I sued to install a water injection system in all of my old cars back in high school (waaaayyy back in 80-83).
For those that are not familiar it was basically just a plastic container, some vacuum hose, a little aqaurium air valve, and a t-fitting. You mount the tank, run the hose to the valve, and then tap in to the carb base vacuum with the t-fitting.

I remember I had a 68 Cadillac that required premium fuel, and got about 11 mpg (about what I get on my truck now).

I set up the injector, leaned out my cabr a bit, and switched to regualr fuel. It ran just the same, no knocking even with the lower octane fuel, and I got about 2 mpg more.

I have not thought of it in years because I have had FI cars for the past 10 years. I am going to put one on my 87 F150 tomorrow and see how it goes.

I will keep you all posted.

 

what other gains is there from water injection? why would you add water to the carb, i thought you wanted to remove the water from the fuel.

i guess i'm too young to understand for now lol

 

getting water out of your fuel system is one thing (it freezes for one, as well as too MUCH water can ruin your engine as it won't compress). This sytem introduces a fine mist and is intended to increase the oxygen content as well as slightly reduce the temperature of the fuel charge, allowing a denser mix.

Can't say I've seen any improvement, but back then my cars were one step away from the junkyard.

Tom
Tucson, AZ

 

Nothing to do with cars/trucks, but in the US Air Force, the old B-52s and KC-135s used water injection for their engines. It was a PITA but it worked. Technology improved though and it isn't used anymore on those airframes. Just some trivia.

 

I can say I always noticed a difference on my big old V8's. When you put a fine mist of water, you lower the temp of the fuel, and therefore you get a longer and more efficient burn, so you see an increase in both power and economy, and a reduction in emissions.

It also helps prevent pre-ignition (pinging and knocking). That is why I was able to run regular fuel on some of my high compression engines back then.

Overall it is a great thing for both gas and diesel engine.

So I know just what some of you 'whippersnappers' are thinking, "if it is so great why isn't it on more cars?"

The answer is pretty simple actually, a lot of people would never think to fill their water tanks regularly and would quickly run dry. Heck people like my kid brother can not even remember to check his oil or get an oil change. Do you think he would remember to fill his water tank once a week?

Let's face it, the average driver never gives much thought to basic maintenance. Thier washer fluid runs dry, thier wipers dry out and crack and do not get replaced until it is actually raining, oil looks like sludge, etc., etc. Most people do not even check their tire pressure!

Nope water injection is for guys and gals like us. The tinkerers. The weekend mechanics. Every saturday morning, I check all of the fluid levels in both my vehicles, tire pressure, wiper condition, tire tread, etc. I religiously change my oil every 3000 miles and check my plugs at the same time as well as changing my filters (air and oil), rotate my tires, I even make sure I pressure spray the dead bugs off the radiator. So taking that extra step to make sure my truck is running as well as it can is not a big leap for me.

Check out this great article on water injection: http://en.wikipedia.org/wiki/Water_i..._%28engines%29

 

By the way, I just want to remind everyone that the system I described is the super cheap, super simple rat rodder method. You can buy sophiticated kis to work well with FI, OBD computer management, dash display, etc.

 

I've done water injection before, and found it extremely useful in forced induction engines, while pushing the limits.

Generally I've not run into detonation problems on naturally aspirated vehicles, so I've just turned the key and not thought about it.

Some of the VW GTI's of yesteryear were one example of OEM water injection... the had this odd-shaped thing on the underside of the hood for the water, but I don't recall how they "injected" it into the engine with the fuel.

Because I've used water injection (actually 50% water, 50% isopropol) with some serious boost, the washer bottle method didn't work for me. I had to have the water pressurized higher than the intake manifold pressure while under boost, and the difference in pressure deteremined how much water I could actually inject, based on injector pulse width. I used an old 80's F-series inline fuel pump, as the original ones had stainless internals, making for a rust-free solution. I used an ordinary fuel injector, with the expectation of replacing them every so often since most of the internals are brass, and brass doesn't like water as a general rule.

More expensive solution, but with 20lbs+ of boost, one has to do something more extreme

I look forward to your display of what you're doing... I'm always curious about such things.

 

cool... so you'd see more of a gain on a higher horse engine than a stock motor i'm assuming. this bring new light to my plan for my mud truck done the line. thanks old timers lol

 

Even with normally aspirated engines, you can dial in additional advance with water injection and gain some power.

I've been toying with the thought of triggering water injection with a knock sensor. Have yet to devise the system.

 

i read an article about tapping the water injection into the smog pump. it didnt explain how it was done but it said it helped over the whole rpm range rather than the other style tapping in to the carb vacuum which seemed to work better at lower rpms and drop off. the do it yourself way of tapping into the vacuum line can be made really cheap, does anyone know how to tapp it into the smog pump. sounds interesting.

 

Don't see how that would help unless the system was re-plumbed somehow. But the smog pump wouldn't last long with water going through it.

 

our shop teacher in highschool and later the mechanics teachers at vocational school would have us use just a spray bottle to mist water into the carb of a running motor before taking the head/s off. Then pull the heads off one that we didn't mist. The ones we misted looked like brand new while the others were covered with carbon. Guess just that would be reason enough. I hadn't thought about it either, maybe I'll try.

Take care,


Dave

 

That's a good trick. When I worked as a line mechanic I used to pour a stream of water through the engine at 3,000 rpm or so. It saves a lot of cleaning time. It's also a flat raters' technique for cleaning spark plugs. Also, if you had a suspected valve leak that turned out to be a little carbon buildup on a valve seat it would blast it on through.

I'm not sure what the effect is on cats though.

 

How much water is needed, I'm sure you could easily regulate this with the size of hose used or an orifice. The idea of the aquarium anti-drainback valve is a great idea. I don't think it would be a good idea though at idle to have water going into the intake and puddling up so there would have to be some kind of valve to openn at certain vacuum.

 

snow performance has water/methanol injections kits. A lot of guys just tap into their windshield washer reservoirs. The methanol in the washer fluid adds extra power along with cooler denser air. The only benefit for naturally aspirated engines is that it cools the intake air and will allow you to advance your timing. They make claims of 40 -80hp gains on turbo diesel applications.