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I was going through an old bookcase and ran across a technical article in the June 1958 issue of speed age. (Yes I said June 1958) I thought I would share it with everybody.
The article deals with the installation and report on the "Monarch Vapo-Jet." They took the head off of a 1951 flat head Plymouth to check it for carbon. They put a new head gasket on and installed the Vapo-Jet and drove it 300 miles. They took the head back off after the three hundred miles and stated that "wiping a finger across the combustion chamber surfaces showed only a soot-like deposit left."
They then took the Vapo-Jet off and put it on a 55 Dodge V8 and hooked it up to a dyno. The first test without the Vapo-Jet produced a whopping 58.5 hp @2000rpm. The next test was with the Vapo-Jet and the horsepower dropped to 56.75hp @2000rpm. The next test was with a mixture of 1/3 denatured alcohol and the horsepower jumped to 59.5hp @2000rpm.
Their final analysis was that for a street engine it's not worth the trouble. No noticeable increase in mileage, and a slight loss of snap. Note: the Vapo-Jet cost a whole $3.00 in those days.
Another guy and I got a carbed F150 up to 75 mpg just playing around with raising the gas to a very high temp. However we dumped it due to safety concerns and lack of $$$. If we had a few million bucks to continue, I bet we could have made it more. I doubt 300 mpg though. I wish we could have got it closer to reality so we could have been bought out by an oil company.
Water injection schemes were common back in the carburetor days. They didn't help fuel economy, as touted, but they did often make engines run a bit better. There were many tests done throughout the 60s and 70s on these units by popular car magazines.
I tried one from JC Whitney, just for giggles, on a 72 F-100 that I had transplanted a high mileage 72 351W into. With a ~6 month old complete tune up, the water injection made a big difference in the overall idle and acceleration "smootheness". It's hard to describe what I mean. The engine ran great, but with the water injection, it just ran smoother(?). The exhaust note was not as "sharp", through headers, glasspacks and outlets just behind the cab. You'd have to try it to understand what I mean. When I eventually pulled the heads on that motor, the combustion chambers were clean as a whistle due to the steam, as were the back sides of the valves.
There was no detectable difference in performance or economy. I always wanted to try alcohol in the bottle but I never got around to it.
(I put that kit on in 1979, my first truck. ) Thanks for the memorabilia.
The vapor systems operated on vacuum. i.e. when you put your foot to the floor the vacuum and the water mist went away. They worked well to keep you combustion chamber clean but didn't suppress detonation they way a modern system can.
I use a Snow Performance unit and am very happy with the elimination of spark knock on a high compression engine.
They did say the engine ran smoother in the article, but also stated that it lost a little snap. They showed on the dyno a loss of a couple of horses. I am not sure I could feel the loss of a couple of horses
I did have a John Geraghty unit on my 1970 Chevy camper and it was like beartracks explained. It used a water pump and a vacuum switch. When you punched it and the vacuum went away the vacuum switch activated and turned the pump on. This pumped water through a spray head which sat inside the carb and looked something like the accel pump spray nozzles in the carb. The unit worked great, but I was to young and stupid to put purified water in it. It keep crusting up with lime deposits and plugging up. I finally ended up taking it off.
I just thought it would be a hoot to post this thread. For the old timers it might make a short trip down memory lane and the younger guys might get a kick out of seeing some of the gadgets we use to fall for in those days.
Beartracks hit it dead on. It's all about control these days when it comes to water meth. Our stage 2 system has a fully digital CPU in the controller that controls the flow of fluid based on parameters set by the user.
Another point that Beartracks mentioned was the detonation suppression. We like to describe water injection as providing immunity from detonation.
We have published some great tech info on our website if anyone is interested in reading more about modern water injection systems. We also have a section that shows our customer's installations of our systems too.
If anybody has any questions about water injection feel free to send them my way.