K20 vs K24: Everything You Need To Know

Do you know the difference between K20 and K24? Honda’s 4-cylinder, low displacement, high revving, DOHC, VTEC technology was propelled to prominence by the B-series line of vehicles.

The 12-year run of the B-series between 1989 and 2001 served as an example of high-quality engineering on a tight budget. The B-series is still cherished and praised today.

The K-series, which the B-series succeeded in, was built on the foundation laid by it. For many of the same reasons as the B-series, the K-series is well regarded; however, it also offers more displacement and higher flow statistics.

The K-series has grown its cult following as a result, there are 44 distinct versions of the Honda K-series, each with unique features and vehicle applications.

That is very crazy. The K-series contains two separate short blocks with the same design but differing deck heights within those variants. Compared to the K24 block, the deck height of the K20 is lower at 8.3 inches.

The K20 and K24 have different displacements due to the variation in deck height. The K24 and K20 have differing performance characteristics and vehicle applications since the K24’s stroke was greatly enlarged over the K20’s.

Honda K-Series Engine History

Honda created the K-series, a line of 4-cylinder engines, to take the position of the B-series. The B-series had been in production for more than a decade by the time 2001 arrived.

The Honda community was very critical of the K-series when it was initially introduced. The majority of B-series enthusiasts didn’t think their beloved 4-cylinder could be topped. Some Honda admirers still hold that opinion.

The K-series, fortunately, lived up to its predecessor in the eyes of many open-minded Honda devotees. The K-series built on an already outstanding foundation while retaining many traits that made the B-series a cultural landmark.

The K-series and B-series are distinguished most noticeably by their different displacements. The 2.0-liter K-series engine is the most prevalent, though it is also available in K24 form as a 2.4-liter engine, whereas B-series engines were available in 1.6- to 2.0-liter size ranges.

There are four distinct K20 (2.0L) engine family varieties, each with its sub-variants. The K20A, K20B, K20C, and K20Z are some examples. The 2.0L displacement, identical stroke, bore, and DOHC valvetrain is shared by all K20 models, making their engine designs very comparable. All engines in the K20 family have forged steel crankshafts and aluminum head and block construction.

Honda’s K-20 engine.

Although they share many fundamental characteristics, each K20 variation was created for a specific vehicle application. The DOHC valvetrain on every engine in the K-series lineup features some variation of i-VTEC variable valve timing. All K20s use variable valve timing, but some eco-friendly variations only have VTEC on the intake side.

The most prevalent K20 engine with the unfavorable i-VTEC-E system is the K20A3. The K20 variations vary in various ways besides variable valve timing. There are substantial differences in the compression ratios between the variations.

A prime example is the extraordinarily high 11:0:1 compression ratio of the highly desired K20A2 engine from the US-spec 2002-2004 Acura RSX Type-S. In contrast, the 9.8:1 compression ratio of the K20A3, K20A4, K20A6, K20A7, and K20A9 is significantly lower. The main distinctions between the variations are in the cylinder head and piston.

Honda K20 vs K24 Engine – Performance

The K24 has 400 more cubic centimeters of displacement than the K20. The K24 has different performance characteristics than the K20 because of its more significant stroke.

The square engine design of the K20, in which the bore and stroke are the same lengths, has its advantages. Generally speaking, honest engines blend torque and high rpm performance well.

The K20’s fair construction enables a greater redline than the K24. Many Honda enthusiasts favor the K20’s use of this feature. Most enjoyment happens at high RPMs because iVTEC initiates at roughly 6,800–7,000 rpm on the most popular K20 versions.

The K24 has an “under square” engine architecture, unlike the K20, which means that the cylinder bore is larger than the stroke length. Under-square engines generally have a larger torque output than square engines, especially at low RPMs.

For some applications, it is unquestionably the case with the K24 and a strong argument in its favor. The K24 has more low-end torque but at the expense of its high-rpm power. The K24’s significantly lower redline than the K20’s turns off some fans.

The K20 and K24 have distinct qualities that make them preferable for particular applications. Honda chose the K20 engine for its smaller vehicles like the Civic, Integra, and Accord due to its smaller displacement and lower torque number.

2023 Honda CR-V in sports hybrid.

Honda chose the K24 for its heavier, more big cars that require more torque to go forward. The Odyssey, CR-V, and Acura TSX are among these vehicles.

Honda K20 vs K24 Engine – Modification

The K-series from Honda is an excellent platform for modifications. Both K20 and K24 varieties fall under this. The K20 and K24 are renowned for their exceptional build quality and capacity to handle enormous amounts of horsepower with relative ease.

Any K-series engine may reach significant horsepower levels, but some modifications are more accessible and beneficial than others.

Generally, the performance K-series variants are more adaptable to change than the versions more concerned with the economy. The K20A, K20A2, K20Z1, and K20Z4 are the most adaptable K20 variations.

The K24A2 and K24A3 are the greatest K20 variations to modify. With factory internals, the K20 and K24 are believed to be capable of handling 280–300 horsepower with reliability. 300whp is probably the highest safe value, while several stock K-series engines deliver far more power than that. Simple bolt-on modifications work quite well on the K20 and K24.

FD2 throttle body, cold air intake, 4-2-1 header, improved exhaust, RRC intake manifold upgrade, and upgrading to the ECU are a few of the most popular K-series modifications. A full-bolt-on configuration like this will produce a horsepower output of around 220-230 hp, depending on your engine model. For not needing to open the engine, that number is quite outstanding.

Some internal modifications could result in even more significant horsepower figures. Stronger valve springs and retainers, more aggressive cams, forged pistons, a light flywheel, and larger injectors are all suitable modifications for a naturally aspirated K20 or K24 construction.

Honda K20 vs K24 Engine – Price

Price is one of the most crucial factors in the K20 vs. K24 engine comparison, especially for those considering an engine switch. It is simpler and less expensive to source a K20 than a K24 because the K20 has been around longer, and the Hondas they initially arrived in have lost value over time. This is especially true for the most popular version of each engine.

A K20A2 can currently be obtained for less money than a K24A2. When you locate one, the K24A2 engine costs more because it is typically quite challenging. Most Honda supporters advise the K20/K24 hybrid combination for this reason.

Obtaining a K24 block (not an A2) and a head for a K20A2 that costs about as much is a far more cost-effective option. This is your best option if you need the performance qualities a K24 offers but want to save money on something other than one.

Which Is Better?

With component mash-ups over the years, the Honda K-series fanbase has gotten rather inventive. The K20 and K24 are frequently combined to create hybrid engines, making them one of the most popular K-series engine constructions.

The K20 and K24 are relatively similar in many areas regarding general construction. Displacement is what separates them the most. Because the K24 has 0.4 more liters of displacement than the K20, it has different engine characteristics.

The K24 offers more low-end torque than the K20, thanks to its under-square construction. The K20, however, outperforms the K24 in high rpm performance. Based on those features, the majority of fans will choose one of these motors over the other for their unique application.

There are a few more factors to consider, even though the K20A2 head fits directly onto a K24 block, the K24 does not use an oil cooler, although the K20A2 does. Some people never use an oil cooler, while others choose to connect the oil to an outboard cooler.

This “Franken-Engine” offers the main advantages of the K20 and K24 while being a cheaper substitute for obtaining a K24A2, which may be very expensive.

The final product will be a 2.4L K-series with the K20A2’s performance iVTEC. The K24’s more substantial torque characteristics will be present in the combo motor without sacrificing the performance of Vitec’s top-end power.


One of the best inline-4 designs ever released, the Honda K-series will go down in history. They are renowned for their iVTEC incorporation, muscular build, unflappable dependability, and extensive aftermarket service.

The K20 and K24 are both excellent platforms for customization and tuning. In terms of aftermarket parts, the K20 and K24 engines are two of the most popular in the entire globe.

One of the most popular K-series mods for high power is forced induction through a supercharger or a turbocharger. The K20A2’s higher flowing cylinder head gives it a minor advantage over the K24 as the best engine for a boost.

Avatar photo
About Matthew Webb

Hi, I am Matthew! I am a dedicated car nerd! During the day, I am a journalist, at night I enjoy working on my 2 project cars. I have been a car nerd all my life, and am excited to share my knowledge with you!

Leave a Comment