Lotus Elan

Auxillary Guages for race car

PostPost by: batfish » Tue Dec 05, 2006 9:56 am

I am building up an Elan race car and I need to buy new oil pressure and water temperature guages. I would like to know whether mechanical or electrical guages are most suitable for a race application

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PostPost by: rgh0 » Tue Dec 05, 2006 10:46 am

Personally I prefer mechanical guages as simpler and more in keeping with the age of the cars. However in reality it probably does not make much difference.

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PostPost by: msd1107 » Tue Dec 05, 2006 5:38 pm


Both types will function properly.

The advantage of electrical guages is that there is only a wire going up to the gauge, not a fiddly coily thingy that breaks.

The disadvantage is that the TC is set up for the mechanical connections, so installation is easier. You would have to source pressure/temperature transducers and adapt them to the engine.

Look on eBay and eBay.co.uk under "smiths gauges" and you will find examples of both kinds. Electrical transducers came from several sources, including Range Rovers. I have seen some posts on various users groups about these transducers.

Do any of our members have any direct knowledge that can help?

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PostPost by: Foxie » Tue Dec 05, 2006 6:57 pm

The slower reaction time of an electric water temp sender/gauge will still be a lot faster than the actual water temp change, and is much easier to fit and cheaper than the mechanical type.

However the almost instant response of a mechanical oil pressure gauge can tell you a lot more than an electrically operated type, especially on start up.

But experiences have taught me to never be without a large red oil pressure warning lamp mounted prominently on the dashboard. The electric sender for this can be teed into the mechanical oil pressure take-off.

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PostPost by: Galwaylotus » Tue Dec 05, 2006 7:34 pm

Probably the main reason for choosing mechanical over electrical is the full scale arc of the mechanical gauge vs less than 180? in the electrical. If a smaller arc doesn't bother you, electrical is fine.
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PostPost by: StressCraxx » Thu Dec 07, 2006 6:57 am

In my experience in a road elan, a racing XKE, and my formula ford, the Smiths, Racetech, Stewart Warner, and Autometer gauges vary quite a bit in accuracy.

So you should check their accuracy before you install.

Put the coolant or oil temp gauge in boiling water and record the temperature. I have seen as much as 15 degC low.

Use shop air regulated to a known pressure around 40 PSIG and test the oil pressure gauge. I tossed out a new gauge that read 22 PSIG @ 40 PSI.

The big red oil light is an excellent idea. Check the pressure switch so you know for sure.

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PostPost by: cliveyboy » Thu Dec 07, 2006 8:10 am

I always remember one of my racing mates used to have an aftermarket fog light bolted to the dash. If ever he had low oil it was guaranteed he would see it

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PostPost by: M100 » Thu Dec 07, 2006 8:26 pm

While not period looking in any shape or form I use these gauges on my "modern" Elan. They are very accurate, have built in warning LED's you won't miss, adjustable backlighting, the ability to set alarm points both low and high and an output to drive a master warning light/buzzer. They are around 130 quid and while at first glance this might seem a lot each gauge gives two functions which can be mixed in many combinations. I've a combined oil temp/pressure, a volts/water temp, and a boost pressure/exhaust gas temp. One niggle is they aren't bang on the standard 2 inch "52mm" diameter so you will need to open the dash hole up to 54-55mm.


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