FAST XFI rate sensor calibration

[GnJoe87]

Quick question on dialing in my mph reading with fast xfi 2.05 and the caspers adapter box. Im running a 28" tall tire and my mph reading seems to be off by a bit in data logs. Does any one know what the factory driveshaft rpm calibration would be. Right now the rate sensor calibration is set at as fallows .

Driveshaft RPM calib. = 1800
MPH Calibration = 730
Aux. RPM Calibration= 100

I tried the formula that fast gives and it came up with 1,596.49 for the MPH calc. with a 28" tire and 3.42 gear, something doesn't seem right to me, any insight would be appreciated.

 

[NY Twin Turbo]

I am also running a 28 inch tall tire with a 3.42 rear. I'm using the XFI rate sensor. 2 pulses per revolution.

Driveshaft RPM calibration........600 divided by 2 = 300

Mile per hour calibration...........28 times 195 = 5460, then 5460 divided by 3.42 = 1596.49

That's it. There's your numbers.

There was a recent thread discussing this. You can tweak the number up or down but you're going to find that its accuracy will be compromised one way or the other depending if your on the high side or low side of the speedometer.

I don't know why.

 

[GnJoe87]

sounds good ill play with the numbers and see what works,

thanks for the reply