Lift and tires killed my mileage and performance

Aristone · December 13, 2011

I dont expect miracles... Im just hopin for better performance and amd maybe a tweek more mileage. I feel now for me to have the get up and go that I want, I have to have to heavy of a foot

jsims002 · December 14, 2011

Justin tuned my truck today, took about 45 minutes total. He disabled the AFM, changed shift points and it was well worth the money. I'm ordering the AutoCal too so I can data log and get license for two vehicles so I can use it on my wife's car.

Aristone · December 14, 2011

Justin tuned my truck today, took about 45 minutes total. He disabled the AFM, changed shift points and it was well worth the money. I'm ordering the AutoCal too so I can data log and get license for two vehicles so I can use it on my wife's car.

Not to sound stupid , but what is the AFM? Did it change the personality and feel of your truck?

Stevens03 · December 14, 2011

AFM - Automatic Fuel Management is how I know it. It transitions the motor from 8 cylinders to 4.

jsims002 · December 15, 2011

Stevens11, real close, same meaning. It's Active Fuel Management. Not really noticeable unless you change the exhaust. If you ever heard a 4 cylinder metric with a fart can, that's what your truck with at least a cat back performance exhaust will sound in V4 mode. As for the driving, its pure pleasure, no throttle lag, if you ever wish your truck would shift up/down with no jerking or skipping down more than one gear (which it seems to do when you mash the gas and after the lag) get the blackbear performance tune. Bite the bullet, drive to a live tune or go the autocal route. 100% sure you will be satisfied. I say all this and I just met Justin yesterday.

Aristone · December 15, 2011

I have a cat back system and know exactly what your talking about. I have been e mailing Justin and I live in southern Nj. He isnt going to be anywhere near me.The auto cal setup he can e mail me the updates and I can install them myself... Other than that Im a little unsure how the whole thing works

kstruckcountry · December 16, 2011

Glad you made progress! I've been thinking about doing the Autocal deal, I want to keep v4 mode capability over sound though. It does sound a lil ricey, but with the radio on and the Bose crankin, I don't really notice it. No complaints from people in the backseat either

jsims002 · December 16, 2011

The AutoCal email tune option is just as good. I basically did the opposite. I got the live tune, now I'm ordering the autocal. You may ask why? That way I'll have my stock tune and can data log and have Justin tweak it if I add any mods, etc......

jimmyboy8301 · January 1, 2012

BB with the autocal is the way to go, if not you can wait for an in person tune from justin. your other option is East Coast Supercharging www.eastcoastsupercharging.com they use EFI Live and are VERY VERY good at what they do, and they are close and always around.

IMO BB is better, but just throwing another option out there since ECS is in south jersey.

Stevens03 · January 1, 2012

It you're looking for good mileage with a lift and big tires, you're SOL. A lift WILL decrease mileage some, greater angles on drivelines and slightly more air resistance on underdody. Tires hurt a lot though. A 4:10 regear helps quite a bit, but helps driveability more than anything. You can't expect near as good of mileage with tires that weigh 3 or 4 times a normal sized lighter tire.

Thats not entirely true. My 03 5.3L with 4.10 gears and 35" tires still averaged 14-15mpg and 18-19mpg highway If I kept the speed below 70mph. If your geared properly you should still get decent mileage.