We're all interested in getting more power and mileage from our sport trucks. The question is how to get it.
Two of the most popular bolt-on performance parts are free-flowing intake and exhaust systems. They're popular for a reason - they work. Any time you reduce the work required to get air into and out of the engine, you not only free up power, you make it more efficient. And that means you get the benefit of increased fuel economy.
1. Borla exhaust systems are high-quality mandrel-bent units featuring proprietary sound management technology that are among the best flowing, best sounding exhausts on the market. The dual rear muffler Borla exhaust system we installed added a tough look and an aggressive rumble to our test truck.
Now since we're talking about two systems here and since most enthusiasts are on a budget, many times we have to choose what to do first. In this case, that's a no-brainer. If you still have the stock exhaust system, you need to step up to a better-flowing exhaust system. We almost always recommend installing a good-flowing aftermarket exhaust as the first mod for any truck.
Why? Because an exhaust system that presents less restriction to the engine does so over its entire operating range, including part-throttle operation. In contrast, intakes tend to be more effective the wider you open the throttle. That's not to say you won't experience a performance increase with a free-flowing intake at part-throttle operation without an exhaust system. You will. But you'll get even more once they're both installed.
In this article, we're practicing what we preach, by first installing a Borla exhaust system and reporting on how the truck responded to the mod. Then we installed an Airaid intake and ran a few performance tests before sending the owner off on his usual street-driving routine for a couple of weeks to get fuel-mileage data.
2. After removing the stock exhaust system, installing the Borla is essentially the reverse process. The exhaust pipe bolts to the flange, and then you bolt the muffler to the lead pipe. Hang the muffler with the stock hangers, then use the supplied fasteners to secure the connection.
Borla Exhaust System
Even if all you got from the Borla exhaust system was its wonderful exhaust note, you'd be getting your money's worth. The mellow rumble of the Chevy 5.3L third-generation V-8 through these pipes and mufflers is one of those sounds that truly makes building your sport truck a satisfying experience. The Borla system produces a great sound on the outside, announcing your rig to the world, but at the same time the system is designed to be extremely quiet on the inside. You can still here the tuned exhaust note, but it doesn't cause an annoying resonance, at any point in the rpm band. That's one of the key benefits of this system.
The other key benefits are improved mileage and performance. With the Borla exhaust only, the owner of this test mule says he saw about a 1-mpg improvement in mileage and noticeable increase in mid-to-high-rpm power. So instead of the 10 mpg he was getting before installing the system, he says it improved to about 11 mpg. Curiously, he says that with the Borla exhaust system installed, he noticed that the truck lost a little on the low end, especially off-idle. The truck had more beans in mid to high range, but he felt he lost a little torque on throttle tip-in.
3. This view shows how the lead pipe and muffler should look when properly installed.
With Airaid Intake
Here's the reason we're always talking about performance combos - parts have to work together. And this concept is proved quite clearly with the intake and the exhaust. After adding the Airaid intake, the owner of this truck says went from an average of 11 mpg in the city to nearly 15 mpg. He also reports that he got 20 mpg on the freeway cruising at 80 mph. But what impressed him most was the improved off-idle throttle response the Airaid system added to this combo.
4. Since this is a dual rear-exit exhaust, you have to install two bends on the exit side of the muffler. Don't tighten the fasteners yet; you'll need to rotate the bends slightly to get the right angle to fit the exhaust pipes that go over the rear axle. | 
5. After you install the exhaust pipe section over the axle and fasten it to the muffler bends, you need to attach the exhaust tips. Normally, this is a straight-up bolt-on procedure. But in this case we had to provide some clearance between the hanger and tow hitch. The shop used a cutting torch to notch the tow hitch. If you don't have one, a grinder will work. It'll just take more time. | 
6. The Borla dual exhaust adds a performance edge to your truck, even if you're running the stock bumper and a tow hitch. |