2000 WS6 Trans Am LS1 Power Plan Part 1- Pontiac Tech

A comparison of the driver-side exhaust manifold and Jet-Hot header really points out the differences in design. Although the factory exhaust manifolds are efficient for a traditional manifold design, Jet-Hot's long-tube four-into-one design with large primary tubes and a 3-inch collector will allow the exhaust gases to be expelled at a much faster rate. In addition to scavenging the cylinder better to allow for a faster intake of air and fuel, the tuned header decreases exhaust gas reversion back into the head and significantly decreases overall exhaust backpressure.

The driver-side header is maneuvered up into position and a single-stock exhaust manifold bolt is loosely threaded into the rear manifold bolt hole. The process is repeated on the passenger side (as shown) and only a small dimple on the driver-side heat shield was necessary to ensure a perfect fit of the headers. According to Matt Garzonie of RPM, "Headers are installed on F-bodies at the shop on a regular basis and the Jet-Hot headers fit great and are easy to install compared to many offerings on the market."

Jet-Hot supplies high-quality header gaskets and bolts, but RPM strongly recommends utilizing the existing GM multi-layer steel exhaust manifold gaskets and exhaust manifold bolts, as they are proven to provide leak-free seals that never require gasket replacement. Minor trimming to the front and rear of the GM gasket allows it to slip into position over the rear bolts, facilitating installation.

After pulling the header and gasket into position on the front of the head, a single bolt is loosely threaded in. Once complete, thread locker is placed on the bolts and the header and gasket are snugged down, working from the center ports outward. The process is repeated on the passenger side (not shown), and once both headers are secure, a torque wrench is used to put 20-25 lb-ft of torque on the bolts.

The system shipped with a Jet-Hot Y-pipe and removable hi-flow catalytic converters (PN 50800, retail $485). The 3-inch diameter Y-pipe is designed with welded-in O2 bungs and is supplied with all of the hardware for installation, including high-quality band clamps, muffler clamps and O2 pipe plugs.

Integral to the modular nature of the Y-pipe are the removable hi-flow catalytic converters and off-road pipes. For owners looking to be emissions-legal, the cats can be installed. In order to avert an SES code, either the factory computer is adjusted to turn off the rear O2 sensors, or O2 sims are installed.

After reinstalling the AIR and EGR provisions, the Pontiac is raised and anti-seize is placed on the front O2 sensor threads and each is tightened securely to the header with a 7/8-inch wrench.

Although there were no misfires noted when scanning the engine on the baseline pull, the boots were showing some wear, so it was good insurance to replace the plug wires. A new set of MSD Ignition 8.5mm Super Conductor Wires (PN 32819, retail $84.95) designed for '97-'04 LS1 engines was sourced and provides for excellent EMI shielding. The wires feature OEM-quality dual-crimp terminals and a proprietary blend of silicon and synthetic materials that will allow them to withstand heat and abrasion. The attractive plug wires are available in red (as shown), or black for a more stock-like appearance. The plug wires were then installed onto the plug ends and the coil pack and dipstick tube were reinstalled on the passenger side.

The completed header and Y-pipe combination fits snugly under the car and will provide excellent ground clearance. A set of Caspers Electronics O2 Sensor Extensions (optional, PN 109006, retail $24.95) were purchased and installed to ensure that the rear O2 sensor connections could be routed to RPM's satisfaction. Although the rear O2 sensors will not be functioning, they will have no detrimental effect on engine operation. The function of the rear O2 sensors is to monitor the temperature and "operational effectiveness" of the catalytic converters but plays no function in closed-loop computer air/fuel management, other than to trigger functionality in the computer to prolong the life of the converter. (For example, cat-overtemp protection will add fuel and reduce timing once the sensor detects a specific temperature has been reached.)

The Y-pipe is assembled by slip-fitting the pieces together, then carefully tapping the components toward the headers to get everything aligned and seated. In this case, the owner opted to use the off-road pipes rather than the high-flow cats. Once satisfied that the Y-pipe was properly aligned, the supplied exhaust and band clamps are tightened down securely.

With the headers and Y-pipe installed, a set of NGK TR6 spark plugs (retail $2.25 each) was installed to replace the factory Delco plugs. The stock plugs were factory gapped at 0.060, but had visible electrode wear and a gap that had grown to 0.067. Although the TR6 plugs are one heat-range colder than stock and gapped at 0.038, they're proven performers in the LS1 and will help to reduce cylinder temperatures and prevent pre-ignition.

The LS6 intake manifold used on the C5 Z06 Corvette and all '01-and-newer LS1 engines offers increased plenum volume and additional airflow over the LS1 intake. SLP Performance offers a cable-activated version of the LS6 intake manifold that retains full EGR functionality for $549.95 (PN 30041). It includes a pre-drilled hole and EGR tube and new intake manifold gaskets, along with a MAP sensor. Since the LS6 manifold sits deeper into the engine valley pan than the LS1 (to support more port volume), the front and rear coolant pipe assembly on the LS1 is replaced with the supplied LS6 pipe assembly, covers and seals.