Ethanol vs Methanol, why both?

[Circlotron]

In many places you can buy E85 which is 85% ethanol. Also some race engines are fueled by straight methanol. Question is - why are both methyl alcohol and ethyl alcohol produced? Is one more costly, dangerous, corrosive, whatever but gives better results? The basic question is - if one is better than the other, why produce both? or if they both give equal results why not simplify tings and just produce one type?

[David Redszus]

In many places you can buy E85 which is 85% ethanol. Also some race engines are fueled by straight methanol. Question is - why are both methyl alcohol and ethyl alcohol produced? Is one more costly, dangerous, corrosive, whatever but gives better results? The basic question is - if one is better than the other, why produce both? or if they both give equal results why not simplify tings and just produce one type?

Methanol and ethanol are not produced primarily for use as fuels. Use as fuels represents only a small part of total consumption.

Methanol is used to produce a wide range of chemicals used in many industries. It is non-potable.

Ethanol is used to produce other chemicals as well as for alcoholic beverages.

Methnol is mainly produced from the hydrogenation of natural gas.
Ethanol is mainly produced from the fermentation of agricultural products.

Methanol is much more toxic than ethanol. Both absorb water and are highly corrosive.

Neither alcohol is considered a desireable fuel for transportation and would not be used except
for the role of politics.

[Circlotron]

Methanol and ethanol are not produced primarily for use as fuels. Use as fuels represents only a small part of total consumption.

That makes sense. Thanks.

[fabr]

It is always claimed that ethanol is highly corrosive. I must challenge that. For automotive use it is my opinion from using e85 blended from anhydrous 98% ethanol and 87 pump gas for approx 10 years that it is is no more corrosive than straight gas. The culprit with ethanol is water absorbed due to poor storage practices till it is near the saturation point that causes corrosion blamed on ethanol. My fuel system is unvented during storage to prevent the water absorption. People running carbs and continuously vented systems might have corrosion issues.

[gregsdart]

Methanol as a race fuel has a small power advantage over ethanol and a bigger one over most race gasoline. If you are a dedicated racer there are advantages in consistancy at the drag strip with methanol, not sure on ethanol. Methanol draws away five times more energy when evaporating versus gasoline. That allows some very serious compression and boost to be used.

[RDY4WAR]

I haven't had any issues with ethanol corrosion either.

As for methanol, I have wondered at what point methanol becomes advantageous over ethanol. Say a 10:1 compression NA engine. Comparing BTU per stoich pound of fuel...

Ethanol = 1274 BTU/lb of air
Methanol = 1328 BTU/lb of air

I think I remember those correctly from David's posts. Comparing BTU per pound of air heat of vaporization...

Ethanol = 39.9 BTU/lb of air
Methanol = 78.5 BTU/lb of air

So ethanol has the ability to remove 39.9 BTU of heat from 1 pound of air where as methanol can remove 78.5 BTU from 1 pound of air. I'm sure this could be calculated somehow, but at what point can you not cool the intake charge down any further. To word that better, at what point is there no more intake heat left to absorb? If ethanol can cool the intake charge down to fuel temperature already, then will methanol be able to improve upon that? If not, how much of a difference will we really see from the BTU energy difference?

I ask this because Engine Masters did an episode on this comparing gasoline to E85 to methanol on a basic, mild NA LS engine and found zero difference in power between E85 and methanol. I tend to take anything on that show with a grain of salt, but that episode has had me wondering ever since.

[Circlotron]

but at what point can you not cool the intake charge down any further. To word that better, at what point is there no more intake heat left to absorb? If ethanol can cool the intake charge down to fuel temperature already, then will methanol be able to improve upon that?

Think of a day that has 100% relative humidity. The air contains 100% of the moisture possible at that particular temperature. Pass that air through an evaporative cooler and provided the water is at air temp, the air temp remains unchanged because no additional water gets evaporated.

I'd expect the same thing with any volatile liquid fuel. Once the air has absorbed and turned to vapour all it can, any additional fuel won't provide extra cooling unless that fuel is below air temp, though only by contact, not evaporation. Any extra fuel would likely remain in droplet form though, not vapour.

Any volatile fuel would be able to cool the air down to well below fuel temp if the air wasn't too hot to start with. Try wearing a wet t-shirt in a hot breeze.

[NewbVetteGuy]

I ask this because Engine Masters did an episode on this comparing gasoline to E85 to methanol on a basic, mild NA LS engine and found zero difference in power between E85 and methanol. I tend to take anything on that show with a grain of salt, but that episode has had me wondering ever since.

There are at least 3 Engine Masters episodes that looked at Methanol.

The most recent ones are Season 6 EP 97 where they tested an NA 496 Big Block Chevy and EP 98 where they looked at a twin turbocharged LS.


EP97 NA BBC 496 Test:
12.8:1 CR, AFR 325cc heads; they tested Sonoco 116, Oxygenated Sonoco 107, E85, and Meth in a few tests -each with a 950CFM carb appropriate for each fuel.

• Sonoco 116: 647.5 ft lbs @ 5,000 RPM, 770.4 HP @ 6,600
• Oxygenated Sonoco 107: 668.4 @ 5,300 RPM, 781.3 HP @ 6,600 (+21 ft lbs & +11 hp vs. non-oxygenated gas and the gains where EVERYWHERE) -torque peak moved up 300 rpm from oxygenated fuel -interesting...
• E85: 671.2 ft lbs @ 5,300 RPM, 776.6 hp @ 6,600 RPM (+3 ft lbs but -5 hp vs oxygenated race gas) -"torque fuel" -also highly oxygenated and also 5,300 RPM peak
• Methanol: 670.4 @ 5,300 RPM, 796.6 hp @ 6,600 RPM -torque like E85 but hp even slightly better than oxygenated gas +24 ft lbs and +26 hp vs. non-oxygenated race gas

-Meth was a little better than everything else on the average, but E85 edged it out at the torque peak by less than 1 ft lb.

Adam

[NewbVetteGuy]

EP98 Twin Turbo LS looking at multiple Meth Injection Tests
No intercooler

• 91 Octane: 681.6 ft lbs @ 5,400 RPM; 833.7hp @ 6,700 RPM
  9.5 lbs of boost at peak, IATs 169F peak
  18 deg of timing for max power without detonation
• Water Meth injection added with same timing as 91 octane test: 687.8 ft lbs @ 5,200 RPM; 831.6 hp @ 6,700 RPM +6 ft lbs -2 HP
  (I think this was a 50/50 water-meth mix- spraying with 2 holley nozzles-I didn't note the size but @ 50% duty cycle and solenoids before the throttle body
  Odd that the torque peak dropped 200 RPM... (seems to be because the timing is now 4 degrees retarded vs what the engine wants on water-meth)
  IAT 123F peak (46 degree reduction)
  Tiny increase in boost
  Note: Despite a 46 degree reduction in IATs, a knock-limited engine (with timing pulled) made LESS power with water meth until timing was properly adjusted.
• Water Meth in jection but timing adjusted for best power (22 deg +4 deg from previous test): 713.2 ft lbs @ 6,000; 866.9 HP @ 6,700 RPM
  Details identical to prior test
  
  
• 50/50 water meth but increased duty cycle on meth injectors (75% duty cycle): Power dropped a lot everywhere- just too much water-meth for this engine
• Increase Meth blend to 75% meth / 25% water: 730.1 ft lbs; 894 hp @ 6,700! -BIG jump in torque everywhere
  -Also saw 15 deg reduction in IATs
• 100% Meth injection and duty cycle set to 100%: 742.3 ft lbs @ 5,700 rpm; 901.4 hp @ 6,700 RPM --the meth gains just get bigger and bigger!
• 100% Meth injection; 100% duty cycle - Ideal Tune: 741.3 @ 5,400 RPM 914.1 @ 6,800 RPM
  I don't remember but there was some Holley tune issue that caused them to have to hack around the default Holley O2 correction and start pulling out gas from the tune to get the 100% meth injection at 100% duty cycle correct:

-The tiny drop in torque on this last test I have to think is because they were just focused on getting the fueling right on the test and it was a super long day so they didn't bother to go back and adjust the timing one last time.

-The higher the % of Meth added and the MORE meth they added the more the whole curve just "shifted up". More meth made more power everywhere in this test when the tune was correct.

-Is injecting a ton of 100% meth pre throttle body in a meth injection system designed for no more than 50% meth a good, safe idea???!? I'm not sure I'd try it except with the engine sealed in a dyno room far away from my body, but curious what the experienced professionals think.



-I'd LOVE to see methanol injected super early like this (pre throttle body) vs. methanol directly injected into a cylinder where it's evaporative cooling wouldn't help add any more oxygen, BUT all the cooling power goes into the cylinder. No idea what would happen but I think it would be very educational.

I'm really hoping that Engine Masters keeps dealing us more meth (dyno tests) after E98.
The torque peaks and IATs make it clear why the Aussie burnout guys love the stuff so much.

Adam

[RDY4WAR]

I don't know where my mind went there. Thanks.

[NewbVetteGuy]

I don't know where my mind went there. Thanks.

I think your memory is probably correct about the earlier season's NA, reasonable compression LS motor. I think that's why they did the test again with a high compression BBC and a boosted LS -and why they tracked IATs and ignition timing. (Guessing they caught a lot of flack for that first test.)

-I didn't take any notes on that episode, or I would've posted that episode's details here. (I've learned not to trust my memory so I have to take notes.)


Adam

[RDY4WAR]

I'm curious about this because I blended a GEM fuel.

40% gasoline (90 AKI, non-ethanol)
12% ethanol
48% methanol

Basically using the ethanol as a binder for the gasoline and methanol. It should have a similar AFR as E85 which is what my engine is running now. It's a mild LT1 SBC with 10.5 compression. I haven't had a chance to take both fuels to the track and test them against each other.

[David Redszus]

I'm curious about this because I blended a GEM fuel.

40% gasoline (90 AKI, non-ethanol)
12% ethanol
48% methanol

Your magic elixar will have the folowing properties:
Power = 1298 BTU/lb air
Oxygen - 28.15%
Specific G = 0.780
Stoich = 10.09

[David Redszus]

I haven't had any issues with ethanol corrosion either.

Ethanol blended fuels (Gasahol) have anti-corrosion additives added by the refinery. Straight ethanol does not. Ethanol can absorb its weight in water and wet ethanol is corrosive, but not as bad as methanol.

As for methanol, I have wondered at what point methanol becomes advantageous over ethanol. Say a 10:1 compression NA engine. Comparing BTU per stoich pound of fuel...

Ethanol = 1274 BTU/lb of air
Methanol = 1328 BTU/lb of air

In terms of power, methanol has a small (4%) advntage over ethanol, while ethanaol has an even smaller (1%) advantage
over gasoline.

I think I remember those correctly from David's posts. Comparing BTU per pound of air heat of vaporization...
Ethanol = 39.9 BTU/lb of air
Methanol = 78.5 BTU/lb of air

The basis for the performance improvement of methanol is its extreme evaporative cooling capability. Fuel evaporation\
will reduce inlet air temperature and increase engine power as follows:
Methanol = 14.96%, Ethanol = 7.78%, Gasoline = 1.76%

So ethanol has the ability to remove 39.9 BTU of heat from 1 pound of air where as methanol can remove 78.5 BTU from 1 pound of air. I'm sure this could be calculated somehow, but at what point can you not cool the intake charge down any further.

The cooling ability of a fuel can be calculated, providing the following factors are known:
Heat of Evaporation
Fuel Stoich
Sp G
Specific Heat
Vapor density
Fuel temp
Air temp
Enrichment
Fraction evaporated

The two most important are the first and last factors.
The cooling limit is reached when all the supplied fuel is evporated.

When fuel is evaporated, it cools not only the induction air, but also the intake manifold.
Therefore, aluminum intakes become cooler and rob some of the cooling effect. Plastic intakes are
more effective with regard to charge cooling.

[Elroy]

Ethanol blended fuels (Gasahol) have anti-corrosion additives added by the refinery.

So pump "e85" whether that be the 60-70 percent ethanol i usually see.....contains these anti-corrosion additives?

Would there be any benefit to adding additional anti-corrosion additives, and what are they?

Thanks