The Honda Civic brags a rich automotive heritage dating back to the first generation '72 model, with its 1.2L engine delivering 60 hp. Eight generations have passed since the Civic's debut, and the most current and arguably best Civic Si comes equipped with a 2.0L K20Z3 i-VTEC engine that produces 197 hp and 139 lb-ft of torque. Coupled to a six-speed manual transmission with a helical limited slip differential, the Civic is anything but a practical four-door sedan, and handles more like a sports car than a daily commuter. While 197 hp is nothing to sneeze at, when a good friend approached us with the prospect of adding more horsepower to his Si, we couldn't resist. His car already boasting bolt-ons, after a little research, we learned rumors of a certain JDM intake manifold/New Zealand camshaft combination rumored to bring monster gains. We sourced the parts, installed them, and hit the dyno.

Prior to installing our new intake manifold and camshafts, our '09 Civic Si was already equipped with a DC Sports 4-2-1 long-tube cat-delete race header, DC Sports SCS (Single Canister System) 2.5-inch exhaust, K&N panel filter, and Hondata Flashpro-programmed ECU. With modifications thus far added to it, the Civic netted baseline power figures of 211.7 hp and 149.5 lb-ft of torque at its brakes (testing with two Dynapack dynos).

JDM '06-'10 Civic Type R Manifold

The "RRC" intake manifold found on the JDM '06-'10 Civic Type R (FD2) K20A engine is considered a hidden jewel among Honda K-series owners looking for more power, and was talked about on internet forums as the next big thing. Testimonials were written swearing that this was the best OEM intake manifold ever released.

Factory USDM Civic SI "RBC" Manifold vs. Type R "RRC" Intake Manifold

At first glance, the factory USDM '06-'10 Civic Si RBC and JDM Type R RRC intake manifolds look nearly identical, but upon closer inspection, you'll notice the RRC is more compact due to shorter, fatter runners with less curvature than the RBC's. You'll also notice a larger plenum on the RRC, along with the number four runner's (farthest to the right in our photo) smoother flowing transition with less dramatic angle from the throttle body inlet. The RRC throttle body inlet measured 2mm larger in diameter, and lacks the airflow impedance of the RBC's Idle Air Control Valve (IACV) ports; the RRC utilizes a drive-by-wire (DBW) throttle body (TB) in which the ECU controls the throttle plate to open and close at idle as needed instead of using an IACV. For those who plan to use the manifold with cable-type TBs, we suggest either machining an IACV port into the TB mounting flange or purchasing an aftermarket adapter that allows plug-and-play operation.

Because our Civic uses a DBW system, the RRC manifold was a direct bolt-on that required no modification when installed. With ambient temperatures measuring 87 degrees Fahrenheit in the dyno facility, the newly installed RRC manifold was tuned with a Hondata Flashpro by Erick Aguilar of Erick's Racing, located in Baldwin Park, CA. The engine made 225.8 hp and 157.9 lb-ft of torque-a gain of 14.1 hp and 8.4 lb-ft of torque over our factory manifold. The RRC manifold made five to eight hp and lb-ft of torque from 3,500 to 5,000 rpm, while top-end power from 5,000 rpm to redline gained eight to 10 hp and lb-ft of torque over our factory manifold.

Kelford Cams Stage 1 Camshaft

While Kelford Cams is a relatively unknown name in the U.S. Honda market, they are by no means new to the camshaft industry. Since 1968, Kelford Cams, located in Christchurch, New Zealand, has specialized in custom camshaft design and manufacturing for all types of engines, and currently supplies cams to the infamous AMS Performance time-attack EVO X. Kelford Cams' Stage 1 camshafts for the Honda K20A, K20Z, and K24A2 engines are considered the mildest and most streetable of three camshafts offered, with primary and intermediate cam lobes fractionally larger than those of the factory TSX. The main lobes on the camshafts are engineered to feature more surface area, increasing mid- to top-end performance for mildly tuned K-series motors equipped with aftermarket bolt-ons like an exhaust, header, and intake. Designed with a cam profile that's easy on valvetrain components and timing chain systems, this drop-in cam works well with OEM valve springs and retainers.

We called upon the installation services of Autowave tech Mike Lapier as we documented the process, before returning to Erick's Racing to test and tune the cams (the site where baseline testing had commenced). Located in Huntington Beach, CA, since 1985, Autowave has 25 years of experience performing Honda/Acura factory maintenance, as well as high-performance engine and transmission builds. We counted seven modded NSXs on hand the day we visited.