Water Injection: All set or all wet?

[FJCamper]

NOS or H2O?

Water injection was evaluated scientifically in the 1930’s by H. Ricardo who demonstrated that one can basically double the power output of an engine using water/methanol.

The first widespread use was during WWII on supercharged and turbocharged aircraft. In 1942, the German Luftwaffe increased the horsepower of the Focke-Wulf 190D-9 fighter aircraft from 1776HP to 2240HP using 50/50% water/methanol injection.

The allies soon followed by fitting the P51 Mustang and other high performance aircraft with water/methanol injection. Following the war, the turboprop aircraft industry used water/methanol injection and called it the “automatic power reserve system (APR)” for use in hot or high altitude take off. It surfaced again in the 60’s when GM used a system on the OEM turbo Corvair. It was used effectively in Formula 1 before being banned for adding too much power.

It's been one of our RetroRacing tricks.

FJC

[MinamiKotaro]

I'm happy with my water injection system. There's a definite boost in power when it comes on.

[Piledriver]

Most folks think it's only useful for supercharged motors...

[Scott Novak]

Another Camper Retro Racing Minimalist "Don't Fix What Ain't Broken" tricks.

Actually I've been curious about water injection ever since I read about it's use in P-51s.

What are the problems associated with water injection?

What kind of performance differences would there be between using methanol and water versus ethanol and water?

Scott Novak

[MinamiKotaro]

What kind of performance differences would there be between using methanol and water versus ethanol and water?

I've used 50/50 (by weight) Methanol and water, 50/50 ethanol and water, and 50/50 denautred alcohol (which is ethanol and methanol blended) and water. I also tried 50/50 isopropyl and water.

My butt dyno told me the denatured worked best. The engine pulled silky smooth and intake temps dropped by 100F or more. Meth/water didn't drop the intake temps as much and the pull to redline was noticeably rougher. Ethanol/water was similar to denatured. Iso/water felt like it made the engine detonate *worse*.

[FJCamper]

Hi Scott,

I consider water injection old school and about as minimal as it gets when it comes to speed tricks. Hard to beat age (experience) and treachery.

The problems are you have to tune for it (this is mostly timing) and if you run out of water or the injection system malfunctions, you can break something.

I used a windshield wiper bottle with a 12v pump motor feeding an aquarium gang valve with a plastic line going to each carb intake. The lines were terminated with needles (printer ink refill kits), and the lines fastened (nylon tie strap) inside our flex air tubes feeding the Kads.

To calibrate the water flow, all I did was turn on the pump and adjust the gang needle valves. All guesswork.

The driver had a switch to turn on (and hopefully remember to turn off) once the engine was warm and the green flag was down.

I used windshield wiper fluid, the blue stuff. It already has the alcohol mixed in.

If you'll play and listen to our Savannah video, you'll hear Barret say "Oil at 240 and heads at 300," coming in off a practice session. That's stock oil cooler.

When I upgraded to the 2,2 engine and bolted in the Webers, I lost my water system. I'm trying to figure out how to re-rig it.

FJC

[brookester]

I have the best results with a 50/50 methanol/water mix. I don't feel more power at a given boost. I get more power by being able to run more boost.
Also, I used to use the window washer pump version but when I switched to a 150 psi system I got a lot more atomization and could run more boost.

[fortyeye]

Editorial comments aside (easy, Scott ) ... "other mixture" injection is a real hot topic. http://www.ethanolboost.com/ Interesting reading. Downsizing displacement, charge cooling, knock suppression, etc.

MK has done some excellent work with different mixtures and documented the results on his turbo MSEFI engine.

You mentioned F1 and their forays into exotic mixtures. During the "turbo era", Porsche, Honda, BMW, Renault rewrote the definition of exotic. How about 70+psi of boost into a 1500cc engine, running on almost pure toluene. Various estimates put engine outputs from 1100 to over 1500 HP. No misprint ... close to or above one thousand horsepower per liter. Whatever they injected to cool those charges ... who knows. Does freon compress toluene? Witchcraft

[Piledriver]

I've jacked with various setups for water injection over the years, the only setup I have found to be practical for DIY (other than the windshield washer pump and a nozzle over each venturi for Webers, which can have long term corrosion issues) involves a small 12v air compressor and a pressurized tank.

Actually simpler, far more reliable, and can be as or more effective than systems costing >100X more.

A platsic soda bottle will hold 100+ PSI, it just cant take any heat...

High pressure/low volume water compatible pumps are incredibly expensive. Compressed air is cheap,+easy+common+reliable, a highly unusual combination.

I suppose for racing uses or utmost reliability, CO2 carts or even a small compressed air tank would be more than sufficient. The tiny ones for paintball etc weigh ~nothing and can hold thousands of PSI... Pumps for that are still silly expensive, but that may be changing given the compressed air hybrids on the horizon. (paintball tech has several possibly useful components)

Control of compressed air, again is easy/cheap, and material compatibility isn't an issue. Any time you can separate water/corrosives from your control system for them it's a win.

I haven't yet played with high pressure fuel injectors as controlled air injectors, and using THAT to suck/atomize water via a venturi, but I really want to. One could time them simply off the fuel injectors signal...

[FJCamper]

Hi Piledriver,

Yes, corroson from the alcohol is real problem. George Folchi at AmpCo Lubricators provided us with some beautiful 1950's era oil metering units that fed a top oil via carb vacuum. I was hoping to help him develop a VW water injection kit.

Our methanol corroded the metal fittings, which had come coated with some nice dark chemical "bluing" process. I tried various types of alcohol mixtures, but corrosion was still a problem.

By the way, my use of water injection was not specifically for any power increase, but to increase reliability and to make lower octane gas usable. I'd be glad to e-mail my PDF format copy to anyone who wants it the 1942: "National Advisory Committe for Aeronautics Report 756: The Induction of Water to The Inlet Air As A Means Of Internal Cooling In Aircraft Engine Cylinders."

[email protected]

[Piledriver]

Ethanol's a LOT less corrosive than methanol, IPA is probably even less so... but even 100% distilled water will eat zinc or aluminum TBs or carb bodies eventually, which is why port injection (below throttle plate) of some sort is probably a better idea.

High pressure==better atomization==works better.

The low pressure setups really need help from the venturii of the carb or a turbines compressor (bad idea long term, and won't go so well with intercooling)... to be as effective as it can be.

And yes, you can run 9.5:1 (~8.5:1 dynamic >full point+ over stock) static CR with a stock cam on regular, with ~stock timing. (~.030 deck 1700 T4) AND have very cool running heads.
Almost works with CIS alone, w/o water. Requires midgrade or premium w/o water (100%, no alcohol except in winter, windshield washer stuff then)

Note that every ACVW came with a regulated 45 PSI pressurized water injection system... The factory just left out the hose and throttle operated valve back at the engine.
The windshield washer will still work, done right...

It'll probably hold well over 100 PSI with a different cap/regulator and air source.
(I have yet to blow one up testing at 125 PSI)

[mike thompson]

It's funny, if I went by the press releases listed by FJC all the drag cars would be using it too. Something is weird here.
I was using a windshield mix pumped into the back barrel of a double pumper on my supercharged vw (350), I used it as insurance. Inadvertantly, I shut it off just before a run and saw a drop of a tenth and a half in my et.. It was slowing me down for a long time and I didn't know it.
I used it on my turbo buggy and never saw any increase in power.
General motors did put it on the turbo v-8 but abandoned it as warranty issues ( I guess) melted motors when people forgot to re-fill the canisters and 10 to one with boost did in the engines. It was never on the corvair.
I am not trying to be critical here, if it works for anyone else -Let's have your view.

[Piledriver]

I imagine if you are running too much it could hurt things...

Most engines only need ~100 ml/min or so.
(and that at 300HP+)

Also might REQUIRE more timing.

[FJCamper]

Dear Mike,

Water injection is simple but trickier than it looks. At the least, it protects your aircooled engine and helps cooling and allows the use of lower octane gas. At best, it gives a performance increase.

You do have to tune for it, which usually means more advance and rejetting. We were able to drop a jet size with no trouble. And we ran 300-350 head temps under flat-out half hour full throttle sessions.

Water injection today is considered a survival requirement by some high-boost turbo people.

If you gained speed after removing your water, you were getting too much water. The big deal is figuring out how much water to inject. I started with just a little, a mist, no more than what I estimated a high-humidty day might provide, and worked up.

Not everybody today uses water injection because it's become a lost art. If kits were common, and the results could be quantified like we do carb tuning (and look how much trouble that causes), water injection would be standard.

FJC

[Eatoniashoprat]

De

Not everybody today uses water injection because it's become a lost art. If kits were common, and the results could be quantified like we do carb tuning (and look how much trouble that causes), water injection would be standard.

FJC

I'm not sure if you're just talking VW's here or not, but in the Subaru world Meth/h20 injection is pretty common. There are several companies that make very good kits with an amazing amount of control (variable flow with varying boost, etc.). The kits are expensive but they are very complete, a ton of people inject in their daily driver/weekend warriors and are injecting all the time (street/track, whatever).

Mike