Trouble with old speedcal...

[FivepointSlow]

Noticed my speedometer is off by about 8 MPH @45MPH
Was thinking I'd need to buy a speedcal but then after digging through some of JDwhite98gt's old threads he mentioned installing one into the car, so i went out and looked, and sure enough!


He had set it up for 4.10 gears, and currently the car has 3.73 gears so theres my problem...

I have spent about an hour searching for the correct answer to the question of, what code do I set the DIP switches to?

Firstly, what is really throwing me off is the switches are currently set to 1000110100

I found a chart from Dallas Mustangs website (where this speedcal originally came from) and every possible code in the list starts with a 0, not a 1.
http://cdn.lrsstatic.com/downloads/pdf/erspeedcal.pdf

I found multiple thread posts throughout the web regarding speedcal DIP settings, and most mention a code starting with a 0, and some mention it starting with a 1. But the only chart I can find for a Dallas Mustangs speedcal starts with all 0's.

The copyright date on the label says 2003, so I assume this was manufactured in 2002/2003

However based on JDs posts, he didn't buy this car until 2008, and didn't swap gears or the rear end til 2009.

Anyone have any idea what I should do? Would love to make this one work, but I need the right code info to do so.

Through my searching many people suggested to other people to call Dallas Mustangs and ask them, but they didn't seem to have any luck with them giving them the proper binary code, and I'm guessing this being 15 years later, I won't be having better luck then them..

 

[07GtS197]

I knew I still had the code for 3.73s on my phone! Its 1001001000. I dont know if transmission gearing affects that but Im going to say no. Try that code and verify it with gps if you can.

Ive literally had that code in a note of my phone for 3 years lol.

 

[FivepointSlow]

If I go out tonight I'll try that one... if that actually works I'll flip out lmao
I'm not sure what my car had stock though, I dont have any stickers in my door jam so idk any of my codes for my car.
But it would be funny if my cars the same as yours and that code works.

If it gets me within ~3mph I'll live. But 8 is annoying

 

[07GtS197]

Oh yea I forgot that code depends on what the original rear gear was. Im willing to bet its the same. 3.27s were standard on all 96-04 gts as far as I know.

 

[RustyRodder]

Oh yea I forgot that code depends on what the original rear gear was. Im willing to bet its the same. 3.27s were standard on all 96-04 gts as far as I know.

Not necessarily. My 97 GT and my ex's 98 GT (Both T-45s) had 2.73's stock.

 

[07GtS197]

Not necessarily. My 97 GT and my ex's 98 GT (Both T-45s) had 2.73's stock.

I didnt realize 2.73s were used in the mustang after 95. You learn something new everyday. Maybe thats why the op’s speedo is still off.

 

[96blak54]

My late made May 96 gt had 2;73. Its also got the 94/95 radiator.

 

[duh09]

I remember having some issues trying to figure out the SpeedCal when I was installing one in my 95 GT back in the day. The car had 4.10s when I picked it up and the factory tag was long gone. I ended up just playing with combinations and taking it for a spin until I found the right one.