Working 'round-the-clock hours is nothing new for the team at Skunk2 Racing as they endure the sweltering Norco, Calif. heat, with a concerted effort to complete the 700hp beast. We asked Skunk2 head engineer/mechanic Jeff Giovino what motivates this hard working crew in building their first highly publicized turbocharged engine. With a smile on his face and a look of content, Giovino simply stated, "The fun part was getting away from all the N/A engines we've been known to develop and finally see some big horsepower numbers with a turbocharged setup. The other was being able to use Honda B-series parts in the K powerplant. For me... that was pretty exciting."
While the Skunk2 engineers were busy developing the powerplant for the RSX-T, the rest of the crew dedicated themselves in prepping the vehicle's chassis to handle the rigors of the street and road course testing that would ensue after the build. The door structure remained in factory condition due to safety issues, if for unfortunate reasons, the vehicle was t-boned while driving on the street. The rest of the vehicle interior pieces received a snip here or a chop there at miscellaneous sections. One area that proved to be advantageous in lightening was the rear quarter panel, which was quickly sawed away and thrown in the scrap heap. Using lightweight stainless-steel metal to replace a large portion of the rear floorboard was another victory for the Skunk2 team in a quest to remove serious weight. Buckets and trash bins lined with skeletal pieces of the RSX were put on a scale in anticipation of how much poundage was really removed from the vehicle. Without compromising the safety of the driver and keeping the cutting and removal to a minimum, the total weight reduction was recorded at 196 lbs. A quick rundown of the parts in correlation to their weight was recorded as the chassis and body components removed 94 lbs.; sound deadening, 14 lbs.; seat belts, 8 lbs.; bumper support, 24 lbs.; and the air conditioning components tore off 56 lbs.
Unibody vehicles were designed as a cheaper solution for manufacturers. Unfortunately, for the more performance orientated individuals, owning a vehicle with unibody construction almost always meant that there was unwanted flexing within the chassis when looking to build a race machine. Chassis rigidity is all-important, and know that this vehicle was built for one purpose and one purpose only; to dominate the front-wheel-drive class at Buttonwillow Raceway. Skunk2 found that injecting expanding urethane foam in the hollow rails of the subframe was key to maintaining a more rigid chassis. Although expanding foam is never a replacement to owning a full roll cage, the advantages of keeping the car more streetable is one reason why this liquid-to-foam solution was used. Carefully blending the two-part mixture, the liquid substance was quickly poured into the open crevices of the body and sealed off with tape to prevent excessive expansion within the exterior of the frame. The liquid concoction quickly reacts, causing it to foam and ooze into the frame rail-eventually drying to a rock hard consistency. Along with plugging every orifice of the Acura's frame with urethane foam, the team took a chomoly piece and welded in a stabilizer bar directly under the factory dash, solidifying both a-pillar sections. One of many ingenious tricks that Skunk2 has up their sleeve.
Skunk2 turned towards the expertise of forced induction guru Todd Kaneko as their technical consultant to determine specific turbo sizing to rocket the RSX to the 700hp level. Factoring in exact specs on engine bore, stroke, and compression ratio, Kaneko selected a custom turbo setup using a GT-35R Tial Turbocharger, manufactured by Garrett Turbo. Consisting of a 56 trim compressor wheel and .70 A/R compressor housing with a custom spec turbine housing, the GT ball-bearing turbo is a superior design over the more conventional journal bearing turbos. "We selected this turbo with the ideology that boost response would be beneficial for the K20 and full boost would be achieved quickly at lower rpm's," states Giovino. Skunk2 enlisted the combination of a Tial 50mm blow-off valve and Tial F46 external wastegate as a means to control boost pressure and prevent unwanted boost creep. Noteworthy features of the Tial wastegate include high-temperature silicone Nomex, a reinforced actuator diaphragm rated to 4 bar and a valve seat comprised of Nitronic 60 stainless steel.