Adjustment ? for 3.73s & Predator...
#1
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Adjustment ? for 3.73s & Predator...
Good day all! Hopefully someone can help.
My brother has a 02 Z28 A4. He just swapped for 3.73s from 2.73s. We have tried tuning with the Predator, however, but, the speedo still seems to be off. The car came with 245-50-16s, of course, and now has 315-35-17s and we have adjsuted accordingly, and there was still a problem.
What am I doing wrong? The speedo' is still like 20-25 MPH off. Please help.
Thanks! Chuck
My brother has a 02 Z28 A4. He just swapped for 3.73s from 2.73s. We have tried tuning with the Predator, however, but, the speedo still seems to be off. The car came with 245-50-16s, of course, and now has 315-35-17s and we have adjsuted accordingly, and there was still a problem.
What am I doing wrong? The speedo' is still like 20-25 MPH off. Please help.
Thanks! Chuck
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I'm not sure how a Predator works, but if you have access to everything, then:
VSS pulses per mile: 117176
Differential Ratio: 4
Trans Output Shaft Revs/Mile: 2929
VSS pulses per mile: 117176
Differential Ratio: 4
Trans Output Shaft Revs/Mile: 2929
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Originally Posted by radz282003
and now has 315-35-17s and we have adjsuted accordingly
2. Does the predator require you enter a diameter or tire size?
The tire size calculator I use http://www.miata.net/garage/tirecalcold.html shows 245-50-16 to be 25.6" dia and the 315-35-17 to be 25.7" dia. Hardly enough to matter. However, GM uses either 24.91" or 24.94" on all the 99-02 F-body files where they have a separate parameter for tire size and gear ratio. I guess I need you to answer the 2 questions before I could recomend a fix.
#7