If you can think back to November 2002, you may remember our real world combos story that we did on our little in-house R/T. In that story, we covered the installation of a K&N Fuel Injection Performance Kit (FIPK), Gibson's after-cat single exhaust, and Hypertech's Power Programmer III. Those products gave us 16 hp and 30 lb-ft of torque, but there was one piece of the puzzle that we didn't cover: headers.
01. Here are the Gibson headers...
01. Here are the Gibson headers we will be installing. They are nickel-plated and feature thick flanges to avoid flex and in turn help prevent leaks.
We went back to Gibson to have the company install a set of its emissions-legal bolt-on headers. The new headers feature mandrel-bent tubing in either a nickel-chrome-plated finish or stainless-steel construction. Gibson spends hours tuning the headers to match the needs of each vehicle. Performance gains are engineered to come in at low- and mid-range rpm/highway speeds, so Gibson will help you pull that grade or jump out of the hole. The headers will not void your vehicle's warranty and come with a lifetime warranty, gaskets, and hardware.
The guys at Gibson install headers and exhaust all day, and they had these headers in and the system buttoned up in a few minutes shy of two hours. You should be able to get them in close to that time with a few common tools and some patience.
02. After the truck cooled...
02. After the truck cooled off, the stock manifolds' collectors were unbolted.
03. The K&N intake was removed...
03. The K&N intake was removed to gain access to the manifold bolts.
04. The heatshield came off...
04. The heatshield came off after the two nuts were removed.
05. Most exhaust hardware...
05. Most exhaust hardware will rust, making the bolts hard to remove, so all of them were sprayed with WD-40. We gave it a few minutes to allow it to penetrate before we started unbolting the manifolds.
06. Once the nuts and bolts...
06. Once the nuts and bolts were off, the manifolds were removed and placed in the swap meet pile.
07. Here is a side-by-side...
07. Here is a side-by-side comparison of the stock and Gibson setup. The Gibson headers keep the exhaust impulses from interacting with each other until they get to the collector; the factory unit has them interacting right after they leave the head. This cuts down on turbulence created and in turn improves flow and efficiency.
08. There are two studs in...
08. There are two studs in each side; these will not be used for the headers, so they had to be removed. Double-nutting the studs is a pretty easy way to get them out. Run two nuts down the stud and tighten them to each other, then you can use them to spin out the stud.
09. Here's a little tech tip...
09. Here's a little tech tip from Gibson to save some sanity. You can tape the exhaust gasket to the header to hold it in place, and once it's all installed you can rip the tape out. Also make sure to clean all, if any, carbon or old gasket material from the head.
10. The header assembly was...
10. The header assembly was dropped in the truck without any problems; there is plenty of room in there to get them positioned.
11. Gibson sends small-headed...
11. Gibson sends small-headed bolts out with the headers, so you can still get a boxed end wrench or socket on them.
12. The air intake system...
12. The air intake system was buttoned back up and the truck raised up on the lift.
13. The intermediate pipe...
13. The intermediate pipe was hooked back up. The headers feature the same factory ball socket-type sealing surface, so there is no need for a gasket.
14 a&b. We went back to the...
14 a&b. We went back to the dyno to find out what we got. The headers added 7 hp and 14 lb-ft of torque to our total power output. The headers give the truck a crisper exhaust note, but it's still not obnoxiously loud.
As you can see, along each step of the way, the products made power, but the numbers aren't super high. Yes you might be able to get 10 hp from an air intake and 15 hp from an exhaust system, but that doesn't mean by doing both you get 25 hp total. Usually the first modification you do will show the biggest gains, but as you add more products, the numbers become only a percent of what they do alone.
Stock:
210 hp @ 4,200 rpm / 286 lb-ft @ 3,100 rpm
K&N, Gibson after-cat, and Hypertech:
226 hp @ 4,200 rpm / 316 lb-ft @ 3,500 rpm
Gibson headers:
233 hp @ 4,300 rpm / 330 lb-ft @ 3,200 rpm