UPGRADING A 2016 DU RA MAX WORK TRUCK’ S PERFORMANCE
Upgrading a 2016 Duramax work truck’s performance
Many diesel truck owners use their trucks for work—hard work in most cases. Jeremy Watson of Madisonville, Tennessee, is one such truck owner. He uses his 2016 Chevrolet Silverado 3500 HD to tow and haul heavy loads on a nearly daily basis for his concrete pole base company, as well as on the farm where he and his family raise cattle. The truck has performed well so far over its nearly 60,000 miles of use, but like any gearhead Watson wanted to get more performance out of the truck and hoped that by improving the tuning and airflow he would also pick up a fuel mileage improvement to help his business’ bottom line.
To upgrade the truck he turned to the expert team at RLC Motorsports in Cookeville, Tenn., where Watson decided to go with a simple and inexpensive tuning option using a Hypertech Max Energy 2.0 Power Programmer to unleash some of the truck’s electronic potential. Then to help the LML Duramax engine breathe easier he opted for an S&B Filters cold-air intake kit to replace the restrictive factory intake and use the dry extendable air filter for longer filter service life. Finally, to dress up the truck a bit, he went with a Dpf-back Diamond Eye 4-inch aluminized steel dual-outlet exhaust system with polished 5-inch-diameter stainless steel tips that exit at each rear corner of the truck. About a week before the installation Watson took the truck up to Beans Diesel Performance in Woodbury, Tenn., to get a baseline dyno pull. In stock trim the truck put 325.0 horsepower to
the dyno rollers through the rear wheels, but an issue with the dyno operation left us without accurate torque readings.
With the equipment decisions made and baseline dyno testing done, we loaded up the truck and headed up to RLC’S shop to begin the installation. Shop technician Drew Richards handled the upgrades with help from owner Michael Dalton when a second set of hands was necessary. He updated the Max Energy Hypertech tuner online before starting on the S&B intake install, then went to work under the hood. Removing the factory air filter housing and plumbing was simple and straightforward, as was installing the new S&B cold-air intake system to replace the factory components. Even with our photography slowdowns, Richards completed the intake install in about 45 minutes. Then he moved on to the Hypertech
Max Energy 2.0 programmer, which uploaded new tunes to the truck smoothly once it was updated. The process felt like a long time since you are literally sitting and waiting for the programmer to communicate, download, upload and verify tuning with the truck, but in fact it took less than a half hour.
After a quick lunch break Richards and Dalton went to work installing the Diamond Eye dual exhaust system, which required some fabrication/customization and proved to be much more difficult than the intake installation or programmer tuning. They encountered two major issues that threw wrenches into what could have been a straightforward installation. First, the instructions supplied with the kit indicated that the factory exhaust system should be cut at a point 4 inches past the DPF, yet that seemed to leave us a few inches short
when it came time to put things back together. This could have been caused by manufacturing changes at GM or simply a typo in the instructions. Either way we would highly recommend cutting the factory exhaust tubing at 8 inches from the DPF hangar, then cutting again as necessary for proper fitment of the Diamond Eye exhaust components. The other area where we ran into issues was clearance of the factory gooseneck mount under the bed. It seems as though the routing of the driver-side exhaust tubing and the gooseneck structure both wanted to occupy the same space, requiring Richards to use a rather large 3-pound “persuader” to flatten out the top side of the exhaust tubing to clear the gooseneck mount.
After the additional fitment, customization and fabrication required to install the exhaust system, Richards and Dalton finished the installation and alignment of the dual polished stainless steel Diamond Eye 5-inch-diameter exhaust tips in a total of about 4 hours with the truck on one of the shop’s two-post lifts. If you are performing the installation yourself without the aid of a lift it will likely take additional time. As always, when working in, on and under your truck be sure to practice safe shop techniques, and if you are at all unsure if you have the skills to perform the task, leave it to the pros at your local performance diesel shop. Follow along over the next several pages to see the basics of the installation process.
When the installation was completed we drove the truck down to Beans Diesel Performance for another crack at their Dynocom chassis dyno. Using the Hypertech programmer, we put the truck in stock mode and measured 333.8 hp and 592.7 lb-ft of torque for almost 10 hp of improvement with the better breathing from the intake and exhaust. In Tune 1 on the Max Energy programmer the truck made a dyno pull of 343.9 hp and 598.2 lb-ft of torque for another 10-hp improvement, as expected from Hyper- tech’s testing. Dyno measurements from Tune 2 showed that the truck was making 368.4 hp and 637 lb-ft of torque for an increase of about 43 hp over stock, while Tune 3 maxed out at 384.4 hp and 679.1 lb-ft of torque for a total increase of right around 60 hp.
Behind the wheel the truck felt very responsive, and even with us mashing the loud pedal several times we saw improved fuel mileage. Acoustically there was very little if any change over stock, but the truck still has the factory resonator on the intake, as well as the DPF and other emissions equipment fully intact, so the exhaust upgrade with the Dpf-back system becomes more of a visual than audible upgrade.
Driving the truck the 90+ miles to RLC in the morning with the truck stock yielded an average fuel economy of 16.6 mpg according to the factory trip computer. Driving from RLC to Beans we saw 18.3 mpg for the factory computed average while we were in Tune 2. Driving back home from Beans in Tune 3 we saw 18.6 mpg. While
the routes driven were a very small sample size and were not completely the same, they did cover much of the same route and similar terrain and speeds when the route was different. The 2 mpg improvement was unloaded (except for carrying the parts), but it is a welcome addition to the extra horsepower provided by the upgrades. As of our editorial deadline Watson had not yet towed his equipment with the upgraded truck, but we do also expect to see improvements in towing fuel mileage as long as he can resist the urge to keep it matted.
The fuel mileage, horsepower and improvements we saw with Watson’s truck are typical of what we have seen with similar intake, exhaust and programming upgrades in various trucks throughout the years. While it may seem counterintuitive to many, we have seen time and time again that making more power and improving the efficiency of the engine provides an additional improvement in fuel economy when the vehicle is driven in the same way. Stay tuned, as Watson is likely to continue the upgrades on his truck now that he has seen and felt the performance improvements that are now available with modern diesel hot rods… err, we mean work trucks! UDBG
Heavy equipment tends to find its way onto Jeremy Watson’s trailers and behind his hard-working 2016 Chevrolet Silverado 3500 HD on a regular basis, so he wanted to improve its power and fuel mileage at the same time.
The S&B Filters cold-air intake kit will dress up the engine bay a little bit while allowing the engine to draw in more airflow for better performance. 3
1 Before starting on the intake installation, Drew Richards connected the Hypertech Max Energy 2.0 programmer to his laptop to download the latest updates directly from Hypertech.
2Looking at a stock LML Duramax isn’t exactly thrilling—it is a powerful engine, but not so hot in the looks department.
The front plastic cover must be removed to access the fender support, which needs to be partially removed to take the factory air box and filter out of the truck.
Richards secures the new air box with the factory mounting bolts, then he installs the remaining S&B intake elbow, connecting the tubes together using the hoses he installed earlier.
After unplugging the humidity sensor and MAF sensor harnesses, Richards loosens the hose clamps on both ends of the intake elbow and removes it from the truck.
After installing the bottom inlet plug (Richards recommends running the plug to prevent water intrusion with the frequent heavy rain seen in the Tennessee area) and silicone tube seal he carefully lowers the new air box into position.
The complete air box assembly can be removed from the truck. Once the assembly is out of the way, remove the bolts securing the mounting bracket below the filter assembly and remove the bracket.
The air filter access is closed off with a clear acrylic window that is etched with the S&B logo on the inside. It gives the cold-air intake a good look as well as being functional, since it allows the owner to easily do a quick visual inspection of the filter any time he opens the hood.
Transfer the humidity sensor and MAF sensor from the factory air box to the S&B intake tube using the supplied hardware, including the spacer and gasket for the humidity sensor.
Richards next installs the silicone hoses and stainless steel clamps in the intake tube and slides it into position.
Next he installs the large S&B high-flow air filter and tightens all the clamps securely.
Once all the tubing was positioned in a way that Richards and Dalton were happy with, Richards installed and tightened all of the tube clamps.
Richards put anti-seize on the threads then reinstalled the emissions sensor in the new location in the Diamond Eye Y-pipe, then rerouted the wire and mounted the module back on the frame.
To remedy the exhaust-to-gooseneck conflict, Richards massaged the exhaust tubing with a good-sized hammer and beat it into submission until it would fit without contact.
As they were installing the exhaust tubes, Richards and Dalton noticed that there was going to be interference between the tubing and the factory gooseneck mount.
27 Dalton gave each joint a solid tack weld to prevent any unwanted movement in the exhaust system.
Richards could not remove the factory emissions sensor from the exhaust while it was in the truck, so he unbolted the connected module from the chassis, unplugged the other end of the harness, and removed it with the complete exhaust system from the rear of the truck. If you are working on the ground without the aid of a lift you will likely need to cut the exhaust into a few pieces to get it out from under the truck.
While the oil is soaking in, Richards measures and cuts the factory exhaust as directed at 4 inches from the rear hangar from the Dpf—but in this case the cut should have been around 7 or 8 inches from the hangar. We recommend cutting your exhaust at 8 inches or more from the DPF hangar and then cutting it again if necessary.
Richards and Dalton applied heat to the exhaust system bung to help release the sensor from the tubing; it will be reinstalled in the new exhaust system later.