First let me say I drive an 85' Ford F150 w/ the 302 V8. The truck is used as a truck so I cant just trade it in on a compact car, I would however like to improve its gas milage. I would love a gas milage gauge like the new Ford F-Super Duties have, but I cant seem to find one.
That is, untill I found this site...
I have some questions about this infamous "Supermid".
1) Exactly how does this little gadget work? How does it calculate FE and how accurate is it?
I'm guessing the 85 is carbbed? The pulse width comes from one of the injector control wires.
I don't think it's too easy to hook up a digital vss from scratch...I've heard some things about getting a magnetic thing to sit on the axel and count rotations, but Iono for sure...someone else will though.
If your engine is carburated rather than fuel injected, its going to be a bit of a job to produce the equivalent of an injector pulse from it. You would have to install a paddlewheel flowmeter in the fuel line feeding the carb to produce a pulse frequency proportional to the fuel flow, then use a frequency to duty cycle convertor to convert increasing frequency to a higher duty cycle. You would need to do some research to determine your range of fuel flows and select a flowmeter that would give an appropriate range of pulse frequencies and then find a freq to DC convertor that could produce an square wave pulse mimicking the square wave pulse that the SuperMID is set up to receive. You would need to contact Yoshi to for the specs on the range of VSS pulses. As far as I know this hasn't been done, but it would be an interesting project for someone with a bit of electronics background.
For a truck, I'd say aero mods would be real good.
Along with good driving, like moderate speeds and P&G technique, and the usual vehicle maintenance and tire pressure as high as is safe.
My old Volvo is not very aerodynamic and I feel a big change after my recent aero work. Better mpg #s also. If you have something with low drag like a Geo or a Prius you might need a degree in aerodynamics to improve it. But with a rolling box like mine, or a truck, I think you can really help yourself with aero mods if you do some research. I'd look here under the Aerodynamics Discussion and in wikipedia under Automotive Aerodynamics. Watch out for the race car stuff. They often want to create down pressure for traction. You don't need that but you do need smooth ar flow.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.