FAQ – What is the K20 Engine?

FAQ – What is the K20 Engine?


The successor to the extremely popular DOHC B series engines from Honda, the K20 engine is the first engine in the K series lineup. Taking what was already a remarkably efficient and powerful recipe, the K20 is truly a cutting edge engine. First produced in 2001 the engine brought back K20A3 brought back the Civic SI in the form of the EP3, and was also the first i-VTEC engine.

The technology known as VTEC is well known in today’s modification circles, but it’s i-VTEC that is truly remarkable. Honda has long carried a history of racing excellence and ingenuity and the i-VTEC is simply brilliant. Meant for performance as much as emissions and gas mileage, the K20 allows drivers to have their cake and eat it too.



During part throttle operation this valve control system sets the pin in the rocker arms, retarding the closure of intake valves. By controlling the throttle electronically and opening the intake valves faster and later during the combustion cycle, Honda’s system decreases pumping losses.

Not only does the i-VTEC system combat pumping losses, but because the valves open later the combustion rate is increased due to duration. This i-VTEC system has evolved over the past 10 years, but the original K20 engine was equipped with 165hp and was cutting edge for it’s time.

It took some time for enthusiasts to start swapping these engines or importing JDM units for their donor cars, but the swap has become very straightforward today. Need a JDM K20 Swap guide, then check here.



There are several versions of the K20 engine, with the 2.0 liter ranging from the K20A, K20A3, K20A4, K20A6. Power and torque varies from each motor, while the K20A3 compression checks in at 9.5:1 – 9.8:1, there are many other versions much more suited for performance.

The K20A is the engine in the 2001-2006 JDM Inegra DC5 and Civic Type R’s EP3 raised the bar with 220 hp and a compression ratio of 11.5:1. There are many upgrades to this engine, from the chromoly flywheel and oil squirters to help cool pistons.

K20A2 is the engine that many USDM EP3 owners swap into their vehicles, and because they are found in the 2002-04 RSX Type S there’s plenty available in the US. Power checks in at 200hp and 142 ft-lbs.

The other more swapped K20 is the K20A3, found in the 2002-06 Base RSX and the Civic Si that has a compression ratio of 9.8:1 and with 160 horsepower. The later models of the 200’s have included the newer K20Z1 and K20Z3, found in the 2005-06 RSX Type S and Civic Si (FG and FA) which both keep compression around 11.0:1 puts down 210 and 196 respectively.

There are several other Euro DC5 applications as well as JDM ones that may vary specifics, but Honda didn’t want it’s new DOHC to be a one-trick pony. Not just an economic engine that people modified for performance but one that could flex it’s muscles stock as well as take care of the environment.

The new 2014 Honda Civic SI at SEMA - Image Courtesy Autoblog

The dual minded intention of performance and emissions was revolutionary in 2001, a theme that is evident in the K20 design.

Balance and efficiency with the ability of incredible power from a small displacement motor, the K20 is extremely square at 86mm of bore and stroke and displaces 1998cc. This allows the K20 to be incredibly balanced, able to deliver high horsepower and torque per liter.

The new Honda Civic Si is fast approaching, equipped with Honda’s next generation of VTEC engines that are turbocharged, we’ll always have a soft spot in our hearts for the K20.

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