Methanol

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#1
I have a ktm 380 that I would love to convert into a drag bike for shooting hills at places like glammis etc. I would like to know if there is anyone out there who has ran alky in a dirt bike. If so what mods are required. What effect does it have on power and will it damage an engine. I know it is very corrosive and it attracts water but what are some of the other side effects. What compression ratio should you run with alcohol. Fill me with knowledge please.
 
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#2
ftz racing has alchol carbs for 250r quad and they can be used in mx bikes some of the plus sides of it would be u could run alot higher compression and it would run cooler im pretty sure that u have to use larger fuel lines and modify the petcock for more fuel the downside besides the water is that it uses about twice the fuel so theres no far rides
 

Rich Rohrich

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#3
There are a couple of things to consider here. Alcohols are single boiling point fuels with a hydroxyl-radical (OH) attached while hydrocarbon based race fuels are made up of hundreds of hydrogen and carbon based components with a wide range of boiling points and technically yes alcohol has a lower flame temperature than typical gasoline . As fuels they couldn't be much MORE different but what’s interesting is if you compare the heat of combustion of 1 cu. Ft of chemically correct mixture at 14.7 psia @ 60F you get the following values:

Methanol (neat methyl alcohol) = 94.5
Gasoline (SG 0.739 @ 60f) = 94.8
Benzene (aromatic hydrocarbon) = 95.7

The second thing is you seem to be equating latent heat of vaporization with heat of combustion. While the two are ultimately inter-connected in the end, it's not in the way that you seem to be leaning. We have to step into science mode for a second to (hopefully) make this clear.

We all know fuel has to be a vapor for combustion to occur, and the process of changing a liquid to a vapor is sort of a two-part phase change. The temperature that a fuel's components will boil at is varied, and the temps are dependent on the pressure exerted on them. Lower the pressure (like at high altitude) and it boils at a lower temp, raise the pressure (below sea level or supercharging) and the fuel will boil at a higher temp. BUT even at the boiling point temperature, for the phase change from liquid to vapor (technically gas) to occur additional latent heat is required. The heat is obtained from the surrounding air and the fuel that remains in the liquid state. In the case of methanol we have a fuel that has a relatively low boiling point, but a high latent heat of vaporization, so lots of heat is removed from the surrounding air which leads to a denser mixture reaching the combustion chamber, which is good for power (higher volumetric efficiency), but the fuel that remains in the liquid state enters the combustion chamber at a much lower temperature and will ultimately need to leech additional heat from the combustion chamber to change to a vapor that can be burned, which isn’t good for power. Some good some bad, but on the whole in the case of methanol the end result is higher volumetric efficiency, more power, higher overall cylinder temperatures but a similar heat of combustion. A common rule of thumb is for every 11 degree F drop in temperature you have the potential to make an additional 1% more horsepower due to increased air density.

To make this more understandable, keep in mind you can have two liquids with the SAME boiling temperature but DIFFERENT latent heat requirements. The liquid with the higher latent heat will steal more thermal energy from the surrounding air and liquid.
Methanol has a boiling point of 149 F and a latent heat of vaporization of 1.17 MJ/kg
Ethanol has a boiling point of 172 F and a latent heat of vaporization of 0.93 MJ/kg
Typical gasoline has boiling points in 85 - 410 F range and a latent heat of vaporization of approximately 0.18 MJ/kg

When you start getting into hydrocarbon combinations with varying latent heat requirements, you have the potential to influence the cylinder filling in similar ways with the right combinations of fuel components.
The end result is the heat of combustion changes very little, while the overall combustion temperatures will rise pretty much in direct proportion to the increase in cylinder pressure that comes with a denser mixture in the combustion chamber. Filling the cylinder more completely whether it’s done with fuel or, porting wave tuning has the same overall effect. Make more power and you get heat, increase the load and the same things happens.
 

MXFastGuy

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#4
I ran methanol in 4 cycle karts and my experience is this:
1. It DOES make more power, providing you setup the engine properly.
2. It runs about 10% cooler
3. It requires richer jetting and advanced ignition timing (you probably knew this)
4. It does not necessarily attract moisture, you just have to be careful (much more so than with gas) to keep it in a cool, dry place and off the garage floor. Just try to use fairly fresh fuel.
5. It's really not all that corrosive, but it will eat aluminum and rubber over time. You need to run the engine dry of all alky after each race day, and ideally run gas through it to completely flush any alky residue out. You will notice if you don't flush with gas, over time everything in the carb will take on a white powdery coating that is hard to clean off.
6. It's safer to handle than gas and isn't so stinky!

We're not exactly comparing apples to apples here, but those are my practical experiences with methanol. Hope it helps.
 
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#6
I've done this on 4-strokes and 2-strokes. It was very easy.

We removed the screen tubes from inside the gas tank for the fuel peck ****, then installed one size larger fuel line.

To the carb: Mike the fatest part of your needle, then drill the down tube out 0.011 over that size. Then you measure the diameter of the main jet and using jet drills, double the size of the mains hole. And no, you can not get a #360 jet if you currently have a #180, drill it out.

The air/fuel mixture screw needs to be turned out a good bit, or drilled out and the spark plug gap changed to 0.018 gap.

Thought I could remember it exactly but I can't. I do have it all written down if you want the exact procedure

You want to run about 10.5:1 or better compression.

I've pulled down many alky engines that were maintained and all I ever really found was ring wash was quite a bit, leading to change your oil alot.

If you flush your engine with gas after every days ride, change your oil often, and watch your compression for more freaquent top end jobs, well you will be very surprised.

Power increase is 20 to 40 percent better depending on tuning. Engine really gets less ware do to vertually no heat, and it's a down rite blast.

Down side, nearly needs jetted every day or every slight weather change, ring wash makes cylinder hone jobs nothing in just a few hours, but not really any bad things happen except loss of compression.

Don't be scared and try it, it's very easy.

and for real fun throw a bit of nitrous in there!
 

GKL

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#7
I've ran alky sometime ago in 4 and 2 strokes. Most of my experiences were the same as above, but we ran 16:1 compression in the 4 stroke. We increased the compression in the 2 stroke, too, but I can't remember the exact figure. We never ran into the problems with jetting, as alcohol will lose minimal power and just consume more fuel when on the rich side. We ran always in the same area and air density didn't have too large of a spread. We did change the seals in the 2 stroke engines religiously, as the alcohol tends to harden them over time.
 

motometal

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#8
Regarding jetting with methanol...since the LHV of methanol is so high (compared to gasoline), if the mixture was rich and some of the methanol remained in the liquid state, it would rob significant heat from combustion (as it vaporized).  In this circumstance, jetting would have a drastic effect on power output.  I suppose on some engines, nearly all of the fuel vaporizes even if the mixture is rich (up to a point)??? which would make jetting not as critical?
 
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nephron

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#9
6. It's safer to handle than gas
Why so?

Question: Methanol is hygroscopic, fully miscible in H2O (moderately polar...methanol that is), and considered only partially miscible with solvents like Hexane. This obviously raises the question of premix compatibility. Any info on bearing/crank life in this situation, or does the oil separate to the bottom of the crankcase followed by windage lubrication?

I'm probably missing something here, and those are not exactly proper terms. ;)
 

Studboy

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#10
Most castor based oils mix well with methanol.

Klotz has a few oils that work well in an alchohol application.
 

motometal

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#11
It could be argued that methanol is safer to handle than gas, because it's only one substance, vs. a mixture of many different components (gasoline).  The properties and effects of methanol should be a constant, vs. gas with different blends, etc.

Sure, we could get the MSDS for a given blend of gasoline, but then if we switch blends (or if THEY  take the liberty of altering the formula), then it's not applicable.
 

nephron

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#12
Working "well" in an auto app where fuel is meant to stay above the rings and, in a major way, mostly distant from oil, is different than working "well" with a premix. That is to say, even the 'good' oils for methanol in 4 strokes result in significant immiscibility and standing levels of methanol in the crankcase. Kendall used to have a green dino (GT) oil that worked very well, but quit making it in lieu of production costs and a new "philosophy".

I would think, but surely don't know, that 2 stroke bearing life is linked vitally to fuel/oil immiscibility and other properties that relate the interactions of the two---particularly if the bearings are lubed by the mixture suspension and not by 'windaged' oil fallen to the bottom of the case.

Some terminology would help in sorting this out, if necessary.
 

motometal

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#13
I ran that 70 Wt Kendall oil in a BB Chevy with "racing" clearances...worked great, although not the best "cold weather" oil :eek: