I’ve gone thru a lot of gauges. A few warning light ideas too. Not for any good reason I suppose, mostly I just get led around by curiousity.
I’d never paid much attention to high end gauges until now. I’m too much of a cheapskate. But if someone had told me some of the neat features of the high end gauges, I’d a bought some earlier. So here’s some info about high end gauges.
Digital vs. analog. The nice thing about analog is that your brain grasps what it tells you really fast. Digital gauges require a heartbeat’s interpretation and we are often pretty busy behind the wheel.
That being said, digital gauges do a better job of telling you exactly what something is. So, if for whatever reason, you want to know if your oil temp is 212 or 214, you can extract that from a digital gauge a lot faster then an analog gauge.
SPA has a large line of digital gauges. Many of them are dual gauges that could, for example, show both oil temp and oil pressure.
Gauge size vs. full sweep. Most of us have cheap 90deg sweep 2 5/8th gauges. These high end SPA and Stack gauges are all the smaller 2 1/16th in, but they are full 270deg sweep. Equidistant from your eyeballs, they are probably readable with equal precision, but it’s not that hard to put the smaller gauge closer to your eyeballs and then it becomes the winner in being able to read quickly with precision.
Linear vs. non-linear. Cheap 90deg sweep gauges are non-linear. If you look closely at the markings on the gauge you’ll see something along the lines of 20deg of sweep = 20psi on the left of the dial, but 40psi on the right of the dial. Humans are linear creatures so that makes the 90deg sweep gauges harder to read accurately. Nice 270deg sweep gauges are linear.
Accuracy not dependent on sensor grounds. The 2 wire sensors have their own grounds.
Programmable alert functions. SPA gauges will illum a light on the face of the gauge. It’s not much of an attention getter tho. Stack gauges change the background illum of the gauge, which gets your attention pretty quickly. Score 1 for Stack. You can set the Stack such that it’s illum changes from green to white at 220deg for a warning and red at 230deg for a more severe condition.
External lights and devices. The Stack has programmable digital outs. I think the SPA does that, but I haven’t been able to confirm it. Programmable digital outs allow you to trigger warning lights, turn on radiator fans, or whatever you want. The alternative for warning lights is to plumb in switches. Every widgit you plub in just adds a failure point, adds wiring complexity, etc. Adustable pressure switches are easy enough to get, but there’s a limited # of temp switches available and some of them are in darn inconvenient thread sizes.
Stack gauges have a 5V analog out for your data logger. This is a very efficient way to connect a data logger because the alternative is separate sensors for gauges and data. Calibrating a data logger such that it correctly interprets data from a sensor is no picnic. And if you’re using two separate sensors, there’s a real limit to how close your datalogger is ever going to agree with your gauge.
Both gauge systems have peak recall. Darn handy when every track weekend is a test of the various ideas you dreamed up in the past few weeks.
I’m putting Stack oil temp and coolant temp on to the steering console. The gauges are far faster to read there then on the conventional center-dash location, and with integrated warning lights, and analog outs for the data logger, I’ve been able to remove several other sensors and switches that were in my system.
Both Stack and SPA analog face gauges run ~$200.