Koyama was up until the wee hours of the morning the night before our photo shoot to complete the air intake on the KRL FRP hood, which forces air toward the external wastegate. He also had to build an air guide that directs air from the central air intake directly onto the exhaust manifold, an area that suffers from extreme heat build-up on the EVO X. (This part was actually removed for the pictures because it completely covers up the manifold and turbine.) The car's aesthetics are completed with race-inspired carbon mirrors from M-sport and a set of Enkei Sport RC-T4 18-inch wheels wrapped in sticky 275/30ZR18 Hankook Ventus TD semi-slick tires.
Koyama's relationship with some of Japan's most noted names in the manufacturing of high-end performance parts means his EVO X is fitted with some of the best components out there, including the Zeal Super Function Type-E adjustable suspension kit. These race dampers sport remote piggyback tanks for easy adjustments and are mated to KRL prototype suspension links, which are still in the testing stage.
Braking is up to the most advanced calipers Endless has to offer, the Mono 6 (six-pot monobloc calipers) at the front and the Mono 4 (four-pot) at the rear. Joining these are e-slotted two-piece rotors, 380mm up front and 330mm at the rear, topped off with special race Endless pads that combine to make a braking system that wouldn't be out of place on a Super GT car.
As you can imagine, under the hood is where this EVO X really inspires. Koyama certainly likes to push the limits with every project car he takes on, and this build required a lot of custom and special-made parts. The bottom end has an all-new KRL stroker kit that pushes capacity to 2,281cc, a bit off the 2.3-liter mark; it's comprised of a special crankshaft, lightweight H-section connecting rods and 86.5 mm forged pistons. Sealing the aluminium block to the head is a 1.2mm KRL metal head gasket that makes sure the engine can cope with all the boost the oversized turbine can throw at it. The head is fitted with KRL 264-degree camshafts on the intake and wilder 272-degree ones for the exhaust side along with adjustable-slide-type cam pulleys.
Koyama called in the help of Blitz on this project, which supplied a prototype turbocharger to be used on the 4B11 along with a custom-made exhaust manifold. Boost control is up to the Blitz Type-E external wastegate that barely fits cramped between the engine and firewall. Koyama explains that this is one of the biggest problems of the new-gen engine, which due to tightening emissions control, has been rotated 180 degrees compared to the 4G63 that powered the previous generation of EVOs. This helps keep the exhaust side hotter, helping the catalyst do a better job of cleaning exhaust gases, something that isn't the priority on a performance-tuned engine. For this reason, Koyama has had to direct as much cooling air as possible to this area.
While at Ebisu, D1 driver Naoto Suenaga took the EVO X out for a series of set-up runs, and Koyama was very happy the new vents worked well to keep the exhaust side much cooler. Once the air has been sucked in from the custom carbon KRL airbox, it's then compressed and sent on to the Blitz intercooler that Koyama positioned in a wide V-mount configuration with a Koyo radiator. This allows for the best possible cooling to be achieved as well as keeping piping to a minimum to help throttle response. The pièce de résistance, however, is the NTS billet intake plenum that works wonders for increasing engine response and supplying an equalized amount of air to all four cylinders. This is joined by the new NAPREC 80mm mechanical throttle body, replacing the far-too-modern-for-its-own-good electrical throttle system of the stock 4B11. Fueling is handled by four Sard 1,000cc injectors, fed by a Sard fuel pump that works hard in the car's trunk.