[Torment]

Anyone have opinions on the effectiveness of water/methanol injection with a roots blown engine? I see Summit is advertising a system that adds 70-100 extra hp utilizing windsheild washer fluid.

[Brian Baker]

I don't see how adding water to the mix can add HP, especially THAT much HP. The water is supposed to help suppress detonation due to camel pi$$ gas. Run race gas and don't worry about it, or run water injection with Umar's Camel Pee and hope your expensive race engine doesn't eat itself alive.

Now the methanol injection could add to some interesting possibilities in both detonation suppression AND power boosting.

[86t/a455]

I think the idea is for the methanol to help cool the air which it should. The water in the mix is beyond me but the claimed hp gain seems a little high

[GTOGEORGE]

Torment,
I was checking out the same system but I was thinking the same as Brian............pure ALKY! There is also a place that sells a alky injection system......ALKYCONTROL.COM.

[ponchobob]

Just a little history here, but water/methanol injection was a common power booster for both allied AND german V-12 supercharged engines in fighter aircraft (as well as N2O) in W.W.II-Belive it allowed a significant increase in boost, and is still used in the Reno air races for the same purpose.-Bob.

[firechicken]

water injection will cool the intake charge as well, but not as much as alky.
I'm running a homebuilt WW fluid system on my hot air turbo car that seems to work well.
100 hp? If the detonation suppression allows you to run alot more boost maybe but otherwise I think that's more than a little hype.

[LouisianaGuy]

I spoke to the fellow that owns alky contorl.com and he said alot of the guys like to run a mix of water and alky but he said he runs straight alky and you will usually see a marked increasae of 50 plus HP when it kicks in...the conncept is the same a running an intercooler...cooler air makes more power right??? and when you drop inlet temps 50 plus degrees you see decent gains.
Mike

[Torment]

Thanks guys. I was thinking straight methanol as well, maybe a small percentage nitro kicker... Let's see... race gas, methanol, nitro methane, and nitrous oxide... hmmm... how many fuels can you mix??? Maybe I'll pick one up and bring it to Norwalk - see if makes any difference.

[Brian Baker]

I would not even dream about the nitro. It will "homogenize" well with the alcohol, but not the gasoline. And definately not with nitrous. Keep it simple, straight alcohol.

[455Turbo]

I have a couple of thoughts on water/methanol injection:

I have a water/methanol injection on my twin turbo 455 but haven't used it yet. I will in a few weeks but for now here are some ideas.

Let's forget about water/alcohol injection for a moment and consider this, fuel added past stoichiometric, 14.7:1 with gasoline, is not going to burn. Why? Because there's no oxygen for it to burn with. Ok, a little more fuel than stoichiometric is necessary because air/fuel doesn't mix completely and some fuel is lost in the intake runner and in sticking to the combustion chamber walls. But for the most part anything beyond stoichiometric is just along for the ride and all it does is cool the combustion. This makes it a useful, albiet expensive, antidetonant.

Excess gasoline, such as running a 12:1 air/fuel ratio, is basically a method of avioding detonation. The extra gasoline doesn't burn, therefore it doesn't add power, in fact by cooling combustion it reduces power.

In the 1930s Sir Harry Ricardo experimented with water injection. He was able to eliminate detonation, lean out the air fuel ratio, and increase power by injecting water into an engine. The engine running on gasoline detonated at 700 psi maximum cylinder pressure but ran at 800 psi max cylinder pressure with water injection and a leaned out air/fuel mixture.

Basically, by Sir Harry Ricardo found that water was a better antidetonant than was the excess fuel of a rich mixture. Not to mention that water is cheaper than gasoline.

injecting water into an engine is going to do the same thing that excess gasoline does, it won't burn, but it will cool combustion, act as an antidetonant and allow greater cylinder pressure.

Methanol, unlike water, will burn. So it will use up some of the oxygen that the gasoline wants to use. This complicates things. I'm not sure but I believe that methanol produces more power than gasoline so this should give an increase in power. It will also cool the intake charge, but for that matter, so does gasoline.

It has been said that methanol will cool the air charge more than water. This is not likely. The latent heat of methanol, the amount of energy it absorbs as it changes from a liquid to a gaseous state, is 1109 KJ/Kg. The latent heat of water is 2256 KJ/Kg, therefore the same mass of water will absorb over twice as much heat as methanol.

Conclusions? I don't have any. It would be nice to see side by side dyno tests of water injection versus methanol injection. Maybe in a few weeks I'll be able to make back to back runs and try things out.

Anyway those are my thoughts. I could be off base but one thing is for sure, scientific controlled tests have shown that water and water/alcohol injection reduce detonation which allows for greater cylinder pressure and therefore more power.

[Jack Gifford]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by 455Turbo:
It has been said that methanol will cool the air charge more than water. This is not likely. The latent heat of methanol, the amount of energy it absorbs as it changes from a liquid to a gaseous state, is 1109 KJ/Kg. The latent heat of water is 2256 KJ/Kg, therefore the same mass of water will absorb over twice as much heat as methanol. </div></BLOCKQUOTE>

Very good topic; gets us all thinking!

455Turbo- Thanks for contributing all those "hard numbers"! Regarding cooling the intake charge, I think we should remember that the state-change to a gas probably occurs mostly in the chamber with water injection. But for alcohol (if injected upstream of the chamber), much of the state-change happens before it reaches the chamber, thus has more opportunity to cool the charge. My 6-71 alcohol engines didn't use much blower overdrive, so they pulled manifold vacuum at idle. Since I was putting about 1/3 of the fuel into the injector on top of the blower, an extended idle turned the blower case into a refrigerator- even formed frost on it a few times! On 90 degree days!

Oops, brain fade again! Forgot that I ran a 7 PSI pop-off in the port-nozzles line, so at idle ALL the fuel went into the hat. Sorry.

[BVR421]

Perhaps the advertised HP gains result from the restoration of optimum ignition timing. computer controlled engines will automatically drop timing in response to the rattle can attached to the block. When water/alcohol is injected under those knock prone/high load conditions, the knock stops, the computer restores proper timing and the lost HP is restored.

[LouisianaGuy]

Jack, a local guy here is running a Twin turbo Mopar with alky nad at idle the thing forms a sheet of Ice on the intake its amazing.
Mike