Water Injection Wizardry

A water injection system can improve your gas mileage 20 to 50 percent.

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    The water injection system uses the feeder hose attached to the air filter cover to squirt water directly into the carburetor.
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    A jury-rigged gauge wired to the dashboard tracks the vehicle's fuel economy.

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  • 059 water injection 02.jpg

During the second World War, fighter pilots could push a button and inject a stream of water into the turbochargers of their monstrous powerplants to get extra thrust on takeoff. Some time later, Chrysler (among other auto manufacturers) installed water injection on a number of its large displacement engines, again for a performance increase. Indeed, water injection—used to produce power increases—is nothing new.

But using "Adam's ale" to save gasoline sure is a change of pace! You see, until recently there just hasn't been any way to effectively control the volume and atomization of the tiny amount of fluid needed to adapt H20 injection to a small, economical engine. And typically enough, while big technology has failed to figure out how such regulation could be handled, a small back-lot entrepreneur (with a wealth of experience and ingenuity, but a paucity of dollars and degrees) has succeeded.

Pat Goodman installed his first water injection system (on a Porsche racing car) in 1964, and the racing organization responded by banning his device—it made the vehicle too fast! Undaunted, Pat decided that even if the racing establishment wasn't interested in "improving the breed," he was.

Today, several near-bankruptcies later, the innovative mechanic owns a vehicle that only the government could argue with: a 1978 Ford Fiesta that gets 50 MPG in normal around-town driving. (This impressive figure has been verified by a MOTHER EARTH NEWS staffer, who accompanied Goodman on a 48-mile jaunt around Winchester, Virginia. During the drive—which Pat accomplished with, if anything, more speed than normal—the small four-cylinder sipped only 0.95 gallon of unleaded gas.)

Back to Basics

Like most good ideas, the Goodman water injection design is an amazingly simple approach to a frighteningly complex problem. In fact, the production system is much less complicated than the prototype model. It consists only of an atomization nozzle, plus two one-way valves from squirt guns, some hose (to supply water to the "sprayer" and draw pressure from the emission system), and a one-gallon water tank.

The nozzle is screwed into the top of the air cleaner housing and sprays minute droplets of water into the carburetor throat in response to orders from the engine's stock smog-control devices.

12/24/2010 10:11:41 AM

http://en.wikipedia.org/wiki/Water_injection_(engines) -----and links gives the good low down on h20 inject---funny they dont make much of the fuel savings that could be possible though around 25% looks obvious from the reading and the h20 inject dosent need(you dont want it to) to start til around 3 or 4k rpm or so which should help with metering//// generally speaking lean the carby and bump up the timing a few degrees----will try to give a more specific example later-- am going to experiment with a 86 350 chev engine in a 1 ton van getting around 10 mpg now i have already unrestricted the carby cover(stock was bad restricted and caused the motor to run alot hotter) and that added about 50-75% more power i didnt measure fuel use before but i'm sure it added 2-3 mpg( I forget the % but quite a bit of fuel on pre computer controlled ignition autos goes for knock prevention ---combustion cooling...thats why you get the big improvement in mpg on the newer setup--it runs leaner--- but when you get the newer repair bill that doesn't/ may not mean money saved --funny how that works--or is it----hmmmm sez da hillbilly

12/20/2010 4:14:53 AM

What happens if you add more h2o than the 95% gasoline to 5% h2o ratio??? Seems adding light oil or diesel to the gas tank might be a good idea----which i do anyway If i recall correctly i read somewhere it is good to have the h2o close to boiling when it is injected---any thoughts there?..Also cause of the h2o cooling effect i should be able to lean the carby some. What would happen if you did this on a diesel motor---blow it up maybe??? Truckers add 4-5% gasoline to race'in diesels fuel..Got a gas guzzler 350 stock chey engine on a 1986 motor home - anybody know the compression ratio off hand? any mileage or tips appreciated. Tks---I plan to add a trailer w a couple of wood gasifiers also and have a duel fuel sos i can actually travel some. Tks Race'inTom

Brian Rich
12/8/2010 6:05:32 PM

I have a 1977 ford thunderbird with a 351w. 11:1 compression ratio. I run a holly 600 and my own water injection kit. My kit I purchased from the aquarium section at my local dept store. useing clear tubing, air stone, airline regulator. I was able to increase my mileage with 93 octane fuel @19 mpg.. With h20 I down graded to 87 octane and increased my mileage to 26 mpg. Thats great for a 4400 lb car.

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