Water/Methanol lubricant

[ZephTheChef]

I have been running one of my cars on methanol for some time. It's a supercharged 98 Buick Park Avenue. I do not flush the system or any of that nonsense, it's a weekend driver/ fun car and I leave straight methanol in the system all the time. Apart from lots of fuel pump failures (primarily after neglecting the car and leaving it sitting for quite some time), I have had no problems. I do run a top end lube mixed in with the methanol. Up to this point I have been using water injection and spraying through the supercharger and the air/water intercooler that sits immediately beneath it, which has worked great. I am making some changes that I'm thinking will make spraying water through the intercooler a bad idea, so I need to come up with a different solution.

I just finished up a refrigeration setup for my intercooler reservoir using the vehicle's A/C system and a rear evaporator core from a suburban. I run 50/50 water methanol as an intercooler coolant and propane as a refrigerant, and have a large, very well insulated reservoir (it's literally a modified cooler). I've measured temperatures as low as 0 degrees F in that tank. I have pretty big doubts about whether it's a good idea to spray a fine mist of water through an intercooler that's significantly below freezing, even with the no doubt very hot supercharger outlet temps. Basically, this improvement in intercooling necessitates that my water injection take place post-intercooler and unfortunately there's really no good space/place to put nozzles since the injector ports are actually IN the heads. Ultimately, I've decided that the easiest, most accurate, and least expensive way around this is to just utilize my existing fuel injectors for water injection by mixing the water in directly with the methanol in my fuel tank.

Do I really NEED the water injection? Probably not, but with it I can run my tune one the ragged edge in terms of fastest flame speed AFR (which according to an epa study is around 13.3:1 for methanol, converted to the gasoline scale most tuners are familiar with) and still have the safety margin afforded by larger liquid volumes/greater heat of vaporization capacity in the combustion chamber.

Point of the story is, I need a lubricant or additive for anti-corrosion that will mix with both water and methanol and not adversely affect the combustion process to any significant degree. I'm investigating several possibilities but I thought I would ask around here to see what other people's ideas are. Thanks in advance for any help.

 

[ZephTheChef]

A little more information: I do have a methanol-rated injectors with supposedly all stainless-steel guts, and have done my homework on methanol compatibility with all my fuel system components...so I'm not 100% sure I really NEED a lube, but I would like to have a little extra peace of mind, especially considering I do not flush the system, and it does sit for several weeks or a month at a time sometimes. I've been considering water soluble machining coolant/oils but don't have much knowledge or expertise in that department, particularly with regard to how they might affect combustion. Definitely open to other suggestions. I know that the methanol lube I've been using definitely does NOT mix with water, however I have not tried it with an 80% methanol/20% water mix to see how that blends but I suspect it will separate.

This car probably won't see the streets again until it's at least 50 degrees out as cold-starting is really a chore on straight methanol, and my propane bottle doesn't build enough pressure for the car to idle on when it's this cold out...so I'm just trying to get all my bases covered and do all my homework over the winter downtime.

 

[1gibson]

Sounds like an interesting setup. There are two spots in the lower intake manifold to put nozzles, on the vertical walls. One is on the front side and one on the back. I've done it. Check valve it so you don't get siphoning. If your temps are as lows as you are thinking, the water won't do much for you because it won't readily evaporate. If you remove the water, then the freezing concern is also eliminated.

That doesn't really answer your question though...

 

[Lou Scannon]

If your temps are as lows as you are thinking, the water won't do much for you because it won't readily evaporate.

A good water or water/methanol injection system will administer small droplets that will be carried into the cylinders and evaporate before and during combustion, conferring enormous benefits in terms of internal cooling and knock abatement, which can be taken advantage of via significantly increased charge density and hence BMEP. This was understood already in the 1940s; exploited in high-powered aircraft engines in the 40's and 50's, and to some extent, more recently, in automotive engines used in certain racing classes and by amateur performance enthusiasts.
The point is, it's not necessary for the liquid to evaporate before reaching the cylinders. It is necessary, or at least very useful, for the droplets to be small enough and well distributed enough that they reach all cylinders with fairly even distribution, and that they don't wet out on the port and cylinder surfaces, rather than remaining suspended in the charge. These requirements are identical to those of a premixed liquid fuel, like gasoline, and the preferred metering solutions are not dissimilar either.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[ZephTheChef]

I had considered a couple nozzles in the lower intake. Figured if I was going to that much trouble I should just go direct port...and then figured that would add another huge layer of expense and complication to that car. Since I have the unique advantage being on straight methanol as opposed to E85 or race gas that I can literally just put water in my fuel. That's not only a lot more precise and controllable than trying to set up a progressive direct-port water injection system based on pump duty cycle or solenoids and some piggyback box estimating engine load...but it's also a lot more inexpensive, easier, more compact, and the amount of water injected will always be based on the amount of fuel injected, which is in turn based on the air mass/engine load. It's a very simple and elegant solution, provided that I can solve the problem that the water may lead to additional loss of lubrication and/or corrosion problems.

To address your other statement, I'm no longer interested in the water for charge cooling since I am confident I have that taken care of by other means. I want to use it to help control combustion temperatures and allow me to run air fuel ratios that would otherwise be considered extremely dangerously lean (as I said before, 13.3:1 or so in terms of a gasoline afr...when most way overboosted M90 guys are probably running in the 11s to 1 for additional cooling). Methanol, as I understand it but have not seen firsthand, can be very sensitive to pre-ignition despite it's excellent resistance to detonation so what I'm really after is a way to keep the combustion chambers cooler to ensure I don't end up with any pre-ignition sources, especially since I intend to experiment with such relatively lean air fuel ratios. I don't know how sound the theory is that it doesn't matter whether the additional liquid mass to cool the combustion process is fuel or water, but I intend to try it both ways and see what works best. Obviously water has the higher heat of vaporization and isn't going to burn to contribute to combustion heat so it seems like sound logic that it will control combustion temperatures better. Whether or not that's beneficial from a power standpoint is a question I'm very interested in and I believe capable of answering.

I do have a TFX combustion pressure logger (which is by far the most expensive and under-utilized piece of equipment I've ever purchased...being a mere hobbyist), and I fully intend to do lots of tests in different configurations to get some hard data and determine what is actually going on inside the cylinder and whether or not water injection in this manner or any other is of any real benefit to me.

Basically what I'm saying is that I have the equipment to determine definitively whether or not this is going to be beneficial to my setup so I'm not really worried at this point about the theory of whether it will or won't work or do me any good, I'm only interested in what I can do to overcome or minimize the lubrication and corrosion problems I may encounter when I do test this.

 

[ZephTheChef]

Hemi, you beat me to explaining my reasoning/purpose for still having water injection. You hit the nail on the head though, I'm looking for extra safety in terms of detonation and pre-ignition resistance, and perhaps to help prevent exhaust valve overheating.

 

[winfieldblue]

This car probably won't see the streets again until it's at least 50 degrees out as cold-starting is really a chore on straight methanol, and my propane bottle doesn't build enough pressure for the car to idle on when it's this cold out...

Are you running propane as a warm up fuel? I would think that cold starting would be much harder with water mixed into the fuel, maybe a bottle of nitrous would be an easier solution!

 

[ZephTheChef]

Yes, I warm it up on propane when it's cool or cold out. Are you suggesting nitrous as additional charge cooling? I do have a nitrous setup in the works with propane for the fuel side of things and while that will certainly net me a lot more charge cooling, it will add considerably to the combustion temps, as well as burn speed, so I am thinking additional water to help control chamber temps will be even more critical with nitrous.

 

[winfieldblue]

It seems that the refrigerated charge cooling system is detracting from further possible combustion temp. reductions by limiting the amount of water that can be injected pre manifold. You could consider raising the temp of the refrigerated cooler to somewhere above freezing which would make injecting water that much easier. Maybe a chemist could work out a suitable lubricant for the proposed methanol/water fuel mix!

 

[ZephTheChef]

I'm currently testing 4 lubricants in jars right now in a 70/30 methanol/water mix. This is more water than I ever plan on running, so it should be a good test. I have a couple hopeful candidates and a couple that clear are not going to work. If nothing settles out after a week, I'll start corrosion tests and burn them to see what kind of residue I get. I have a couple other lubricants I want to give a shot that I don't have on hand yet, namely some water soluble machining lube and one of the various "water pump anti-rust/lube" products they have at the auto parts store.

And yes, I do anticipate cold starts to be even worse with water in the mix. It will definitely be warmed up on propane...I currently have a pretty primitive propane injection setup, I expect to have to improve that a bit both in capacity and control mechanism if it's going to be seeing more frequent use. The car does idle like a champ on propane though, and it doesn't take long at all even on the coldest days to be warm enough to run on the methanol. Maybe 30 seconds tops.

 

[winfieldblue]

I'm not familiar with methanol fuel systems, but have injected a water/oil mix into my turbo diesel engine. Aside from the harder starting issues the only problem I came across was a short fuel filter life, as some moisture was absorbed by the paper filter media causing the fibres to swell up essentially blocking flow. Good luck with your experiment!

 

[ZephTheChef]

Yes, that's definitely one of the changes you have to make for methanol...paper filters are no good. Gotta go to a coarser, strainer-type filter with a stainless element. Thanks!

 

[ZephTheChef]

Well, I guess I was making this a lot harder than it needed to be. Of everything I've tested so far, the BEST candidate by far is the fuel lube that I've already been using. There is no visible separation whatsoever even at much higher doses than would typically be used. Corrosion protection tests in progress.