Even with hp ratings being similar, the larger engine will produce a great power curve. Add to that the extra torque…..the K24A2 is better in pretty much every way, including the fact it is built with stronger heavier duty parts.
Registered. From what I understand, it’s completely different. Your K24A2 has 3-lobe VTEC while the K24A is just intake side. With that being said, you’d at least need a new wiring harness, and probably a different ECU.
Featured in the Acura TSX, alongside the Honda Oddessey and the JDM Accord Type-S, the K24A2 was capable of achieving between 197-205hp and between 164-171 lb/ft torque.
The K24A2 has large primary (low-lift) lobes on both the intake and exhaust cams. The TSX exhaust camshaft also has larger secondary (high-lift, VTEC) lobes than the RSX-S or ITR, making it a good nominee for a swap into a naturally aspirated K20A2 engine for those interested in just staying with stock Honda parts.
This motor has no VTEC mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening. It also has smaller ports than the Type S and Type R. If using a K24a4 block the pistons will need to be swapped with aftermarket or a1, a2 pistons to avoid valve to piston contact.
The Birth of the Honda K24
While decades’ worth of experience has played a part in the creation of Honda’s K-series, we can narrow down the moment when the idea behind this engine was conceived. In 1999, Honda launched its S2000 that came equipped with the F20C. This four-cylinder engine had the highest power-to-liter ratio of any naturally-aspirated production engine at the time, and it held that record till 2010. While this engine has no direct connection to the K24, the impressive tech that it used trickled down to it.
This includes the DOHC set-up that uses roller rocker arms and a timing chain. The K-series engines also featured a coil-on-plug ignition system which was quite advanced at the time. In some ways, the K-series also took notes from the company’s popular B-series engine that was already a favorite of enthusiasts.
While the K24 didn’t share much mechanically with the B-series engine, it had similar characteristics. Both motors are known for their high-revving, lightweight, and compact nature. Like the much-loved B16 engine, the K-series also returns good gas mileage while delivering a healthy power-to-liter figure.
The K-series engines have two short blocks with the same design. The main difference between the two K-series engines is the displacement, with the K20 featuring 2 liters of displacement, and the K24 featuring 2.4 liters. The former uses a square design, with an 86 mm bore and an 86 mm stroke.
To give the K24 an extra 400 cc of displacement, Honda increased bore to 87 mm and stroke to 99 mm. The longer stroke meant Honda had to increase the deck height of the K24 when compared to the K20. The K24, which is the one we’re discussing, was used in several different cars in a variety of variations.
Honda didn’t shy away from using the K24 pretty much wherever they could. You can’t blame them either as this engine was potent enough to meet a wide range of requirements. Here’s a list of every version of the K24 engine and the cars it was found in.
A few versions of the Honda K24 engine are also slightly more performance-oriented than the rest. We’ll touch upon those variants later.
Found in: 2002-2008 Honda Accord Type-S (JDM) and 2003-2008 Honda Odyssey Absolute (JDM)
K24 engines tagged as the K24A weren’t sold in the domestic market. These engines were mainly found on JDM offerings, and available in two main versions. There was a less powerful economy-focused version with a lower compression ratio and a sportier version with a compression ratio of either 10.5:1 or 11:1. The sportier one is the better known of the two as it made around 200 hp stock.
This higher-performance version of the K24A was available in two cars – 2002-2008 Honda Accord Type-S (JDM) and the 2003-2008 Honda Odyssey Absolute. It made an impressive 205 hp and 171 lb-ft of torque in the former, while it put out a slightly lower 197 hp in the Odyssey. Torque, meanwhile, remained the same.
Found in: 2004-2008 Acura TSX
The K24A2 is considered to be one of the best ready-to-go versions of the four-cylinder engine. However, the hype around it has also led to an increase in its price tag, making it less cost-efficient than a slightly tuned version of the less popular K-series engines.
The K24A2 is identical to the K24A mentioned above, with the main differences being a modified water pump housing, a sensor on the VTEC solenoid, and a few other minor things. While the K24A has to be imported, K24A2 is readily available stateside as it came in the Acura TSX from 2004-2008. Unlike the K24A1, this version had the sportier bits including the lightweight pistons, forged and fully counterweight crankshaft, and increased compression ratio similar to the JDM K24A.
The K24A2 the TSX used in 2004 and 2005 made 197 hp and 166 lb-ft of torque. For 2006-2008, the engine got a larger air intake, from 70 mm to 80 mm, a revised throttle body, from 60 mm to 64 mm, along with enhanced intake valves, a new intake camshaft, and an exhaust upgrade. This increased the power to 205 hp but dropped the torque slightly to 164 lb-ft.
Found in: 2003-2007 Honda Accord (JDM/EDM) and Honda Accord Euro (AUDM/NZDM)
The Honda K24A3 is identical to the K24A2. It had a different designation for some international markets. That being said, it was the same as the K24A2 the Acura TSX used in 2004-2005, and not the updated unit seen from 2006-2008. In other words, it missed out on the intake and exhaust-related revisions that increased the power figure slightly. So, power and torque remained quite close at 200 hp and 171 lb-ft.
The K24A, K24A2, and K24A3 are very similar in their architecture and continue to be the best out-of-the-box swaps for enthusiasts looking to do the least amount of work.
Found in: 2002-2006 Honda CR-V
Moving on to other K24 designs, we’ll address the more economical versions chronologically, and we’ll begin with the K24A1. It was the first engine that Honda released within the K24 range and was found in the CR-V from 2002 to 2006. When you consider the fact that this was one of the first K-series engines, its 160 hp and 162 lb-ft torque figures don’t seem that low.
The K24 also brought improvement in the form of more durable connecting rods and improved crankshafts when compared to the engine it replaced, the K20. Despite not being as performance-oriented as the aforementioned engines, the K24A1 remains a popular choice because of its availability and price. Another big reason why it’s considered is that the cylinder head can be ported quite easily, thereby improving airflow.
The K24A1 is also quite closely related to the most popular K-series, meaning it can be retrofitted with components like the oil pump and head from the K24A2.
Found in: 2003-2005 Honda Accord (USDM), 2003-2008 Honda Odyssey, 2003-2006 Honda Element
The K24A4 draws inspiration from the K24A1, which means it misses out on the performance-oriented bits found on the A2. It also runs a lower compression like the A1 at 9.7:1. As a result, it puts out figures closer to the A1 at 160 hp and 161 lb-ft. However, it wasn’t the same as the A1 and changes included a single-stage intake manifold and redesigned intake and exhaust ports.
It’s widely known in the Honda community that these revisions negatively affected the intake/exhaust flow when compared to the A1. This is not surprising, as these changes came about to meet the stricter emission norms. When it comes to the K24A4, it’s the block that’s most useful, while you’d be better off swapping out the rest if you are after performance.
Found in: 2006-2007 Honda Accord (USDM), 2007-2011 Honda Element, 2008-2014 Honda Odyssey (JDM)
When compared to the K24A4, the K24A8 brought two notable changes – the RTB manifold and an electronic throttle body. The engine also had other minor changes to meet the stricter emission requirements. Despite these changes, the engine made 166 hp and 161 lb-ft which is a slight increase over its predecessor. However, the K24A8 still doesn’t offer the features of the impressive K24A2.
Found in: 2007-2009 Honda CR-V
After six years, Honda made the switch from the K24A1 to the K24Z1 in the CR-V. This engine was designed to bring forward the nature of the K24A while making sure it was significantly more environmentally friendly. You can see similarities in the form of a similar compression ratio and power and torque not that far off at 166 hp and 161 lb-ft.
There were some big changes like a forged-steel crankshaft and electronic throttle body from the K24A8. It also has the RTB manifold. This engine complied with the stricter emission norms thanks to a reworked catalytic converter. Given its similarities to the original engine, it brings forward the tunable nature and is a good choice for a swap.
Found in: 2008-2012 Honda Accord LX/LX-P (USDM) and 2016-present Proton Perdana
Like the Z1, the K24Z2 brought with it changes to meet the stringent emission norms at the time. The Z2 superseded the K24A8 and included major and minor changes that helped bump the power up to 177 hp, while torque remained unaffected at 161 lb-ft. Changes on the Z2 include a compression ratio of 10.5:1. It also features redesigned fuel injectors and a redesigned intake and exhaust manifold.
Found in: 2008-2012 Honda Accord LX-S/EX/EX-L (USDM), 2009-2014 Acura TSX, 2008-2015 Honda Accord (CP2, CS1), 2012-2015 Honda Civic Si and 2013-2015 Acura ILX
In 2008, Honda released a revised K-series platform called the K24Z3. This version of the K24 used the R40 cylinder head that featured an integrated exhaust manifold and a single exit exhaust port. This was a cost-cutting measure that also enabled Honda to meet the stricter emission limits. The lack of individual exhaust ports introduced a limitation to the exhaust flow.
Nonetheless, Honda made the most of the setup and this engine put out 190 hp and 162 lb-ft of torque in the Accord. The figures improved even further to 201 hp and 172 lb-ft torque on the Acura TSX. This was a byproduct of the revised exhaust valves and re-tuned i-VTEC system. The compression ratio was also higher on the RSX.
Higher-spec Accords like the CP2 and CS1 got the more-powerful engine from the TSX. Interestingly, this engine is also said to be the same as the K24Z7.
Found in:
K24Z4 – 2008-2012 Honda CR-V (RE7)
K24Z5 – 2010-2015 Honda Spirior
K24Z6 – 2010-2011 Honda CR-V (USDM) and 2012-14 Honda CR-V (USDM)
With emission regulations getting stricter as the years went by, Honda had to make sure it was meeting them. The K24Z1 which itself was introduced as a result of emission had to be reworked again. The popular Japanese car manufacturer made minor tweaks to what we know as the K24Z4 to pass the emission requirement, and they did it while using the same compression ratio, while power and torque figures now stood at 161 hp and 161 lb-ft.
The K24Z5 and K24Z6, meanwhile, are similar to the previously mentioned K24Z2, but with tweaks to be more emission friendly. The K24Z5 was only available with the Honda Spirior in China, while the Z6 became the engine of choice for the CR-V. Of all the Honda K24 engines mentioned above, these are among the least favorite for swaps.
Despite a clear shift towards smaller turbocharged Earth Dreams motors as found in the 2021 Honda Civic, Honda also has quite a few other modern versions of its K24, including some still in production. Although they aren’t just significantly different from the much-loved early K24s, they also wouldn’t make sense as a swap from a cost perspective.
K24W (Earth Dreams)
Found in: 2013-2017 Honda Accord (USDM) and 2015-2019 Honda CR-V (USDM)
K24W4
Found in: 2013-present Honda Accord (Malaysia/Thailand) and 2014-present Honda Odyssey (Australia)
K24V5
Found in: 2017-present Honda CR-V (Thailand)
K24V7
Found in: 2016-present Acura ILX
K24W7
Found in: 2015-2020 Acura TLX
K24Y1
Found in: 2012-2016 Honda CR-V (Thailand)
K24Y2
Found in: 2012-2015 Honda Crosstour
K24Z7
Found in: 2012-2015 Honda Civic Si and 2013-2015 Acura ILX
As we mentioned before, there are multiple aspects that make the Honda K24 extremely popular. However, these qualities wouldn’t be of much use if the engine wasn’t so versatile. Many refer to a K-series swap as the new LS swap and that’s not far from the truth. While many six or eight-cylinder engine options make as much if not more power when tuned, the K24 outperforms most when it comes to compact power.
That’s not to say that the K24 is not powerful. With the right mods, it can surpass almost any other engine of its size. Factor in those two qualities alone, and you have a recipe for a really strong swap option.
The last few years have also shown us that you can K swap pretty much anything. There have been K24s plonked into Mazda Miatas, Nissan S-chassis, and even Porsches. Other Honda cars are the most common hosts. You’ll see K24s in anything from an EK Civic to the NSX and S2000.
Another popular car to get the Honda K24 treatment is the Mini Cooper. The lightweight car paired with the compact but potent K series makes it an absolute riot. Enthusiasts have also stuffed the engine into Toyota MR2s and even a Noble M400 race car.
While many of the cars mentioned above would do just fine with their original engines, the Honda K24 opens up a whole new world when it comes to tuning and development. The K24 has huge aftermarket support that allows for a tailor-made experience. You can customize it to make not only exactly the power and torque you want but also the fashion it delivers it in. Like that isn’t enough of a reason, the Honda K24 is also available in abundance, meaning you can extract impressive performance at an attainable price.
A stock Honda K24 engine is decent, but it’s not going to push you back into your seat when you step on the gas. Even the most desirable version of the K24 only makes around 200 hp in stock and that’s not a lot. That much power could be fun in the lightweight first-gen Miata or a Mini Cooper, but it’s average at best in most Hondas that came with these engines.
Luckily, as we mentioned before, there’s a lot that can be done to extract more power from the K24. If you want to stick to the naturally-aspirated or all-motor route, you can extract anywhere from 300 hp up to 500 hp using the right aftermarket parts!
Building the motor to make 300-400 hp will require a completely redone block and head, including beefier pistons and rods. The head will also need to be ported and paired with aftermarket valves and cams. These mods will also need to be supported with a higher-performance fueling and cooling system, among other things. 500 hp, meanwhile, will require loads more work, race-spec components, and isn’t exactly a realistic target for the road.
Reliable 400-500 hp builds require forced induction of some kind.
While the Honda K24 engine will require supporting modification if you opt for a turbo or a supercharger, it will still be able to reward you with healthy numbers on stock internals. There are examples of K24s putting out 400-500 hp with a few simple mods.
Both supercharging and turbocharging have their advantages and disadvantages, and choosing between them comes down to your preference. Both types of forced induction work very well with the K-series engines and there’s plenty of information available on both builds. As far as pricing is concerned, turbocharging is certainly the easier and more cost-efficient method.
When was the last time you heard of an unreliable Honda engine? Exactly! They don’t exist. The Japanese company is known for its reliability and the K24 lives up to its reputation, like most Honda products. That being said, like every other engine in the world, the K24 also has its weak points. Here are some known issues of the K24.
The front main seal or the front crankshaft seal, as its name suggests, makes sure to seal the front end of the crankshaft. It stops oil from making its way out of the engine, but increased wear and tear will result in it wearing down. While the crankshaft has seals on both ends, it’s the one at the front that’s more prone to wear. It’s best to replace this component after approximately 120,000 miles.
Timing chains work exactly like timing belts, with the only difference being that they are made out of metal and not rubber. Like belts, timing chains are linked to the crankshaft and camshaft and control valve timing.
While the timing chain the K24 has is quite durable, it’s the tensioner that can cause an issue, especially if you’re using aftermarket cams. The K24 generally doesn’t like aftermarket cams at all. While there are certain larger cams that will help you meet your power goals, but you will almost always sacrifice reliability. Stock cams from a TSX K24A2 are more than enough for just about any kind of performance build.
A timing chain tensioner problem occurs due to a spring that fails within the tensioner. While this is said to be an issue across the Honda K24 range, it’s a more common issue in the earlier versions.
Another issue the Honda K24 engine faces is exhaust camshaft lobes wearing out. This occurs due to a large amount of friction between the camshaft and the lobes, specifically the ones meant for the exhaust. It’s the K24A1 and K24A4 which are the most prone to this issue. That said, it’s still quite an uncommon issue.
Toda saved the day by providing a prototype header it has designed for the TSX, as well as a test pipe. With the decrease in backpressure and better tuned lengths of the Toda exhaust manifold, Macmillan programmed in more cam advance. Advancing the intake cam allows for pressure waves from the exhaust to travel into the intake. At the right rpm range this reaction can assist the movement of the intake charge into the cylinder.
The exhaust ports and bolt patterns are identical, but headers are not interchangeable due primarily to the differing chassis. On the TSXs CL9 the header squeezes between the engine and subframe, while on the DC5 of the RSX it runs between sub-frame and firewall. As a result both are shaped quite differently.
From his testing MacMillan determined the TSX engine needs a race header (long tube preferred) for the camshafts to work optimally. Installing aftermarket cams first will actually result in a loss of power. For the emissions minded, a high-flow catalytic converter would be best mounted to the race header about 40cm behind its current position. Finally, a VTC mechanism modified for 45 degrees advance is a must.
The darling of the new-school Honda tuner, the K20A2 engine found in the RSX Type-S has inspired a bevy of performance options from the sport compact aftermarket. From engine internals to bolt-ons, choices abound whether you choose to roll under added pressure or keep it naturally aspirated. Lightweight, strong, and gifted with VTEC and Variable Timing Control (VTC), the K unit is the wave of the future in our scene.
According to MacMillan, the biggest gift Honda has given to tuners of the K series is the Variable Timing Control mechanism, or VTC. VTC uses a spool valve that directs high-pressure oil to chambers inside the intake cam gear that allows for continuous adjustment of the camshafts phase, or its position relative to the crankshaft, over a range of 25 degrees advance or retard. In the K20A that range extends to 50 degrees of advance or retard. A separate VTC electronic control unit monitors RPM, camshaft and throttle position, ignition timing and engine exhaust condition to determine the necessary cam phase adjustments.
For most customers, a 2.4L Acura TSX engine is the ideal starting point for any of ours swaps. The K24A2 from the 2004-2008 TSX is the most potent K24 in stock form, and can also be built to make significantly more N/A power. The JDM K24A engines with an RBB head are nearly identical to the TSX engines and are also a great starting point.
While other K series engines can be used for these swaps, they will all make less power than the engines we recommend. A K20 swap can be done with some minor adjustments to our K24A2 swap parts, but K20 engines are more expensive, harder to find, and don’t make as much power or torque.
You’ll need a belt and pulley setup of some sort. We offer options to both retain or delete the factory K series auto tensioner. Our 4 pulley setup can be used in any application to delete the tensioner. However, thanks to our new intake manifold, the popular EP3 idler pulley setup can be used so the factory belt routing and tensioner can be retained.
FAQ
Does the K24A2 have VTEC?
What year TSX has K24?
What cars did the K20A2 come in?