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26 Posts
Discussion Starter #1 (Edited)
Knowledge is power. I like to share what Ive come to know about meth/water and its abilities, heres some info I have gathered. Gets pretty deep into theory, and tuning. Any questions, Pm me. Enjoy.

Set up shown in links made 639 hp/649 tq on a 2.48 liter, pump gas in the tank, and 15* timing. Meth water is a great tool.

I use unlubricated Methanol purchased at PBJ,120 octane, and I believe its in the $2-$3/gal range, I only refill a 5 gallon blue diesle jug (makes accidently filling the lawn mower with meth impossible) about once ever 3 months so don't hold me to the price. I mix my meth 50% meth / 50% ice cubes inside of a winshield washer jug. Its mixed, the methanol melts the ice while staying in the 32-33* range, then put into the freezer before I go out, next time I pull the bumper Im going to wrap my tank with header wrap to help keep the mixture colder for longer. I log with my Scan gauge, this mixture nets me 60*-80* intake temps at WOT on warm days. This # is without spraying N20 in the charge pipe.

Covers AFR's, latent heat, ignition timing, pre detonation, detonation, lambada sensors, benifits of meth, benifits of water and so on.

Id also like the people who are spraying meth/water to list their personal expirences with it, what kit, mixture, how it helped, how it didn't help and so on.

As one of (if not the, I don't really recall for sure) the first supercharged guys to do water/methanol a few years back, my setup has basically "just worked" for a long while now. Now that I've moved to 11 pounds w/ 06 tsx cam in 100+ degree heat, I find myself needing to make adjustments to keep the detonation fairy and her pings of doom from claiming my 75k oem motor. For a while, off and on, I've dropped little nuggets of explanation in chat threads and random threads -- but I haven't really created a technical resource for those who really want hard info on what is going on behind the scene. This thread aims to fill that void, confuse some of you, and enlighten (hopefully) the rest of you that want to understand things better. If you get confused, ASK questions -- you won't be the only one, and hopefully we can turn this thread into something really useful for others.

First, before we start, we need to get vocabulary out of the way. Without knowing the following terms, you won't get very far here.

-Air/Fuel Ratio

An air/fuel ratio describes how many parts of air and fuel are present during combustion.


Stoich comes from stoichiometry. Stoich, for our purposes, describes the condition where combustion of the air/fuel mixture leaves no remaining oxygen or fuel. I sometimes refer to it as perfect combustion, but don't confuse that with being what you should want at all engine operating conditions.

-Stoich Point

A ratio that defines how many parts fuel to oxygen you need for stoich mixture. The Stoich point of gasoline is 14.7:1, or 14.7 parts oxygen to one part fuel. The stoich point of methanol is 6.4:1.


Loosely defined for our goals, it describes, via a percentage, how much fuel or oxygen was needed for stoich combustion. A lambda value of 1 is stoich. A lambda value of .85 means 85% of your fuel was burned, and 15% of it was left over. A lambda value of 1.15 means 15% of your oxygen was not used, and 85% of it was.


Lean describes a condition when too little fuel is present in your combustion event to be stoich. Rich describes a condition when too much fuel is present in your combustion event to be stoich. A rich mixture has a lambda less than 1.0, a lean mixture has a lambda greater than 1.0. Rich/lean is also used to describe having too much or too little fuel in relation to what is desired, not just in relation to stoich. For instance, even though 14.7:1 is stoich for gasoline combustion, and by definition is not lean, it is far too lean for wide open throttle to be safe, and should be richer.

-Lambda sensor

Your wideband oxygen sensor. It is called a lambda sensor, or air/fuel sensor, because it detects and informs the engine computer the lambda of the combustion event that has just happened -- in other words, how close it was to stoich. Kmanager converts the lambda values to "gasoline air/fuel" ratios for you by multiplying the lambda by the stoich point of gasoline. For example, .85 lambda is .85 * 14.7 = 12.5:1 a/f. The lambda sensor, engine computer, and kmanager are totally unaware of what fuel you are running. If you were to run pure methanol, and tune your car to a perfect stoich air/fuel ratio of 6.4:1, the lambda sensor would see 1.0, and kmanager would report this to you as 14.7:1. It is important that you realize that the air/fuel ratios you know and love are simply a calculation based upon empirical measure that is NOT actually parts of fuel to parts of oxygen. It is also important to realize that when you run a combination of methanol and gasoline, your air/fuel number scale in your head that says "11.5 is safe for boost, 13.2 is not" is still 100% valid and useful -- just think of it as "this is the air/fuel ratio I would be running if I was running purely on gasoline." 11.5:1 gasoline air/fuel ratio literally means 11.5/14.7 = .78 lambda, or 78% fuel was burned, 22% remained unburned (and absorbed heat).


Methanol is a simple alcohol with a stoich point of 6.4:1. It melts/freezes at -98C and has an octane rating of around 120. It has a relatively low flash point, so mixing with water, in addition to adding more cooling benefit to your water/methanol mixture, adds safety by increasing its flash point.


An engine noise -- not good. Knock generally falls into two categories: spark knock (detonation) and rod knock (or other physical problem with the motor that makes you tear it down).


Detonation is far less harmful than it sounds, but leads to things more dastardly such as pre-ignition or engine damage if left unchecked, especially if the detonation is severe or the engine is already operating near it's physical limits. Detonation is an event that happens AFTER normal ignition of the compressed air/fuel ratio as the cylinder is moving down on the power stroke. Detonation occurs when the air/fuel mixture transitions from burning (granted, very fast) to exploding (hence the word detonation). Ideally, the air/fuel mixture should burn across the time when the piston is moving down on the power stroke. If for some reason the mixture cannot sustain normal combustion under the heat/pressure it is being exposed to, and explodes, this is called detonation. It delivers a large amount of force to the piston very quickly for a very short period of time producing an audible sound referred to as a "ping", and hence "pinging" is another term to describe a motor that is detonating. It heats up the combustion chamber quickly. Normally, when you encounter detonation, it is near the end of the normal combustion event. This is especially true for detonation you encounter from running too much ignition timing -- you can literally think of this as the burn beating the piston. Denser mixtures burn faster -- that's why more boost dictates less ignition timing. Detonation can be caused by too much ignition timing, too little octane, too hot of intake temperatures, or too lean of a mixture.

26 Posts
Discussion Starter #2

Pre-ignition almost always leads to detonation, but... pre-ignition also has a terrible habit of destroying motors. Pre-ignition is when the air/fuel mixture is ignited BEFORE the normal ignition point (dictated by ignition timing) by means other than the spark plug firing. Pre-ignition causes the piston to compress an expanding mixture, which causes a huge strain over a long period of time compared to detonation (which happens quickly and is over). The mixture usually detonates when pre-ignited. Potential ignition sources could be an overly hot combustion chamber, glowing carbon embers, a glowing spark plug, and any other residual heat in the combustion chamber that shouldn't be there. The problem with pre-ignition is you simply don't know if the detonation you are hearing is from pre-ignition until your motor blows. Rest assured, most detonation encountered is not from pre-ignition -- however, if your motor detonates enough, it could raise the combustion chambers so much that your engine pre-ignites, which tends to put the piston on the ground, and we all know that isn't where it goes, now is it! That is why you address detonation, in addition to the fact that severe detonation can damage the motor as well.


Octane is a rating used to describe a fuels resistance to detonation. It is also a compound, but we don't care about that.

-Ignition Timing

The point at which the spark plug fires before top dead center on the compression stroke to ignite the air/fuel mixture. More ignition means you ignite the mixture sooner. The idea is to expose the power stroke (piston moving down) to as much of the force of combustion as possible while not detonating and not compressing an expanding mixture by starting the burn too soon. Ideally, you start the burn while still compressing the mixture because it takes some time to burn. If you have a high enough octane fuel, you can actually run too much ignition timing and compress an expanding mixture -- this puts enormous stress on your rods and rod bearings and is akin to mini pre-ignition. You CAN over-advance the motor with water/methanol. Don't advance ignition timing without being on the dyno to see if it adds more power. If it doesn't add power, take it out, it's just adding stress. Ideally, you should be just below peak power ignition for a long lasting boosted motor tune.

-Latent Heat

Latent heat, for our purposes, describes the amount of heat absorbed by a liquid as it changes matter states to a gas when vaporized.

-Why do we run rich?

This is something many folks take for granted -- you run rich, or fuel enriched, under load. More so for boost, less for n/a, but not at all for cruise. Why? It's simple. We don't want our motors to blow up. Why would it blow up? Because it gets hot in there damn it! Running rich means there is extra fuel left over that didn't get burned. This fuel absorbs heat. This keeps the engine from being damaged. At cruise (in vacuum), the power produced by the engine is tiny -- you don't need to run richer than stoich to protect the motor, and catalytic converters need stoich combustion exhaust to work correctly.

-How exactly does fuel cool the combustion event?

The unburned fuel is vaporized (evaporated) -- it changes from a liquid to a gas. This change in matter state, from a liquid to a gas, takes heat with it. Think of when you sweat -- liquid exits your pores, wind blows across your skin, the sweat evaporates, and your arm gets cooler. The problem with blindly adding fuel to cool down the combustion event is that it makes the air/fuel mixture richer... and after a while, it doesn't want to burn, and it stops making power (and other problems as well). The amount of heat absorbed by a liquid as it changes to a gas is described via its latent heat.

-Enter methanol...

Methanol, an alcohol, is a fuel that your engine can burn. It takes more than twice as much methanol to make the same power as gasoline, which is directly related to it's stoich point being about half that of gasoline. It literally takes half as much oxygen to burn an equal mass of methanol as it does gasoline, and that directly represents it's energy potential. Ethanol is an alcohol also (om nom nom), and has a similarly low stoich point, and similarly lower power output, which is why e85 folks have to run huge fuel systems compared to gasoline folks. The good thing about methanol is that it has an octane rating of around 120, and cools about THREE TIMES as well as gasoline when vaporized in a rich mixture. I know that sounds wonderful, but just wait until we get to water. By adding a little bit of methanol, you can raise the octane of your mixture a decent amount, and any remaining fuel is partially methanol, and thus will remove more heat than if it was purely gasoline.

-Enter water...

Water is a.... wait, we drink this stuff, it shoots out of our pores when we're hot... perhaps we could use this for cooling?! Indeed! Water removes TWICE as much heat as methanol, and OVER SIX TIMES the heat of gasoline. Want to know the really cool part? (Oh man, I sincerely apologize for that pun, it wasn't intentional, but now that I see it, I'm not removing it because it hurts sooo good.) What's really cool is that any water injected into the mixture does not burn. ALL of its heat removing goodness is left there to absorb heat, regardless of the air/fuel mixture you used.

-The proper mixture of water/methanol to inject:

This is debated a lot, but it generally ends up being 50/50 by mass, not volume. Sorry guys who are mixing your own and filling two jugs equally, you failed -- you should have used a scale. Methanol is about 74% the weight of water, so if you thought you were running 50/50 and you measured by volume, you're actually running around 37% methanol to water. DOH! Don't worry though -- if you're not detonating, then you're in the money, because all that extra water is there to cool the combustion event and perhaps the boost charge as well, especially if it's hot enough and has some distance to travel (see turbo piping and high boost supercharger.) Ideally, in my opinion, you'd run the perfect mixture that had just enough methanol to up your octane rating enough to ward off detonation with the cooled combustion event -- this is because the water cools better than methanol. If you run 35/65 (-30F washer fluid, what I used to use), and it prevents all detonation, moving to 50/50 would just add octane while removing cooling ability. This is why I never messed with mixing before I went to 11 pounds. Now that I'm here, one 100F+ day and I detonate a little -- time to add more octane. By running 35/65 instead of 50/50 when that was all I needed, I cooled the combustion event (and to some degree, the charge) quite a bit more. Remember that the methanol that cools is what is left over, so more water means more cooling, not only because it cools better than methanol, but because it isn't burned. The methanol is still burned, and the remaining methanol from running rich is all that is left to cool! This is why I'm so against people running more methanol than they need -- not only is running pure methanol dangerous, it's not required most of the time. Any methanol you can replace with water means more cooling and less flash danger. Seems obvious now, but good luck convincing some folks.

26 Posts
Discussion Starter #3 (Edited)
7- Now we have the tank, pump mounted, and all lines ran, wiring, this is where everyone gets scared. Don't, shits easy. Controller gets negative and positive for power, so ground the black wire somewhere under the dash, and run the pink(or red) wire to an ignition source. Now push the green, and blue (red if using the gen 2) through the firewall and into the engine bay. The green wire is for your MAP/MAF input. This is different for every car, but there will be a wire from out of this sensor that will read 0-5vdc that the controller reads off of. Tap green into this wire, and blue goes to pump power if using the gen one controller, or blue goes to ground if using the gen 2 controller, and finally red is tapped 3 ways, off of the same ignition source you used for controller power, and then through the fire wall and to the pumps power. Controllers are $155 brand new from Devils own. Order it in a 2 bar, or 3 bar depending on what your map sensor is. You can reprogram them but its a pain in the ass.
8-Sigh, that was easy right? Next, clean up your hack job wiring now, and you better not have used any crimp on butt connectors. Shits going to fail and something with VTEC will beat you in a race and youll have to trouble shoot what you did wrong in your garage, while posting in that guys kill thread on you that you took the easy route.
9-Set up the controller to your needs and double sided taping it to a nice location, these are set it and forget it but I like to have mine out in the open, you can see when the pumps at full voltage out and I like the peace of mind. These controllers "pulse" voltage to the pump. Set your controller up to what boost it will start at, and then what it will end at. I keep mine at 5 and end at 18 since I run 20 lbs. This means at 5 lbs my controller pulses voltage (at what value and speed Im not sure) to the pump so there isnt an instant flood of meth/water into the system for ease of tuning, and because you need it more up top then while at low boost. Also, set it high if you have a small turbo that part throttle boosts easily. You dont need meth to spray when your just moving through the gears in traffic up a hill.

-Food for knowledge, if you are tuned for meth, a serious ammount like I am running, ie four d04 nozzles (12g/hr), your car is now a "meth" car. Run out of meth/system fails because of something you did, your going to go lean and break something. I suggest a wideband/knock monitor to say the least.

Personal expirences: Ran a Devils own kit on the srt4 for a few months, single m12 nozzle in the cold side charge pipe, location is about 12" away from the throttle body. Never got it to the dyno with the meth/pump gas/50 hit set up. But, 26 lbs (while spraying) 93 octane, 50/50 meth mixture and a 11.9 afr at redline (tuned with an safc neo) mild pulling so timing wouldn't go through the roof (ill explain if needed) car ran like a rapped ape for 4-15 bottle refills. Never had a way to watch for knock so I just went with the flow and figured the motor would be trashed when I pulled it for the new motor set up in the car right now, only major flaw was one pin sized detonation mark in cyl #1. Pretty impressive for the abuse the motor went through.

-New set up is a 220 psi system,
-meth tank is stock windshield washer tank, tapped at the bottom.
pump mounted under driver side headlight.
-modded m12 in the charge pipe still ( same location) removed.
-direct port m2's on each intake runner, using all DevilsOwn items, really nice Devils own manifold block and nozzles (pics below).
-93 octane, 19-20 lbs of boost 1 count of knock at the top (not bothering to remove it, being tuned by PBJ soon) Using a check valve on the charge pipe nozzle, and a solenoid wired to the pump singal out put.
-Solenoid is used to keep boost pressure out of the meth system, and prevent the system from pulling meth into the intake under vaccum. I didn't install this unit at first, and quickly changed my mind after I noticed at idle the car was sucking meth into the intake, 10.0 afrs at idle, black bumper, not cool.
-Control is done by a DevilsOwn progressive unit. I start the spray at 2 lbs, and go full voltage to pump at 10. Progressive unit pulses voltage to pump as it it reads it through the factory map sensor, much like a progressive N20 kit is done.
-This is the controller I am using, there are 2 versions, this is Gen 2 and theres a Gen one, You can tell the Gen one buy the devils own logo being flush with the face. Only difference between the two is the Gen two 1) sends positive 12vdc line voltage and the ground to the pump, while gen one only sends 12vdc line voltage, and 2) the Gen two has a level sensor wire. If desired you can add a float switch to your tank, and if your tank runs out the pump will shut off so it doesn't run dry. I did no use this feature.

general meth/water pictures.
The intake manifolds direct port manifold bottom view.

Top view of direct port.

Windshield res tank breather filter to fight off possible vac from pump pulling meth out of tank

Bottom of Meth tank tapped, notice these are all quick fittings aka John Guest fittings. Makes for ease of install to say the least.

Finished install pics, notice all quick fittings on all of the nozzles, cant beat it. Also, notice the use of saftey clips on fittings, we use these on all kinds of equipment at my work, found some online and bought them. Makes the chances of blowing a line off just about zero.

better shot of the saftey clip.
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