I have an 05////I noticed when I brake say from 65 MPH, the speedo stays at the 65 mark for a real SHORT time than comes down. Is this cmputerized now THXXXX for the info.

 

YES... the Speedo is computerized.

A good thing too, because you can adjust the speedo to react so specific tire sizes with a tuner like the Preditor to be accurate after you change tire sizes.

 

How do you do this PW? Is it a mechanical adjustment on the car, or a function that has to be a adjusted with the Preditor? My car is off by 10% because of the Saleen 20's. I'm not too concerned about it, but if its an easy adjustment I might look into it when I final do a CAI and tune.

 

Sowaxman... it is a parameter adjustment to the PCM Computer.

With the preditor, it is an option in the menu.. but you do have to do some math to tell it how much to make the adjustment.

In My Preditor Manual on page 8.

Tire Size
Tire revs per mile = Adjust for larger/smaller tire diameter
to correct speedometer. Tto get revs per mile use overall tire
diameter in inches. 20168, divided by tire diameter,=revs per
mile.


You can also adjust for different gears in the rear.

Axle Ratio = Adjust for different axle ratio to correct
speedometer, note, numbers are in one decimal, ex. 3.5 this
is the same.

From the Preditor Bbook on page 10

Axle Ratio Menu – There are two choices in this menu Axle
Ratio and Tire Revs per Mile.

Tire Revs per Mile – To calculate your revolutions per mile,
measure your tire diameter in inches and use it in the following
formula.
Example:
20168 divided by tire diameter = revs per mile Ex 20168/26
= 775 rev/mile

The stock gear ratios on the 2005 mustang are 3.31:1 for the
automatic transmission cars and 3.55:1 for the manual transmission
cars. If you have changed your rear differential crown and
pinion gears, (select the appropriate ratio using this parameter to
correct your speedometer and shift points). Use this parameter to
select the appropiate ratio to correct the gear ratio.