The Emerald ECU and the Elise S2 coolant gauge

[Uncle Fester]

I have noticed the Emerald ECU has a function to control the Elise S2 coolant gauge.

Now I have a TVR Griffith fitted with an Emerald ECU. The standard TVR arrangement for the temperature gauge sender is rubbish.

So, what I am wondering is, can I use this function to control the gauge in my TVR?

The options would seem to be.

Fit a Lotus S2 gauge. What is this like, as it would need to be a fair cosmetic match? Does anyone have a picture please?

If I knew how the S2 Elise gauge was calibrated then I try and figure out something to calibrate my gauge, or modify the signal to match.

Can anyone give me the values for signal to temperature for the S2 gauge?

TIA

[Benmac]

The temp gauge in the Elise is just a readout on the small LCD display underneath the tacho and speedo. The same display also houses the fuel gauge and odometer. As such, not really a 'fit' with that in the TVR.

[ptp170]

Just measure the output at the selected pin on the emerald against GND and see what the output voltage is. It won't be that same as my car as it uses a custom coolant curve

[Scuffers]

the short answer is no...

the output for an S2 temp display is a PWM signal, not a voltage...

[Uncle Fester]

Thanks guy's, that closes the option of using a Lotus gauge.

Any idea if it is a analogue voltage, or a digital signal that controls the gauge. Someone suggested to me that it might be digital and I might have to fit a digital/analogue converter to make it work.

I would prefer to keep the original dial and case if I could. Once I know what the signal is, I can approach an instrument maker and see if they can rework my gauge to match the signal/

BTW.

I assume that as Emerald have included dedicated Lotus features, there must be a few fitted by Lotus owners.

I worked out that you can fit an engine coolant overheat buzzer.

I wired a buzzer with a live feed and the earth connected to a suitable free pin on the ECU. There are several you can use and you need to find one not used for something else.

Then you configure the ECU to ground the pin when the coolant temperature hits the level you set.

Might save a few cooked engines.