I dont know where I should post this so I'll just put it here. Bought my truck a couple months ago, it's got about a 6" lift with 35" tires & has a superlift speed sensor calibrator wired in under the dash. Does anybody know anything about these or have any experience with them? My speedo is still 5 miles off & flutters around at the low speeds so not sure it's even working. I thought I remember from my last truck that you can adjust the speedo in these trucks using autoenginuity so wondering if I should just take it out

 

AE can change the tire size. (really revs per mile)

 

FORScan will change your tire size as well. There is a how to and video in the 7.3L PSD Tech Folder

 

^^^^ What they said.

With 35" tires the FORScan adjustment will work fine. The Superlift speed calibrator is not needed. Sell it to a guy with 37" or bigger my man!

Autoengenuity is great if you have it and it works. I still have it, but I don't use it. FORScan makes it obsolete.

 

Tagged for this. I recently downloaded FORScan and was hoping to try the speedometer adjustment. I wasn't aware of the video in the tech folder (and other videos I was watching were having you calculate a code and put it in a different place). I'm trying to figure out the revolutions per mile (computer way and not actual driving and measuring per mile way). In the video his was set to 649 for 265 tires, but what I'm finding online (many sites) doesn't match that number. Discount Tire has a calculator that gives Rev/Mile, but again the numbers don't match (at least what he had).

 

@sjbj , I have failed you in referencing the 7.3L PSD Tech Folder!

I thought for certain that the thread by @akcooper9 with written instructions was in the Tech Folder as well, but it was not. I have since edited the Tech Folder contents to reflect written instructions as well, which I have also pasted below...

https://www.ford-trucks.com/forums/1...g-forscan.html

My apologies sir, I will try to be better instead of sorry...

Image of updated tech folder below.

 

Thanks for the info Sous. I've been pulling RPM's off of tire websites. I will hopefully give this a try on my days off this week.

 

35 * π = 109.95" per revolution.
109.95" / 12 = 9.1625 feet per revolution.
5,280 / 9.1625 = 576.26 revs per mile.

This is nothing more than a reference point to get you "on the paper", to use the target shooting vernacular. GPS on the phone with Google Maps, or using highway mileage signs and the ODO will polish the number - because no amount of math can accurately predict real-world performance on a 20-year-old vehicle with mods.