AV gas vs Race fuel?

mountainsledmania

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Hey, got some questions,

Is there any benefits to running say race fuel over AV gas or vice versa?
Reason im asking is the both seem to positives and negatives. obviously the end goal is just to achieve an octane that wont pre detonate but can one fuel be better then another cost wise or performance wise?

Race gas pro's
- mixing requires you carry less fuel with you in the trailer
- more accurate octane levels

Race gas cons
-mixing is annoying
-cost of fuel is much higher then AV

Av pro's
- no mixing
-readily available at pretty much any air port

AV con's
-have to carry large amount with you to run sleds
-has tendency to run lean, so need to fatten up the fuel map
- can sometimes need to be chased with pump gas to help burn in the combustion process.


For those of you running av gas how are carrying you fuel around with you? is it legal to have a drum of it in the trailer going down the highway?

anyways any insight would be much appreciated, id like to know whats the best way to go.
 

venom

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Hey, got some questions,

Is there any benefits to running say race fuel over AV gas or vice versa?
Reason im asking is the both seem to positives and negatives. obviously the end goal is just to achieve an octane that wont pre detonate but can one fuel be better then another cost wise or performance wise?

Race gas pro's
- mixing requires you carry less fuel with you in the trailer
- more accurate octane levels

Race gas cons
-mixing is annoying
-cost of fuel is much higher then AV

Av pro's
- no mixing
-readily available at pretty much any air port

AV con's
-have to carry large amount with you to run sleds
-has tendency to run lean, so need to fatten up the fuel map
- can sometimes need to be chased with pump gas to help burn in the combustion process.


For those of you running av gas how are carrying you fuel around with you? is it legal to have a drum of it in the trailer going down the highway?

anyways any insight would be much appreciated, id like to know whats the best way to go.
AV gas is aviation fuel so I don't think your gonna get a more accurate than that! Pretty strick regulations on that stuff. I ve ran av gas in sleds for years with no issues. 100LL guaranteed 100 octane, if that meets your needs I'd say go for it. Cheers!
 

mountainsledmania

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Av gas has a slightly slower burn rate compared to race fuel or pump gas. It does NOT contain any more BTU's than pump fuel and contains usually less BTU'S that race gas depending on the type of race fuel. [FONT=verdana, arial, sans-serif] avgas chemically retardes the timing a small amount. An engine with the timing retarded tends to run hotter.[/FONT]

[FONT=verdana, arial, sans-serif]This goes back to the performance question i have? i know lots of you guys run it my question is this actually a thing or am i just reading to far into it? I did recently hear one of the Canadian turbo builder around here say they started chasing their av fuel with pump gas to get rid of a low end bog. would this be due to the slower burn rate of the AV fuel?[/FONT]
 

Merc63

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The higher the octane the slower the burn and more resistance to detonation. Similar octanes should burn at the same rate.

Whats the stoichiometric value of av gas? Most gasoline fuels are around 14.7:1 but some can differ, requiring tuning.

if you're seeing bog, it's not the fuel, it's the tune.
 

mountainsledmania

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It looks like the stoichiometric value is 14.7. But the vapour pressure and uses lead for pre det protection vs TEL. so the petro chemical make up of pump gas vs race gas vs av gas are all different.
 

Merc63

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It looks like the stoichiometric value is 14.7. But the vapour pressure and uses lead for pre det protection vs TEL. so the petro chemical make up of pump gas vs race gas vs av gas are all different.

Just run whatever is cheaper and works, you'll never feel a difference. Unless you want to spend thousands dyno testing different fuels.

if you're looking for a race fuel, I run Fuse 116 in my boosted car. I mix it with 94 pump and still have 105 octane. Car loves it.

That article above says avgas is not 14.7:1, either the article is FOS and biased or I don't know... vp109 will evaporate if you look at it while Fuse116 seems to last. I believe that's the vapour pressure? I'd run avgas but I'd want to know the motor octane and stoich values for sure.
 
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1100

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I was doing some reading a while back, most avgas When measured the same a pump gas comes out to 96 octane. I have run it lots in various sleds quads I have had over the years. I'm obviously not exceeding its octane rating though.
 
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