Methanol ?

6 replies to this topic
  • roofer dude

Posted September 18, 2011 - 06:58 AM


Thinking about changing over to methanol from gas, anyone have any experience with this on a 2003 450 ? Will the power gain be worth the trouble?

  • grayracer513

Posted September 18, 2011 - 10:59 AM


It's not a real great idea, no. For one, methanol is a relatively low energy fuel, a fact that is offset by the fact that it can be run very much richer than gas, and in fact, has to be in order to run right. The stoichiometric point (where fuel and oxygen are matched evenly and is neither lean nor rich) for gasoline is 14.6:1, air to fuel. With methanol it's 6.8:1, so you need to run more than twice as much methanol just to get the mixture right.

As far as power goes, you don't really get any just from switching to methanol in an engine suitable for gas, and a lot of race gasolines will produce more power. The gain with methanol is achieved through taking advantage of its extremely high equivalent octane number, or detonation resistance. This allows the use of compression ratios as high as 18:1, and THAT is where the power gain comes from.

  • roofer dude

Posted September 18, 2011 - 01:07 PM


So going to methanol and going up on timing would not gain HP. Of coarse with methanol carburetor. Already have Big Bore , Web Cams, and high compression piston. Would also help with temp. ?

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  • wrzoso

Posted September 18, 2011 - 03:02 PM


running richer means running cooler, its easier to give away the heat with that amount of fuel. Take a look at the top speedway engines - GM (giuseppe marzotto) they are all methanol powered with no cooling whatsoever. the cylinder radiators are really tiny, yet they produce around 70hp out of a 500cc. The engines run full throttle all four laps. While the engine is built completely out of conventional materials that is steel and aluminium. Using titanium and its alloys is forbidden. You should also check this http://www.physicsfo...p/t-316560.html and read up on speedway engines

  • Eric1231

Posted September 18, 2011 - 03:48 PM


Methanol has less btu of energy per unit however the stoichiometric ratio allows you to run nearly twice as much fuel. Since you need to use more fuel to achieve the stoichiometric you have more fuel in your combustion chamber per cycle. However, since the fuel has less energy per unit your power increase is only about 10%. Methanol has other advantages, it has a higher octane rating than gas so you could run a higher compression ratio and it cools the intake charge when it is used. My race team uses it on our supercharged prostreet car. We use it mainly to keep the engine temp cool. You want to add lube to the methanol if your racing class will allow it. Otherwise it will eat your engine up. Since it is basically an engine degresser and washes the the oil off the cylinder and off the valves. Another disadvantage is when it mixes with your oil it breaks it down so you will need to change your oil pretty frequently. Finally after running it you should spray wd-40 into the spark plug hole of your head so your so your cylinder doesn't rust.

  • roofer dude

Posted September 18, 2011 - 04:30 PM


I know some of the down sides to running methanol , such as flushing carburetor,and changing oil a lot more often. Will it give you 10 percent more HP with correct carburetor set up ?

  • grayracer513

Posted September 18, 2011 - 06:37 PM


running richer means running cooler, its easier to give away the heat with that amount of fuel.

Richer does not equal cooler. In the particular case of alcohol engines, the vaporization rate of the fuel is so high and the fuel density of the intake charge so great that a tremendous amount of heat is absorbed by the incoming fuel charge. In fact, carburetor icing is an issue that often crops up with methanol engines.

But internal combustion engines create mechanical power by extracting heat from liquid fuel, and you can't do that without heating the engine up. But speedway engines are only run at race pace for about a minute and a half, and that at speeds that never drop below 30 MPH, so the raditors don't really need to amount to much.

Nitromethane has to be run even richer than methanol, I no one would ever say it ran cool.

Methanol has less btu of energy per unit however the stoichiometric ratio allows you to run nearly twice as much fuel.

The stoich ratio requires you to run twice as much to avoid running dangerously lean. Saying that it allows it glooses over that fact somewhat.

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