speedo wiring?

[suparuss]

howdy,
i have a porsche speedo (cant remember which model, started with a 9), which i would like to use in a kitcar but im having trouble with the wiring, any body know if they are inductive or hall effect? or even have a wiring diagram. i believe it was from a 964 but im not 100% sure, it has tiptronic lights on it and 4 other lights which i think are rev indicators. any help appreciated.


Cheers,

Russ.

[domster]

I have seen the back of a 964 speedo, after having once removed mine, and they have plug in sockets, so don't seem that easy to wire in to a kitcar. The tiptronic lights mean it is from an auto, and you won't have a tiptronic kitcar surely?

Unless there is an overriding reason for using it, I would suggest an easier life could be attained by buying an aftermarket racetech/stack/smiths speedo.

Cheers
Domster

[ninemeister]

The basic electonic speedo function has been the same on all 911's from 1975 to 1990, i.e. there is a reed contact switch in the gearbox that makes/breaks when it magnets on the differential rotate past the switch. I think from memory that there are 8 magnets in the ring, so 8 pulses per wheel rev. The switch earths out a 12V signal fromt the speedo. Can't remember the speedo plug connections, but they cannot be too difficult to work out.
1991 onwards changed the trigger to work from the abs system, but the speedo remained the same so the principle is unchanged. The most you will need if there are no wheel sensors on your car is a magnet ring disc on the gearbox drive flange passing next to a 1989 964 gearbox speed sensor.

[suparuss]

nice one, i think what youve described is an induction sensor, i should be able to sort something out from that.
could still do with a wiring diagram tho, there are loads of different plugs on the back, as said above.

ill have a good ole tinker when ive got hold of a sensor.

Cheers,


Russ.