Methanol Pros/Cons

[80DGY]

What are the advantages/disadvantages to using methanol in a 'race' engine...

The car would be a drag only beatie, no rego so no real need to run on normal fuel? I'm also under the impression you can run heaps more boost/not run an intercooler?

What steps would you take if you were considering building a motor suitable for straight (?) methanol?

Lastly, is it/supporting hardware expensive? :D

[dattoman1000]

Runs cooler
uses more fuel
needs uprated fuel system as its "thicker"
Big compression or boost is better to make full use of it
Its cheap to buy in 44 gal drums

[hamish]

Tends to corrode a lot of components in conventional fuel systems. I believe it's because alcohol has oxygen in it.

[gtst4]

hamish, are you talking about methanol or are you talking about alochol - 2 different things.

Methanol burns with a clear flame, so you can't tell if your pit crewman is on fire or has a scorpion down his jocks.
Methanol is poisonous (yeah, so is petrol).
Methanol is hygroscopic (absorbs water), so its power output might vary over the life of a 44 of it.

You will probably need a special license to by 44s of it.

[Alspos]

Methanol is corrosive and needs to be flushed from the system or it will eat metal parts.
Higher compression and/or more boost can be run but u need lots of fuel to make the power.

[sssgtr]

Not to mention the "cheese" it leaves in the motor when not used for short periods of time.

[Lonx]

3 times more fuel needed in a methanol engine...

its optimum ratio is 6.5:1 or therabouts, compared to fuel's 12.5 - 14.4. Can handle compression ratios up to around 15:1

[hamish]

gtst4, methanol & ethanol are 2 different types of alcohol, ethanol is the type you find in your beer etc. (I think I've got that the right way round)
You can run an engine on ethanol if you wanted to, requires different Af ratios to methanol, & I'm pretty sure it's more expensive & less available than methanol. I'm sure a drag racer can correct me on this

[earlyrolla]

Chemistry lesson 101

Regular Petrol
Specific Calorific Value (MJ/kg) 42.7
Theoretical Air Requirement (kg/kg) 14.8
Latent Heat Of Evaporation (kJ/kg) 380-500
Ignition Temperature (C) 300

Premium Petrol
Specific Calorific Value (MJ/kg) 43.5
Theoretical Air Requirement (kg/kg) 14.7
Latent Heat Of Evaporation (kJ/kg) 380-500
Ignition Temperature (C) 400

Methanol CH3OH
Specific Calorific Value (MJ/kg) 19.7
Theoretical Air Requirement (kg/kg) 6.4
Latent Heat Of Evaporation (kJ/kg) 1110
Ignition Temperature (C) 450

Ethanol C2H5OH
Specific Calorific Value (MJ/kg) 26.8
Theoretical Air Requirement (kg/kg) 9
Latent Heat Of Evaporation (kJ/kg) 904
Ignition Temperature (C) 420

Yes, ethanol is what is in beer, spirits etc.
Yes, methanol is poisonous. Much worse than petrol. Consuming only SMALL amounts will lead to blindness and eventually death.

Methanol only has about half the energy per volume compared to petrol, therefore you need to burn twice the amount of methanol to get the same output power. The air fuel ratio has nothing to do with this.

Methanol is not corrosive itself. As said by gtst4, methanol is hygroscopic (absorbs) water. It is the water that causes the corrosion. It is very labour intensive. As said by Alspos, the fuel system needs to be flushed if vehicle is going to be left for more than a week. You should also spray RP7 or the like down the bores and turn over the engine if you are going to leave the engine overnight.

It is cheaper in 44g drums. And no special license is needed (well at least not in WA). Best to store drums in a dry place and off the ground on a couple of bits of wood as the methanol will absorb water through the drum.

Drag racers use methanol mainly for its cooling properties (see Latent Heat Of Evaporation). Methanl will absorb more than double the amount of heat from the intake charge as opposed to petrol. This is why the blower hats on drag cars often have water droplets and sometimes ice form on them while the engine is running. Turbo drag engines can run without intercoolers as the methanol 'acts' as the intercooler. That is not to say that the engine wont benefit from running an intercooler.

In order to take full advantages of the properties of methanol, the engine compression should be increased, or boost levels increased. The limits of either are determined by engine parameters, eg cam profile etc etc etc.

Long lesson, but hope it answers everyones questions.

[Warpspeed]

Excellent post Earlyrolla.

[hamish]

Thanks for clarifying the point about corrosion.

[earlyrolla]

One more point to add about running methanol. Methanol is like LPG in that it is a 'dry' fuel. I.e. it has no lubrication properties. When running methanol in an engine you need to add a substitute lubricant to the methanol (and I don't mean adding two stroke oil !!!). An appropriate additive is available from most speed shops etc.