View Full Version : Z32/S14 speed sensor question

08-06-2008, 05:55 PM
Hey guys, I hooked up the speed sensor from my Z32 tranny knowing that it would read double the speed I am really going. Without doing so and with the Tomei 270's I would stall sometimes at lights. What I was thinking but I don't know enough about electronics to know if this will work. I know Chris had explained the voltage from the speed sensor a few times and thought maybe some of you electrical guru's could help.

I know the Speed sensor is an +- 8V signal? Then it goes to the speedometer and is divided by I believe 5 for the ECU. What I was wondering is if you could use a resistor to divide the signal at the speed sensor in half? Thus sending half the voltage and reading the correct speed without having to buy a Dakota digital speedometer calibration device. I believe with my limited knowledge this would work and may take some trial and error to find the right resistor but I didn't know if this will work right with the signal that goes from the cluster to the ECU? Thanks in advance for any help and if no one has any idea I may try wiring in some resistors and see if I can get the correct voltage. Unless I'm completely off adding a resistor would at most drop some voltage and cause the speedometer to be off but shouldn't damage anything?

08-07-2008, 03:31 AM
It is an AC voltage, so I would think a diode to block half of the wave would be a better idea. Simply cutting it down in voltage isn't going to change the waveform.

08-07-2008, 11:28 AM
Good point, i didn't even think about that.

08-07-2008, 11:43 AM
in all honesty, the dakota digital solution is so ridiculously simple to use and allows you to get such a pinpoint accurate reading if you have a good solid way to calibrate it that you'd be crazy not to just use it. they are so simple to install too

08-07-2008, 11:51 AM
I'll probably pick one up through you guys soon. I've just been doing so much wiring that I was trying to figure this out. I'll probably get that before I head to the dyno so I can calibrate it there.