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Photo Gallery for the Article "Learning Curve"

LEARNING CURVES AFFECT HORSEPOWER CURVES, so as Javier Loarca can attest, with greater knowledge comes greater horsepower. Loarca had raced an all-motor pro class car for a number of years. There he learned about making power without boost or nitrous oxide. When his all-motor racecar was sold, he purchased this Civic EG hatch as a commuter in 2007. But a short matter of time brought him back to racing as he sought to do something a bit different. Not only would he embark on a forced-induction journey, he would do so with Honda’s newer K-series powerplant instead of the B-series he was accustomed to.

Special K

The quest for big power and quicker times started under the hood. Despite the aftermarket being slow to embrace Honda’s K-series engine, Loarca was determined to power his EG with the new mill. He states, “I wanted to do something different. Honda’s B-series has had over 15 years of development and high horsepower examples are not uncommon. But not many have gone very far with the K-series since it first appeared in the EP3 Civic in 2001. Building a turbocharged K-series was a challenge that I looked forward to.” A 2.4-liter K24A2 block sourced from an Acura TSX formed the foundation of the build. RS Machine reinforced the block with ductile iron sleeves before boring the cylinders to the factory spec 87mm. A set of 9.5:1 compression JE Pistons filled the cylinders, making the connection to a Honda S2000 AP2 crankshaft by way of GRP aluminum connecting rods. The direct fitment of the S2000 crankshaft made the build straightforward and de-stroked the engine from 99mm to 90.6mm. The new displacement now calculates to 2,155cc.

Help From Little Brother

While Acura equipped the TSX with the larger K24 engine, the higher-flowing i-VTEC head from the 2.0-liter RSX reigns supreme in the world of K-series engines. Not only are the K20A2 ports larger, the i-VTEC functions on both the intake and the exhaust cams for maximum tuning flexibility. Loarca sourced a K20A2 head and reinforced the valvetrain with Supertech springs and titanium retainers. These improvements keep the valves from floating when engine speeds exceed 10,000 RPM. ARP head studs crush a Cometic MLS head gasket to ensure a good seal.

Big Boost, Big Snail

Venturing into the world of forced induction, Loarca turned to the manifold experts at Full Race. A stainless-steel manifold channels spent gasses from the exhaust ports to the divided inlet of the Precision Turbo & Engine GT42R turbocharger. Aluminum intercooler piping joins the compressor discharge with a Full-Race intercooler en route to an IPS Motorsports intake manifold. An 80mm Accufab throttle body regulates the incoming aircharge as it is distributed to each of the intake runners. As the air is distributed to each combustion chamber, monstrous DeatschWerks 2,300 cc/min injectors supplied by an Aeromotive Eliminator fuel pump deliver VP Import racing fuel for combustion. To regulate fuel delivery and spark timing, a Hondata K-Pro III engine management system was employed. With a Hondata boost control solenoid regulating the dual TiAL Sport wastegates to 42 psi, the Civic generated an incredible 1,125 horsepower and 725 lb-ft torque on Church Automotive’s Dynapack dynamometer.

Gearbox Blues

While big power and torque numbers spell success for the engine, it spells certain doom for the driveline. A Competition Clutch does the job of transferring power from the crankshaft, but the factory Honda transmission just wasn’t designed for this amount of horsepower and torque. After destroying five factory bell housings, a solution had to be found. Working with Tyler Hara from Cosworth USA and his friend Eric Valdez, a billet aluminum bell housing was machined to handle the duty. The transmission was then fortified with a four-speed, dog-engagement gear set from Frana Gears and a torque-biasing differential from Quaife.