Speedomter / Gear Ratio Change
Moderators: robertisaar, dex
Speedomter / Gear Ratio Change
New to tuning. I have a 93 chevy blazer with 5.7. I recently changed the gears to 4.56. Does anyone know how to modify the speedometer reading for the new gears?
You'll probably have to add the parameters to the XDF. Here they are:
Code: Select all
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* SPEED SENSOR CALIBRATION PARAM'S
* (2^14 TIME BASE)
************************************
;
; LAG FILTER CONSTANTS
;
L5A0F: FCB 64 ; 87 msec, RPM filter
L5A10: FCB 252 ; 6 msec, Input SPD FILTER
L5A11 FCB 252 ; 6 msec, XMISH INPUT SPD FILTER
L5A12: FCB 1 ; 20 msec MAX PERIOD BETWEEN XISH OUTPUT PULSES
L5A13: FDB 43691 ; 40 PULSES/REV OUTPUT SHAFT SPD
; 1092.3 usec/bit
L5A15 FCB 252 ; 6 msec, Xmish output spd filt
;
; GEAR RATIO'S
;
L5A16: FDB 44564 ; 2.72:1 4WD LO RATIO
; VAL = RATIO * 16,384
L5A18: FCB 45773 ; 44.7:1 NO/VS RATIO <------------****
; VAL = RATIO * 1024
L5A1A: FCB 252 ; 6 msec, Vss filter
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TunerPro Author
1989 Trans Am
TunerPro Author
1989 Trans Am
http://tunerpro.net/tutorials/CreatingECUs.htm
The info is a bit outdated (old version of TunerPro), but the takeaways are the same.
The info is a bit outdated (old version of TunerPro), but the takeaways are the same.
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TunerPro Author
1989 Trans Am
TunerPro Author
1989 Trans Am