Back in the days of the Slant Six and turbo V8s, one of the easiest ways to tell a luxury car from its less expensive counterpart was to look at the dashboard. The more lights, the more expensive the vehicle. At the other end of the price scale were vehicles like the Ford Falcon, whose cost-conscious design required a single bulb in the dash to illuminate the left and right turn signal indicators.
Over the years, discerning motorists realized that the “idiot lights” on the dash weren’t as good as they’d hoped. Too often, by the time a light indicated a problem, it was too late for the driver to take corrective action. In effect, these lights were not telling the driver what was happening but what had already happened. Hence the birth of a new trend: the more elegant a vehicle was, the more indicators it had on the dashboard.
Unfortunately, OEM gauges, when present, tend to be wonders of ambiguity. Constrained by cost and style considerations, they rarely have enough graduations or precision to give you more than vague clues as to what’s going on under the hood. How hot is your engine running? If the answer is “two-thirds of the way between the yellow and red bars”, you may want to reconsider your indicators.
For this reason, aftermarket gauges are one of the most popular upgrades on tow vehicles and RVs, not only to supplement factory-installed devices but to replace them entirely.
look at the needle
Many gauges are offered in mechanical and electrical versions, and the distinction between the two is important. While most mechanical meters directly convert temperature or pressure into the physical movement of a pointer on the dial face, electrical meters first convert it to voltage or current before converting it back to the physical movement of the pointer. This last conversion step is usually accomplished by electrically heating a piece of metal that expands and contracts to move the needle or by using an electromagnet that pulls the needle against an opposing clock spring.
It is difficult to obtain consistent and accurate pointer movement with these two techniques, and this generally makes electric meters less accurate than their mechanical counterparts. Additionally, mechanical gauges tend to respond faster to changes in pressure or temperature and are not affected by voltage fluctuations in the vehicle’s electrical system.
Even so, electric meters have several important advantages. First, they are generally easier to install, simply because electrical wiring is easier to route through tight spaces than the copper or plastic capillary tubes used in most mechanical meters. Second, in the case of oil or fuel pressure, they do not bring engine fluids into the vehicle. (For safety reasons, mechanical fuel pressure gauges generally require the use of a fuel-to-inert fluid isolator, which should be installed outside of living areas.) specific length of tubing, electric meters can be located at any desired distance from their emitters, a particular advantage in rear-engine RV applications.
For these reasons, many people prefer electrical to mechanical, or at least a combination of both. Fortunately, meter manufacturers often sell mechanical and electrical versions with identical appearances, making it easy to mix and match without sacrificing aesthetics.
Recently, digital gauges have become available on the aftermarket. Most of these designs use the same basic type of emitter units as their electrical counterparts, but convert the electrical signal from the emitter into digital data that is displayed on
a liquid crystal display (LCD). This approach provides most of the advantages of electric meters, without the loss of accuracy associated with converting an electrical signal to the mechanical movement of a needle on a dial face. Some digital gauges still retain a mechanical dial, but use the data to drive a stepping motor that precisely controls the deflection of the needle, an approach that combines the precision of digital circuitry with the visual appeal of “real” dials. .
The resolution of the indicator is another important consideration. Economic indicators tend to be marked with few graduations, sometimes with some colored bars instead of actual numbers. The best quality gauges will mark every few degrees of temperature, every few pounds of pressure, etc. Most high-quality gauges also display their readings on a wide-sweep dial, making it easy to read the actual numbers at a glance. Naturally, gauge size also plays a role in resolution: readings are easier to see on a larger gauge, and a large gauge face provides room for the manufacturer to include more graduations.
one is never enough
Aftermarket gauges tend to be installed in pairs or groups. After all, engine and powertrain performance can be monitored in any number of ways, from rpm to fuel temperature and pressure, so consumers eager to get the full picture often won’t settle for one. After all, installing one indicator presents a convenient opportunity to install several others at the same time.
However, on many vehicles, it can be difficult to find enough dash space to mount multiple gauges. Aftermarket indicator manufacturers have partially solved this problem by offering “pods” or “pillars” that replace the vehicle’s original windshield pillar cover on the driver’s side, allowing two or three indicators to be mounted in this location. . In addition to providing excellent visibility, column mounting prevents cutting or drilling into the dashboard itself. Gauge modules and pillars are available for most of today’s trucks and SUVs, as well as some passenger cars.
Some manufacturers also offer instrument cluster upgrades for certain vehicles. Basically, these packages allow you to take the entire factory-installed gauge cluster out of the dash as a single unit and replace it with an upgraded gauge cluster that retains the mounting space and aesthetics of the original unit.
multifunction monitors
Most modern engines employ at least one computer to control engine operation. These little brains are based on sensors that measure things like coolant temperature, fuel pressure, camshaft position, and manifold absolute pressure. Many vehicles have a second computer to control various transmission functions, with sensors to measure fluid temperature, tailshaft speed, and line pressure, among other things. Typically, the readings are available on the vehicle’s data bus, which transfers data from the computer to peripherals.
Today’s sophisticated gauges allow RVs to use this large amount of data to display a wide variety of functions. In fact, many monitors can use various basic data to display more complex information. Need to know the average or instantaneous fuel economy for your rig? Some monitors calculate fuel injector life and vehicle speed to determine these numbers for you. With the help of the aforementioned LCD screens, most models can display multiple functions simultaneously or quickly switch between functions with the push of a button.
Since the monitor requires only a few connections to the vehicle’s data bus (no new sensors or senders to install inside the engine bay), installation is quick and easy. In some cases, this also allows the monitor to be removed and relocated to another vehicle at the time of trade-in, leaving the old vehicle unmarked for removal.
Moving a heavy RV down the road places heavy demands on the engine and powertrain and requires extra diligence from the driver to maintain proper temperatures, pressures and fluid levels. In this sense, a comprehensive set of accurate and reliable gauges (or a monitor with similar capabilities) is inexpensive insurance against unexpected mechanical failure, travel delays, and repair expenses.