Welcome to the dark side. We have airflow, an amazing intake port design, an incredible aftermarket. Coming soon, to a swap near you - the Honda K20 and K24

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So first, a bit of history. The K20 first appeared in 2001, very soon after Honda's F20C engine that heralded many of the amazing technologies we would see in the K20. The first cars to get the K20 engine in 2001 were the JDM EP3 Civic Type R and the Integra Type R. Europe got the K20 in the same year in their version of the Civic Type R. Australia and New Zealand got their K20 in 2002 in their Honda Integra Type R. USA got it's first K20 engines in 2002 as well, in the Acura RSX and the Civic Si. The first K24 engines also appeared in 2002 in the Honda CR-V and the JDM Accord Type S. Very soon after this the K20 and K24 engines spread like wildfire throughout the Honda model range, powering much of it's vehicles (anything from the Honda Odyssey to the Honda FR-V and many cars in between)

Today, 19 years after it's introduction the Honda K20 and K24 engines are still as popular as ever, surrounded by an incredible aftermarket, enthusiasts, tuners and racers all around the world seem to be creating ever more impressive builds. This is likely the greatest testament to the brilliance of this engine's design.

But not all K20 and K24 engines are the same. They differ between each other substantially and can be divided into performance and economy versions on the K20 and K24. The performance and economy versions are different from the very core. Inside a k20a3 engine for example you will find a forged steel crankshaft, while inside a k20a2 or a k20z1 or k20z3 engine you will find a forged steel crankshaft that is also fully counterweighted, something that's important if you want so spend a lot of time in high rev range. The connecting rods and pistons are different too. Performance k20 and k24 conrods are beefier with a higher tensile strength. Pistons are cast and have molybdenum coated skirts in all k engines, but they feature noticeably larger domes for higher compression in performance k20 and k24 Honda engines.

But perhaps the biggest different is in the v-tec system of these engines. Both performance and economy honda k20 and k24 engines feature i-vtec, which adds intelligence to v-tec. In reality it adds camshaft phasing, the ability to advance or retard camshaft timing based on various inputs given to the engine's ECU. Now performance i-vtec features has three two different camshaft profiles, a mild one for low rpms and an aggressive one with higher camshaft duration and lift for higher rpms. In addition to this it has VTC, which is the variable camshaft timing we already explained and described. In contrast to this economy ivtec functions in a different way. At low rpms in opens just one intake valve fully and the other only slightly to prevent fuel from pooling behind the valve, this saves fuel and improves emissions. At higher rpms both valves are opened, but lift and duration remains unchanged. Also, economy i-vtec doesn't have VTC and has nothing variable on the exhaust valves.

Another important feature of the Honda k20 and k24 is a narrower valve included angle, compared to older Honda performance engines such as the B16 or B18. This enabled engineers to design an optimal intake port shape and maximize airflow. Stock K20 heads are capable of flowing 290-300 cfm, which is more than impressive. The other reason why k20 and k24 heads flow so well is the size of their intake and exhaust valves. k20 engines come with 35 mm intake and 30 mm exhaust valves, while in some k24 you will find 35 mm diameter intake and 31 mm diameter exhaust valves on some k24 engines.

The potential of the k20 and k24 means that k-swaps are everywhere now, and people have ventured well beyond the usual k20 / k24 into ek, ef, eg, civic or da integra. Nowadays k20 are often making into rwd chassis cars too.

When it comes to naturally aspirated tuning, the k20 and k24 engines are one of the few engines capable of reaching 300hp with relative ease (it's not easy) and can generate as much as 500 NA hp if you're crazy enough. But of course everyone's into forced induction nowadays and turbo k20 and k24 as well as supercharged ones abound. Bolt on kits are everywhere and you can build pretty much anything, the only limits are the thickness of your wallet and the sky. "Safe" turbo power for a stock k20 or k24 block is around 300 hp, but many people have gone beyond that, whether it's on borrowed time or not, really depends mostly on your tuning. If you're willing to spend on forged pistons and maybe even reinforce the block with some block guards, upgraded fasteners and ductile sleeves the k20 / k24 is ready to take you beyond 1000 hp.

A very special thank you to my Patron:
Daniel

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