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Water/Meth...again

6.5L

6.5L

Old Iron Runner
Messages
1,177
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433
Location
Northwest Wyoming
Please don't hate me guys but I have to ask some stuff again. Again, really sorry to keep asking. just still isn't clear yet to me. So everybody says not to run over a 20-25% mix of methanol and water. Well, I was doing some reading on the throne earlier of a dieselpowermag I just grabbed off the shelf and came across a whole write-up on using water/methanol injection, and would like to share a brief paragraph from it with you that got me thinking. I give all credit to dieselpowermagazine and snow performance from the July 2013 DIESELPOWER, page 208 specifically (citation following).

""Methanol is the fuel of choice because of its high auto-ignition temperature. What this means in the methanol being added to the combustion chamber will not ignite until after the primary fuel (diesel) does. If the fuel source added were to have a lower auto-ignition temperature than diesel, it could cause pre-igniton, which can damage engines. To put it in perspective, diesel ignites at around 210* C, while methanol doesn't ignite until 470*C. This makes methanol the perfect fuel to be added along with water injection."" Gonderman, Jason, and Snow Performance. "Water-Methanol Injection." DIESEL POWER July 2013: 204-08

""For methanol concentration, 50% methanol and 50% water is the maximum recommendation. At this level, the flash point of the methanol is so high that the threat of accidental combustion is extremely low, making it safe for everyday use."" Gonderman, Jason, and Snow Performance. "Water-Methanol Injection." DIESEL POWER July 2013: 204-08

So I ask the question of why use a low % mix and what damage in very specific details can be caused by a high % mix. This information seems to contradict those statements so I would just like to have some clarification. And please, nobody be jerks and go the whole "well if you don't trust us, why don't you give it a shot and find out for yourself". I'm not doing this to be a jerk and keep asking to irritate people. I am asking because the concept is still lost to me or maybe in reality it is fine to use a high % mix. Just wanting some answers. Really hope someone can give it to me in "dumb" terms. Because to me, it seems a 40-45% mix may be just right to get a methanol concentration high enough to avoid any problems. Maybe the problems come from auto-igniting at too low a concentration. Just thinking out loud folks. And by the way, Happy Thanksgiving!!!!!!!!
 
Alcohol has a very high oxygen content and octane 'rating' as well. (Thus its resistance to preignition/detonation) I'd think you'd run the risk of burning a piston with huge levels of alcohol. Your engine would run too lean.
 
If methanol is a source of fuel though, how would that run it too lean? Wouldn't the addition of the water keep it cool enough that when using it, it wouldn't burn a piston? I'm not thinking huge amounts of methanol. I don't think a 50/50 mix is a lot of methanol, especially since I won't be using a large nozzle, I can't see it injecting that much, or even using it all the time either.
 
I am not sure but suspect its how fast it burns and quickness of temperature rise. Just because it delays in auto ignition compared to Diesel doesn't mean it doesn't have faster flame front advance or faster rise in temperature and thus cylinder pressure.
 
I alway thought the addition of water meth lowered EGT's which is a result of cylinder temp? Also always looked at water meth as a was to "clean up" the burn.

Just my thoughts, feel free to correct me.
 
Does anyone know of anybody who has personally had some damage related to the use of a high % mix of methanol/water? I would think the only think it may do is accidental ignite and maybe blow a precup up. But I don't think the chance of that is likely. Diesel hasn't blown a precup out yet and it would be a much lower concentration of methanol compared to diesel.
 
6.5L said:
Does anyone know of anybody who has personally had some damage related to the use of a high % mix of methanol/water? I would think the only think it may do is accidental ignite and maybe blow a precup up. But I don't think the chance of that is likely. Diesel hasn't blown a precup out yet and it would be a much lower concentration of methanol compared to diesel.
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It's cylinder pressure that's the concern with a 21:1 (or 20:1) engine and the way the fire decks are bolted down.

Mine actually started "knocking" when I went over about 25-30%. Drained that tank out directly onto the ground and went back to straight water. Didn't show enough gain to care about on the rollers anyways.

I could care less what "diesel power" has to say. I don't even look at that rag anymore. Maybe if it's on a rack at the airport and I need to kill some time with a good laugh. They're not quite the "experts" they make out to be....

I now run straight water for IAT/EGT control. Drain it in the winter (when ambient is -10 C and lower, it doesn't really make a difference anyways).

I add more fuel in the programming, not with meth. That's like drooling propane in there. There are better (safer) ways to make more power.

I'm conservative with the fuel as well because I can suck my 8 gallons dry in a 45 minute hard towing climb. Then I'm back to partial supplemental IAT cooling so I don't want the tables too "hot".
 
I've heard it nails with the IDI 6.5 like too much propane and figured it was high pressure at TDC and figured it was how fast it burned and increased pressure at TDC. Not sure if it is a faster flame front but lower overall temp due to latent heat of evaporation of the water. Or its more mass in the cylinder and more pressure but not necessarily higher temperature????
 
Just to be fair Great White, a lot of that information in that article was provided by Snow Performance, who I have to say is probably an expert in water/methanol injection kits.
 
I don't think auto ignition temperature directly correlates to how fast something burns once ignited. For instance gasoline(s) I think burns about the same speed but Octane how much it resists pre-ignition varies.

I googled it and skimmed some papers over my head and don't know if numbers are accurate or how they actually compare but I THINK some comparable numbers are
Diesel burns at 15 cm/sec and mixture of methanol in air is faster at 25-30 cm/sec. But those numbers vary over temperature and pressure. And the numbers probably vary greatly with dilution of water. And why if you use low % of methanol with water its fine but higher concentrations nails and stresses the lower end because of crank timing and pressure rise in cylinder.

So in a nut shell it is true that methanol and water retard pre-ignition but once ignited it may increase cylinder pressure faster than Diesel. The Diesel is squirted in and the methanol is brought in by air mixture so again a bit difference in amount of fuel to burn all at once and again at TDC or even a skosh before TDC.

Does that describe how it can be dangerous even though Snow states it resists auto ignition?
 
Kinda, but have you gone over a 20% mix? Maybe it was always slightly knocking but it was so diluted it was minor and you couldn't hear it. Maybe after a certain point the concentration of methanol will be so high 45-49% that it will get to a point where it can resist the auto-ignition? Just thinking out loud. I wrote Snow Performance and asked them about this whole thing and attempted to get them to verify these results on a test 6.5L motor. Haven't heard back yet. Doubt they will but worth a shot, right?
 
Water is highly corrosive. Why would you consider running it through your engine. The diesel e gone was never designed to have water run through it.
 
Big T said:
Water is highly corrosive. . . .The diesel engine was never designed to have water run through it.
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Ha! Then you would not want to live here as the air frequently gets to 80% of saturation during a typical summer day; 100% at night :D So no need for WMI on the East Coast as there is plenty of water already pre-mixed!! :rofl:

(Sorry, could not help myself ;) )
 
So the people at Snow Performance assure me that runnin a high concentration of methanol will not cause any problems so I don't know
 
They said that they know of a few 6.5L's that have gotten there products that run the Boost Juice (49%) with no problems during high % mix as long as they use the right nozzle combination
 
I was always told that our engines are an issue because they are indirect injected. The direct injection motors can run higher amounts of methanol, for some reason. Heard this many times but don't remember what the reasoning was.
 
Idi has a PRECUMBUSTION chamber designed to increase pressure which lower flashpoint, slows burn, it increases localized temperature to do this. Common rail = different world. Let them give you a warranty in writing if they are that sure.
 
They assure me that there are no problems as long as the proper amount of fluid volume is used and can verify multiple 6.5L's running high % mixes with not a single problem.
 
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