Gas or alcohol , more power?

[Truckedup]

For example take to SBC's, one on alcohol, one on the best race gasoline ,optomize each one to deliver maximum power on the given fuel...Does the alcohol engine make more power?

[NormS]

According to the calculated BTU output of gasoline, ethyl alcohol, and methyl alcohol, each at its proper air/fuel ratio, the power increase for ethyl alcohol, over gasoline, is about 8%, and the increase for methyl alcohol is about 12% over gas. Years ago, I built 3 carbs of the same model for a dyno back to back to back test of racing gas, ethanol, and methanol on a normally aspirated small block chevy on our dyno, for a company that produced ethanol.

They were under the impression that ethanol would make more power than methanol, and we told them no. They funded a test to see what the real story was, and found that our estimates for 8% gain for ethanol, and 12% gain for methanol, were pretty close...to their disappointment, of course.

When it comes to turbocharged or supercharged engines, the story is somewhat different. Because of the higher amount of heat energy required to vaporize the alcohols, the power increase with the alcohols, over gas, is even more than the 8% and 12% we see with normally aspirated engines, due to the "intercooling effect" of the alcohols.

[ProPower engines]

Any power adders like turbo or super charger in the plan ??
I personally would choose alky. I have run it for a very long time and have go used to the extra work needed over race gas.
We did some tests on a well tuned sm blk recently and switched to alky and picked up 50 HP 38 torque on same intake
just swapped fuel systems
This was a limited 2bbl carb deal as well

[Dragsinger]

Methanol is a good race fuel with advantages even if the power was equal to gas. Good torque, excellent throttle response, cooler running.

[Truckedup]

Any power adders like turbo or super charger in the plan ??
I personally would choose alky. I have run it for a very long time and have go used to the extra work needed over race gas.
We did some tests on a well tuned sm blk recently and switched to alky and picked up 50 HP 38 torque on same intake
just swapped fuel systems
This was a limited 2bbl carb deal as well

Suppose we say N/A on both, no nitrous....

And tune it down for street use,something that idles with a mild lope... E85 compared to 93 pump gas, maximum usuable compression for both....I would assume E85 engine would be stronger... and use twice as much fuel...

[David Redszus]

A comparison of various fuels based upon their heat of combustion per pound of air burned (BTU/lbAir) we find:

Specific power
Acetone------1399
Methanol-----1328
Ethanol-------1278
Gasoline------1273

The above does not include the charge cooling effect due to complete evaporation.
Evaporative cooling (BTU/lbAir) tell a slightly different story:

Charge cooling
Acetone------13
Methanol-----78
Ethanol-------41
Gasoline------10

These are theoretical values based on optimum ignition, complete complete evaporation and
combustion at the proper crank angle. Actual performance results from a combination of heating
and cooling and ambient conditions.

[Ericnova]

Any power adders like turbo or super charger in the plan ??
I personally would choose alky. I have run it for a very long time and have go used to the extra work needed over race gas.
We did some tests on a well tuned sm blk recently and switched to alky and picked up 50 HP 38 torque on same intake
just swapped fuel systems
This was a limited 2bbl carb deal as well

Suppose we say N/A on both, no nitrous....

And tune it down for street use,something that idles with a mild lope... E85 compared to 93 pump gas, maximum usuable compression for both....I would assume E85 engine would be stronger... and use twice as much fuel...

We've found it to be only about 25-27% more fuel,....no where near twice as much. 13.5:1 comp SBC's versus pump gas compression ratio. Really noticeable torque improvement low and mid range and of course the top end power

[Krooser]

Any power adders like turbo or super charger in the plan ??
I personally would choose alky. I have run it for a very long time and have go used to the extra work needed over race gas.
We did some tests on a well tuned sm blk recently and switched to alky and picked up 50 HP 38 torque on same intake
just swapped fuel systems
This was a limited 2bbl carb deal as well

Suppose we say N/A on both, no nitrous....

And tune it down for street use,something that idles with a mild lope... E85 compared to 93 pump gas, maximum usuable compression for both....I would assume E85 engine would be stronger... and use twice as much fuel...

We've found it to be only about 25-27% more fuel,....no where near twice as much. 13.5:1 comp SBC's versus pump gas compression ratio. Really noticeable torque improvement low and mid range and of course the top end power

I'd agree... I help on a local dirt late model crew on occasion. Seems like we use about 30% more than when the car was on race gas.

Maybe we should bump up the jets for more HP... My eyes barely water when standing next to the exhaust!

[FC-Pilot]

I have only "raced" using alky, but with some of the new oxygenated race gas out there I would imagine the gap has closed quite a bit if not completely regarding the power difference between oxygenated race gas and alky. I don't know really, just a thought.

Paul

[David Redszus]

I have only "raced" using alky, but with some of the new oxygenated race gas out there I would imagine the gap has closed quite a bit if not completely regarding the power difference between oxygenated race gas and alky. I don't know really, just a thought.

Paul

Methanol is 50% oxygen and 50% fuel. Only the fuel portion produces power. The oxygen allows more fuel to be run.

Oxygenated race gas very seldom contains more than 3-4.5% oxygen.

The number that matters is not the amount of oxygenate in a fuel but rather its stoich value that determines how much fuel you can use.

[FC-Pilot]

I have only "raced" using alky, but with some of the new oxygenated race gas out there I would imagine the gap has closed quite a bit if not completely regarding the power difference between oxygenated race gas and alky. I don't know really, just a thought.

Paul

Methanol is 50% oxygen and 50% fuel. Only the fuel portion produces power. The oxygen allows more fuel to be run.

Oxygenated race gas very seldom contains more than 3-4.5% oxygen.

The number that matters is not the amount of oxygenate in a fuel but rather its stoich value that determines how much fuel you can use.

I understand the concept. I get that the oxygenated fuel can burn a greater amount of fuel efficiently. My point is that I have never done any back to back testing to know if or how much that gap might have been closed. Nor have I heard of any testing done. All I am saying is that I have "heard" some say the high quality "oxygenated race gasoline" makes the same power as Methanol does. I have never seen anything to confirm that, but have not seen anything to deny that either. I was just bringing this up to see if anyone here "has actually done the testing" and if so what the results might look like. I am not trying to pester anyone, just looking to see if someone has facts to shed some light on the topic.

Paul

[David Redszus]

I have only "raced" using alky, but with some of the new oxygenated race gas out there I would imagine the gap has closed quite a bit if not completely regarding the power difference between oxygenated race gas and alky. I don't know really, just a thought.

Paul

Methanol is 50% oxygen and 50% fuel. Only the fuel portion produces power. The oxygen allows more fuel to be run.

Oxygenated race gas very seldom contains more than 3-4.5% oxygen.

The number that matters is not the amount of oxygenate in a fuel but rather its stoich value that determines how much fuel you can use.

I understand the concept. I get that the oxygenated fuel can burn a greater amount of fuel efficiently. My point is that I have never done any back to back testing to know if or how much that gap might have been closed. Nor have I heard of any testing done. All I am saying is that I have "heard" some say the high quality "oxygenated race gasoline" makes the same power as Methanol does. I have never seen anything to confirm that, but have not seen anything to deny that either. I was just bringing this up to see if anyone here "has actually done the testing" and if so what the results might look like. I am not trying to pester anyone, just looking to see if someone has facts to shed some light on the topic.

Paul

The comparative testing of fuel performance has been done...prior to and during WWII.
There are several NACA papers that fully described the testing that was performed on NA and
supercharged aircraft engines. I'll try to find a few.