2006 Pontiac GTO Sleeper: Please Do Not Disturb

    When the new GTO was introduced in model year 2004, many classic Goat owners scoffed at the idea that Pontiac put its beloved designation on what a few called a "hopped up Cavalier" from Australia. Now that some of them have actually had the chance to drive-or ride-in one, many have realized how much the vehicle has to offer, especially if the GTO's refined, but not too intimidating, appearance was used to its advantage by building a street sleeper.

    Not everyone failed to recognize the GTO's greatness or its sleeper potential back when it was factory fresh, however. Rick Tirado, a United States Marine from Jacksonville, North Carolina, realized it in February 2006. He was at a Pontiac dealer to trade in his BMW Z3 for a Solstice. He had no idea the division began selling the GTO again, so he inquired about it. He took a peek inside and was pleasantly surprised at how nice the fit and finish was. That wasn't what he was really interested in, though. When he popped the hood and saw a 6.0L 400-horsepower LS2 staring back at him, Rick decided the Solstice could wait while he took the GTO out for a quick spin. That day, he drove home in a six-speed Phantom Black Metallic '06 GTO.

    A 400hp LS2 should be enough for most sane people, but not Rick. He was fully aware of the aftermarket potential of this fuel-injected mill, thanks in part to frequenting www.LS1GTO.com. So from day one, he knew he was going to add more power.

    The first modification he made was an STS rear-mounted turbo kit. This unique system delivered a bone-crushing 550 hp to the rear wheels. The STS not only helped Rick destroy his Nitto tires, it also retained the Pontiac's incredible streetability and fuel efficiency. Even with all that power and economy, Rick still wasn't satisfied with the GTO's performance. "The car was able to keep up with higher horsepower cars from a roll, but at the track it didn't reach the full 10 psi of boost until Third gear. By that time, I wasn't able to catch up."

    In June 2007, Rick received orders to move to North Carolina, so he really began to tear into the Pontiac before he left. The STS Turbo Kit provided him with adequate performance, but he wanted more. This time around, his goal was a sharp increase in power, while retaining the poised street manners that originally attracted him to the new Goat.

    He contacted late-model GTO specialist Tom Tiberio, of Tiberio Performance in Tampa. Tom instilled in Rick the confidence that he could provide the Pontiac with the power he sought, while still being very driveable and comfortable. "Tom's attention to detail and craftsmanship are evident in every car he does," Rick says. Thus began the GTO's performance makeover.

    The aluminum LS2 block was in perfect working order, but the increased boost levels would be better contained in cast iron, according to Tom. An LQ9 iron-block was chosen for its great reputation for durability when used with forced induction. It was sent out to Eisele's Automotive Machine in Tampa to receive all the machine work. While there, it was bored 0.030 over to 4.030 inches, achieving a 370ci displacement when combined with the LS2's 3.62-inch stroke nodular cast iron crankshaft. Eisele's polished the crank and chamfered its oil holes to improve high-rpm oiling (and an SLP high-volume oil pump was utilized to increase flow). The rotating assembly was balanced for smoother operation, resulting in more power.

    After the block returned from Eisele's, Tom began to assemble the engine in his shop. Forged 4.7cc dished Diamond pistons (and rings) lowered the compression to a more boost-friendly 9.2:1 and were attached to forged Callies Compstar connecting rods. The bottom end also gained strength from a set of ARP main studs, while Federal Mogul bearings increased durability.

    The valve events are controlled by a Flow Tech roller camshaft with 230/228-degrees duration and 0.612/0.600-inch lift on a 115 LSA. Rick conscripted Jeremy Formato's Fasterproms in Tampa to port and polish the stock No. 243 LS6 heads. These heads also benefit from a set of 1.7-ratio Scorpion aluminum roller rockers, dual valvesprings, and ARP head studs.

    Next, Tom installed an APS Twin Turbo kit on the Goat. According to APS, this will provide a more balanced application of power and reductions in the back pressure, cylinder pressure and temperature imbalances from cylinder bank to cylinder bank than a single turbo on a V-8 configuration. APS also promises better low-end and mid-range boost response using its twin moderately-sized turbos instead of a single large turbo. "These turbos build boost almost instantaneously!" exclaims Tom.

    APS says its turbos "are based upon custom Mitsubishi gasoline-spec [units] with an Inconel 713C turbine wheel, liquid-cooled bearing housing (50 pounds per minute mass airflow at 18 psi), APS single-entry 0.84 A/R turbine housing with external wastegate port/provision and APS-designed and manufactured 0.65 A/R compressor housing."

    They are lubed and cooled by oil, as is common practice, but heat is further dissipated by engine coolant via passages around the bearings. Reducing bearing temperatures eliminates the coking and lacquering issues suffered by turbos cooled with oil only. APS High Volume Twin Vent blow-off valves are employed as well.

    This kit places the turbos nearly out of sight, making for a particularly unassuming engine bay appearance when a factory intake manifold is installed. That isn't the case with Rick's Pontiac, though. To complement the increased airflow capability, Tom installed an Edelbrock Victor Jr. intake manifold with a custom intake elbow. Made by Smitty's Speed Shop in Sarasota, Florida, this elbow allowed Tom to reuse the factory fly-by-wire 90mm throttle body. The mass air meter was removed and the system was changed over to speed density. This makes it easier to tune the car on forced induction, according to Jeremy. Smitty's also crafted a set of coil pack relocation brackets and valve covers, giving this GTO an ultra-clean look under the hood.

    The factory fuel system wasn't adequate to feed the beast and meet the increased fuel demand. APS's kit includes 60-pound injectors, and Tom kicked up the fuel flow further by replacing the factory fuel pump with an Aeromotive A-1000. He also installed an Aeromotive boost-referenced regulator for precise pressure control. This extreme combination provides Rick with the option of increasing the power levels down the road.

    Once the hood is closed, there's little inkling to the power that lurks underneath. Rick wanted to increase efficiency and retain this sleeper look so he used APS's intercooler since the company paints it flat black for a super-stealthy feel. The goal of the APS unit is to "achieve the maximum-charge air temperature drop with the lowest possible pressure drop across the entire intercooler system."

    But the increased cooling efficiency didn't end there. A Devil's Own progressive alcohol kit was used to lower the intake charge temperature even further and allow for more boost on pump gas.

    Exhaust exhales into the APS iron manifolds where the pressure is routed to each turbo. Excess pressure flows through custom 3-inch pipes and high-flow catalytic converters. Rick's GTO utilizes a set of Magnaflow mufflers that effectively quiet the roar of the beast, yet flow very well at high power levels. This gives the GTO a tame sound-until he rolls into the throttle.

    He rows through the gears of this stock T-56 using a GMM Race Shifter and a Bird of Prey Talon clutch. Now that the power levels are soaring, Rick is planning to fortify the weakest links of the Goat. The T-56 will be freshened up soon, receiving stronger internals and a viper input shaft. While the transmission is out, the stock two-piece driveshaft will be replaced with a one-piece unit. Rick has decided to replace the stock rearend center section with an 8.8 rear, which has greater power-holding ability to better withstand whatever boost levels are thrown at it.

    Currently, the GTO has BMR Drag Bags to minimize wheelhop on launch. To help hook it up at the strip, Rick installed a set of 275/40-17 Mickey Thompson drag radials mounted to the factory 17-inch wheels. On the street, he prefers a set of TSW Montage wheels measuring 18x8-inch front and 18x9.5-inch rear with 245/40-18 and 275/35-18 Bridgestone Potenzas.

    Once all the parts found their way into the GTO, Jeremy took to the laptop for tuning. Rick claims, "Jeremy was able to make this musclecar drive and feel like stock until you mash the throttle." The current setup is good for 12 psi boost where it made 700.86 rear-wheel horsepower and 648.10 rear-wheel torque on the dyno. This kind of stimulus propelled the Pontiac to 132mph trap speeds on its first trip down the quarter-mile during a private track rental. "I haven't had enough time in the saddle," Rick states. "It's already a 10-second capable car, even if the driver isn't. My only goal is to have a 10-second, truly comfortable, daily driver."

    He is also planning to install an unobtrusive 10-point rollbar and add the required safety mods to make the GTO NHRA-legal to run in the 10s. Once this and the upgrades to the driveline are completed, he will increase boost even further. Until then, Rick will continue to terrorize the streets of Florida and North Carolina.

    Copious power production, a sleeper appearance and the potential devastation that this GTO can unleash on anything that crosses its path lend credence to the idea that the GTO badge has in fact found a worthy recipient.