Editing VTEC (section)

=== K-Series ===
{{main|Honda K engine}}
{{Unreferenced section|date=July 2013}}

The K-Series engines have two different types of i-VTEC system implementations. The first type is for performance engines like the K20A2 or K20Z3 used in the 2002-2006 [[Acura RSX|RSX]] Type S or the 2006-2011 [[Honda Civic Si|Civic Si]] and the second type is for economy engines like the K20A3 or K24A4 used in the 2002-2005 [[Honda Civic Si|Civic Si]] or 2003-2007 [[Honda Accord|Accord]]. The performance i-VTEC system is basically the same as the DOHC VTEC system of the [[Honda B engine#B16A4|B16A's]]. Both intake and exhaust cams have three cam lobes per cylinder. However, the valvetrain has the added benefit of roller rockers and VTC continuously variable intake cam timing. Performance i-VTEC is a combination of conventional DOHC VTEC with VTC (which operates for intake valves only). The VTC is available in the economy and performance i-VTEC engines.

The economy i-VTEC used in K20A3/K24A4 engines is more like the SOHC VTEC-E in that the intake cam has only two lobes, one very small and one larger, as well as no VTEC on the exhaust cam. At low RPM only one valve on the intake opens fully, promoting combustion chamber swirl and improved fuel atomization. This allows a leaner air/fuel mixture to be used, improving fuel economy. At higher RPM, both intake valves run off the larger intake cam lobe, improving total air flow and top-end power.

The two types of engines are easily distinguishable by the factory rated power output: the performance engines make around {{convert|200|hp|abbr=on}} or more in stock form, while the economy engines do not make much more than {{convert|160|hp|abbr=on}}.