With a little help from our friends at Tune Time Performance, we were able to find a willing TrailBlazer (owner Jim Skeenes) in which to test the new FAST (Fuel Air Spark Technology) truck intake manifold (FAST LSXRT 102mm cathedral port). Let us begin by saying this was the most impressive stock replacement-type intake manifold we ever tested. Having a forced induction (turbo) combination to enhance the higher airflow volume of the FAST truck intake certainly helped make for huge power gains. However, the LSXRT intake is clearly taller and has longer runners, which enables it to move a greater volume of air than the LS3 and LS7 car intakes. We could see using the LSXRT intake on a LS-powered car (like an '80s G-body) without the hood/cowl clearance concerns to maximize engine performance on a cathedral port combo.
Recent tests with the FAST LSXR 102mm on Tune Time Performance's supercharged 2010 Camaro SS produced some great results. However, the notoriously tight engine bays on late-model F-bodies and Corvettes, which also have limited hood clearance, restricted the runner length (and shape) that FAST could design into its car-designated intake manifold, which adds high-rpm horsepower (above 5,000 rpm) without the massive mid- and low-end benefits of the truck version. We were anxious to test the FAST truck piece knowing it would boost mid-range torque like an old tunnel-ram manifold of yesteryear. Trucks and SUVs really benefit from bottom-end torque and a broadened power curve to get their added weight rolling. That's a good reason why the stock GM truck intake is taller than the car unit.
Eventually, down the road we'd like to see a four-way shootout (engine dyno) on both the stock intakes (car and truck) and the FAST units using a popular build-type LS engine. Each intake would demonstrate the gains in the power curve to help determine the right intake choice for the intended combination (gearing, converter, weight, etc). For now follow along and see how admirably the FAST LSXRT 102 intake performed in this test. As a side note, we think a naturally aspirated LS2 would have shown roughly half the gains we realized using a boosted TBSS. Still, half the gains are impressive numbers from just an intake swap.
We needed an LS-powered pickup...
We needed an LS-powered pickup or SUV to flog the new FAST LSXRT (Race Truck) 102mm intake manifold and thankfully Jim Skeenes, one of the many TrailBlazer SS customers of Tune Time Performance, was happy to loan us his turbocharged '07 model. His TBSS features Manley forged pistons, H-beam rods, CNC-ported 317 casting heads, Comp/Tune Time custom turbo cam (with over 0.580-inch lift and duration in the 220-230 range on the intake, 230-240 on the exhaust), SLP headers and exhaust, methanol injection, and an 82mm Precision turbo.
The stock intake is tucked...
The stock intake is tucked tightly under the cowl/firewall of the TBSS. Fullsize pickups, Tahoe, Suburban, H2 Hummer, and Cadillac Escalades offer more underhood clearance. Before intake removal, be sure to disconnect the negative battery cable. Fuel pressure was relieved by depressing the Schrader valve, then the fuel line was disconnected from the fuel rail.
After removing the air tube,...
After removing the air tube, MAP, MAF, and electronic throttle body plug, fan, and serpentine belt, Tune Time's George Hatzinikitas (aka Huzzy) unbolted the alternator. Next, he unplugged the fuel injectors, vacuum lines, rear brake booster line and moved the wiring harness out of the way. To ease the R&R process he unbolted and removed the coil pack assemblies mounted on each valve cover.
Once the 10 intake manifold...
Once the 10 intake manifold bolts were loosened, the stock manifold was carefully lifted and removed. The coolant was drained and the coolant crossover tube was removed to make room for the new intake.
Left to right: the FAST truck,...
Left to right: the FAST truck, stock truck and stock '10 Camaro intake. It's obvious the stock truck intake won't fit under the hood of a C6 or F-body, but it does what it's designed to do-help develop low-end torque to get the heavier hulks moving. The car intake with its shorter runners will usually develop better top-end power (depending on the combo). It appears the FAST truck piece is roughly an inch taller than the stocker it'll replace. It's made for GM trucks with the 4.8L, 5.3L, and 6.0L from 1999 to present with cathedral-port heads (where hood clearance is not an issue).
Looking at both the truck...
Looking at both the truck intakes from behind, it's simple to see the FAST unit is taller. Vacuum nipples are present for the brake booster and MAP sensor. It's designed with longer, straighter runners to deliver a stronger average power range. This two-piece manifold can easily be taken apart to be ported and polished.
Tune Time Performance mid-mounted...
Tune Time Performance mid-mounted this large 82mm Precision Turbo. It provides the well-worked, meth-injected, intercooled LS2 with 11 psi of safe boost. This TBSS has run a best of 11.7 with Third gear slipping (and transmission failure). A fresh rebuild of the trans was performed right before we began the intake swap. Check out GMHTP's website for an update once we have a chance to get the TBSS back to the track.
In order for the FAST intake...
In order for the FAST intake to fit, the stock lifter valley plate (hex-headed) bolts need to be replaced. Button-head cap screws are provided with the FAST intake and are tightened to 18 ft-lb.