For car and truck performance enthusiasts, more power is the modern-day Golden Fleece sought by Jason and his Argonauts, as power brings about authority and stature among one’s peers, as did possession of the long sought-after trophy of Greek mythology. A set of aftermarket headers and its appropriately matched exhaust system are one of the easiest and most popular means to gaining the power so many of us are searching for.
Indeed, research bears out the fact that a header/exhaust system is a widely popular upgrade to a vehicle, as SEMA (Specialty Equipment Marketing Association), the automotive performance aftermarket trade group that monitors such things lists headers as one of the top 10 modifications made by enthusiasts to their vehicles. With that in mind, we embarked upon an installation of headers and an exhaust to see just how much power we could gain with another extremely popular item, a 5.3-liter V8-powered Chevy pickup truck.
For this particular job, we looked to JBA Performance Exhaust (a Pertronix company) for the power-building equipment. We found a set of shorty headers (No. 18505-2JT) and a dual rear-exit cat-back exhaust system (No. 40-3049).
The headers were specifically designed for the 2002 to 2013 4.8-liter and 5.3-liter V8s without EGR, and the dual three-inch exhaust system fits 2005- to 2013 Chevy Silverado/GMC Sierra pickups. First, we checked out some of the benefits and features of these pieces of equipment to make sure they filled the bill.
Our header coating also helps lower under-hood temperatures, keeping intake air cooler. – Don Lindfors
The exhaust system from JBA delivers large diameter mandrel-bent tubing to help increase power, a stainless steel high flow muffler to give it good flow and a righteous exhaust note, polished chrome stainless steel tips that will remain bright and look cool, high-quality hardware, and factory style hangers for easy installation.
We also talked to Don Lindfors, director of exhaust R&D at Pertronix, about the JBA headers. “Whenever we do a new header design in the JBA Cat4Ward line, our design targets are to build a header that will work within the confines of stock catalytic converter placement to maintain emissions legality, while increasing horsepower and torque.”
For the exhaust, we can concentrate on the sound. – Don Lindfors
Lindfors gave us the skinny on the JBA exhaust system as well. “For the exhaust, we can concentrate on the sound. Since these are all after-cat systems, emissions are not a concern. We strive for a deep throaty sound without being overly loud. We also make sure the system is easy to install using the factory hangers, delivers increased flow for more power, and that it looks good on vehicle, especially the tip.”
Once we broke open the boxes and inspected the JBA headers and exhaust, we noticed a few things prior to beginning the installation. First of all, JBA uses sealing beads on the headers. The raised bead around each port increases the pressure on the gasket directly adjacent to the port, helping to prevent gasket leaks.
We also noticed a spike rising from the center of the four tubes inside each of the header’s collectors. Lindfors identified these spikes as the “JBA Firecone” and that they “help direct the flow from each cylinder’s primary tube into the collector for a smooth transition, and help scavenge gases by creating a vacuum in the other primary tubes. When the next exhaust valve opens up, the exhaust velocity is increased, helping scavenge the cylinder of burnt gases, which in turn allows more fresh air/fuel mixture to enter the cylinder for more power-making potential.”
The Job Begins
We began the installation by disconnecting the spark plug wires. This is best done by not pulling on the spark plug wire boots, but gently twisting them out. If the truck is not brand-new, as was the case with our 2008 Chevy pickup, it may be a good idea to spray WD-40 or some type of penetrating oil on the fasteners and fittings to be removed at this time, easing your job later.
On air pump equipped vehicles, remove the air tube from the manifold and slip it loose from the rubber hose at the rear of the engine next. If your vehicle is equipped with an EGR tube, remove it from the manifold. Now is the time to remove the bolt attaching the dipstick tube bracket to the head and remove the dipstick tube.
Our next move was to remove the through-bolt from the steering shaft, and slip the steering shaft apart. After this was accomplished to get some more elbow room around the manifolds, the factory exhaust system can be unbolted from them.
The six bolts on each exhaust manifold that hold them to the heads were removed, and then we could remove the manifolds. It’s also a good idea to take the time now to clean off any carbon deposits on the heads; a small wire brush can be used for this operation. Next, we prep’d the kit-supplied header bolts with a small amount of anti-seize on the threads.
With the bolts readied, we began the installation of the new headers using the supplied gaskets, and the supplied lock washers. It’s normal for the flange to be raised off the cylinder head by the thickness of the sealing bead. However, care must be taken during installation to first install all bolts loosely, then tighten them evenly to ensure the flat installation of the flange.
The torque sequence from one flange to another will vary, but generally every bolt on the headers should be first fit snug, starting from the inside of the flange working out, alternating from top to bottom so that the flange and manifold barely touch. Then we used the same inside to outside pattern to tighten each bolt until reaching its specified torque. This helps prevent leakage.
At this point we reinstalled the spark plug wires, and reconnected the steering shaft link, air tube, and dipstick tube. Now we could move on to the exhaust system below. For this operation, we placed the truck on a lift to save ourselves from crawling around on the ground.
The Second Half
Our first move was to completely remove the stock exhaust. The rubber insulators will be reused, so we left them on the truck. We kept the dual catalytic converter/Y-pipe assembly as that will be used again, too. Then we began the installation of the new JBA exhaust system. There were two different intermediate pipes, depending on the configuration of your truck, one has a ball socket and the other has a two-bolt flange. We chose the two-bolt flange style that was appropriate for the 5.3L V8-powered 2008 Chevy pickup.
Next, we hung the JBA muffler by slipping the three hangers on it through the stock rubber insulators. A quick shot of WD40 made it easy to slip the hangers into the insulators. With the muffler now located, we could hold the intermediate pipe up to the catalytic converter flange, and depending upon the cab configuration of the truck (ours was an Extra Cab) know where to cut the intermediate pipe to the right length.
We made a mark on the intermediate pipe where it met the inlet pipe of the muffler and a second mark two inches farther out (toward the muffler). The pipe should be cut at this second line. We then slid one of the exhaust clamps over the inlet pipe of the muffler and installed the intermediate pipe. The other end of the intermediate pipe was then bolted to the catalytic converter flange. We finished up in this area by installing the U-clamp-hanger combo on the intermediate pipe so that it slipped into the rubber insulator, then tightened the clamp.
Next, we slipped an exhaust clamp over each of the exhaust outlets, and installed the left and right over-axle pipes, but did not tighten the hardware. We then slipped an exhaust clamp over the left and right tail pipes and slid them onto the over-axle pipes, again not tightening these yet.
Our next step was to slip the right side (passenger) tail pipe hanger into its stock rubber insulator. On the left side (driver) side of the frame there is a hole just above the location of the hanger on the tail pipe. The JBA L-shaped hanger was bolted through this hole with the provided hardware, and then JBA’s rubber insulator was used to connect the L-hanger with the hanger on the tail pipe. The L-shaped hanger is height adjustable to match the height of the pipe on the other side.
Almost done except for the final dyno runs, we slipped an exhaust clamp over each chrome JBA tip and attached them to the tail pipes. Once the tail pipes, over-axle pipes, and chrome tips were adjusted to make sure all fit and were even, all the clamps were tightened. As well, the tips can be moved in or out to accommodate different bumpers, roll pans, and for just the right look.
As with all these sort of performance parts installations, we were not done until the post-install power runs on our in-house dynamometer were completed. After all, what’s the point of bolting on aftermarket headers and an exhaust system if you don’t gain any power? When we ran the 2008 5.3-liter V8 Chevy Extra Cab pickup on the dyno before the installation, it recorded a peak hp rating of 246.1 at 5,370 rpm and peak torque of 250.1 at 5,100 rpm.
The after-installation run on the dyno showed 260.9 peak hp at 5,380 rpm and peak torque output of 277.7 at 4,690 rpm. That is a gain of 14.7 peak hp and 27.6 lb-ft of peak torque. However, as with any truck application, we’re more interested in gains in the low- and mid-range. The dyno chart below reveals healthy gains in these areas as high as 45 lb-ft of torque at the critical 2,500 rpm point. A power gain such as this down low will substantially help the truck’s acceleration and improve performance during normal driving conditions.
As predicted, the installation of the JBA headers and cat-back exhaust system went smoothly, looked absolutely fabulous, and achieved the desirable power gains we had hoped for. That’s a win-win in our books.
Talking to Lindfors again, he told us more about the exhaust system, “all the bends in our exhaust system are wrinkle-free mandrel bends, and the tips are 304 stainless steel for a top-quality finish that won’t rust. The systems are built to use the OE hangers wherever possible and the hangers we provide mimic the OE parts.”
“The Cat4Ward headers are all 409 series stainless steel for durability and corrosion resistance, and have 3/8-inch flanges with a sealing bead for a no-leak installation. In addition the gaskets we provide are a top-quality HTX material, and we include specific header bolts and locking washers. The metallic ceramic coatings not only add corrosion resistance, but also help increase power by holding more heat inside the header to increase exhaust velocity. Our header coating also helps lower under-hood temperatures, keeping intake air cooler.”