Gauging a Winner

Images of gauge pointers spiking and tachometers pushing the redline illustrate the explosive power of stock car racing. From your home track to national venues, a cluster of gauges tells the driver more than just his speed.

Monitoring the instrument panel under race conditions allows drivers to optimize the performance of their cars by maintaining specific temperatures, rpms and pressure levels that assist in gaining peak horsepower from a particular combination. Gauges also alert the driver of potential system failures.

To help us understand gauge use and placement from a driver’s perspective, we caught up with RE/MAX Challenge Series racer Ron Breese Jr.

When it came time to outfit his 2001 Monte Carlo with gauges, Breese chose his gauges based on a combination of visibility and reliability. An easy-to-read, clear gauge allows the driver to spend less time looking at the gauge and more time with his eyes on the track.

It’s best to have a bold contrast between the dial face, numbering and gauge pointer. The contrast can be essential, especially when factors like sun glare and limited viewing opportunities arise. Most drivers are only able to view gauges during the straight-aways. On a shorter track, this may be more difficult because the turns come quicker.

Accuracy is critical. A reading that is off by even a small margin can cause a driver to make the wrong decisions. An inaccurate reading could also have catastrophic consequences to the car’s engine and other systems. The response time of the gauge is also important to the driver.

Standard gauges include a series of liquid-filled gauges. The gauges are actually filled with a dampening fluid to assist in accuracy. The liquid-filled gauges have become popular with Baja racers and off-road vehicles.

Many stock car drivers keep weight reduction in mind when choosing gauges. Breese, for example, selected five standard gauges and the 5-inch Memory tachometer from Auto Meter’s Ultra-Lite and Carbon Fiber gauge lines. His gauges include oil pressure, water temperature, oil temperature, voltmeter and a clock. Yes, a clock.

Clear Readings

The use of an oil pressure gauge is crucial in any form of racing. A noticeable drop in oil pressure could be an early warning of serious engine problems. Breese’s 355 engine produces approximately 500hp at the rear tires. Breese’s team determined that at idle speed, the oil pressure gauge should read between 50-60psi. When the car reaches full throttle during a race, 80psi is the preferred reading.

An amber signal light on top of the tachometer provides an immediate indication of dangerously low pressure. If the pressure falls below 20psi, the light will easily signal the driver in case he isn’t monitoring the gauge. In many cases, a problem detected early can be corrected, allowing the driver to continue the race and avoid serious engine damage.

Water temperature is another essential gauge. The engine runs at high temperatures for extended periods of time, especially if the driver alters the airflow by “taping off” the grille to increase front-end downforce.

A range between 200 and 210 degrees Fahrenheit is optimum, Breese says. This is the range in which the engine produces the most horsepower with the greatest efficiency. Anything above 250 degrees could be dangerous to internal components and the cooling system. The water temperature gauge should be able to measure in small increments, since even minor changes in temperature can have a drastic effect on performance and engine preservation.

Breese’s team uses an oil temperature gauge, but it’s not mounted in view of the driver. Instead, the gauge is in the top of the dash so crewmen can easily see it through the corner of the windshield. The crew monitors the gauge during test sessions and at the onset of the race to ensure the engine oil is hot enough to be both viscous and effective. Prior to qualifying, crews can determine that the oil is the proper temperature to run full throttle.

Many teams also run an oil-tank temperature gauge. This gauge monitors the pre-heater so the oil is not overheated. Breese’s team installed the oil temperature gauge in the top of the dash on the driver’s side, because the oil tank is mounted directly on the other side of the firewall. It was simple to install and view.

If a driver notices a loss of voltage during a race, he can take temporary action by shutting down certain accessories. He can immediately shut down his “personal fan” and the quick-change cooler pump to save power until it’s clear to pull off the track. The voltage gauge will alert the driver of a failed alternator and give the driver enough warning before he loses full power. Breese’s team likes to see the gauge at 14 volts.

As mentioned earlier, Breese has also included a matching clock in his dash. The clock gives the race interior a unique look, personalizing the gauge setup. Breese monitors the clock as well, he says, because sometimes the time seems to pass quicker than the counted laps. Running 400 laps takes about three hours, so the clock gives the driver a time reference when racing. Breese also says, “It looks cool too.”

Fuel pressure and water pressure gauges also are commonly used. When fuel is very low, the gauge starts fluctuating, indicating a need to refuel or signaling a problem with the fuel system. A water pressure gauge can alert the driver of a broken hose or blown head gasket.

Take Your Pick

While you may always find the standard gauges like oil pressure, water temperature and voltage, other gauges are commonly added according to the style of racing and needs of the engine combination.

Drivers can choose from two types of gauges: mechanical and electrical. There is very little difference between the two when measuring accuracy.

In one of his cars, Breese chose the Auto Meter Ultra Lite series. The silver dial face, black numbering and red fluorescent pointer makes them extremely visible. Another Breese team car uses gauges from Auto Meter’s Carbon Fiber Series that incorporate a real carbon-fiber dial, white numbering and a light aluminum pointer.

Breese uses mechanical oil temperature and water temperature gauges. He says the mechanical gauges have an advantage for these two applications, because the gauges are a 270-degree sweep style. The numbering is spread around the full gauge, unlike the 90-degree electrical. This makes the pointer movement easier to read since, in the 270-degree style, the increment readings are farther apart. If the oil pressure drops 10psi on a full sweep, the needle will move farther than with the 90-degree sweep. When the driver only has a split second to look, the movement of the gauge will be more obvious. The voltage gauge is electric, of course. Breese mounted his gauges on the far-left side of the dash. Since he’s constantly turning left, the location keeps the gauges in his field of vision and makes them easier to monitor.

Aside from gauges, the tachometer puts the entire combination into perspective. Tachometers can be mounted in the dash itself or on the steering column. The steering column is a popular choice because it places the tach where it can be easily seen. The driver must align the instrument so it is visible around the wheel itself and not obstructed by the driver’s hands.

Breese uses a standard 5-inch memory tachometer mounted on the steering column. He closely monitors the tach during a race, especially going into and out of turns. The driver maintains a target range between 7,600 and 8,300rpm in an attempt not to over-rev the engine. The large size of the tach improves visibility since it is difficult, especially on short tracks, to divide time between gauges, tachometer and racetrack.

Some tachometers offer features that aid the driver in tuning the car. The memory option lets the driver recall the peak rpm during a race or test session. Also helpful on short tracks, the memory option will catch and later display the highest rpm during the race in case the driver misses it during a turn.

The tachometer is of great use to racers who commonly race different tracks. The setup difference between a ¼-mile and a mile-long track can mean extreme changes in suspension tuning and gear ratio selection. Too tall of a gear can cause a loss of horsepower and force the engine to work harder. A gear that is too small for a particular track will make it difficult for the tires to match the rpm. Torque will be present, yet horsepower will be lost. As the straightaways become longer, the gear choice moves from a higher numerical gear to a smaller numerical gear.

Suspension tunings can also benefit from monitoring the tach. As the car travels in and out of turns, chassis drag pulls the car down and rpm is lost. During a test session, the driver and crew can assess the suspension tuning by trying to reduce the rpm loss through corners.

Some stock car drivers have found a use for Auto Meter’s Pit Road Speed Light. The gauge can be set to flash a green light when, based on rpms, a driver reaches the speed limit on pit road. If the driver exceeds the speed limit, a red light will flash.

Many other developments in race technology have turned simple instruments into an advanced science. Auto Meter’s Playback box for oval track and road racing converts any Auto Meter tachometer into a recording device. When installed, the box will record up to 10 minutes of rpm to replay later at half or full speed. The replay can be viewed right on the tach, or downloaded and graphed by a printer. This gives racers a look at engine performance with their undivided attention. Crewmen and engine builders also can analyze the data.