Just checked the manual and it isn't clear. For sure the nitrous input is 12V but I'm not sure if it is capable of high frequency.

It's not horrifically complicated to level convert it down to 5V though. I'd just make a simple circuit with an opto-isolator.

 

On the MS3X, getting a clean VSS up to 120mph. Haven't tried faster than that, but it seems stable.

 

Thread revival.

I did some digging and saw that the FD speedo gear is digital instead of cable driven. It's a VR sensor. All that needs done for a T2 trans is to swap the gear behind the E clip of the shaft. ( https://www.rx7club.com/2nd-generati...meter-1084507/ )

Does MS3pro take the VR signal straight in and have the other wire ground at the ECU area? Trying to figure out how to get this working.

 

you can on MS3 EVO.

 

Correct, the Evo and Ultimate have 2 pairs of VR+/VR-. Not sure about the first gen MS3Pro. I'm using one of the VR inputs on my Ultimate for VSS from a T56 and it works great.

 

I also tried this and found that on my FC the cluster did not output a pulsed 12V. Instead it pulled the signal to ground.
Therefore to make it work I had to install a 1k pullup resistor to 12V, maybe because I don't have a power steering ecu anymore?
Anyway it's working perfect now :-)

 

I thought I posted this info on a thread somewhere on the forum (I guess not this thread), but yes, the cluster needs a pull-up on the VSS line. I had several clusters on my bench with an oscilloscope to verify. I believe the PS computer, as you referenced, handles this, but never had one to crack open to verify.

 

Hrm, I never had to add a pullup, but maybe there was one built in for the " N2O IN" input. I'm pretty sure the power steering CPU was still intact since I never removed it, but I didn't have a factory PS pump at the time. My car is very different now and completely rewired, so I can't confirm if that's true or not. Funny how much you forget in 4 years

 

I know some ECUs (I'm not a MS guy) will enable the pull-up based on the pin configuration as well. So it's entirely possible there are people having success without the PS computer and with an aftermarket ECU, so it's never been an issue.