SCT Tuner Help
I have an SCT X3 will a tune from Don at LaSota Racing. I am having troubles getting the speedometer correct with the correct Revs per miles.
I have 265/75 r16 tires so the calculated Revs/Mile is 637.6. Now I know all tires are slightly different and there is the 'squish' calculation so I did some playing around on my last road trip with a GPS and am now at 645 on the tuner, which yields a odometer error of 1% error for everyone 100 miles (reads 99.5 at 100 miles). Close enough.
The problem is the speedometer is off by 2 MPH around 60 and 3 MPH around 80. I have tried 2 different GPS.
Anybody know why this is happening? It's not the biggest issue in the world but if I am able to fix it I would like to. It doesn't make sense to me because the odometer and speedometer should match each other.
Also, don't know if it matters but I changed from 3.55 gears to 4.10 gears but I DID adjust that as well on the tuner.
Mods-32 BFG K02s, SCT 91 Tune, Flowmaster Exhaust, 4.10 Ford Racing Gears, Tinted Windows, Tonneau Cover, Kenwood Headunit, Infinity Kappa Speakers, 12 in Alpine Type-R sub, 4x50w and 1x600w Alpine Amps, Signal Mirror Kit, Custom Painted Interior, HIDs, 2 150w KC 6" lights, Mustang Dome Light