i have a 2003 gt and im am goin to replace my speedo cluster with a 2000 saleen that goes to 200 and mine goes to 150. will the speed be reading right wth the saleen one since it is the entire cluster.

 

nope.

 

so ill have to use a programer? to get it correct

 

Yea, you might have to try different gear ratio calibrations until you get one correct...
Otherwise do calculations on what % decrease your speed needs to read and plug in the gear ratio accordingly.

 

o ok see i thought it would work fine since it has the gears inside the whole cluster i thought. but wouldnt i just find out what gear ratio a 2000 saleen had and sent my computer to that

 

Actually I might be wrong, but as far as I know, there's a magnet or laser at the wheel that sends a signal to the ECU and that sends another signal to the cluster for your speed reading. I would think you'd need to reprogram your car computer for the new speed ratios, but like previously stated, I could be incorrect.

 

That sounds about right. The best bet is go to the ford dealer and ask what you will need done. I know of some vehicles that require the computer re-flashed for the speedo reading, and some are programmed in the cluster itself.

 

Our cars have a Hall effect sensor on the transmission output shaft that generates a fixed number of pulses per output shaft revolution.

For the '96 through '98 models the instrument cluster counted those pulses and drove the speedometer/odometer--that's why a new drive gear or SpeedCal is needed to correct the speedometer.

On the '99 through '04 models the PCM does the counting and sends the speed data in digital format to the instrument cluster. That's why you can fix it in the tune on the newer models.

 

are you guys sure that by swapping the PC board it won't correct itself? i would think that it would...

 

You need to run the instrument cluster flex-circuit that came with your car, or the PATS will activate and you will not be able to start the car.

The instrument cluster computer and the PCM are components of the PATS, that are "married" by a shared identifier at the factory. This can be reset with the IDS if you find an operator with the knowkedge.