Adjustment ? for 3.73s & Predator...

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Jan 20, 2006 | 09:41 AM

radz282003

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From: Tree-Hugging, Bug eating CALI'

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

Jan 20, 2006 | 11:33 AM

DramaFoYoMama

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From: Katy, TX

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

Jan 20, 2006 | 12:19 PM

radz282003

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From: Tree-Hugging, Bug eating CALI'

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

Anyone else have suggestions?

Thanks - Chuck

Jan 20, 2006 | 12:26 PM

SSpdDmon

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From: Commerce Twp, MI

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

Jan 20, 2006 | 12:38 PM

2xLS1

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From: Warr Acres, OK

Quote:

Originally Posted by radz282003

and now has 315-35-17s and we have adjsuted accordingly

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.