Has anyone figured out a way to replace the factory speedo cable with an electronic sensor? IIRC the stock one is pressed on making it difficult to remove and press onto a FD sensor. Fd sensors don't work since the gears are the opposite spiral profile(?) and would not work.

I want to say I recall a potential Honda/Toyota one working but never got that car.

 

https://www.rx7club.com/2nd-generati.../#post10941669

Clokker was able to swap the gear a few years back. Otherwise you could get one of the Dakota Digital boxes that converts the cable to a VSS signal, or (the free option) tap the green/red wire coming from the speedometer in the cluster (conveniently located at the cruise control computer plug as well) since the speedometer generates a VSS signal. Either of those solutions doesn't really eliminate the cable, but they do get you a VSS signal.

 

This is the solution I am using. It's a dakota digital VR sensor, I believe they list it as GM compatible 8k ppm sensor. FD sensors are expensive used , hard to find, and as mentioned need the gear replaced with the FC one to be used in the FC trans.

This also requires some diy to make it work,but it's relatively easy to do. You need to rob the tang tip of the FC cable To either braze or solder on. Basically you drill The FC tang tip out to just fit the size of the supplied square keyway piece. Then you either braze or solder it . I brazed it with silver solder. But silver solder and the flux is expensive. I'm sure you could solder it with modern plumbing solder and it would be plenty strong to do the job.The other note is the dakota digital has a 7/8-18 imperial thread, the FC trans is M22x1.5. I thought I was going to have to work some sort of different adapter and read online where the 7/8 thread will thread on a couple of turns as a bs way to make it work. Actually it threads on quite far when I tried it and was relieved that I didn't need to dick with making some sort of adaptor.

The pluses are these sensors are cheap at around $40,and bolt in to the FC trans without having to do anything but take the cable end off. The downside is you need to rob a tang off a FC, FB , or miata cable and do a little bit of DIYing.

 

I'm hoping to use a full digital cluster so that won't exactly work but this also leads me to believe that if the gear fits the trans like he mentioned then I can just change the data to match in the megasquirt. I was under the assumption the helix of the gear being backwards wouldn't be compatible.

 

If you are planning to use the FD sensor this sensor will work. the FD VR sensor is 8200ppm vrs. the digital dakota of 8k. This works as I grafted a FD cluster into the FC dash. this sensor works on the FD speedo perfectly. Don't ask why, it was a miserable time consuming project. Turned out cool but the juice was not worth the squeeze.

 

The other option (cheapest, easiest, not very clean) is to take disassemble a stock cluster and take out the speedo gauge. Strip away everything that isn't strictly necessary so you just have the frame and the reed sensor, then mount this someplace under the dash and tap the output for your VSS signal.

 

I forgot about this one when I was originally searching for a sensor. Pretty sure it's a bolt in solution if you have a programable speedo or aren't stuck on using a 8 pulse VR sensor as in my case. It's a toyota 4 pulse "hall" 3 wire sensor. Has the same tang and is a M22x1.5 thread.
Driftmotion VSS Vehicle Speed Sensor

 

Oh wow this actually looks like a perfect solution! I should be able to feed this into the Megasquirt no issue.

 

Update on this thread
The above listed link is an overcharged piece.
What you want to look for is a speed sensor flr izuzu rodeo from 92-04.

 

I feel like the FD speed sensor comes up a lot, and I can confidently say that almost any of the other options shown above are a better solution. I currently have an FD speed sensor in a T2 gearbox, and it's not a plug and play solution, even after you change out the gear.

for clarity, yes, the FD speed sensor will NOT work with the FC gear inside the trans. Not only does it run in reverse, but it has a different number of teeth.





furthermore, the speed sensor will NOT bolt up to the trans and work correctly. The FD sensor gear is offset from the centerline of the sensor unlike the FC.






this means you need to rotate the sensor to get the sensor gear spaced correctly to the trans gear. If you just bolt it up it WILL push the output shaft over and you'll never get the driveshaft installed. so you need an adjustment bracket of sorts. This was my solution:


So while it CAN be done, it's likely more work than it's worth unless you're super handy and have the FD gear and sensor already.