2004 GMC Sierra Engine Upgrades - FAST LSXRT 102mm Intake Manifold

We chose the factory fuel rail bolts as the ideal mounting location of each solenoid and with all four hoses secured to the solenoids, we moved on to the wiring. Each solenoid wire was connected together and the red wire ran to the blue wire on the supplied relay and the black wire ran to ground.
We chose the factory fuel rail bolts as the ideal mounting location of each solenoid and w
Moving on to wiring the NOS window switch, we first spliced the window switch's yellow/white wire into the purple wire of the drive-by-wire harness that plugs directly into the throttle body.
Moving on to wiring the NOS window switch, we first spliced the window switch's yellow/whi
The window switch's tan wire was then spliced into the green wire coming off of one of the coils. The NOS power relay was then wired by running the red wire to the window switch's red wire, the orange relay wire was connected to 12 volts, the green relay wire to ground, and the arming switch wired.
The window switch's tan wire was then spliced into the green wire coming off of one of the

We opted to mount the NOS window switch on the driver-side of the dash, but rather than drill holes and screw it in, we used double-sided tape. The switch displays rpm, voltage, and has colored LED lights that indicate when the nitrous is armed.
We opted to mount the NOS window switch on the driver-side of the dash, but rather than dr
After covering all of the wires in the wire loom and hiding them the best we could, the nitrous was ready to go. We checked for fuel leaks, made sure the NOS window switch was reading voltage and TPS correctly, then drove to Superior Automotive in Anaheim, California, for several dyno runs. A best dyno run of 308.5 rwhp and 333 lb-ft of torque was recorded. That's 51 rwhp on a 75 shot with the factory heat-range iridium plugs. A cooler, non-iridium plug swap was in our future.
After covering all of the wires in the wire loom and hiding them the best we could, the ni
Moving on to the electric fans, we ordered Flex-A-Lite's premier electric fan kit for GM trucks, the Monster Fan 282. This dual 15-inch fan kit is designed to bolt right in place, it will pull up to 5,500 cfm, and has a Variable Speed Controller and adjustable thermostat for different applications.
Moving on to the electric fans, we ordered Flex-A-Lite's premier electric fan kit for GM t

After removing the plastic radiator cover, the intake inlet tube, and using zip-ties to keep the upper radiator hose out of the way, we used a 17/16-inch wrench, and with someone pushing on the belt to keep tension, we gave the wrench a couple counter-clockwise whacks with a rubber hammer. The fan clutch nut then gave way and we pulled the clutch fan assembly free.
After removing the plastic radiator cover, the intake inlet tube, and using zip-ties to ke
We then mounted the Variable Speed Controller (VSC) to the electric fan housing and began the wiring process. The keep the install as stealthy as possible, we used heat-shrink tubing to cover the wires and drilled small holes for each wire to be routed through the housing.
We then mounted the Variable Speed Controller (VSC) to the electric fan housing and began
The fan motors come pre-wired, all you have to do is connect them to the VSC. Each red fan wire was connected to the thermostat's yellow wire, and the black fan wire was connected to the purple thermostat wire. We used small zip-tires to keep all the wires nice and tidy.
The fan motors come pre-wired, all you have to do is connect them to the VSC. Each red fan

It was now time to insert the thermostat probe into the fins of the radiator. We made sure to insert the probe as close to the upper radiator hose as possible for a more accurate temp reading. The small probe wires were then connected to the 10 and 11 terminals on the VSC.
It was now time to insert the thermostat probe into the fins of the radiator. We made sure
After bolting the supplied mounting bracket to the radiator support, we dropped the Flex-A-Lite Monster Fan assembly in place and bolted it to the bracket using the factory hardware.
After bolting the supplied mounting bracket to the radiator support, we dropped the Flex-A
The new bracket even included provisions to secure the upper radiator hose. As you can see, the wiring is ultra-clean and barely noticeable. Not pictured, we also ran a wire to the A/C compressor wire harness, so the electric fans will kick on any time the A/C is on.
The new bracket even included provisions to secure the upper radiator hose. As you can see

We then wrapped up the install by running the large red wire to a 12-volt source and running the large black wire to a good ground. A cool new feature, the fans come on at 60% once the thermostat hits the designated temperature. This reduces the impact on the charging system as the fans can draw up to 28 amps at 100 percent duty cycle. After a 10 degree rise from the set temperature, the fans run at 100 percent to keep the engine nice and cool. Back on the dyno, the electric fans shocked all of us by spinning the wheels at 279 hp and 286 lb-ft of torque. A couple hours of work yielded an amazing 22 hp (before the nitrous).
We then wrapped up the install by running the large red wire to a 12-volt source and runni
It was now time to get serious, as we moved onto the FAST LSXRT 102mm intake manifold. This bad-boy is designed for serious LS1, LS2, and LS6 engines, but with its relocated higher throttle-body mount, it will bolt right into a '99+ GM truck with cathedral-port LS (4.8, 5.3 and 6.0) heads. We were curious to see how the intake would work with a stock internal and stock head-equipped LS engine. Along with the intake, we ordered the FAST billet high-flow fuel rails and throttle body adapter bracket that will mate our 75mm factory throttle body.
It was now time to get serious, as we moved onto the FAST LSXRT 102mm intake manifold. Thi
Starting this install was easy, as we simply removed the plastic engine cover and began loosening and removing sensor clips/wiring harnesses. The intake air-inlet tube was also removed and set aside.
Starting this install was easy, as we simply removed the plastic engine cover and began lo

Using a 10mm socket, the three nuts were removed holding the throttle body to the intake. The coolant crossover tube was disconnected and the throttle body was pulled free.
Using a 10mm socket, the three nuts were removed holding the throttle body to the intake.
With that same 10mm socket, all ten intake manifold bolts were removed.
After removing the fuel injector wiring harnesses from each injector, the fuel rail was unbolted from the intake and the injectors and rails were removed.
After removing the fuel injector wiring harnesses from each injector, the fuel rail was un

Once all of the remaining sensors and vacuum lines were unplugged, the intake was lifted up and out of the engine bay. We then removed the one-piece intake gaskets from the heads, vacuumed out the oil valley and heads, and then placed blue tape over the intake ports to keep debris out.
Once all of the remaining sensors and vacuum lines were unplugged, the intake was lifted u
Side by side, there's no comparison in size and intake runner length. Designed for high rpm horsepower, the FAST LSXRT intake is the perfect bolt-on for cathedral-port heads with a cam or higher-flowing aftermarket heads.
Side by side, there's no comparison in size and intake runner length. Designed for high rp
A cool perk to the LSXRT intake, is its two-piece design and the ability to remove individual runners for modification. The intake comes with the upper shell bolts loose to allow for any necessary mods.
A cool perk to the LSXRT intake, is its two-piece design and the ability to remove individ

To get the FAST LSXRT intake ready to go onto our 4.8L, we first needed to install the MAP sensor on the back of the intake. Using a 3/8-inch drill bit, we drilled the MAP port location hole and installed the O-ring-style MAP sensor using the supplied T-20 Torx screw.
To get the FAST LSXRT intake ready to go onto our 4.8L, we first needed to install the MAP
Our truck came equipped with a purge valve/solenoid and the FAST LSXRT intake has a provision for the valve, but because of the multiple applications for the intake, we had to drill out our specific location. All of the shavings were blown out of the intake before reassembly.
Our truck came equipped with a purge valve/solenoid and the FAST LSXRT intake has a provis
We were now ready to reassemble the upper shell to the intake base with the supplied Allen bolts. There are five upper shell bolts (two in the front and three in the rear) that we torqued to 70 in-lb and then went back and torqued them to 89 in-lb.
We were now ready to reassemble the upper shell to the intake base with the supplied Allen