Lotus Elise speedo and water temp outputs from dta

[DJWilma]

The s2 I have got its speedo and water temp signal fro. Its ecu

As I now run a dta s80 can this give me a pwm for the temp gauge and a square wave pulse for the speedo. Input to speedo is a simple hall effect.

If not any ideas on how to do it

[stevieturbo]

Any PWM is effectively an off/on signal.

So in that respect yes. Whether it is actually workable with your devices, I dont know.

For the speedo, can you just fit a wheel speed sensor and use it instead ? You're going to have to have one fitted already in order for DTA to see a speed reading. So seems pointless to then have the DTA try and replicate it and send it back out.

For water temp, all you can do is use an Aux out referenced to engine temp and hopefully that will do what you need. A PWM for a temp gauge would be unusual though ?

[DJWilma]

Thanks

The car has speed sensors for the launch and traction control so happy to use these, but can I get the dta to output a square wave pattern

Thanks on pwm

[stevieturbo]

on/off PWM can only be square wave. The square pattern comes from the abrupt on/off.

[Rob Stevens]

I don't think the PWM will work the speedo, the 'vary frequency' option on Aux 3 might work but then you may need to add a 5v pull up resistor to make a signal that looks something like the output of the S2 elise, I have no idea what that looks like however. I have S1 elise, this speedo is straight VR from the wheel.
Aux 3 gives you the frequency range 20 to 500 Hz, trying to think if this is the sort of range you need, my S1 has probably 36 teeth on its trigger so at 10kph this would be about 3000 pulses per minuet or 50Hz, or at its max frequency at 100kph, not much use. Bud do check my maths!
I don't know how the S2 water temp works, my S1 has its own temp sensor independent to the ecu, I guess the S2 shares the ecu sensor.

[stevieturbo]

Just hope the ecu doesnt send out a datastream to the dash....then it does get awkward !

I put Hayabusa clocks in my car, and everything was easy apart from the temp gauge. It was sent on a datastream from the bloody ecu, and the gauge itself was a stepper motor.
I now have the bike ecu in place solely to run the temp gauge lol.

Speedo was easy, just took my wheel speed signal, fired it through one of Jaycar's speedo corrector kits and it worked a treat.

[Rob Stevens]

Steve, sounds like you actually need the 250mph capable speedo in your car!

[stevieturbo]

I only have the 180 clocks in it. I do have a 220mph set too, but the faces are pretty crap on those and the kph is barely visible ( MOT requires both mph and kph visible here, although I'm sure the 220's would pass too, I just dont like them )
The 180's just work better. I have done 200+....but as it wont happen often, the 180's are fine lol

The cluster actually fitted fairly well as a complete unit. it isnt perfect, but it's fine. Had to add a sheet of non reflective perspex in front, as the curved glass on the clocks reflected my face badly ! They were like a mirror.

[Wally]

A PWM for a temp gauge would be unusual though ?

We use that, 100 Hz and works fine.

Wally