Speedometer Input Signal Question

Speedometer Input Signal Question

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jcolley

Original Poster:

182 posts

71 months

Thursday 1st August
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Greetings all,

I am working on an Ultima GTR for a client fixing a myriad of issues. among these is decent engine management and tuning via installation of a Motec M150. After almost 16 hours of dyno steady state testing wrapping things up and working out the final details.

The factory drive shaft speed sensor is a magnetic sensor, 36 tooth ring, feeding the speedo on the dash. This would mean a sine wave signal where speed displayed would be dependent on signal input frequency.

With the M150, there is no output which can be configured as variable frequency dependent of vehicle speed. There is however an output that can be configured for variable duty cycle, square wave fixed frequency.

Has anyone done similar on the stock speedometer or do I get to be the guinea pig?

Cheers,
Jim

jcolley

Original Poster:

182 posts

71 months

Monday 9th September
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Just to follow up, there was no other means withing the stock Motec M1 GPR software, so we used a development package and wrote code for a custom output for the Ultima speedo.

Will be submitting this to Motec as a Partner Package along with some more Ultima specific functions in the future. The nice thing about the M1 series is being able to write code to allow literally anything to work.

deadscoob

2,059 posts

205 months

Wednesday 11th September
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Sounds interesting, amazed no one else replied.

Out of interest, why not use a front wheel mounted sensor so the speed is always right (although I guess it means if you wanna pretend your car is quicker than it is cos it’s wheel spinning driveshaft mounted is best biggrin).

What is the engine setup you mapping to?