I got my smarty on wednesday and put the tune in in the parking lot of the shop, I just couldn't wait any longer. It's much smoother and has a bit more power but I'm running it on the lowest setting till my gauges get installed. The truck used to lag and then take off right around 2500rpm, now it's just smooth easy power all the way up. The over head console showed a 3mpg gain but we'll see what it actually is when I fill up next.

I also changed the tire size but noticed that the stock setting was 30.6" this seems awefully short to me. I put it up to 32" which is slightly taller than the actual tire diameter as measured on the truck to allow for heat growth when I'm on the road. It's nice to have a speedo that's right, but the stock tire size worries me. Has anyone else seen this? I haven't had a chance to check my speedo with a GPS or anything else so I'm not sure if it's correct now or now.

 

The tires calc will read low. Just how it is. You really need a GPS to determine. For example my Toyo 285's need 31.4" in the SJR, they are actually 32.7" tall and have a rolling radius of 636 rev/mil (31.7"). So you can see what the truck needs to make it accurate is not any of the mfgr specs. And mine is pretty much dead on, less than 2 miles difference between the truck and 2 GPS's in a 1100 mile road trip.

I actually had to go to 30.4, IIRC, for stock tires to be accurate.

 

I love my JR. (although its currently OOS until I reprogram it due to the dealership reflashing my truck a few months ago).

I ran mine on TOW and 100hp mode... it was GREAT. Didn't use any gauges since I always heard and read that the truck actually runs cooler with the programmer on.

Its a great buy !!!

 

I couldn't be happier with the Smarty Jr purchase. I have stayed on the 70hp setting. I know it has been discussed, but does anyone run the smarty jr on the 100hp setting with no tranny mods without damage to the tranny? I am temped to try it, but really want to keep the stock tranny as long as possible.

 

I've been running around in the 100hp mode for about a year now with no change in the tranny. I drive it pretty easy though.