FLASHBACK TO PROJECT LOOKS. MUSCLE. LONGEVITY

IMPROVING A 2012 LML DURAMAX

This Silverado 2500HD project was introduced in the March issue of Diesel World, so if you haven’t seen it, go snag a copy and get fully up to speed. You’ve missed just Part One of the build and the backstory behind what it’s about, so we’ll quickly recap. I had been driving a 2002 LB7 Duramax for almost 6 years, used it for what most owners used their trucks for it was my daily driver, hauled kids to pre-school and dragged our family fifth wheel all over the mountains of Utah and Southeast Idaho camping. In those 6-years it turned from a basically stock capable pickup into a fully built 750hp twin turbo street stomper that could still do all the things I needed to on a day to day basis. It was a lot of fun to build and even more fun to drive. Unfortunately, the love affair was ending and newer technology, quieter engines, and comfier leather seats had been calling my name and it was time to search for a truck to replace it and start over with.

After selling that built LB7 and searching used car lots and classified ads, this fully loaded 2012 LML Duramax caught my eye. For the first part of the build-up I had to do something about the stock horsepower level, as jumping out of 750hp and into 350hp was not only a hit to my pride, but a bore to the driving experience. The LML engine used in 2011-2016 GM trucks makes respectable power in stock form and is more than capable of towing just about anything you want, but the aftermarket can always find a bit more on tap with a few tweaks. The newest Jammer Stage 2 kits from Edge Products offer a cold air intake, high flow stainless steel exhaust system and their Evolution

CTS2 monitor and tuning device that all work together to produce efficient, usable, CARB and emissions friendly horsepower. The kit specific to this truck was all very easy to install and literally took less than an hour to do it all. With the improvements to airflow being fed to the engine, the modifications to the ECM programming and better flowing tailpipe system this truck gained 127hp and over 200lb-ft of torque. Now we won’t be daily driving the truck in that 500hp tune until we do a few more supporting mods like a fuel lift pump, but even in the Towing program the truck still produced over 440 rear-wheel horsepower and helped bump the mileage up to a solid 17-18mpg average.

DRP 3” Hot Side Pipe

To take the airflow side of things one step further, the factory driver side intercooler pipe on 2011-2016 trucks uses a somewhat restrictive 2.5” two piece tube to connect the turbo outlet to the intercooler inlet, where that 2.5” pipe expands out to meet the 3” inlet of the charge air cooler. It seems like simple logic in the way air flows through something, that a large diameter could move more volume with less restriction. To help remedy this, Deviant Race Parts (DRP) of Hayden, ID developed a full 3” high flow hot side intercooler pipe that easily replaces the stock unit. By removing the front driver side inner fender well liner, you get pretty easy access to the charge air pipe and can disconnect it from the intercooler and turbocharger and fish it up and out of the engine bay from above. The DRP piece not only uses a large diameter pipe to improve airflow to the intercooler, but they’ve gone to great lengths to ensure easy airflow

The Bestop Ez-roll tonneau cover system couldn’t be any easier to install with all the hardware included to make this a simple one person 15-minute job in the driveway. The tough, premium grade leather-grain vinyl-coated polyester will withstand any climate and weather, along with being treated for excellent mildew and UV resistance.

This truck came out of Canada and the previous owner had installed a nice fiberglass truck cap to keep his things dry in the cold winter weather, but as the new owner, plans of towing a large fifth wheel trailer in the summer meant that shell had to go. Besides, that camper shell gave off an unwanted ‘grandpa truck’ vibe that just wasn’t cutting it.

Following along with the provided instructions, the driver side and passenger side bed rail pieces in the box need to be positioned so that extruding edge is flush with the front bed rail. This will ensure the end cap seals tightly across the front of the bed.

Bestop included six aluminum bed clamps to attach the new soft tonneau cover to the truck. Some soft pads are also included to offer some additional support and protection on the bedsides for a secure and simple install.

Losing the shell for easier bed access for gooseneck trailer towing doesn’t mean you have to lose protection for all your things from the elements. The EZ Roll tonneau cover is a simple solution to keep your stuff out of the weather, easy view of anyone interested in taking it, and give the truck a more finished look. Simply unclicking the back latches and rolling it up out of the way offers access to that bed anytime you need it.

The 2011-2015 LML platform runs extremely well in stock form, but that doesn’t mean GM hasn’t left some performance on the table the aftermarket can’t take advantage of. Case in point, the hot side charge air pipe. Deviant Race Parts developed a high flow mandrel bent 3” intercooler tube that not only looks good under the hood, but will increase flow to the intercooler for better turbo response and a slight drop in EGT’S.

Once the bed rail sides are in position, the rollup cover can be slid into the front grooves and unrolled the length of the bed. You’ll want to take some time to make sure the entire assembly sits square on the bed and is centered front to back and side to side. Once in perfect position, the six bedside clamps can be tightened down.

The mandrel bent piping comes direct from Deviant Race Parts powder coated in gloss black for good looks and durability. The two-piece design makes for an easy installation and each pipe end offers a nice bead rolled into it to keep the provided boots secure, even under max boost pressures.