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

 

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

 

Sorry. Predator does not allow me to access much information. I appreciate your help, however

Anyone else have suggestions?

Thanks - Chuck

 

http://www.runninwiththedevil.com/faq.htm

 

1. Can you go into a little more detail on what you mean by this?
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.

 

Nevermind, looks like someone posted the fix while I was typing..

 

Here is Diablo link

http://www.diablosport.com/Downloads_allgm.php

Jim

 

THAT IS WHAT I REMEMBER SEEING!!! Thanks ya' ll. I appreciate it a lot

Have good weekends