We "maybe" look at the gauges 1 or 2X per lap (longest straights) OR, when something else happens - loss of power, a change in exhaust sound, increased vibration... The tach gets more attention but a shift light is likely better when distracted by close wheel to wheel race traffic.
Keeping it simple... For your engine build, what info will cause you to coast to the side of track during a race and wait for a tow? These are the "STOP DRIVING NOW" gauges you want directly in the driver’s line of sight.
On our racer we have: Oil Pressure, Water Temp, the Tachometer and a low oil pressure light immediately in front of the steering wheel. The 15 PSI low oil pressure light turns on to warn of impending doom (the big bang). IF that flashes on at race RPM’s, things are likely to be seriously bad real soon. (It does turn on at idle which is a little concerning…)
Other gauges (high in the center pod) include - a gas gauge (endurance racer) and a location for an Oil Temp gauge (not yet installed). Finally, there is an hour counter which we use for maintenance tracking (away from the driver’s line of sight in the right most dash vent location).
Gauge placement and how to make the gauges easier to read quickly (opinion):
- Gauges with 270 degree sweep needles. Any change in reading makes for a 3x larger movement in the needle than a 90 degree sweep gauge – easier to read,
- About 2” diameter gauges work for me. 2 5/8” and larger take up too much dash space / Smaller are too hard to read quickly,
- Turn all gauges so the “normal reading” (or tach red line) has the needles pointing straight up, again fast to read at a glance. Needle not vertical? Look more closely at the reading.
- Although likely less precise, I like mechanical gauges when possible. No chance of electrical issues causing intermittent readings. If a mechanical gauge is broken, it likely 100% done never to return.
- Idiot lights for Oil pressure and shift light. Possibly others like alternator might be good too…