Well I finally got around to correcting the speedo error. I'm running 35" KM2's and 5.13's and the speedo was off by 6 to 7 mph low at 75.

The Hypertech unit (purchased from Northridge 4x4 for 199) was easy to use. I had to pop out the fuses for the MyGig and remote start and that was the hardest thing about doing it. Other than that it was a matter of plugging it in and following the simple instructions on the two line screen. My first input on tire size put me off my 3 mph too fast. Dropped down 3/4" and went for a drive with my GPS and it is dead nuts on. With cruise on (the cruise actually works when you have 5.13's BTW) and at exactly 75 on the speedo the Garmin GPS was reading 74.9 to 75.2. Can't ask for better than that. It's propably now the most accurate speedo I've ever owned.

Shift points feel stock and it feels spunkier to drive. Before changing tires and gears my wife took it on a 2000 mile trip from Western CO to Eastern Nebraska and the digital indicator said she average 18 mpg which we were both pleased with as she never goes less than the speed limit (75 in CO).

After making the corrections with the Hypertech, while on the freeway at 75, it indicated 18.3 mpg. On the way home from the freeway doing 45 it climbed to 18.4 and 18.5. I think this is pretty good considering that I'm spinning 2600 at 75 as opposed to 2250 before the mods (stock Rubi 32"/4.10). Given the additional wt and rolling resistence of these tires it indicates to me that the engine is happier and working less hard at 2600 than at 2250. Which argues that the stock gearing should not be 4.10 but 4.56 or 4.88.

The above is with an Automatic and at 4600 ft.

I give the Hypertech unit high marks and think it is worth owning; especially with an Automatic.

 

Good Review I have had similar results only I have a 6 speed and 4.10 gears and my 35's are pretty happy right now also. I have no plans currently to upgrade gears as this works great for me. I must add though that hypertech also has a power programmer function for an additional 175 bucks and that thing works great. I love the way my jeep drives with the programmer and the tire size corrected.

 

Thanks for posting this info! Was wondering, with the hypertech, did you also program it for fuel economy, performance mode or anything, or just the tire size? Good price too on the hypertech from northridge I currently get 23-24 mpg between here and Denver and very pleased with how it's performing stock, but after I add a lift, I wanna know what to expect

 

ACCU PRO Speedometer and Odometer Calibrator - Jeep JK Wrangler
Price: $199.95

HYPERTECH Max Energy Programer
Price: $379.99

Northridge4x4 is where I bought my MAX ENERGY PROGRAMMER, I believe the OP bought just the Calibrator.

 

his post says he got the hypertech, but I was wondering about that since the cheapest I've found the hypertech anywhere has been $360

 

Yeah, that is why I think he may have bought the Hypertech version of the accu pro which is the same thing anyway.

 

so did you program yours for economy mode or anything?

 

https://www.jk-forum.com/forums/jk-write-ups-39/hypertech-review-install-write-up-31233/

 

very good write up on the programmer What do you get for hwy mpg and are you still running stock?

 

16 mpg city/highway mix. 18 highway

I have 35's on 17 inch aluminum machined MB Motoring V-Drive wheels, a K&N Filter in stock box, 4.10's, 6S Manual, and Hypertech Max Energy.