Determining Gear ratio?

[kenny_k82]

I was told by the original owner of my car that it had 373 gears. I had it tuned by Brenspeed for 373's. While driving with my GPS and past a speed trap I noticed my speedo said 65, gps and trap said 70mph. I got under the car and the white sticker says 355's. I'm guessing the previous owner was wrong? What's your take?

[06281E]

Originally Posted by kenny_k82

I was told by the original owner of my car that it had 373 gears. I had it tuned by Brenspeed for 373's. While driving with my GPS and past a speed trap I noticed my speedo said 65, gps and trap said 70mph. I got under the car and the white sticker says 355's. I'm guessing the previous owner was wrong? What's your take?

Just contact Brenspeed and have them adjust your tune for 3.55 gears and see if that solves the speedo problem..

[kss113]

You can call Saleen and they should tell you.

My window sticker says 3.55 then in the Saleen upgrades it tells me 3.73.
I would think that any of the stickers underneath the car would be factory ford GT stickers and not Saleen.

[redruder]

You can adjust the speedo with your hand held tuner. You also need to determine if you are running the stock size tires. If you have a taller rear tire that will have running faster than what the speedo shows.