Japanese Power With Help From Cosworth
As a professional racing team, SSE left little to chance in the quest for time- attack domination. Cosworth Racing’s many years of involvement with a wide variety of motorsports made them a logical source for a powerplant. In the process, they received an added bonus: the technical advice of the team at Cosworth Racing USA. The engine build started with a brand new 4G63 shortblock, complete with Cosworth forged-steel rods, forged-aluminum pistons and stroker crankshaft. This combination increased the displacement of the EVO VIII to 2,235cc. To make the most of the added displacement, a higher- flowing Cosworth CNC-ported, big-valve cylinder head was mated to the 4G63 block. The enlarged ports and larger valves work in conjunction with high-lift, long-duration Cosworth M3 camshafts to improve airflow and horsepower output. A Cosworth 1.3mm head gasket provides a positive seal between the head and block, while Cosworth H-11 tool steel head studs deliver the clamping force to keep the longblock together.
More Displacement, More Boost
Taking advantage of the increased displacement, a Garrett GT3582R turbocharger was chosen to provide boost pressure. Relative to the stock turbocharger, the larger GT35R turbo would ordinarily create more boost at the expense of additional lag. However, thanks to the added displacement, this large turbo still provides adequate response. Response is also optimized through a Full Race exhaust manifold that feeds exhaust gasses into the Garrett turbocharger. The equal-length manifold supplies exhaust pulses to the turbocharger smoothly for steady and seamless spool up. A custom SSE turbo-back side-exit exhaust channels spent gasses to the atmosphere through the right side skirt. On the cool side, compressed air exchanges heat within a custom Garrett intercooler core. The cooler, denser air then flows through custom piping to the big Accufab 80mm throttle body and HKS Kansai intake manifold.
Fuel For The Fire
Generating significantly greater horsepower would require an improved fuel delivery system. SSE built a dual-pump system composed of a pair of Bosch 046 fuel pumps to draw VP Racing C16 race fuel from the Fuel Safe fuel cell. These fuel pumps deliver the C16 to a quartet of 1,000 cc/min RC Engineering fuel injectors. Fuel metering and ignition timing are handled by a Cosworth electronics SQ6 engine management system. Fuel and ignition timing calibrations were made with the assistance of a Mustang AWD dynamometer. With the SQ6 regulating boost pressure to 27.6 psi, the EVO VIII generated 629 horsepower and 515 lb-ft torque on a Mustang AWD dynamometer.
Transfer and Control
SSE chose a Tilton Engineering Carbon Clutch and lightened flywheel to transfer power from the crankshaft to the Quaife Group N Rally-spec transmission prepared by Taylor Race Engineering. A Quaife gear set replaced the factory cogs with close-ratio straight-cut gears featuring dog engagement. This gear set provides superior strength over the factory pieces and the dog engagement handles the abuse of higher horsepower and clutchless shifts. The trans- mission then sends power out to a Quaife automatic torque biasing limited-slip differential (LSD) at the front and a factory LSD in the rear. Once divided, the horsepower attacks the pavement by way of 18×10-inch Advan RZ wheels mounted with 275/35R18 Hankook C91 DOT-R compound race rubber inside each of the wheelwells.
Making best use of the improved grip also required improved stopping power. Leaving little to chance, SSE’s past experience led them back to Brembo for a brake solution that could more than handle the needs of this project. Brembo responded with its Group N Rally-spec calipers at all four corners. These ultra-stiff racing calipers endure the brutal conditions of rally racing and were a good match for the SSE EVO. The Brembo calipers squeeze Cobalt brake pads that apply friction to larger vented rotors, adding to stopping capacity and heat dissipation.
Ready To Attack
Working feverishly to prepare for competition, SSE failed to have the EVO VIII ready for the Redline Time Attack season opener at Buttonwillow Raceway. Undaunted, the team pushed to be ready for round two at Willow Springs. Making their debut appearance among a fiercely competitive field, this veteran team had much to prove to the established Redline Time Attack teams. With Formula Atlantic driver Jonathan Bomarito at the wheel, the SSE EVO turned a blistering 1:20.454 lap time on the Big Willow track, setting an AWD record and taking the DSPORT Magazine Unlimited AWD class victory. Richard mentioned that while the team was happy to claim a victory at its debut competition, SSE is constantly striving for more. With each trip to the track, something new is learned, improvements are made and room for improvement uncovered. SSE’s motto is “Continuous Improvement” and this EVO VIII certainly embodies that spirit.