Part I: Intake And Exhaust Installation And Dyno Test
While just about everyone would love to have a new 505-horsepower LS7 powering their Bird, budgetary restraints and the desire to retain the original powerplant leave many owners considering other methods to increase engine output. For those who have already done many of the free mods (HPP, "Bolt-On Inspiration," July '06) but still want to bump up the power and retain driveability. Over the next two issues, we'll show you a combination of parts that will increase flywheel horsepower close to 75.
Jet-Hot headers are available...
Jet-Hot headers are available for all '98-'02 LS-equipped Firebirds. PN 2533 (retail $500.95) is specifically designed for '00 applications that have both AIR and EGR provisions. The full-length headers are designed by Jet-Hot and feature 1.75-inch primaries and a 3-inch collector.
To set a foundation for big-power gains, LS-series engines can reap the benefits of exhaust and intake upgrades to make the most of the factory camshaft. If more power is desired, the next phase is a cam swap and valvetrain upgrade, which will come in Part II of this story. Known as "cam-only" cars, these LS-powered Pontiacs are potent performers. While gains greater than those that will be noted are certainly possible, our goal is to increase horsepower and torque across the board and create a power package that could just as easily run across town for a local cruise as it could lay down some serious power at the track.
According to Keith Lohse, of Real Performance Motorsports (RPM), in Lewisville, Texas, "Once an owner has completed the free mods and done some of the popular cost-effective upgrades, such as an aftermarket airlid or after-cat exhaust, many step up to a cam-only combination that nets them between 370-410 rear-wheel horsepower, based on the components selected."
In order to make that type of power, first a quality set of long-tube headers and free-flowing exhaust must be installed. Then, for pre-'01 Birds, the LS1 manifold is swapped out to an LS6 manifold as it has consistently shown the ability to generate at least 10 rwhp on an LS1 and can support upwards of 500 rwhp on nasty stroker builds. In order to get the exhaust and intake to support the cam-only build, we turned to Jet-Hot Coatings and SLP Performance Parts.
Constructed of heavy 16-gauge...
Constructed of heavy 16-gauge steel and featuring thick 3/8-inch flanges, the headers have high-cost features for a budget price. In addition to ensuring that the primary tubes don't protrude into the flange to rob power, both sides of the flange are welded, as are the AIR and EGR provisions. The Sterling finish is attractive as well as functional.
Matt Pertrauskas of Jet-Hot Coatings states, "Although there is a large variety of header and Y-pipe combinations available on the market for the LS1 F-body, our comprehensive catalog of headers and Y-pipes allows an owner to choose a system that will support his power goals. For this application, our long-tube headers with high-flow catalytic converters and Y-pipe will maximize the power potential of the LS1 and are unique in that they allow an owner to remain 49-state emissions legal or to swap out the converters for test pipes to run in an "off-road" configuration. Our headers and Y-pipes are coated inside and out with our proprietary Jet-Hot Sterling Silver coating, which will decrease underhood temperatures approximately 300-400 degrees and look great for years to come. In fact, the system carries a lifetime corrosion warranty and a three-year finish warranty."
Follow along as we install a set of Jet-Hot headers and a Y-pipe on an '00 WS6 Trans Am, then swap out the LS1 manifold for an SLP Performance Parts' LS6 intake manifold that retains the stock EGR system capability. The subject car is owned by Harold Baker, an information systems security engineer from Richardson, Texas. Now retired from daily driver duties, the automatic-equipped Bird carries 64,000 miles and is cruised for fun and used to bracket race in the Texas Muscle Car Club Challenge series. Equipped with a Corsa after-cat exhaust, BBK 80mm throttle body, a bevy of free mods and aftermarket suspension, this potent T/A is primed for an LS1 Power Plan.
Installation and testing of the modifications were done at RPM, which specializes in late-model General Motors performance and can take care of all of your Firebird, GTO and Grand Prix needs.
 After disconnecting the negative...  After disconnecting the negative battery terminal, the T/A is raised and the rear O2 sensors are disconnected. Penetrating oil is sprayed on the exhaust junctions, then a 15mm socket is used to loosen the factory band clamp at the junction of the stock Y-pipe and Corsa after-cat exhaust. |  The two front sections of...  The two front sections of the Y-pipe-to-catalytic-converter junctions are attached with two bolts on each side that are removed with a 15mm socket wrench. The flanges are pushed back and the pipes are separated. |  A 15mm socket and long extension...  A 15mm socket and long extension are used to remove the three bolts that connect the exhaust manifold collector to the catalytic converter assembly. The driver-side converter is carefully lowered, then the process is repeated to remove the passenger-side converter. |