I'm very interested in my mpg--especially a digital readout of my current mpg (just like on fuel-injected systems.) My current problem is finding a reasonable fuel flow sensor, but let me explain where I am on my stock '65 dodge dart...

So, the formula seems simple: current mpg = current mph / current gph. So, I wanted to first figure out how feasible this is.

Speed can be retrieved from the speed cable. Since the speed cable rotates with the transmission, I count the number of rotations per second and calculate the speed based on tire size/ratio in the tail. This will require making a rotational sensor, wiring up a microprocessor (to calculate speed), a timer to trigger when a second has passed, and an small display. O, and program the microprocessor, of course.

So, that last paragraph I can do for < $20. What I'm having difficulty with is finding some information on fuel flow senor at a reasonable price (to retrieve gph from the carb intake.) The best I have found is:
http://www.amazon.com/Eagle-Red-Fuel-Fl ... B000Y845QS
Which is $80, and uses NMEA 2000, which would require me to build a NMEA bus (something I haven't looking into the cost of nor the effort level.)

Anyone know of a better alternative? I'm interested in calculating mpg while driving, not doing some trick, like wait till gas tank is empty, fill with a gallon, drive 55mpg until dead. calc from there...

Anyone know of a better(cheaper) place for a sensor? Someone mentioned that old cars would have a fuel flow sensor in front of the carb. Does anyone know what cars do? Maybe I could hit up the junkyard.

I feel like this should have been done before, but I haven't found anything that doesn't significantly modify my current setup.

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~Less think, more do

This what you describe was available in the 1970s/early 1980s. See here and here and here … maybe check eBay for NOS kits?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan,

Thanks, there seems to be a lot of 'FloScan' devices around. 'Spacekom', and 'autocomp' seem to be harder to find. I'll research the 'FloScan' stuff, maybe I get a system or get, at least, the flow sensor for cheap.

I have not dealt with NOS kits before. Do some hook up to the fuel line? The one I looked at http://www.amazon.com/NOS-07001-Sniper- ... B000COXACE seems to hook into the square bore, which would not provide any type of flow sensor/mpg meter.

Now if I'm in the junk yard I know what to look for.

~PauloftheWest

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~Less think, more do

Er…oops! NOS = "New Old Stock", a car part that is new (never been installed on a vehicle) but old (was made many years ago). It's confusing because "NOS" is also a brand of nitrous oxide systems, which are not applicable to any but race vehicles and have nothing to do with measuring fuel consumption.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Let's see, stomp on the gas, hit the button, watch the gas gauge go down. There seems to be a direct correlation to mpg...