The Guide to Honda K24 Turbo Upgrade. The Honda K-series has been one of the most well-known 4-cylinder engine series since 2001. The K-series had a lot to live up to after succeeding the B-series, which held the Honda DOHC 4-cylinder crown from 1988 to 2001. The good news is that it was successful. The K-series engines have VTEC, a high redline, and are bulletproof, which are three of the defining traits of the B-series that have been carried into the twenty-first century.
The Honda K24 2.4L 4-cylinder engine series is the K-series’ largest engine. The K24 engine is the preferred engine for large power goals, sharing many of the same components and overall architecture as the smaller 2.0L K20 engine.
With strength and high-rpm performance being two of the K24’s key strengths, turbochargers fit right in. Historically, turbocharged K24 TSXs, Accords, and other wild K24 swaps have demonstrated that the Honda 2.4L can be pushed exceedingly far while remaining dependable. If the turbo setup is done correctly and with care, a Turbo K24 may easily produce 300 horsepower, with power ratings in the mid-400s being considered running speed.
This tutorial covers K24 turbo kits and upgrades, the limits of a turbo K24, and some of the important factors to consider while upgrading a K24 turbo. We’ll concentrate on K24A and K24Z varieties because they’re the most prevalent in the US, and covering the entire engine series would require a 100-page novel.
What kind of power can a Turbo K24 handle?
One of the K42 engine’s distinguishing features is its ability to manage an outrageous amount of power with stock internals. Despite the fact that the crankshaft is the only forged internal component, the cast pistons, rods, and other internal components withstand the additional pressure introduced by a turbocharger quite well.
The amount of horsepower that a turbo K24 can manage is determined on your tune and other factors such as fueling changes. It’s not uncommon to see a turbocharged K24 produce 400 horsepower without having to rev the engine. For a K24 turbo build, that is a relatively safe and achievable horsepower figure. Once you pass the 400 horsepower mark, reliability will almost certainly suffer if you don’t take proper precautions with your tune.
A race gas conversion kit should be considered for K24 turbo designs that exceed 450-500 horsepower. Internal temperatures are reduced when a turbo K24 is run on E85, which has a high ethanol concentration. This enables larger peak horsepower figures as well as a safer atmosphere for high boost levels. In a subsequent part, we’ll go into fuelling modifications in greater depth.
While many Honda enthusiasts claim that a turbo K24 can produce 600 horsepower without opening the engine, that is pushing the boundaries a little too far on stock internals. If you intend to generate that much power from a K24 engine, you should consider forged internals. When you reach 600 horsepower, the main components you’ll want to consider upgrading are the pistons and rods.
Honda 2.4L 4-Cylinder Turbocharger
The Honda K24 engine has four distinct variations, each of which is further subdivided. The K24A, K24W, K24Y, and K24Z are the four primary K24 versions. While many of the K24 engines have the same characteristics and specifications, some 2.4L K24 variants are better for forced induction than others.
Honda K24A2 – Highest Performance Choice
- Acura TSX 2004, 2005, 2006, 2007, and 2008.
The K24A2 is without a doubt the best turbocharged K24 engine option. There are several important reasons behind this. To summarize, the K24A2 is the best K24 version in factory form. The K24A2 has the greatest redline of any K24 engine we’ve received in the United States. Once VTEC is engaged, this translates to high RPM performance. Concerning VTEC, the K24A2 features true performance VTEC on both the intake and exhaust sides. In addition, the A2 boasts one of the highest flowing cylinder heads in the K24 range. However, cylinder head flow figures can be easily improved by swapping on a K20Z1 head from an RSX Type-S. Additionally, many K20 and K24 parts are interchangeable, resulting in improved performance from a Frankenstein K-series engine.
Overall, the K24A2 is one of the better K24 models available and is ready for boost right away. While the news is almost entirely positive, there are a couple of limiting factors that plague even the best K24 variants when it comes to forced induction. The K24A2 features an unusually high compression ratio of 10.5:1, which is quite excessive for the addition of a turbocharger. Lower compression is often favored for turbocharging since it promotes the engine’s internal component safety. As a result, people trying to get a lot of power out of a turbo K24A2 usually switch to low compression pistons. That isn’t to say you shouldn’t use the K24A2 as a foundation. It can still withstand moderate quantities of boost with ease.
Honda K24A1/A4/A8 – The Most Affordable Option
- Honda CR-V model years 2002-2006
- 2003-2005 Honda Accord
- 2003-2008 Honda Odyssey
- 2003-2006 Honda Element
- Accord 2006-2007 Honda
- Honda Element 2007, 2008, 2009, 2010, 2011, and 2012.
- 2008-2014 Honda Odyssey
As evidenced by the lengthy list above, K24A1, K24A4, and K24A8 engine versions were used in a wide range of Honda cars between 2002 and 2014. As a result, they are exceedingly cheap and easy to find. If you’re on a tight budget, any of these three options is your best bet, as you can probably locate one on Craigslist for less than $500. While the three variants are slightly different, they share a very similar construction, making the differences insignificant.
In comparison to the previously stated K24A2 engine, the A1, A4, and A8 have slightly less desired qualities. For example, all three have a diluted VTEC system that only applies to the engine’s intake side. As a result, you won’t get the same high RPM performance as a K24 with full-performance VTEC. Furthermore, the K24A1, K24A4, and K24A8 cylinder heads are not ideal in terms of airflow. In comparison, the three A variants have restricted heads that can benefit from a port and polish to some extent. The three A variations described above, like the K24A2, benefit from a cylinder head swap. Heads from a turbo K24A1, K24A4, or K24A8 will all give superior airflow than heads from a K20Z1, K24Z2, or K20Z3.
Considerations for a Turbo Honda K24 Upgrade
Okay, we’ve already discussed briefly why a turbo K-series engine is a good choice, so let’s get into what goes into turbocharging a Honda K24 engine. There are several elements to consider when adding forced induction to a previously naturally aspirated engine. However, in comparison to many other engines, the K24 is a relatively simple engine to turbocharge. Internal modifications, auxiliary fuel management systems, E85 conversions, and other supporting modifications required for some engines to even get off the ground with forced induction aren’t instantly required for a modest turbo K24-powered car.
While there is a fairly well-defined formula for turbo K-series engines, turbocharging a car is never easy.
Honda K24 Turbo Dimensions
When putting together a K24 turbo build, turbo sizing is an important consideration. The size of the turbo impacts both how much horsepower may be generated by forced induction and how that power is delivered. There is a significant difference in the amount of power that a T3 and T70 size turbo can produce. While a larger turbo can produce more power and run at higher boost levels, there are other factors to consider.
In general, Honda engines perform best with smaller, faster-spooling turbos. The most typical sizes for turbo K-series applications are T3 and T3/T4 hybrid turbos. Small turbos are ideal for daily drivers because they benefit the mid-rpm range the most. While a K24 top-end VTEC, large-turbo monster might be entertaining, it won’t be practical on the street. Power will be available quickly with a modest, fast spooling turbo.
That being said, you won’t be able to get the same power statistics as you would with a larger turbo. Larger turbos, such as a Garret GTX3584RS or a GT40 series turbo, have the potential to produce more horsepower at the same PSI as a smaller turbo. Because larger turbos take longer to spool, they are ideal for racing applications where power is required early in the rev range. These turbos are intended for K24 owners aiming for 600 horsepower.
A decent rule of thumb is to pick the smallest turbo possible for your power goals while yet leaving some opportunity for expansion. T3 and T3/T4 turbo hybrids may produce close to 400 horsepower.
Engine Management System and Tuning for the Turbo K24
The accompanying tune is one of the most important parts of any turbo system. A competent tune will not only extract the greatest performance from your K24 turbo configuration, but it is also the first and last line of defense against any damage. Working with an experienced Honda tuner to produce a safe and conservative tune is the best way to keep your turbo K24 in one piece.
While the K24 engine has flash/piggyback tuning options, modified ECUs, such as the Hondata KPro, are far more common. Almost every turbo K-series user recommends the Hondata KPro as their turbo ECU of choice. The KPro is not just one of the most flexible solutions for the K-series platform, but it is also one of the simplest to install and use. The KPro allows you – or a skilled tuner – to change engine characteristics, fuel and ignition tables, and pretty much everything else you may possibly want to change. It is a one-stop shop for K24 tuning, and practically every turbo K24 owner uses it.
As we mentioned briefly earlier, if you’ve never tuned a car before, now isn’t the time to try. Engine management characteristics should be left to the professionals for the safety and reliability of your K24 engine. They’ll most likely be able to take you to your desired destination while minimizing the possibility of anything essential going wrong.
Fueling Modifications for the Honda 2.4L K-Series
Proper fueling is an important component of the turbo K24 equation that must also be considered. Because your K24 will be consuming more compressed air, your engine will require more fuel. The fuel pump and injectors are the two most significant components that require replacement. A high-flow fuel pump is important to your K24 engine’s capacity to feed enough gasoline to the injectors. To keep up, you’ll need bigger flow injectors as well.
Walbro gasoline pumps are commonly used as an ungraded option. While a variety of fuel pumps can provide adequate fuel flow, a 450LPH pump is a good bet for K24 turbo applications producing up to 600 horsepower. Walbro pumps are compatible with both pump gas and E85, so if you plan on switching to racing gas in the future, Walbro has you covered.
Aside from a new fuel pump, you’ll also need upgraded injectors with a higher flow rate than stock. Of course, the flow rate you choose is entirely dependent on how much electricity you aim to generate. 550cc injectors should enough in the 300-450 horsepower range. 1,000cc injectors may be optimal for enhanced K24 power levels reaching 600+. Along with upgrading the injectors, some K24 owners choose to upgrade the fuel rail as well. While the stock rail is adequate for most mild turbo K-series applications, it may be necessary to upgrade for those seeking high triple-digit power figures.
Oil Pump Replacement on an Acura RSX Type-S
The oil pump design is one of the most serious factory flaws with the 2.4L K24 engine. In contrast to the oil pump that came standard on the 2.0L K20 engines, the K24 pump features balance shafts, which Honda claims improve idle quality. Most Honda enthusiasts dislike the K24 design because the balancing shafts sap horsepower from the engine and lower the redline. Aside from the performance disadvantage, the factory K24 oil pump has been known to cavitate at higher RPMs. This is especially problematic in turbo applications, where rpm rise quickly.
Fortunately, there is a simple solution to this problem: replace the factory oil pump with one from a 2.0L K20Z1. The K20Z1 is most typically found in the 2001-2006 Acura RSX Type-S, and because K20Z1s are rather common, finding an oil pump shouldn’t be too difficult. The replacement pump will allow your turbo K24 to rev extremely high without the drawbacks of the factory pump. Along with the pump, you’ll need to replace the oil chain guide, tensioner, and chain. All of this is available from a K20Z1.
Turbo Kit vs. Honda 2.4L Custom Turbo Setup
In general, there are two approaches you can follow when turbocharging your Honda K24 engine. You may either piece together all of the individual components required for a full K24 turbo configuration or buy a preassembled kit. Each of these paths has advantages and disadvantages, and there is no clear winner.
When it comes to a custom, piecemeal K24 turbo setup, you’ll have to rely on extensive study and meticulous organization to ensure that you have all of the necessary components. You’ll also need to source all of the individual components, which can be costly. However, if you go this route, you’ll be able to find used parts on forums, Craigslist, and other secondhand websites. While you will most likely require additional odds and ends, the following components are required for a custom K24 turbo setup:
- Turbo manifold K24
- Turbocharger of your choice (T3 or T4)
- K24 large and high-quality intercooler
- Pipes and fittings for intercoolers
- Wastegate and blow-off valve
- Downpipe for the K24 turbocharger
- Injectors with a high flow rate
The Hondata K-Pro
If you don’t want to hunt for all of the individual components for a K24 turbo system, a K24 turbo kit is an option. All of the necessary components are assembled for you in a kit. While you won’t have the same level of customization when it comes to individual parts, a kit will ensure that you have everything you need. K-series turbo kits are often either incredibly cheap or highly expensive, with few alternatives in between. In the following part, we’ll go through a couple of kits in depth.
Honda K24 Turbo Kits That Work
Turbo kits are the most convenient method to obtain all of the parts needed to turbocharge your Honda K24 engine. A turbo kit, as opposed to a custom turbo configuration, is made out of components assembled by a supplier or manufacturer. This eliminates a lot of the bother associated with turbocharging your K24. It should be noted that most K20 turbo kits are also compatible with the K24 and vice versa. That is only possible because the K20 and K24 are built similarly. Some turbo kits, on the other hand, are designed for a specific vehicle application and include chassis-specific intercooler piping and a turbo manifold. For the purposes of this guide, we’ll concentrate on K24 turbo kits.
CX Racing 2004-2008 Acura TSX K24A2 Intercooler Turbo Kit
CX Racing offers a diverse selection of complete turbo kits. They cover the entire vehicle spectrum, from 5.0L Mustang Foxbodys to 4-cylinder Civics. That certainly demonstrates their adaptability, but what about their quality? The majority of CX Racing turbo kit owners are pleased, especially for a package with an intercooler that costs just over $1,500. That being said, when it comes to kits like the CX Racing K24 turbo kit, a safe tune is the key to success.
The CX Racing K24 Turbo Kit includes practically all of the essential turbo hardware to get you up and running. Obviously, engine management and fueling modifications aren’t included, but the kit is otherwise ready to go. The T04E turbo with a 38mm 8 psi wastegate is the kit’s focal point. As a T3, the included turbo will spool quickly and produce the most power in the mid RPM range. It’s an extremely streetable turbo with 350 horsepower, according to CX Racing.
A unique cast steel K24 turbo manifold, 2.5″ stainless steel downpipe, and big core size intercooler are also key components. CX developed the manifold with correct installation in mind, knowing that it can be a tight fit in the engine bay. The 2.5″ K24 downpipe will minimize exhaust constraints while also attaching up to the stock midpipe. Finally, the bundled intercooler assembly is perfect for a K24 turbo kit. With a core dimension of 20′′X6′′X3′′, it is more than large enough to offer appropriate cooling for your K24 turbo configuration.
Complete ProStreet K24 Turbo Kit
The Full Race ProStreet turbo kit is the best pre-assembled turbo kit for the Honda K-series. Given that this kit costs around three times as much as the CX kit mentioned above, some quality improvements are unavoidable. The turbo is the most significant area of quality improvement in the ProStreet K24 turbo kit. Turbos (plural), in reality, as ProStreet offers 11 different turbo setups. Obviously, power objectives are important, but all of the turbo options use Garrett internals. For those searching for enormous horsepower ratings, Full Race offers a variety of T3-size turbos as well as T4 twin-scroll alternatives.
To accommodate for longer intake manifold runners, the Full Race K24 turbo kit has a unique turbo location. This enables for improved low-RPM performance, which aids in power delivery until the boost kicks in. The majority of the kit’s other components are both high-quality and custom-made, including high-quality TIG welding and machined flange surfaces. The Full Race kit’s various components are what set it apart from the competition and justify its exorbitant price.
The Full Race K24 turbo kit includes, in addition to the turbo and race manifold, a huge 3″ V-band downpipe, a big vertical flow intercooler, charge and intercooler piping, and all of the necessary hardware for assembly. Overall, the Full Race K24 turbo kit is the way to go if you want a full K-series turbo kit that values quality above price.
Summary of Honda K24 Turbo Upgrade
The 2.4L Honda K24 is a rock-solid basis for turbocharging. Honda 4-cylinder engines have historically responded exceedingly well to forced induction and have a reputation for dependability. The K24 is no different. A 400 horsepower power target is easily achievable with a mild K24 turbo arrangement, and the K24’s standard internals can also meet that need. If you go too far beyond that, you should consider some safety modifications like an E85 conversion and strengthened pistons.
While there is a lot to think about when putting together a K24 turbo setup, it is not as difficult as it is with many other engines. Of course, you’ll need to think about turbo sizing, engine management, and fueling modifications, but that’s the bulk of the work. Of course, putting together a custom system will be a bit more difficult. A K24 turbo kit would relieve the burden of gathering all of the individual parts at the expense of personalization. A 2.4L K24 can provide amazing performance using either way.