Calibrating the speedometer with CAT E.T.

I own 98' 379 Pete with 40-pin CAT in it... To calibrate my speedometer I used dip switches twice. Fist time when switched my tires from 11R to Lowpro.. Second time when switched from 24.5 to 22.5. There are several formulas can be used to do that... Here is PDF file. I think I used Type B formula to get a correct frequency number.
https://www.dropbox.com/s/9ir81we1036uvr9/Speedo calibration.pdf?dl=0

 

Maybe this will help.
https://www.google.com/url?sa=t&sou...yeoxJZCMNzBqC-i4A&sig2=sUwaiM-VJZByjCZMHucEsw

 

FYI, the calculation of pulses per mile were spot on for my ECM, but the dip switches were supposed to be set at 240. I had to set my speedometer for 252 to match ECM and GPS speed.

 

Use cross multiplication. Ppm/gauge times ppm/actual
Should get you fixed up. Have had to do it quite often to get speedo perfect

 

*I have a 98 Pete myself with 370s and 24 low pro. Do you remember the order you used when you had your with 24s?

 

You need to find out your tires revolutions per mile... Then use formula to calculate the frequency...
Tire revolution (example 500) x your rear diff ratio (example 3.55) x 16 x 80.... Then the number you get divide by 3600.. this would be your frequency... Then open the link I provided and go to section 4... Next to your frequency number is your switch numbers that are to be in closed position.
I think my switches were like - 2, 3, 4, 6, 7, 9, 10 when I had 24.5s
Let me know if the link I provided still opens.. It was long ago I posted it.

 

Thanks I'll look into it.