The Honda K-series blocks haven't gotten anywhere near as much attention as their B-series brethren. Perhaps price and availability concerns are still holding up what could be a literal floodgate of tuning information for these cars. What's more, the 2002 Civic Si, junior sports car that it was trying to be, did nothing to attract new Civic buyers and win over old ones. Sure, there was a powerplant increase, but the body styling left some people wondering, "Is this a Civic or an Odyssey?"

Still, we managed to catch up with resident wrench Phi Phung as he installed and tuned a series of APEXi parts on the EP3 platformed Honda K20A3. The testing was conducted at XS Engineering on their Dynojet chassis dynamometer, with Phung following the appropriate ECU reset protocol to make the performance gain numbers more consistent.

The baseline run was conducted and determined that the K20A3 was putting down 131hp to the wheels with the peak power production essentially levelling off from about 6100rpm to redline. There was little drop-off at the end, indicating that a higher rev limit could very well unleash more horsepower.

The first item installed was the APEXi Power Intake. This "short" style unit includes all necessary adapters and a mounting pipe that's properly flanged to fit the existing OE hardware. The paper-based filter element is of the "dry" variety, meaning it does not use oil saturation in the filtering media to aid in the capture of the filtered particles. Because the filter stays in the engine bay, the installation was relatively straightforward. Final numbers put out by the Dynojet show minimal increases in the low-mid rpm range from about 3000rpm to 4200rpm. At 4300rpm, additional power is seen consistently until redline, with the overall average gain in this range being about 3hp. The new peak horsepower number checked in at 134.2hp, the intake claiming a 3.2hp peak increase over the stock airbox.

Up next was the APEXi N1 cat-back exhaust system. Again, the installation was relatively straightforward and included all the necessary hardware. This installation - as expected from a free-flowing, almost straight-through exhaust system - had a broader range of increased power. From 3600rpm, power production increased to about 4200rpm and levelled off, staying consistent all the way to redline. In that range, the engine was able to produce a consistent 4.0hp. Peak output reflected this trend; the maximum power measured increased by exactly 4.0hp - from 134.2hp to 138.2hp.

The third item installed was the first user-adjustable tuning element - the ubiquitous APEXi V-AFCII VTEC and fuel controller. In the process of hammering out the installation, Phung forgot to make notes on his final fuel, ignition, and VTEC actuation points, but he did manage to tune in an additional 8.7 peak horsepower. Most of the gains were realized in the 5500rpm to redline range, with measurable but negligible gains in the lower rpm ranges. Still, Phung's tuning managed to meet or exceed current levels, all while keeping the motor in a safe operating range.

Last in line was the nit-picky installation of the APEXi Super Ground system. We say nitpicky not because of the additional box that has to be mounted, but more for the nature of grounding systems which gain their power, if any, by trial-and-error placement of each individual ground "arm." After some time, Phung managed an 0.8 peak horsepower gain, with the additional power concentrated in the 3600rpm to 6000rpm range. Above and below this range, horsepower gain was negligible but never fell below the previous marks.

As is the case with most parts, there is always room for improvement, especially when it comes to parts that are user-adjustable - we're thinking specifically of the V-AFCII and the Super Ground system. Both of these items can, and should, be readjusted when any changes are made to the system. Subsequently, if no changes are made, these "adjustable" items may help counteract the effect of time and normal wear and tear on the system.