I could swear I've seen someone install an aftermarket speedometer in place of the stock one on the 280ZX, but I don't remember if it was on here, or at a show. Does anyone know what size would best fit the stock gauge cluster hole? 3 3/8", or 5"? 3 3/8" seems too small, but 5" looks like it might be too big (unless it's just right, in that the diameter of the gauge body is smaller)

Also, I know the speedo is cable-driven, but I've read that wire 29 of the ECU harness is some kind of speed sensor wire. I assume, this is where I'd hook the speedo up to, right?

 

The speed sensor is for the cruise control & it's on the back of the stock speedo... take the stock speedo out, no more speed sensor.

Here's an Autometer speedo pic I found in my intraweb travels. I'm not sure what size it is, but it's probably a fairly common one.

 

i wonder if you need a cable adapter or if every speedo has the same hook up at the back. i know im starting to think about replacing my guages, but i dont think its gonna be easy. im starting small and going with the volt guage.

 

you need a hall effect speed sensor for the trans and an autometer speedo, or if you go with another brand what speed sensor they use. tony D explains it in misc tech on hybridz

 

Ok, that must be a 5" speedo. But since it looks like some of the other gauges, like fuel level and warning display are missing, I hope the depth of the gauge doesn't require gutting the whole cluster.

I checked Tony D's writeup on HybridZ, but unless I'm looking at the wrong thread, his writeup is about the Z32 speedo.

 

So I went to my local speed shop to check out the Autometer hall effect speedo sensor, but can you tell me where this thing is supposed to go? Does it screw right onto the transmission, or does it require special thread adapters?

 

"Adapts most GM and Chrysler transmissions with speedometer cable output to work with Auto Meter Electric Speedometers." google my freind.

https://www.stiperformanceparts.com/...productid=1202

 

Yes, I already know the company description; as I just mentioned, I saw the speedo sensor thing in person. It still doesn't answer exactly where it goes on the car, or whether it's a bolt-in install or if I need additional parts.