Drive Speed vs Wheel speed? OEM VSS for input shaft speed?

[Darkknightsw20]

Hello, this is my first post here and I just have some questions about a few things. I have an M130 with a GPR Package and it’s controlling a 4cyl rwd car (Toyota MR2 so not FR it’s mid engine and set up like FWD”. I have hall wheel speed sensors reading off of the front right wheel’s lugs and also off of the rear left wheel’s lugs. This is a relatively new set up for me because although I’m sure it will work fine im wondering, would the oem VSS I used to use in the trans off of the diff be considered drive speed?
Because the set up used to be like this, oem VSS In the trans in the rear was rear drive speed and all I was using was up front was a cherry hall sensor Reading off of the front 48 tooth abs ring. That worked perfectly fine but I had an emergency diff change at the track and had no more speedo ring for that diff so I threw in a cherry hall sensor on the back of the rear lugs and left the front alone. The front was naturally picking up slightly quicker than the rear though so now I have them matched with lug referenced sensors front and rear. Right now rear drive speed is still reading off of the back of the lugs.
BUT I recently added the speedo ring to the diff and the oem VSS sensor is back in play. So I want to use it and I’m just wondering, two questions, could I just adjust the pulses etc so that it displays the same as engine rpm and have it be an input shaft speed Input? Clutch slip basically?
Also if I hooked up the VSS again, is that now “drive speed”, the rear hub wheel speed, an led the front hub also wheels speed and the ECu automatically gives me a clutch slip % etc?

My goal is to have a clutch slip/input shaft speed reading, a slip between front and rear wheels reading and make sure I have the sensors all set up correctly.

This was a lot but I wanted to be thorough and have a more clear understanding of this. Thank you!

[Stephen Dean]

Wheel speeds.png (338.87 KiB) Viewed 4653 times

Hi, I think that this will help you.

I would recommend using the tone rings rather than the lugs, as these will provide a much greater resolution for the speeds.

[Darkknightsw20]

Thank you for that. When I get a chance to add the oem rings in the rear I will switch back.

So I will add the oem VSS back and have the three of them. So I assume for input shaft/clutch speed I should use a completely separate sensor.

[Stephen Dean]

Gearbox Input shaft speed should equal Engine Speed if the clutch is engaged, otherwise it can be calculated from the output speed and gear ratios. Clutch slip can be calculated from the difference.

[Darkknightsw20]

I noticed this in the software yesterday that it does calculate clutch slip! Very interesting and I had to adjust my gear ratios