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Discussion Starter #1
I want to make sure my 96 GT has an exact odemoter/speedometer reading after I install 4.10 gears. Its a T45 car w/ 245/45/17 inch tires. The speedo gear dosnt make the odemoter/speedo match up perfectly. I remember seeing a box that can be programmed by a speedo calibration shop for you gear and tire combo, but I couldnt find it. Can anyone give me some help as where to find it or how to make my odo/speedo exact.
 

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BoRoBomB:

Yes, a local speedo shop can to it with a mechanical gear.

Electronic compensators are a better option. These things intercept the signal from the sensor, adjust it, and forward the "correct" signal to your speedo. Your choices are the SpeedCal ($100 from Dallas Mustang or $80 from Brothers Performance [same electronic box but discounted price]) or the Abbott ERA ($130). Do a search and you will find plenty of info. FWIW, I have the SpeedCal and I recommend it. The Abbott will work just fine, too.

Use your stock plastic gear (in the vehicle speed sensor) because it has thicker teeth that are less prone to breakage.
 

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Discussion Starter #3
I didnt know there was a signal? I thought it was all based on a little plastic peice, the speedo gear. I had one on my 89 LX 5.0, it was red i think, but the miles wern't perfect. They where over.(for example the ride to my G/f's house is 25 but my car would read 32 at the end.)

Can you explain this to me some more, as I didnt think they had electrical speedos until 99+. Thanks
 

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I checked out brother performance and the SpeedCal is only for the 99 and up w/ electric speedo. The box I am talking about get the speedo cable plugged right into it and was somewhere around 20-60 dollars.
 

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BoRoBomB, your 96 has an electronic speedo and the electronic adapters work for 96 and up. The 99 thing is not correct and they have not updated their web site... Since yours is a 96 you can also change out the driven plastic gear which will get you close, dont remember the actual error.
 

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BoRoBomB:

Sorry, haven't plugged in for a bit.

Like TriBlkCobra says, you have an electronic speedo. When the little gear spins, it actually generates pulses (alternating current??) that the speedo and PCM interpret as speed somehow. TriBlkCobra can give you the detailed explanation since he is the designer/inventor of the SpeedCal.

Anyway, you'll like the SpeedCal. Welcome to the "club" :)

chris
 
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