I am using the factory style VSS from my 92 T5.

Just in case you need other options.

https://fyi.boardhost.com/viewtopic.php?id=10400

no, I put it away in my shop, so the hunt begins
 

sounds right, it's a gift I have, not everyone has it, but I am willing to share. as my 5 year old great grandson tells me sharing is caring.
 

divide the number of teeth on the drive gear in your T5 transmission by the number of teeth on the drive gear in your "old" transmission, then multiply that result times the number of teeth on the driven gear you used with your old transmission.

That will give you the number of teeth you need on the driven gear for your T5, assuming that your speedometer was accurate with the old transmission.

Last edited by John Ha (8/06/2021 5:17 AM)

Well, like John said... if the speedo was correct BEFORE, the same number of teeth on a new gear MIGHT get it right, IF the drive gear in the tranny has the same number of teeth.
 To eliminate that possibility for error, this method removes all the OLD data from the equation, except for the number of teeth on the existing cable must be known.

It uses a phone app GPS speedometer app.  Drive the car at an indicated 60 MPH on the phone app.  Note the indicated MPH on the car's speedometer.  You already noted the number of teeth on the speedo gear.  You now have three pieces of info you can use to calculate the fourth requirement, which will be the number of teeth on the gear to get the speedo reading correctly.

If speedometer reads higher than GPS, you will need more teeth than you currently have on the gear. 
If speedometer reads higher than GPS, you will need fewer teeth on the driven gear.

Divide speedometer speed by GPS speed.  That is "A".
Multiply "A" by the number of teeth on the existing gear.  Result is number of teeth needed on the new gear

This method removes all variables such as gear ratio, tire size, etc and will get it perfectly right every time.
All you have to know is the number of teeth on your driven gear that is installed in the car.

val fulesday wrote:

thank you, I got the gps installed on my phone this morning. I am almost positive the falcon gear was 10 tooth haven't counted the original t5 cable yet. I think i'll just put the t5 gear on the new cable and see where it all falls, and i'll make adjustments from there.
 

Yep
That is the first step in getting it right.

val fulesday wrote:

most everyone has heard of " that's two in a row, or maybe three in a row"? how about "that's one in a row"? let me explain it, when working on your car or looking for something in your garage, like me looking for a speedometer cable, and you walk right up to it and it's the first thing you pick up, that is where you'd used that term. like yesterday decided to look for that speedometer cable and I walked right up to it and it was in the first box I picked up, hence one in a row.
 

YAAAAAAAAAAAAAAAAAA!!! Such a 'rare' occurance. (still hoping it happens to me one day!)
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