oil pressure and water temp gauges

[Bill Baer]

We use a mechanical oil pressure gauge and an electric water temp gauge. At one time I used a mechanical temp gauge but the capillary tube is difficult to run and easy to damage. I use autometer gauges the mechanical oil pressure gauge which is liquid filled to help resist the vibrations which may not be necessary they (autometer) also have a trick low temperature electric gauge the I really like because it helps keep the launch temp accurate.
A note of caution about using electric temp or oil gauges they must have a good ground to be accurate and the motor plate,especially if it's anodized makes for a poor ground connection to the chassis. I run a seperate ground wire for my temp gauge and the transbrake solenoid I also ground the battery to the starter. My Dyno guy has seen on incidence of picking up power by running a ground wire from cylinder head to cylinder head and back to the battery,I have not tried this myself but it makes sense that the ignition needs a good ground path too. You also need to make sure that the sending unit is not at the high point in the cooling system or you may have to run the water pump to get an accurate reading and you don't want the sending unit in an air pocket.

If you use a mechanical oil pressure gauge I would use a #4 AN Braided line as it will not dampen the response of the gauge don"t use copper, aluminum or steel may be ok but the #4 AN (Earls/braid covered rubber)is easy to route and has been reliable.
I also run a large 30# Idiot light (Longacher or Speedway motors) I also have an Idiot light for the trans brake that lets me know it's energized and I have a shift light that continues remind me that I have overreved the motor on the burnout

As far as wiring goes make sure that everything can be shutoff by one switch [/U]and that it has a sufficent aperage rating to handle the load.
I have seen a couple of cars equiped with a cable to turn off or on the main power switch with a lever in the cockpit which I think is a good idea especially when I'm strapped in ready to go and I forgot to turn the damn switch back on
I don't run the starter current thought the main power switch it will eventually fail and if you using an electric fuel pump put a safety pressure switch in it circuit.

Well that probably a lot more info than you wanted anyway but if you have any questions let me know.

[h500r]

can never be too much info
that really helps thank you !!

[S/G 386N]

I also use mechanical oil and electric water. However, make sure you have a spare water sending unit. Never fails that once a year, mine will quit reading accurately half way through a race.

[Michael Pliska]

Disclosure notice: I am the engineering manager for a gauge manufacturer (ISSPRO, Inc).

That said, I have been hard-pressed to do away with old-school mechanical gauges. I pulled my old bracket car out of mothballs last year, and continue running the 30 year old mechanical oil pressure and coolant temp gauges, but I have added modern electronic gauges (actually prototype test units from work) in parallel (hooked to a tee on oil pressure, and the other head for coolant temp). The modern sensors have come a long way, and I trust them as much as the mechanical gauges. My mechanical coolant temp gauge still sticks occasionally, and the electric one tells me what I'm really running for temperature.

If your electric oil pressure sensor uses only two wires, then it is an electromechanical potentiometer based unit and not very reliable. If it is a 3-wire unit then it is likely a solid-state capacitance based unit, and these are typically reliable.

The electronic temperature sensors are typically thermistor-based. While this general technology has not evolved in decades, the mechanical design of the units have changed a bit (providing better thermal conductivity for quick response, and better mechanical durability of the electronic components). Typically the newer (and more durable) designs of sensors have integral electrical connectors and an isolated ground (2 wires running to it).

I am in the process of returning my Super-Gas car to the track after a 15 year hiatus. I will start out with the old mechanical gauges in it, but will probably convert it to electronic gauges when I have the spare time.

Regards,

[Chris Williams]

Not much help for you, but we switched from mechanical gauges to all electronic through a Racepak w/ a Racepak dash over the winter. Absolutely love it. Not only do you get good info, but it's all logged.

We now carry our full sweep performance electronic gauges:

http://shop.classicinstruments.com/v...white-series-2

[Tom Goldman]

Think about a Racepak digital dash . Gauges are really only useful for warm up , on the track the only thing you need is an oil pressure warning light .
If you're looking at the gauges on the track , you have given your engine more attention than your opponent !
And that comes from someone who lost a $5K final doing just that on the starting line .