Ok, I've got a '95 LT1 swapped into my '92 RS. We never hooked up the VSS because we didn't realize just how much it matter as to the running of the engine. I was going to get the Dakota Digital box since I'm running a T-5 transmission and VSS to convert the signal for the 4th gen PCM.

So I'm looking through the Tunercat website and I'm checking out the information for the $EE Definition file when I see this line, "Speed Pulses Per Driveshaft Revolution." Maybe I'm just naive and not sure what I'm looking at, but does that mean I could go into the 4th gen PCM and change the VSS signal its looking for to work with my 3rd gen VSS?

 

Ok, I know a little bit more about what I'm looking for now. In Tunercat there is a Speed Calibration tool that allows you to calibrate the speedo for different size tires or gear ratios, things like that. There is also an option for the stock speed sensor or an different. The only problem is it reads "pulses per driveshaft revolution" and is set at 17 for the default value.

By my calculations, the 4th gen VSS reads only 3 pulses per driveshaft revolution, that is if I am right in that the 4th gen VSS is 8000 pulses per mile. I calculated it by taking the circumference of the tire, dividing it into a mile to find revolutions per mile, then multiplying that by the gear ratio to give the d.s. revs per mile. This I then divided into the 8000 to get pulses per d.s. revolution.

Now here's where my question comes in. The 3rd gen VSS operates at 4000 ppm and just to check, by doing the same calculation you get 1.5 pulses per d.s. revolution. Is there anyway I could change the value in the Speed Calibration tool to reflect this?