The Honda K20 vs K24 Engine Comparison. It is impossible to argue with Honda’s ability to design fantastic engines. Honda’s B-series launched their 4-cylinder, low displacement, high revving, DOHC, VTEC formula to superstardom. Over the B-series’ 12-year run between 1989 and 2001, it exemplified quality engineering on a budget. So much so that the B-series is still celebrated and praised to this day.
The B-series laid the groundwork for its predecessor, the K-series. The K-series is highly valued for much of the same reasons as the B-series, while also bringing more displacement and higher flow statistics to the table. For that reason, the K-series has developed a cult following itself.
The Honda K-series has a total of 44 variants, each with their own set of characteristics and vehicle applications. That is completely ridiculous. The K-series is one of such varieties, with two unique small blocks that have the same design but have differing deck heights. The deck height of the K20 block is 8.3 inches, whereas the deck height of the K24 block is 9.1 inches. The difference in deck height causes a displacement difference between the K20 and K24. Since the stroke of the K24 was increased significantly over the K20, the two have different performance characteristics and vehicle applications.
In this essay, we will compare and contrast the Honda K20 and K24 engines.
History of Honda K-Series Engines
Honda’s K-series is a family of four-cylinder engines meant to replace the B-series. The B-series had already been in production for over a decade by the time 2001 rolled around. The K-series was first met with scathing criticism from the Honda community. Most B-series enthusiasts didn’t think their beloved 4-cylinder could be topped. Some Honda fans still believe this.
Fortunately, the K-series lived up to its predecessor in the eyes of many open-minded Honda enthusiasts. The K-series kept many of the features that made the B-series famous while improving on an already fantastic platform.
The most noticeable distinction between the B-series and the K-series is the difference in displacement. While the B-series engines vary in displacement from 1.6 to 2.0 liters, the K-series is most usually seen in 2.0-liter form, but it is also available in 2.4 liter form in the K24.
The K-series also had a different engine configuration than the B-series. Previous Honda 4-cylinder engines were noted for their counter-clockwise engine rotation. The K-series reversed this system and employed a clockwise rotation, directing the intake ports to the front of the vehicle. This facilitates exhaust modification and routing.
Engine Specifications for the Honda K20
The K20 (2.0L) engine family consists of four distinct variations, each with its own set of sub-variants. The K20A, K20B, K20C, and K20Z are among them. All K20 models have a very identical engine construction, with the same 2.0L displacement, stroke and bore, and DOHC valvetrain. All engines in the K20 family are made of aluminum and have forged steel crankshafts.
Despite their underlying similarities, each K20 variation was created for a specific vehicle application and differs slightly from the others. The K-series engines all use a DOHC valvetrain with some type of i-VTEC variable valve timing. While variable valve timing is used on all K20s, some eco-friendly variations only feature VTEC on the intake side. The most common K20 engine is the K20A3, which has the less desirable i-VTEC-E technology.
Aside from variable valve timing, the K20 versions differ in a number of respects. The compression ratios differ significantly between variations. The very desirable K20A2 engine from the US-spec 2002-2004 Acura RSX Type-S, for example, has an extremely high 11.0:1 compression ratio. The K20A3, K20A4, K20A6, K20A7, and K20A9, on the other hand, have a much lower 9.8:1 compression ratio. This comes due to changes in the cylinder heads and pistons across the models.
K20C models feature relatively low compression ratios, particularly when compared to K20A variants. This is because the K20C models are turbocharged. Lower compression is advantageous for turbocharged engines since it reduces strain on the engine’s internal components.
Applications for the Honda K20 Engine
K20A
- Honda Civic Type R (JDM) 2001-2006
- Honda Integra Type R (JDM) 2001-2006
- Honda Accord Euro R (JDM) 2002-2008
- Honda Civic Type R (JDM) 2007-2011
K20A1
- Honda Stream (RN3, FWD) 2001-2006
- Honda Stream (RN4, AWD) 2001-2006
K20A2
- Honda Civic Type R (EDM) 2001-2006
- Acura RSX Type S 2002-2004
- Honda Integra Type R (AUDM/NZDM) 2002-2004
K20A3
- 2003-2006 Acura RSX
- Honda Civic Si 2002-2005
- Honda Civic SiR 2002-2005
- 2002-2005 Honda Civic Type S
- 2003-2006 Honda Civic 2.0 i-VTEC (SEA)
K20A6
- 2003-2006 Honda Accord (EDM)
- 2003-2006 Honda Accord (ADM)
K20C1
- 2015-present Honda Civic Type R (EDM)
K20C2
- 2016-present Honda Civic LX (USDM)
- 2016-present United States Formula 4 Championship
K20C3
- 2016-present Honda Avancier (China)
K20C4
- 2018-present Honda Accord
Engine Specifications for the Honda K24
The K24A, specifically the K24A2, is the most prevalent and sought-after K24 version. The K24A2, like the K20A2, has Honda’s performance version of i-VTEC, having VTEC on both the exhaust and intake sides of the engine. Aside from the more recent K24W7, the K24A2 has the highest stock horsepower figure in the K24 family. Each K24 variation, like the K20, changed slightly in terms of compression, ranging from 9.7:1 to 11.0:1 for performance models.
The community prefers earlier K24A variations because most later K24 variants focused primarily on fuel efficiency and emissions regulations. K24Z1 and Z2 variations are updated versions of older K24A types. In comparison to K24A engines, K24Z variations include revised intake manifolds, throttle body design, reworked catalytic converters, and upgraded fuel injectors.
Engine Applications for the K24
K24A1
- Honda CR-V model years 2002-2009
K24A2
- Honda Accord Type-S (Japan) 2002-2008
- Honda Odyssey Absolute 2003-2008
- TSX Acura 2004-2008
K24A3
- Honda Accord (Japan/Europe) 2003-2007
- Honda Accord Euro (Australia/New Zealand) 2003-2007
K24A4
- 2003-05 Honda Accord (United States)
- Honda Odyssey 2003-2008
- Honda Element 2003-2006
K24A8
- Honda Accord (U.S.) 2006-07.
- Honda Element 2007-2011
- Honda Odyssey (Japan) 2008-14
- Earth Dreams (K24W)
- 2013-17 Honda Accord (United States)
- Honda CR-V (U.S.) 2015-19
K24W4
- Honda Accord (Thailand/Malaysia) 2013-present
- Honda Odyssey (Australia) 2014-present
K24V5
- Honda CR-V (Thailand) 2017-present
K24V7
- Acura ILX (2016-present).
K24W7
- 2015-2020 Acura TLX
K24Y1
- Honda CR-V (Thailand) 2012-16
K24Y2
- Honda Crosstour 2012-15
K24Z1
- Honda CR-V (RE3, RE4) 2007-2009
K24Z2
- Honda Accord LX/LX-P (2008-2012)
- Proton Perdana from 2016 to the present
K24Z3
- Honda Accord LX-S/EX/EX-L (U.S.) 2008-12
- 2009-2014 Acura TSX
- Honda Accord (CP2, CS1) 2008-15
K24Z4
- Honda CR-V (RE7) 2008-2012
K24Z5
- Honda Spirior 2010-15
K24Z6
- Honda CR-V (U.S.) 2010-11
- Honda CR-V (2012-14) (U.S.)
K24Z7
- Honda Civic Si 2012-15
- 2013-2015 Acura ILX
Honda K20 vs K24 Engine Comparison
As previously stated, the K24 has 400 ccs more displacement than the K20. The K24 has different performance characteristics than the K20 because to its longer stroke.
The square engine geometry of the K20, which means that the stroke and bore are the same length, has its own advantages. Square engines, in general, strike a fair compromise between high rpm performance and torque.
The K24, unlike the K20, has a “under square” engine configuration, which means that the stroke length is longer than the cylinder bore. Under square engines create more torque than square engines, particularly at low rpms. That is absolutely true of the K24, and it is a compelling argument in its favor for some applications. The K24’s increased low-end torque, however, comes at the sacrifice of high-rpm power. The K24 has a significantly lower redline than the K20, which may turn off some enthusiasts.
The distinct properties of the K20 and K24 engines make each engine better suited to specific applications. Because of its smaller displacement and lower torque number, the K20 was Honda’s engine of choice for compact vehicles such as the Civic, Accord and Integra. The K24 was Honda’s choice for larger and heavier vehicles that require more torque to get started. The Odyssey, CR-V, and Acura TSX are among these cars.
Design Differences Between the Honda K20 and K24 Engines
In terms of truly significant design differences between the K20 and K24, there isn’t much to say. Many parts are interchangeable across the K-series lineup, and certain K20 parts can be swapped into a K24 and vice versa. The K20 and K24 have essentially identical cylinder head designs. Having said that, there are some minor distinctions worth noting.
The design of the intake ports differs somewhat between the K20 and K24. The intake manifolds on the K20 and K24 are likewise different. The popular K20A2 variation has a PRB intake manifold from the factory, whilst the K24A2 has an RBB intake manifold. Overall, the K20A2 head flows slightly better than the K24A2 head.
Aside from that, the camshafts, springs, and spring retainers on the K20 and K24 are slightly different. The primary lobes on K24A2 cams are larger than those on K20A2 cams. As a result, K24 cams often give more low/midrange power than K20A2 cams. However, the VTEC lobes on K20A cams are more prominent, making them ideal for high-rpm performance.
K20 and K24 cams are interchangeable despite their variances. However, it is critical to understand how this will influence each engine. Because of the additional pressure on the valvetrain, swapping K20A/A2 cams into a K24 is risky. The K24’s engine geometry was not designed to tolerate the rpm that the K20 can.
Modification of the Honda K20 vs. K24 Engine
Honda’s K-series is an excellent basis for customization. This contains both K20 and K24 models. The K20 and K24 are both noted for their exceptional build quality and ability to tolerate massive levels of horsepower with relative ease. While any K-series engine may produce significant horsepower, some are easier and more worthwhile to alter than others.
In general, the performance K-series versions are more adaptable than the economy-focused variants. The K20A, K20A2, K20Z1, and K20Z4 are the best K20 variations to modify. The K24A2, and K24A3 are the greatest K20 variations to modify.
The K20 and K24 are believed to be capable of handling 280-300 horsepower with standard internals. While there are numerous examples of factory K-series engines producing significantly more horsepower than that, 300whp is about the safest amount. Both the K20 and K24 are amenable to simple bolt-on modifications.
RRC intake manifold upgrade, cold air intake, 4-2-1 header, upgraded exhaust, FD2 throttle body, and modified ECU are some of the most prevalent K-series mods. A full-bolt-on configuration like this will produce a horsepower output of around 220-230 hp, depending on the engine version.
That’s a fairly good figure for not having to start the engine.
Obviously, with some internal improvements, even greater horsepower figures are possible. Stronger valve springs and retainers, more aggressive cams, forged pistons, a lighter flywheel, and larger injectors are all viable alternatives for a naturally aspirated K20 or K24 construction.
Engine Honda K20/K24 Hybrid
The Honda K-series fans has grown very inventive with component swapping over the years. In fact, merging the K20 and K24 into a hybrid engine is one of the most common K-series engine constructions. The most typical way is to use a K24 bottom end from an Element, Accord, or CR-V with a K20A2 head from an RSX Type-S.
The K20A2 head is a direct fit on a K24 block, but there are some extra considerations to be made. The K20A2, for example, has an oil cooler, although the K24 does not. Some people choose not to use an oil cooler at all, while others connect the oil to an outboard cooler.
This “Franken-Engine” combines the best features of both the K20 and K24, while also being a less expensive alternative to locating a K24A2, which can be difficult to find. The end result will be a 2.4L K-series with the K20A2’s performance version of iVTEC. The combo motor will have higher torque characteristics than the K24 while retaining the top end power given by performance iVTEC.
Related : The Honda K20A2 Engine Manual
Engine Comparison: Honda K20 vs. K24 – Forced Induction
Forced induction is without a doubt one of the most popular ways to produce a high horsepower K20 or K24. Both engines can operate at a moderate level of boost right out of the box. As previously stated, both the K20 and K24 can safely handle 300+whp with factory internals. The same can be argued when forced induction is introduced into the equation.
There are numerous off-the-shelf FI solutions for both the K20 and K24. Both engines respond well to either a supercharger or a turbocharger, so the choice comes down to personal preference.
The Honda community largely agrees that supercharging a K20 or K24 is inefficient. If you want to achieve exceptionally high horsepower figures, a turbocharger and custom internals are the way to go.
A K20A2 head is said to be better for forced induction than a K24 head because it has higher flow numbers. The K24A2 head, on the other hand, can be ported and polished to attain similar flow figures as the K20A2. Depending on the basic model of the automobile, the K20 may possibly be a superior transmission option. The EP3 5-speed transmission is the most durable choice, according to most Honda aficionados.
Honda K20 versus K24 Engine Cost
Price is one of the most essential components of the K20 vs K24 engine discussion, especially for those considering an engine switch. Because the K20 has been around longer and the Hondas that they initially arrived in have depreciated over time, locating a K20 is easier and less expensive than locating a K24. This is especially true for the most desired form of each engine.
At this stage, obtaining a K20A2 is less expensive than obtaining a K24A2. The K24A2 is a difficult-to-find engine that commands a high price when found. As a result, most Honda fans suggest the K20/K24 hybrid pair. Obtaining a K24 block (non-A2) with a comparably priced K20A2 head is a significantly more cost-effective choice. If you desire the performance attributes of a K24 but don’t want to spend the money, this is your best bet.
Honda K20 vs K24 Engine Comparison
The Honda K-series will be remembered as one of the best inline-4 layouts ever released. They are well-known for their unbeatable dependability, solid build, iVTEC incorporation, and extensive aftermarket service.
In many ways, the K20 and K24 are fairly similar in terms of overall construction. The main difference between them is displacement. The additional 0.4 liters of displacement of the K24 results in different engine characteristics than the K20. The K24 has more low-end torque than the K20 due to its under-square configuration. The K20, on the other hand, outperforms the K24 at high rpm. Based on those traits, most enthusiasts will choose one of these engines for their specific use.
The K20 and K24 are both excellent platforms for upgrades and tweaking. In terms of aftermarket parts, the K20 and K24 engines are possibly two of the most popular in the world. One of the most typical K-series modifications for high power is forced induction, either by supercharger or turbocharger. Because of its higher flowing cylinder head, the K20A2 marginally outperforms the K24 as the best engine for boost.
If pricing is a major factor in your decision between the K20 and K24, the K20 is the more affordable alternative. If you’re sold on the idea of more low-end torque, a K20A2 head on a K24 block is a less expensive option than getting a K24A2.
