Boosting Fuel Economy Using Water!

Driving in the rain has always given me higher fuel economy and the hot dry season here really kills fuel efficiency. This is how I simulated high humidity conditions to give me that fuel economy boost in the rain.

Step 1: Pump and Reservoir.

I used an aftermarket windshield washer pump complete with reservoir. This provides good pressure and flow for the intended project.

Step 2: Programmable Timer.

This frm01 12v timer I programmed for 0.2sec on, 5min off, infinite cycles. It switches the 12v power from the accessories circuit to the aftermarket windshield washer pump.

Step 3: Installation and Results.

I used a length of nylon tubing to make a ring at the top of the cone air filter. I drilled a dozen small holes on the inner circumference of that tubing. A Tee fitting completed the ring sprayer. To ensure the engine breathes only air through the damp section of air filter, I sealed off the top section typical of cone filters.

The pump and reservoir I bolted near the engine radiator. The negative wire I connected to chassis with the positive going into the cabin via the firewall. The timer relay is mounted inside the dash.

Since Commissioning this project, I have gotten an extra 60km per full tank of gas. I am most pleased with the results here. During drives the engine idles smoothly in traffic and has slightly better power during acceleration. This project is similar to water injection without the direct misting of water into the air intake manifold. The benefits for my implementation will not be as large as a water injection setup but the fuel savings is what I'm after.

A downside to this project is the air filter frame has gotten rusted. I don't mind since I have several spares and for the fuel savings involved, changing the air filter every 4 years is worth it in my opinion.



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    Reply 7 months ago

    Water injection is actually a thing, and is used on many different platforms, from high-performance piston engines to jet aircraft. No, the water doesn't add energy, but it does reduce intake air temperature (improving density), reduce exhaust gas temperature (reducing strain on the exhaust system), and as the heat of combustion makes the water flash to steam, it gives the engine a little extra push using energy that is otherwise wasted. Meth injection systems (50/50 water and methanol) also combat detonation, allowing for higher compression ratios or more boost. Of course, OP's filter moistener isn't exactly water injection, and his little four-pot isn't exactly a jet engine, but I wouldn't be surprised if his rig is actually doing something.

    Look at where that air filter is. Right over the engine. Most cars duct air from the fender or grille, because the air outside the vehicle will always be cooler and denser than the air under the hood, and I wouldn't be surprised if the OP's car actually came with one. Without one, it's sucking hot air when it's hot outside, and it's not running as well as a result. It seems reasonable
    that fitting what's basically a swamp cooler over the intake--reducing the temperature of the air charge, thereby improving its density--would
    offer some modest gain in power and efficiency. I'd be curious to run an intake duct out of the engine bay and see if it solved the issue the swamp cooler was built to combat.

    I'm not rushing to do this to my own car, but I still think it's a cool idea. Thanks for sharing, OP.