Found this on a 235 I loaded up today. this was new for me. Seen the glass bowl filters but not the extra vacuum port. curiosity lead me to this this particular 235 came from a fleet vehicle, bet the bosses made em use these "fuel economy" tricks wonder if it worked or was a gimmick?
Aren't those just the "in" and "out" ports? Dual carb use maybe? There's one on eBay just like it, with the two lower ports.
It looks like a Barnum product, designed to separate suckers from their money. I’m sure it worked well for its intended purpose. Sent from my iPad using The H.A.M.B. mobile app
The little info I found was a fuel economy gadget. It came off a single carb fleet vehicle. I’m guessing a gadget sold to fleet guys. I’m still processing how it worked. The vacuum port goes to manifold vacuum. It does have an un-machined/threaded location that could possibly be used as an extra feed. Maybe
I know nothing about it but find it humors that way back when Gas was .25 cents a gallon we were still trying to get more miles out of a Gallon.
One of those trinkets sold in the back of car magazines to "improve your fuel economy". My auto shop teacher told about a gent who was a regular patron of the shop classes for a number of years who was always buying every one of those increase your gas mileage trinkets and stick them on his car until the car just flat didn't run right then he would take it in for the guys to tune up and sort out. They would take all of his latest batch of gadgets off and stick them in a box in the store room and every couple of years give the latest box full back to him. He never learned that they didn't do anything except take his money. He either wasn't driving anymore or had left the area when I was a student as I never saw him or his car.
the diaphragm in the base seems to be stuck so I left it in as not to kill it. Seems since it uses manifold vacuum and has springs pushing downward on the diaphragms that it would be wide open at idle and low load situations and close under load restricting fuel?
Got the other diaphragm loose. The diaphragms/springs opens and closes this valve that controls the outlet. So I’m assuming it restricts fuel at low vacuum
Maybe it uses changing engine vacuum to operate that diaphragm and act as a fuel pump. That would take some of the load off of the fuel pump, reducing the friction at the interface between the fuel pump lever and cam lobe, thereby increasing fuel economy by 1/10th of an inch per hundred miles. It would reduce engine wear, increase fuel economy, make your engine run smoother, extend the interval between oil changes, make bald men grow haystack sized mounds of hair, and impotent men would regain their virility and be able to impregnate entire women's college rowing teams.
I might have it backwards. High vacuum at no load should cause the diaphragms to compress closing the fuel inlet valve. You cant completely shut off fuel flow it seams. Then a low vacuum situation would open it up This engine was pulled from a Mail Service van. Probably idled a lot. GM probably made millions by saving the government a penny. my head hurts.
Pretty much essential for blow through supercharger setups, fuel pressure increases as boost signal increases, without something like this you will run rich at low boost or lean at higher boost.
Dang it. This engine is missing its supercharger. I bet that unfinished extra port could have been cast there for a gauge if manufactured for the set up you posted.
Well I'll be dipped. I mean that thing looks to have all the makings of some kind of a Whiz-bang, J. C. Whitney Miracle Power and Fuel Mileage Improver. You're probably wishing that I'd invested more of your money on that bet.
There used to be a Cagle fuel pressure regulator that worked with vacuum. I think the idea was to lower the fuel pressure at high vacuum and thus the fuel level in the bowl, so there would be less head pressure to the light throttle carb circuits. I tried one and didn't see a difference. Gary
I remember when Gary Cagle, Rest In Peace my old friend, sold fuel pressure regulators that were to help fuel mileage by setting it at very low pressure 1 to 1-1/2 and driving your car with mileage in mind they worked. If these lower the pressure allowed into the carb when the vacuum was high they could work also. A person driving with mileage in mind can achieve better mileage with less fuel pressure. Many Mobil Gas Economy Run cars used this as one of there many many tricks.
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