I have a 2012 2500 diesel with automatic transmission and 373 ratio. I am getting 15running to work to 17 mpg on a trip. I have about 5500 miles on the odometer. I am looking to get better fuel mileage and to try to change some of the factory settings that I don't like. For instance, I would like to change the exhaust brake cutoff from shutting off at about 1,000 rpms down to about 600 rpms; also, I would like to eliminate the low tire pressure light and stop the seat belt warning light that is on all the time. Is there a programmer and exhaust that would increase mpg/performance and also be able to change all this unwanted factory settings and more?

 

seat belt light will go off if you wear your seat belt... lol

you realize if you get in a wreck in that truck with no seat belt on, that airbag is going to snap your neck like a twig... they come out with explosive force...inflate and deflate before you realize wtf just happened...


anyway, you will void your warranty if you tune the truck or modify it in any way.

assuming you don't give a rats *** about your warranty: delete the DPF in the exhaust, its like a giant cork in the exhaust... next delete the EGR valve. its plugging up your intake and turbo with soot. those two deletes alone will gain you 5mpg. no joke. but warranty will be out the window and truck wont pass emissions.

now for power: you will need a set of gauges: EGT, Boost, trans temp, rail pressure.

once you get those, next is building the trans...torque converter and valve body will go a ways, or if you want serious power just ditch the trans for a fully built trans so you can do it right the first time...

then for electronic power you can get either a smarty programmer, or EFILive. both will boost your power a good 200hp to the rear wheels. if you want more than that, you can do injector nozzles and throw a S480 under your VGT for compound twin turbos. you will need head studs, o-rings in the head, and upgraded push rods and valve springs for running twins on your truck. always do supporting mods first or you WILL break your truck. (I learned a lot of it the hard way and it cost me a lot more money than it had to...)

 

Speaking as someone who has owned a 6.7 Cummins, the trans is perfectly fine with ~500hp/1100lb-ft and reasonable driving. Start being stupid and yeah, you can destroy stuff. In my case, being stupid means doing a 4wd power brake for a few seconds too long waiting for the green. I liquefied my underdrive clutches. Nothing hard or expensive (read: metal) broke.

What I highly recommend - H&S programmer - Black Maxx or Mini Maxx, EGR delete, DPF delete (turbo-back 4" exhaust), and fuel rail shim. The programmer satisfies your need for gauges, takes care of the computer issues from deleting the emissions crap, will allow you to turn off the seatbelt minder, TPMS, and alter other settings. Get their Overdrive software for a much improved transmission shift logic. However, last I checked it won't allow you to extend the engine braking that low.

As far as fuel economy goes, my heavy foot averaged about 15.6 mpg on a ~10 mile commute in a 50 zone with traffic and stoplights. Driven conservatively you will get better mileage.

 

With only 5500 miles, you are not even broken in yet so your going to gain some mpg around 20k or so. If you keep your truck stock, to avoid some headaches with the emissions systems, dont baby your truck. Idk if they fixed the issue on the 6.7HO, but early 6.7's would clog up the EGR and DPF if the engines were not "worked"

 

In theory, they "fixed" the soot clogging problems with a flash update to enable renegerations during extended idles among other things.

You still have to use the exhaust brake regularly to prevent the VGT moving parts from seizing up.

 

I just got a 2011 2500 HD. The DPF and EGR were deleted with a Flo-Pro turbo back 4" and Sinister Diesel EGR delete. Also has AFE intake. I get 16/17 in town and 21/22 on the freeway. Used to have a tuner/programmer I think. There's a hole in pillar trim. I think I need the tuner/programmer cuz I was told with those mods I should get better on the highway. Plus the trans seems to slip some. Need to talk with someone bout that.

 

Without a programmer you'll get a CEL caused by the lack of EGR/DPF bits. Sounds like it probably has the ECM reflashed but the previous owner kept it (or sold it to some poor SOB) or the dealer threw it out.

I seriously doubt you will get better than 16/17 in town and 22 on the highway - these newer trucks are heavier and less efficient in general due to the extra weight and added displacement. The mileage you're getting is quite a bit better than I was able to ever get out of my 08, although I had a really hard time running a whole tank through it without either towing or running it hard.