I have an automatic transmission, 3.73 gear and 235/75 r15 tires(manufacturer says 719 revs per mile). what do I change to get my speedo to read right. I looked everywhere for a formula, to change these values

speedometer scaler
speedometer scaler, fraction
speedometer scaler, scan tool
time between pulses for stop

 

My Hypercrap has a gear size entry point and a tire size also that would fix it. What are you changing it with? I just measure the width across the tires. Mine are 26 1/4"

 

If you are using Tunercats go to speed calibration in the tools menu. Enter your info and the values will be calculated and added to the tables.

 

I'm using tunerpro. Tunercat uses the same calibration. Could someone please enter in my information and tell me what changes in these fields

speedometer scaler
speedometer scaler, fraction
speedometer scaler, scan tool
time between pulses for stop

Or if someone would like to zip up an unaltered $ee definition file for tunercat and send it to fastvolkswagen@aol.com. I'll be more than happy to do it my self and forever gratefull to whoever sends it to me.

 

For M6

719 revs per mile

speedometer scaler 11
speedometer scaler, fraction .965
speedometer scaler, scan tool 44.698
time between pulses for stop 78.962



235/75/15

speedometer scaler 11
speedometer scaler, fraction .961
speedometer scaler, scan tool 44.884
time between pulses for stop 78.633

 

Thank you very much!

 

for some reason it didn't work. It read way to fast. The tunercat has 40.02 for speed pulses for driveshaft revolution, right.

 

Oh man, I'm really sorry. I did the calculation for M6, 17 speed pulses. Here is for the A4, 40 pulses.


719 revs per mile

speedometer scaler 27
speedometer scaler, fraction 1.007
speedometer scaler, scan tool 44.698
time between pulses for stop 33.559


235/75/15

speedometer scaler 27
speedometer scaler, fraction 1.003
speedometer scaler, scan tool 44.884
time between pulses for stop 33.419