Water Induction to Save Fuel - DECOMMISSIONED





Introduction: Water Induction to Save Fuel - DECOMMISSIONED

About: Update 12 September 2017: A very special thanks to Sam Elder, a manager here at Instructables, who tracked down the cause of my lost publications and fixed the issue. Take a bow Sam!

Driving in rain or to work on early mornings I had noticed my fuel economy improved by a small amount. Could it be the higher water vapour content in the air? Via research I came across an old technique called water injection used in the world War 2 era. Basically a fine mist water is introduced into the air intake manifold and this is burnt in the combustion Chambers.

The water mist is converted to steam which increases the compression ratio of the engine. The steam also cleans the built up carbon in the cylinders and also the oxygen sensor.

One month after implementing my own blend of water injection (water induction), I gained an extra 40km on a full tank of gas! The original stock range on my lev civic was a pitiful 290km. Four years after implementation of water injection, I typically get 460km. On consecutive long drives I will get over 560km per tank.

This project works reasonably well on cars without a catalytic converter. I have tried this on a car with its cat still installed and the project was a failure. Also, the needle valve used to control the flow of water into the intake manifold is critical in its percent open state: even a little too much water and the engine will splutter so its very important to use the smallest possible flow of water to achieve misting.

Now let me Show you what I did to obtain these results and it cost me less than 100TT dollars.

Step 1: Vacuum Line to the Air Intake Manifold.

I used the vapour line that pulls gasoline vapours stored in a charcoal canister. Years ago the rollover valve in my gas tank got stuck in the closed position. As a result I condemned that vapour line and removed the fuel vapour recovery hardware. The vacuum line as a result was available for my use to get a controlled amount of water into the air intake manifold. In the pic that's the hose with the copper tubing link.

Please note that if you introduce water mist before the air intake throttle you will sieze up your intake air control valve (and the electronic throttle if you have that) . Water mist must be introduced downstream of these devices for a reliable solution.

Step 2: Valve to Control the Water.

Using a brass needle valve for water control, I connected to the vacuum line. A very small amount of water is needed as even a little too much will cause the engine to cough and stall! If that happens it will need water removal from the air intake manifold and lots of heavy revving to start back.

Using a quarter inch inner diameter tubing, my flow is approximately 20mm travel of water in 15 seconds. I made a red mark to know how much to turn from the lock off position.

As water becomes mist via this valve, it gets really cold. Small scale refrigeration! This is a future project I will try to tap into.

Step 3: Water Reservoir .

Any bottle will work. Just have the tubing inserted and that's it. My bottle there gives me a month's supply. The water required is very small and it is only sucked into the engine when the throttle is closed (strongest vacuum at that position).

Important to note is I had removed my Catalytic converter. It was over ten years old at the time and past its service life. I used this water injection technique on another car without a Catalytic converter and it got much better fuel economy. I tried on a vehicle with a converter and that vehicle experienced the opposite!

When I start my car, steam exits the exhaust and carbon residue is deposited on the inside of the tailpipe. I no longer get the typical gasoline car exhaust smell. It smells much cleaner however I don't go sniffing that tailpipe for the good vibes.

This has been one of my most successful hobbies and literally pays for itself.

Step 4: Exhaust Debris.

As shown on the pics, Steam condenses to form a small quantity of water on the tail pipe. Carbon from inside the engine has been deposited due to the cleaning action of the steam. My Tail pipe is always cool to touch thanks to this effect.

Step 5: Side Effect: Refrigeration

I added a small radiator and separate water bottle with needle valve to test a theory. Under the pull of vacuum line, liquid water become water vapour much easier. To become vapour it needs to absorb thermal energy. This is why the vacuum line became so cold when the car starts. I have decided to use this phenomenon to produce low level air conditioning.

The temperature difference measured was greater than 14C. The radiator got cold enough to form condensation on a hot day in Trinidad.
I will make use of the refrigeration side effect to further another project.



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Computerized water injection systems are still in use today, mostly on diesel engines. Edelbrock made a similar electronic system in the 80s called Vara-jection. With one of these installed one could advance the timing on a non-computer controlled engine to get more power. The water (or alcohol) cooled the intake charge enough to prevent detonation. The downfall of these is that if you forgot to fill the water reservoir or the electronic control module died you would have to back off the timing right away or risk a holed piston.

Could it be possible to use this same concept but with added pressure, so instead of feeding controlled vapor into the intake have water heated to produce a pressurized steam/vapor type induction, making greater compression with the benefits of the vapor?

1 reply

Decommissioned. No further development.

Diesel's generally do not have any manifold vacuum as they run lean (and often don't have a throttle valve.) Most diesel's intake manifolds will be under pressure from the turbo.

Wait, you REMOVED your fuel vapor vacuum line? This would cause a drop in fuel efficiency! That line recycles unburned gas!

1 reply

Sigh yes I know. I'm working on a way to get that line back into the process. The problem is my rollover valve in the gas tank got stuck closed after a minor accident. The rest of the car is good but absolutely no vapours come from that line since. This is the sole reason I performed water induction in my car. You have a keen eye. Thanks for the comment.

Very interesting.. Probably not worth doing in wetter countries like mine though :)

1 reply

It may be worth a shot since the steam cleaning action of this setup has benefits on the engine and fuel economy.

I use an Sta-bil to dry out the ethanol and my engine runs much smoother, less vibration. It is like running 100% gasoline except less mpg due to ethanol having less power output. My point is, ethanol absorbs moisture from the atmosphere and causes the engine to run rough and rusts out your exhaust quicker. Not sure I would want to ADD water. A cooler engine prevents detonation, early combustion which fights a piston still on the upstroke. My theory is water injection cools the engine when regarding the timing or using higher octane would do the same thing.

1 reply

Hi fred. My Gasoline engine actually runs a bit cooler since the water injection mod. The water to steam helps remove some thermal energy. A nice side effect are my spark plugs remain perfectly clean. I have not changed them since. This mod has proven itself quite effective on my engine. I have also successfully done this on another car engine without catalytic converter. Of course this is my experience and I stand liability to anything I do on my car(s). Implementation of this mod is as always the decision of the hobbyist who wants to try it. I just wanted others to know of what I did and the benefits I enjoy from it.

I am assuming this is a diesel engine? it looks like all the well documented cases of fuel economy gain is in diesel engines.

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Water injection was originally used on diesel engines. My Civic is gasoline without the catalytic converter. Any vehicle with a catalytic converter will not accept this mod and have improved fuel economy. The opposite will happen plus the converter will get clogged by carbon deposits. Very bad for the engine when a converter gets clogged.

I do inspect and service the air intake manifold and have no found any rust. The quantity of water consumed is very small but has greatly improved my Fuel economy.

I think this should be done only when the engine has reached standard operating temperature. Otherwise, part of the energy generated by the fuel will be used heating the water and it is likely that the balance be negative.

It's interesting how you solved the problem of prevent water entering the engine when it is turned off.

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You are correct in that when the engine is at proper operating temperature should water be part of the combustion process. My poor hobbyist approach was meant as a very low cost solution and has proven itself most effective. Simple systems are most reliable.