An accomplished driver and weekend road-race fanatic, Umemoto improved upon the factory suspension and wheel setup with two goals in mind-to obtain the ultimate in handling characteristics while maximizing the DC5's traction capability. Building some of the fastest Honda vehicles in Japan, it comes as no surprise that J's Racing would extrapolate their knowledge when building the footwork for the crimson-colored DC5 demo car. The factory struts were quickly thrown into the dumpster in favor of a set of custom J'S Racing SPL dampers (RG Version) with 30-way adjustability and a set of Swift springs with 12kg/mm up front and 20kg/mm in the rear. Adjustable rear pillowball upper arms, SPL tie rod ends and J's Racing SPL high caster pillowball lower arm assemblies improve driver feedback at the wheel and vehicle handling through the twisty mountain roads. The DC5 was also modified using a staggered front and rear wheel setup that's common among gymkhana and autocross participants. Bringing an aggressive stance to and already intimidating machine is a set of 17x8.5 Rays CE-28N's wrapped in 245/40/17 Advan A048's up front and 17x7.5 wheels with 225/25/17 tires in the rear. Seidouya R-master N1-500 Kai brake pads bite into the J's Racing slotted brake rotors as J's Racing stainless steel braided brake lines are fed an abundance of Oberon F555 Dot 5.1 brake fluid with every mash of the pedal. Blasting though the corners, the DC5 relies on an Exedy Hyper-single clutch to deliver the K20A's power to the J's Racing 5.1 final gear set and through its company branded 1.5 way limited-slip differential.
"The DC5 is an excellent vehicle, but unwanted chassis flex is one if it's major downfalls and is a common occurrence when taking this vehicle to its limits" states Umemoto. The J's Racing engineers built a 12-point roll cage in a quest to stiffen the chassis while throwing every imaginable reinforcement bar at the vehicle including a J's Racing SPL floor bar, aluminum rear tower bar, rear C-pillar bar and side inner brace. The reinforcement frenzy continued as the DC5 received an aluminum lower arm bar, rear gate bar and a J's Racing engine torque damper tower bar. With so much emphasis on the chassis, the staff wasn't about to skimp on upgrading the interior of the vehicle, especially when they knew the driver would be the head honcho. The factory seats were replaced with a pair of Recaro SP-GT alongside a set of Takata MPH-341R harnesses. Style points were awarded for interior amenities when it came to the J's Racing Titanium shift knob with blue gradation.
The term "dress up" is often used in Japan to describe exterior modifications such as body kits or trim that adorn the outer shell of the vehicle. But for Umemoto, the term seems to have a more negative connotation. "Aero manufacturers like to market their 'dress up kits' as the ideal body kit for time attack and race associated vehicles. Yet, these same companies have never tested their vehicles on the track before. J's Racing engineers have taken valuable data from our race-campaigned S2000 for the past two years and researched key points such as down force, aerodynamics and cooling effectiveness with prototype body kit testing at numerous tracks," he says. Further discussions with Umemoto revealed an otherwise unknown setback on the factory DC5 factory bumper. The factory front bumper restricts air flow, which in turn causes a rise in coolant temperature. This affects the ECU, which decreases horsepower. After months of research and hefty dollars spent on aero kit R&D, a final production kit was developed and installed on their DC5. The J's Racing carbon-fiber front bumper, carbon side skirts, J's Racing rear bumper and Type-V carbon-fiber hood all play an integral role in form and function. J's Racing Type-S canards and side wing panels were also carefully thought out and installed to deliver additional downforce to the vehicle while maintaining stability and traction.
As J's Racing continues to raise the bar in Honda performance, Umemoto and his crew work hard to prepare for their annual 2007 time attack event, held in May. According to Umemoto, "Hondas might not be regarded as the ultimate cars in Japan, but J's Racing will continue to keep the tradition alive. You can always count on J's Racing to deliver the best in engine tuning and product development across the globe."