dc_sniper9130

does anyone make an aftermarket fuel mileage gauge?

I'm not talking those bullsh*t vaccuum gauges, I'm talking a little 2 1/16" with a digital readout that shows your current mpg based on your speed and fuel consumption.

I'd like to put one in my new cluster when I get it, does anyone know of anything that would be somewhere in that direction? thanks

online170

Heres two links i found just by typing MPG GAUGE into google.

http://www.geardiary.com/2007/06/10/...uge-ii-review/

http://www.videoelectronics.tv/gauge.htm

I know some of the newer cars come with this built in, but it never occured to me to put it in my firebird.

My car has a holley 750 DP, and its far from a daily driver, (reliable, but too gas guzly) so i figured i didnt need one . But i guess it could be nice to figure out if you DO drive it daily.

dc_sniper9130

yeah, I looked at those before I posted, but you need a functioning computer. I'm sure my computer is garbage and my new motor is going to be 110% mechanical. the closest I'm getting to a computer is electric sending units for my gauges. what would be nice is something that interfaces with the auto-meter electric speedometers and a flow-metering fitting along the fuel line and just does a simple calculation. i wish i had any skill with a soldering iron so i could jsut make one... oh well.

thanks fr looking though

online170

The problem is, you will need some kind of computing going on, and a couple of sensors atleast. Just like you mentioned. Essentially this is a "computer" and you cant get around that part.

Also if you graphed out what this gauge would be displaying, you have alot of things changing with respect to something else, that is also changing.

For example, you want to know what the MPG is at an instantaneous part of the graph, but your RPMs are not always constant, neither is your speed, and neither is the fuel flow. So a few things to take into consideration.

You may want to contact autometer, maybe they sell something like this, or maybe a dealer, perhaphs they could sell you something like this, and you could "McGuiver" the thing into your car.

Keep us posted either way, sounds like a cool addition to the car none the less.

dc_sniper9130

yeah, that's kind of what I was thinking. Auto-Meter doesn't make anything like this... yet...

I was going to call them actually.

And yes, there is a lot of constant computing going on, but it could be localized in the gauge. all it would need is input from a fuel-flow sensor and input from the speedometer sender. My only real challenge, aside from, you know, making the thing, would be getting everything calibrated right.

I could program it to take an average of the flow over the last second and the rotation of the rear wheels, and then convert that into mpg and display it. It would be really nice though if it could be done to read the electric speedometer's calibrated output... I should call auto-meter...

Fullsizewagon

These trip computer things were popular in the '80s. I installed one in a european car I had, and it taught me a thing or two about what affected mileage and how to select gears to use less gas going uphill. I don't remember its name but it was made in the UK. I doubt they still exist though. It had a flow sensor in the line to the carb., giving a number of pulses per volume, and some magnets on the driveshaft with a coil pickup.
Calibration was just a matter of driving a known distance and then enter it to get a calibration number for the distance/ speed. Same with the flow, use some gas, top up the tank again and enter that volume to get a cal number there too. It would display instantaneous and average mileage, in addition to speed, trip speed, distance, etc.

online170

This has been bugging me. Ive been trying to find something about this since you first posted. As youd expect im bound to stumble over something eventually.

Here is something. Aparently, someone has gone through the trouble of writing up programs to calculate what you are looking for and more. You have to do some calibration though.

And you will need a MP3 player (i think) and a GPS system. Kinda $$$ but hey, its progress. .

http://www.mp3car.com/vbulletin/rr-p...nsumption.html

Also, here is a link for a Fuel Flow Meter, in GPM.
http://assuredautomation.com/flow/index.php

dc_sniper9130

FSW, that's exactly what i was looking for. Like, down to a T.

Any idea what they were called?

Those flow meters are a good start... My dad said that there might be some ind of a way to use a PROM chip to store the math on it... looking into it.