Speedometer Accuracy After Hypertech Tune
11-14-2018, 08:11 PM
#1
Junior Member
Thread Starter
Speedometer Accuracy After Hypertech Tune
I purchased a Hypertech Max Energy 2.0 to correct my speedometer since I have slightly larger tires (275/70R18 which is a 33.2" tire). I uploaded the tune for a 33.25" tire along with Hypertech's recommended settings for the 2010 5.4L and everything runs great but the speedometer is still not accurate. Its off by about 15%. After trying different sizes I was finally able to get it pretty spot on with programming a 36.5" tire size in the tune. Why is it that its so far off?
11-14-2018, 10:58 PM
#3
Junior Member
Thread Starter
11-15-2018, 06:26 AM
#4
Senior Member
Cluster worked fine before tuner i assume? I would think it is a tuner issue. I had the same issue when installing the sct4 on my truck, SCT programmer said a 34.2in tire was 590ish revs per mile, but BFG said their tire in that size was 610ish revs per mile. I changed tuner to match the revs per mile and not the tire size and my speedometer issue was corrected.
11-15-2018, 01:20 PM
#5
Senior Member
That is weird as most tires are actually smaller than what they say so you have to go down in tire size and not bigger......I think something else is wrong.
11-21-2018, 10:20 AM
#6
I had the same issue with my Hypertech Speedometer Calibrator. I put on larger tires and bought the speedometer calibrator to correct the speedo. By just putting in my new tire size, I as still off by about 5 MPH. I had to tweak and test about 5 times before it was finally correct. I think it's just Hypertech's programming.