Methanol corrosiveness and water?

[AnArKey]

I have heard it equally both ways.

"Methanol becomes MORE corrosive when water gets in it"

AND

"Methanol corrosiveness goes down considerably with just a little water"

OK guys, for the last time, what is it?

My guess is that it depends on what we are talking about.

In a pure methanol car, with fuel injectors, a little water causes corrosion in the pump and injectors or carb from rust. In this case I see why we get statement #1.

In a extra alcohol injection system like most of us run, where we worry about pumps that were made for water (Shurflo), and 0-rings failing, I think statement #2 applies.

Now, tell me if I'm totally wrong about this?

 

[Turbo__Tim]

http://www.chicagolandmgclub.com/techtips/562.html

Part of that article reads...


Most stories of corrosion problems date back to the earlier days of methanol-containing "gasahol", and are derived from corrosion of light metals (notably aluminum and magnesium) caused by anhydrous methanol. However the addition of either 0.5% water to pure methanol, or corrosion inhibitors to methanol/gasoline blends will prevent this. Oxygenated fuels may either swell or shrink some elastomers (rubber and plastics) on older cars, depending on the exact formulation of the fuels. If you observe or suspect any such corrosion or damage, talk to your local gasoline supplier. Most currently available reformulated gasolines do not seem to cause corrosion problems.

And this...

http://yarchive.net/car/methanol.html

 

[Steve Hill]

well as happens some times with "theories" ..... the real world may be quite a different animal. There are some variables, such as when air gets into the system, that the above line of reasoning doesn't consider.
From time to time, in my line of work, i get to see first hand how some pretty tidy theories can become unforseen gotchas. Just food for thought, and my personal experience.

 

[Turbo__Tim]

A bit off subject, but after reading this I wondered why one should go through all the trouble of running meth, when ethenol (denatured alcohol) works 80% as well as the meth at the job we want it to do - cool the charge.


Latent heat of vaporization for:
Gasoline .18
Nitrometh. .56
Methanol 1.17
Ethanol .93
Iso-octane .27

Specific Energy at stoich AFR:
Gasoline 2.92 at 14.6:1
Nitrometh. 2.3 at 1.7:1
Methanol 3.08 at 6.45:1
Ethanol 3.0 at 9.0:1
Iso-octane 2.9 at 15.1:1

Bear in mind nitro is typically raced at a 1:1 ratio, 40% richer than stoich and more. Methanol is typically raced at 30 percent richer than stoich and more. Gasoline is typically raced at 20% richer than stoich.

__________________
Don Wang

DRW Transmission Specialties, Inc.
84 GN with a BAAAD alcohol habit
Broken motor at the moment

Now that Don has been given credit for his research, I have a take on the Meth vs ethenol question.

Research has shown that 50-60% water- meth (water at 50-40%) is the best combination for cooling. So water is doing most of the cooling, since most of the alchy is burned up in combustion.

It seems since we can't get a fog like mist, dense, and super concentrated with the nozzles, and the limited power of 12 volt motors, we need to compromise and use the alchy as a carrier to get the water in there, in a form that it will not interfere with combustion.

I don't think that cooling the intake charge is such a great factor either. The alchy solution that hits my up pipe is about 90* (from heat soak to the bottle itself) so how can it cool the charge that much? If it does cool, where does the heat go? The up pipe isn't much of a radiator...

I believe that after combustion, the left - over water mist (which is now vapor, or steam actually) is what 'flushes' the heat from the combustion surfaces. That is where all the cooling takes place.

The belief that methanol provides more power in the process (over ethanol) doesn't stand up to the numbers. After all, the aclhy charge, as a whole, represents around 10 percent (or less) of the total intake charge. Alchy users here report using from 3 to 6 ounces in a quarter. I think it's reasonable to assume that a 342 horsepower engine will use 40-60 ounces of gas on a run.

A 10 percent difference in the power making ability of methanol over ethanol would make in theory a 1 percent difference in the total power generated.

This is why I'm not going to run Methanol. All the expense and hassle, and gain only 3 horsies?

Of course I could be wrong, I often am.

 

[Steve Hill]

Tim, I agree. I find no discernable diff between the two.

 

[BoostKillsStres]

Tim,
Do you have latent heat and energy numbers for IPA as another comparison?

 

[Turbo__Tim]

Fuel Type Energy Content (kJ/g)
Kerosene 46.3
Paraffin Wax 42.0
Ethanol 26.8
Isopropyl 24.04
Methanol 19.9

 

[tyndago]

I saw a large difference in between running methanol/water , and running straight ethanol in air inlet temps.

The methanol really dropped the intercooler temps dramatically. So much that the intake maifold was cold to the touch after a run.

But the more I think about it now...the methanol killed the pump on the SMC kit...it is possible that the pump was on its way out or not working at all when did the did the passes afterwards.... It was a few weeks later - the pump could have been dead already....

So now I guess I have to try it out again now that the SMC pump has been replaced... see what the air inlet temps drop too....

 

[Turbo__Tim]

That would be really cool if you did that. I can't understand how the temps get lowered, so ot would be great to see some numbers. I killed a pump also. Just a half ounce of tranny fluid to a tank (SMC) would have prevented it.

 

[AnArKey]

No solid answers yet. I have the kit on my car now, and will be running isoproply through it until I can pick up some methanol on Monday. What should I do? Add 25% water? Additive or no? If yes, what kind?

BTW I have a Shurflo pump.

 

[WFO]

i'd go over to the bike shop and buy some of that synthetic 2 stroke lube that lee thompson uses.he's running it with 100% methanol,so far,so good.

later,sean

 

[AnArKey]

Looks like I gotta run methanol. I can't find local denatured for less than $7 a gallon, and that's in bulk. I found methanol for $2/gallon. Tough choice.

So far I get a straight 50/50 on "water makes it better" vs "water makes it worse" opinions. I think this may have something to do with that:

"Dry methanol is very corrosive to some aluminum alloys, but additional water at 1% almost completely inhibits corrosion. It must be noted that methanol with additional water at more than 2% becomes corrosive again. The same happens with less than 1% water. Nitride and neoprene rubbers, generally satisfactory as elastomers in contact with methanol and polyacetal plastics, are very resistant. Silicon rubber as well as vinyl can be used for gasket material."
Full page HERE

Ah ha! 1% water is a magic number. More or less and the corrosion is there. Even luckier for me, the methanol I found claims to be 99%, not 99.95% or something like that.

I'm gonna mix up some 75/25 meth/water and 99 meth with lube and drop some nozzles, brass fittings, pieces of hose, and some Santoprene (pump diaphragm) in each container. I'll check them a few days later and note the results.

 

[boostm3]

But the more I think about it now...the methanol killed the pump on the SMC kit...

Just for a data point, the Aquamist pump works very differently. Aquamist's own tests have shown them that the viton seals used in their pump can tolerate up to a 50/50 methanol concentration, but only a 25% Isopropyl concentration, and just a 5% Ethanol concentration, before the Viton seals swell.

The current Aquamist racing and regular pumps were designed primarily for use with water, although it will tolerate alky concentrations as mentioned above...However....they are currently in the latter stages of production of a new pump, which will tolerate Methanol up to 75% strength with no deleterious effects. This pump will be available to the market toward the end of the year.