Going way back to this post on exhaust air speed and air ride tune-ability, we’re finally starting to get serious about figuring out the ride height of the ’32, instead of just air pressure. Air pressure is ok for an overview of ride height… if you know what pressure the bags have to be at, with a given load. What we were finding in the ’32 (and maybe it’s because it’s a relatively lightweight vehicle), is that just because the pressure in the bags was 50 psi, didn’t mean the car was sitting where we thought it was. The PSI could read the same with 2″ of ride height variation, depending on the load.
Bags are at 50 PSI and there is 2″ between the wheel well and tire. Add 200 pound passenger. Ride height goes down, PSI goes up, wheel well gap decreases. How much pressure do I have to add to get the gap back at 2″?
Enter the ride height gauge.
We had a few ways to accomplish this, but the idea is pretty simple. Get rid of the pressure gauge (I could care less what pressure is in the bags… I want to know where the car is sitting!) and substitute with a ride height gauge. The gauge would measure actual ride height; optimal being in the middle, with low and high on either extreme. The gauge would measure the relationship between a point on the body and a point on the axle, and show that relationship on the gauge. A friend of mine with an air ride equipped ’76 Mercedes was thinking along the same lines with a thermometer type gauge that would be hard lined to the body with a solid inner cable (think choke cable) that would move similar to the mercury in a thermometer, indicating the ride height.
Another friend (there’s two so far!) actually made a prototype light sensor that would turn on an LED when the beam was broken, indicating optimal ride height.
We discussed the idea with John and Zac at Classic Instruments and they suggested two fuel tank sensors, one mounted on either side, running to a three way switch (driver side/off/passenger side) and then on to a custom printed “fuel” gauge. Two days after telling us they’d first get on it, we have the gauge and two fuel level senders sitting on the bench! Next step will be figuring out where to mount them.