd love to get some too but I think the EPA might frown on it just a
little bit.
Keith Sayre
Conquest Boats

atomickitn
08-22-2006, 10:23 AM
Your going to be better off running a race fuel rather than AV gas. Av gas is designed to burn a bit slower than most high performance motors are " set up for".
Darrell.
race fuel is designed to burn slower as well ....av gas is waaaayyyyy cheaper , but remember to use marvel mystery oil , due to the fact that av gas is a very dry fuel and has almost no lubricating properties...i also use it in a blown / carb small blk......and it smells nice :)

dirty old man
08-22-2006, 10:58 AM
Have run av gas for many, many years with Marvel Mystery added per instructions. Engine builder says thing always good on tear down. Av gas readily available and some small town airports have good deals. Have run in n/a, supercharged and turbocharged. Race gas is best for racing, av gas OK for play time

copterzach
08-22-2006, 11:38 AM
Keith Sayer: There is an lead addditive that can be bought over the counter. :argue: :D
Don Johnson: How much Marvel oil do you add when mixing? I have only heard about doing this, but I will start using Av gas. For me the price is right....FREE. All that I can use.

Sleek-Jet
08-22-2006, 11:42 AM
Keith Sayer: There is an lead addditive that can be bought over the counter. :argue:
But it's not TEL... that stuff is bad mojo as far as the EPA is concerned, and it's only for the grace of aviation fuel being such a small percentage of gasoline produced in the USA that we still have it there.

Jbb
08-22-2006, 12:01 PM
I run Avgas in mine.... 8:1cr...12 lbs boost..no detonation issues...runs great and smells good .... :p

don johnson
08-22-2006, 04:34 PM
Don Johnson: How much Marvel oil do you add when mixing? I have only heard about doing this, but I will start using Av gas. For me the price is right....FREE. All that I can use.[/QUOTE]
I run 4 ounces for every 10 gallons

Havasu Hangin'
08-22-2006, 05:42 PM
I run 4 ounces for every 10 gallons
Yep- me too. My intercooled blown 509's run quite well on AV gas/Marvel.

cola
08-22-2006, 06:32 PM
I've run Marvel oil in my Harley for years. About 1oz. per tank 5 gal. every so often. With 91 pump gas.

don johnson
08-23-2006, 07:36 AM
Avgas will require you to jet your carbs, avgas by burning slower, means you willl jet a little leaner than reg gas.
I ran av for a while, lost 500 rpm's, refilled on 91 and gained the 500 back, it was then I was told about jetting a little leaner, that was from knowledgeable people.
There were many articles including one by Teague that explained and showed why you could actually loose hp by running avgas.
just fyi, do you really need it or like the smell :p :p
Thats interesting. I have been caught in areas where I needed fuel where AV Gas was not available and personally I have not seen any significant difference in the way my motors run between pump gas and av gas. The motors did not go rich. I was actually curious and plugged in my O2 sensor and there was very little difference in the air/ fuel ratio between the Av Gas and Pump Gas. O2 readings ran 12.5 with Av Gas and ran 12.2 with pump gas.
Now there are many documented examples of how an engine will lose HP when higger octane fuel is used then the motor requires. The bottom line is marrying the fuel for the application. The Mercruiser HP 500 is a great example. It is designed to run on 87 octane. If you run 91 octane the motor goes rich and loses HP.
Obviously my setup at 11 lbs of boost is on the edge of needing a higher octane fuel then pump gas. When I do have to run pump gas I do not lean on the motors. Also with a blower motor it is cheap insurance to burn a higher octane fuel then risk detonating it.

3 daytona`s
08-23-2006, 03:18 PM
I thought would share some information on my experience.I don`t know if any of you have experience with Price Chemicals in Texas.They make several different additives I`ve used Max Race for approx 12 years,it is 40% Nitro they also make Mighty Max which id 80% nitro.They a very detailed brochure to give all info needed to set motor up correctly and % to mix.If you`re interested Max Race in search engine the home page will give more info.I started with Av Gas then after talking to them more changed to Premium unleaded and Max Race at a ratio of 1 quart to ten gallons.I love the product.I hope this can be of help.Contact me if need help or any info. :)