Water Injection

[Original_Ranger84]

I was talking with a Teacher of mine who has a geo metro that get 50 mpgs. And He plans on putting a water injection system on it to get better gas mileage. Anyway I looked it up and I seems to make sense to me. I want to put one on my truck and get better gas mileage and more power.

It works by putting an injector on top of your air cleaner that will put the water right into the carburator. There is a ratio of 5% water 95% gas. and the water does a few things. 1. cools down the cylinder for a better compression ratio 2. raises the octane of the gas 3. when the gas ignites the water turns to vapor and water expands better than gas 4. Not as severe of temperature change (keeps engine at a more stable/even temp even after the cylinder fires).

I think it would be cool and a good Idea. And I guess it really works because he already has a car that has it and seems to work. And I read that they used to put these things on world war II planes to get more power and speed at take off.

 

[Hahnsb2]

Fairly common on diesels, usually to control EGTs. Never heard much about it's use on gassers.

 

[Original_Ranger84]

yeah I was reading diesel power actually. an artical about using it on towing rigs.

 

[85_Ranger4x4]

Fairly common on diesels, usually to control EGTs. Never heard much about it's use on gassers.

It was used on fighter aircraft in WWII, they were gas engines but being turbo-supercharged they were much different than a run of the mill car engine. It would be interesting to see how it would work though.

During the war years, Pratt & Whitney were always coming up with new ideas to upgrade this already powerful workhorse, most notably water injection to give emergency power in combat.

http://en.wikipedia.org/wiki/Pratt_&_Whitney_R-2800

 

[Sunk]

A guy did this a while back with a Mazda 4 cyl motor. There was an article in Popular Mechanics, if you look on the site, you should find it... Pretty cool stuff.

 

[Simple_serf]

We use water injection on spark ignition kero burners and Oil engines. Keeps the knocking under control. These engines came with water injection from the factory.

 

[Jspafford]

So in theory the 5% of water it uses, causes it to use only 95% of the fuel therefore saving the extra 5% as in increase in MPG?

 

[Carlos Murphy]

Water injection

I worked for a performance BMW shop called Hardy & Beck in the early 80's, we installed many turbos on big sixes and 4-bangers.
We started installing water injection on some engines to eliminate detonation so we could run more boost, worked well and a side effect was that it kept the valves and combustion chambers very clean, cooler EGT but mileage was hard to check because of the lead foot that comes with the turbo kits.
The one thing you must be careful of is to make sure the system dose not SIPHON when the engine is off, the reservoir must be lower than the injector.
If you have driven a turbo car for any length time you know it works best in the rain.

 

[shadetree]

I doubt seriously if you will notice any difference on a stock engine if you run the water at normal temps. Possibly there may be a difference if you cool it, or raise the compression on the engine.

I put a system on a 78 Chevy pickup many years ago. It was nothing but another hassle. I did not notice any change in power or mileage. Actually, the addition of water will displace that much fuel and probably not be as efficient. As was said, it may have the benefit of keeping your combustion chambers cleaner, but not much else.

If you want to get radical with the intake, plumb the a/c to cool the incoming air. That will give you a kick you can feel. shady

 

[crbnunit]

I put an Edelbrock Vara-Jection water/methanol injector on a turbo Mustang. The only real advantage is I was able to advance the ignition timing and crank the boost higher without detonation. When you do that, it is not really about the fuel mileage. Truth is, it was a pain in the ass to maintain. I never remembered to keep the thing full.

 

[WildSide]

I remember WI having a popularity boom during the early 80’s for higher compression engines when higher octane fuels were becoming scarce and a few engine drawbacks were internal corrosion, oil contamination and increased wear due to improper or overuse. Today your best bet is to try water vapor injection with a slightly higher thermostat ,timing increased to the max using a CD multiple spark ignition such as MSD and a really good synthetic oil and you will see better fuel economy.