Alky vs Race Fuel ?
- Thread starter moose
- Start date
Nasty Wendy
Perverted Lurker
- Joined
- May 24, 2001
Quit wandering, you'll get lost.
Yes you can make more power with race fuel. Straight methanol has an octane rating of about 117 which is about the same as C16 race fuel but the alky doesn't produce as many btu's when burned as race fuel. BTUs = POWER. That's about as simple as that answer can be put. The long version gets really complicated and requires lots more specific info to be provided about the conditions in which each will be used.
Yes you can make more power with race fuel. Straight methanol has an octane rating of about 117 which is about the same as C16 race fuel but the alky doesn't produce as many btu's when burned as race fuel. BTUs = POWER. That's about as simple as that answer can be put. The long version gets really complicated and requires lots more specific info to be provided about the conditions in which each will be used.
Race fuel allows a lot more aggressive timing to be run at lower boost levels.
At the same time pumping enough alcohol in came duplicate the performance.
Why not run both, and that way the alcohol can drop IAT's down to ambient and the race gas gives you the extra headroom on timing.
Fastest 109 on race fuel is 8.9. Fastest 109 on pump fuel+alky is 9.6 at 143
Big advantage is not dealing with buying 5 gallon drums for 90 bucks.
Bigjack7440
Member
- Joined
- Jul 18, 2009
I got some 110 for $6 gal at a gas station here in town. Bumped up the timing to25 deg and the boost to 25lbs and drop the alky to around 5 on the dial. The #s were 756 with 0.0 mv and it was ALOT faster with the 110 and alky. I hope to find a little something in the st. Tonight , Im sorry did I say st. I ment the track lol
that does not work at all , it's not just octanes but cooling effect of Alky which spraying race gas can not duplicate , Julio or others could answer it better then me but I .....tried it myself
it did not do SH....the best way to fly is a combo of high octane fuel for timing and Alky spray for cooling intake charge
If the question is racing gasoline against running pure methanol, then the answer is pure methanol. If people realized how the laboratories come up with octane numbers for methanol, they would see how flawed the published octane numbers are. They take no or very little into account the superior cooling affect of methanol.
In the real racing world, when all the physical properties of methanol are taken into account, methanol has an octane rating beyond 130+. Now how can anyone compare that to racing gasoline. Come on. How do you think some blown methanol racers are getting away with boost pressures in the 80s psi.
I'm still searching for the limit of pure methanol fuel myself.
In the real racing world, when all the physical properties of methanol are taken into account, methanol has an octane rating beyond 130+. Now how can anyone compare that to racing gasoline. Come on. How do you think some blown methanol racers are getting away with boost pressures in the 80s psi.
I'm still searching for the limit of pure methanol fuel myself.
Did you already forget I was burning pure methanol? Tisk, tisk.
When both fuels are burned at proper stoich values, methanol actually puts out more btus. When you further take into account the much wider mixture range of methanol, gasoline loses out even more.
Nasty Wendy
Perverted Lurker
- Joined
- May 24, 2001
Nope. You are the reason why I said that the answer could get really complicated.
When you take into account how much fuel you can get into a combustion chamber and ignite the nod goes to race fuel to produce more btus. Think about how much larger of a volume of methanol it takes to produce the btus of a given volume of race fuel. There is only so much room in the combustion chamber.
Sorry to have to tell you, but your reasoning is flawed.
True, it takes about twice as much methanol to a given amount of air to come up with a stoich mixture compared to a stoich ratio with gasoline given a same amount of air, but take a closer look at the btu values for gasoline and methanol for the same quantity of each... Now take that btu value for methanol and times it by 2 because that's how much more fuel you're going to need to come up with for a stoich ratio with methanol. What do you come up with?
Given equal amounts of air and the proper amounts of gasoline and methanol to burn at stoich ratios, the methanol wins out, hands down.
Not enough room in the combustion chamber when burning methanol is more flawed reasoning. Sorry.
A stoich methanol/air charge is 6.45 lbs of air to 1 lb of methanol. Air will compress. Vaporized and for the most part dissociated methanol will compress. So why would there not be enough room?
Plus, spark plugs, piston tops and combustion chambers are spotless. No carbon buildup. Less thermal loading of the engine components, lower exhaust temps, more products of combustion. No worries of the fuel quickly going stale. Milder flame speed.
And did I mention the famous wide tuning range of methanol? Reach your hands into the sky my fellow racers and give a shout out of thanks!
Let's look at the btu question in a different way.
The stoich a/f ratio for gasoline is 14.7:1.
That's 14.7 lbs of air and 1 lb of fuel.
Now let's setup a stoich ratio for methanol using the same 14.7 lbs of air in our figure.
You only need 6.45 lbs of air to one lb of methanol to come up with a stoich a/f ratio. Now we're given 14.7 lbs of air to play with. How much more methanol will we need with 14.7 lbs of air to come up with a proper stoich a/f ratio with methanol?
14.7 lbs of air is 2.279 times the amount of air compared to 6.45 lbs. So we will need 2.279 times more methanol to be used with the 14.7 lbs of air to come up with a stoich a/f ratio.
Maybe someone can help us with the btu values of gasoline and methanol. Take the btu value for the methanol and times that value by 2.279. Compare the answer to the btu value of gasoline. What do you come up with?
The stoich a/f ratio for gasoline is 14.7:1.
That's 14.7 lbs of air and 1 lb of fuel.
Now let's setup a stoich ratio for methanol using the same 14.7 lbs of air in our figure.
You only need 6.45 lbs of air to one lb of methanol to come up with a stoich a/f ratio. Now we're given 14.7 lbs of air to play with. How much more methanol will we need with 14.7 lbs of air to come up with a proper stoich a/f ratio with methanol?
14.7 lbs of air is 2.279 times the amount of air compared to 6.45 lbs. So we will need 2.279 times more methanol to be used with the 14.7 lbs of air to come up with a stoich a/f ratio.
Maybe someone can help us with the btu values of gasoline and methanol. Take the btu value for the methanol and times that value by 2.279. Compare the answer to the btu value of gasoline. What do you come up with?
dr_frankenstein
Mad Scientist
- Joined
- Mar 17, 2008
BUT.......
Methanol isnt as readily available as say........ denatured Alky.....
so would the type of alky have as much of an effect?
A.j.
Methanol isnt as readily available as say........ denatured Alky.....
so would the type of alky have as much of an effect?
A.j.
Dreamcar86
Active Member
- Joined
- Apr 13, 2006
amen!
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