FAST XFI rate sensor calibration


Jun 22, 2016
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.
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.
Resurrecting an old thread but WHERE is this calibration accessed on the interface? I can find all the other calibrations but my MPH is off by about 7% on the XFI dash and I can't find where to adjust it anywhere.
click veiw> system configuration >sensor calibration >rate sensor calibration

Weird, mine does not have that one yet the display shows the MPH and MPG... also doesn't show a fuel or oil pressure cal on mine?? It's the XFI 2.0, too...
just reread your post said " interface"
by interface ill assume you mean the cant change the rate only lockup mph

you have to connect witha pc and ccomWP XFI

fuel and oil calibrate under sensor calibrate is 2.05 only

2.01 looks like this
2.0 rate.jpg

2.0 rate.jpg
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You're correct with the CCOM, that's what i'm using, will d/l the 2.05
if you dont have the 2.05 flash you dont want to use CCom WP 2.05 to make changes
its in the 2.05 software download... but be aware if you arent 2.05 right now once you do the update you will need to make some changes to your current GCT program just to be able to run
its in the ccom 2.05 folder as xfi flash B9
was posted in this thread
first thing you should do is save a copy of the current gct that the car came with
once connected to box goto file>save all tables .. name the file and make note of where its going on your pc so you can find it again
the ccom will search in the current version gct folder but when you open another version of ccom it will look in that versions gct folder
after that veiw > display ecu status will show the ecu serial # and the firmware version so you know what version firmware the box has