March 9, 2012

Air Fuel Meter Installation

I've decided to move my ability to tune into the 21st century by installing an Air/Fuel Meter, first in the Galaxie, then into every carbed car I own. From the beginning of time, anyone who's ever tried to tune a carb has generally done so blindly. The only somewhat reliable method to getting a carb set-up properly was with an exhaust gas analyzer (EGA). I bought and restored an old Sun tune-up machine, with EGA, but even to, it measured latent hydrocarbon production, not Air/fuel ratio. By measuring AFR, you can dial in the mixture at different RPM ranges for the optimal settings for various loads. Sure beats the millions of attempts made by guys with a screwdriver looking like they knew what they where doing when twisting mixture screws in the driveway!

In order to use the same meter in several cars, all one has to do is weld a bung into each exhaust down pipe and then plug it when not in use. I think it'll be a worthwhile exercise, especially since - once the bung is installed - it'll only take about 20 minutes to move the meter from car to car.

Here is the lower portion of the install - I'll wire up the top side tomorrow, then we'll see how close I was with the old screwdriver-tune method of yore.

After a bunch of research I bought this AEM unit from my local Speed Shop.

The AEM gauge has a bunch of different back-lights available and a couple face plates.

Here's the bung welded into the pipe and the sending unit screwed into it. I know, I know - that's FAR from a pretty weld! I'm a little embarrased to show it, but it wasn't the easiest spot to weld. That's my excuse and I'm sticking to it!
The wiring from the sensor will run up and through the firewall to the gauge, then from the gauge there's another set of wires that go to the battery and ignition power. I've been thinking of installing it in such a way that it could be easily removed and sawpped into another vehicle. I'm just not sure if swapping it around from car tocar is worth the cost of the unit ($250).....although me thinks it would be. An A/F gauge is mostly used for tuning, so it doesn't really need to reside in the car all the time....

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