By definition, the term restrictive is a limitation, or something to hold one back from progress. When the term restrictive is used in the automotive world, especially toward the exhaust system, it can only mean one thing, slow. Now, don’t get mad at the manufacturer of your truck; their designers and engineers for the most part are enthusiasts much like yourself, and the last thing they want is to produce a low horsepower, low torque engine. Their design requirements, however, must suit the masses whereas a quiet and efficient exhaust is what their final goal is for the system on your truck when it leaves the assembly plant.
Let’s take, for example, the latest General Motors truck line that sports a brand-new powertrain, dubbed the LT1. By design the LT1 is an upgrade to the tried-and-true LS-series engine, where improvements such as direct port injection, have really pushed the horsepower numbers to rival classic big-block numbers found in some of the early muscle cars that were born in Detroit. The greatest thing about the latest engine technology is the fuel efficiency, as the horsepower-to-fuel mileage ratio seem to have found a happy medium. Most of that can be attributed to the new cylinder head design that shares many of the same components as the Corvette cylinder heads. In fact, the 6.2L engines found in the truck as well as the Vette are surprisingly similar. The main difference between the two is the tall intake manifold that helps to build more torque for hauling heavy loads.
| 2014 GMC Sierra Front View
Those are great features to look into when making a purchase for a new vehicle for work, but we’re looking for more than that, right? Moreover, tall intake runners, direct port injection, and a large displacement is the perfect recipe for, you guessed it, horsepower! So have some fun with your new truck. Unleash the potential of the new powerplant and let everyone know you’re driving a good ol’ American V-8! The first step is to let it breathe, and what better way to increase the LT1’s velocity of spent gases, you ask? Well that’s the question we asked the engineers at Borla Exhaust. Borla has been engineering high-quality exhaust systems for more than 30 years using exotic metals such as stainless steel, titanium, and even carbon fiber. One of the greatest features of Borla’s exhaust line is the choice that one can make on the sound level of your new exhaust system. And the important thing is that whether you choose a mellow tone or a raspy roar, Borla’s engineering allows your engine to breathe properly and to maximum potential. We decided to get a closer look at the installation of one of these systems, and headed out to PPC Customs to bolt up the Borla on a ’14 GMC standard cab. Follow along as we walk you through the process.
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1. The first step in the process is to remove the factory exhaust clamp located on the passenger side, just behind the catalytic convertor.
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2. Using a pair of exhaust hanger pliers like these from Blue Point, the stem portion of the hanger is pushed out from the rubber grommet, which will allow the factory exhaust tube to lower from its position. It’s unlikely that the viewers from home process a pair of exhaust hanger pliers, but some spray lubricant, a pair of adjustable pliers, and a U-shaped alignment shim used for body and fender mounting purposes will do the job just as easy.
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3. Remove the remaining hangers from the rubber grommets and slide the factory exhaust out from the axle moving it forward toward the front of the vehicle. This is fairly easy if you have access to a lift, as the length of the factory system won’t allow you to fish it through the axle if your truck is on jackstands. You may need to cut the factory exhaust into two pieces in order for it to clear the rear axle.
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4. Here’s a look at the Borla system designed to work with this ’14 standard cab GMC truck. Note that this system is a “single in/dual out” type of muffler that allows the installer to locate two exhaust tips out the back of the vehicle. Not only does this give the look of a true dual exhaust system, it also puts out a deeper sound. The choice of metal for this type of construction is stainless steel for a long-lasting service life that Borla stands behind, as they happen to provide a million-mile warranty.
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5. Hoist the muffler into position and thread the hanger stem into the factory rubber grommet to hold the muffler into place.
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6. Be sure to give the grommet a shot of spray lube beforehand to makes things fit smoothly.
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7. Next, fit the head pipe tube into place with the factory catalytic convertor and the muffler. Then affix both mounting clamps at the joints of the head pipe both forward and aft.
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8. Tighten them down snug, but not tight, as later during the install you may need to flex the muffler around.
9, 10, 11. Moving to the rear of the muffler, locate the forward mounted bolt that holds the trailer hitch to the frame and remove the nut. Next, slide over the provided hanger bracket that will hold the driver-side exhaust tube in place. Finish out this portion by installing another urethane grommet, again provided in the kit from Borla.
12, 13, 14. Working from the rear of the muffler, install the driver-side tailpipe into the muffler, after which pairing the remaining pieces of the tailpipe with the exhaust hanger that was just installed. Close out the install by repeating the process on the passenger side, but this time using the factory rubber grommets to hold your tailpipe pieces in place. Be sure to then go back and check all the clamps to ensure that they have been tightened down. This step will not only prevent leaks, but more importantly keep the exhaust in place during operation.
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15. Lower the truck back down on the ground and fire it up! We loved the way the system looked after the install, and were quite impressed by the sound as well, as it wasn’t too quiet, or too loud. As a matter of fact, it was just right.
