Guide to tuning the K24 engine from Honda

"Tuning the Honda K24 and best performance parts."

We provide a guide to K24 tuning and highlight the ultimate modifications.

The Honda K-series engine is a 4 cylinder 4 stroke  engine that was first launched in 2001. The cylinders contain cast iron sleeves like the B- and F-series engines, rather than the FRM* cylinders seen in the H- and newer F-series engines, which are only found in the Honda S2000.

*FRM cylinders were fiber matrix reinforced which used aluminum alloy and aluminum oxide, it was strong but often led to burning of oil as mileage increased.

The K24 was fitted to a wide array of cars, and makes a superb base for your modified car project, and benefits from a massive array of aftermarket parts.

Honda K24s make awesome project cars and with a few sensible tuning upgrades you can greatly improve your driving experience.

History, Power & Specs of the K24 Engine

The K-series engines have DOHC valvetrains and decrease friction via roller rockers on the cylinder head.

With a coil for each spark plug, the engines use a coil-on-plug, distributor less ignition system which uses a computer-controlled system instead of a traditional distributor-based ignition timing system, allowing the ECU to alter ignition timings based on multiple sensor inputs adding to the power of the engine and its response without compromising fuel economy.

Check out our video introduction to Honda Tuning, all you need to know about mods and upgrades on your Honda.

K24A1

• 2002–2006 Honda CR-V 9.6:1 160 hp @ 6000 RPM 162 lbft @ 3600 RPM

K24A2

The TSX K24A2 is considered the best block but usually carries a significant price premium. A K24A1 is generally best value for a project engine as the money saved can be invested in upgrading the rods/crank and pistons.

• 2002–2008 Honda Accord Type-S 10.5:1 197 hp; 147 kW @ 6800 RPM 171 lbft @ 4500 RPM
• 2003–2008 Honda Odyssey Absolute 10.5:1 197 hp; 147 kW @ 6800 RPM 171 lbft @ 4500 RPM
• 2004–2005 Acura TSX 10.5:1 197 hp; 147 kW @ 6800 RPM 166 lbft @ 4500 RPM
• 2006–2008 Acura TSX 10.5:1 205 hp @ 7000 RPM 164 lbft @ 4500 RPM

K24A3

• 2003–2007 Honda Accord 10.5:1 197 hp @ 6800 RPM 171 lbft @ 4500 RPM
• 2003–2007 Honda Accord Euro 10.5:1 197 hp @ 6800 RPM 171 lbft @ 4500 RPM

K24A4

• 2003–2005 Honda Accord 9.7:1 160 hp @ 5500 RPM 161 lbft @ 4500 RPM
• 2003–2008 Honda Odyssey 9.7:1 160 hp @ 5500 RPM 161 lbft @ 4500 RPM
• 2003–2006 Honda Element 9.7:1 160 hp @ 5500 RPM 161 lbft @ 4500 RPM

K24A8

• 2006–2007 Honda Accord 9.7:1 166 hp @ 5800 RPM 160 lbft @ 4000 RPM
• 2007–2011 Honda Element 9.7:1 166 hp @ 5800 RPM 161 lbft @ 4000 RPM
• 2008–2014 Honda Odyssey 10.5:1  180 hp & 6100 RPM 161 lbft @ 3600 RPM

K24W (Earth Dreams)

This was a major revision of the K Series engine which saw direct injection introduced and many other changes to enable Honda to meet current emissions regulations.

• 2013–2017 Honda Accord (USDM)
  11.1:1 185 hp  @ 6400 RPM 181 lbft @ 3900 RPM
• 2015–2019 Honda CR-V (USDM)
  11.1:1 185 hp  @ 6400 RPM 181 lbft @ 3900 RPM
• K24W4
• 2013–present Honda Accord (Thailand/Malaysia)
  10.1:1 174 hp @ 6200 RPM 166 lbft @ 4000 RPM
• 2014–present Honda Odyssey (AUDM)
  10.1:1 174 hp  @ 6200 RPM 166 lbft  @ 4000 RPM
•  K24V5
• 2017–present Honda CR-V (Thailand)
  10.1:1 170 hp @ 6200 RPM 165 lbft @ 4000 RPM
• K24V7
• 2016–present Acura ILX
  11.6:1 201 hp  @ 6800 RPM 180 lbft @ 3800 RPM
• K24W7
• 2015–2020 Acura TLX
  11.6:1 206 hp (154 kW) @ 6800 RPM 182 lbft (247 Nm) @ 3900 RPM

K24Y

• K24Y1
• 2012–2016 Honda CR-V (Thailand)
  10.5:1 170 hp @ 6000 RPM 162 lbf⋅ft @ 4300 RPM
• K24Y2
• 2012–2015 Honda Crosstour
  10.0:1 192 hp @ 7000 RPM 162 lbft @ 4400 RPM

Best K24 modifications

Just because a part is popular with K24 owners it doesn't mean you should fit it, instead, we will highlight only the parts which we have found to be the optimum ie: Those that will give your K24 the biggest power gain return for your cash.

The camshaft profile plays a big part in the engines power output so camshaft upgrades on most cars will make quite a large difference. The intake & exhaust durations will alter depending on the chosen camshaft profile and valve lift, so large bhp gains are on offer for camshaft upgrades.

Fast road camshafts often increase horsepower and torque across the entire rpm range; you may lose a little low-end horsepower, but your high-end rpm power will be improved.

Why did Honda choose the cam profile and manifold design?

They wanted to meet emissions regs, improve fuel economy and ensure the car is reliable and doesn't need frequent servicing. VTEC allows them to offer more power at the top end, which in some regions is not a major consideration in emissions measurements as typical driving scenarios are simulated.

This leaves plenty of scope for tuning and improvement, so let's get into the best upgrades and options for your K24.

Do we think performance cams are a good option on the K24?

The logical route is just to use the VTEC and get this to kick in sooner, so you'll have a fast road cam profile, smooth bottom end and other than the aftermarket ECU cost very little outlay.

Bear in mind the K24 came with VTEC and Lift control. Dropping in a different cam profile will usually require an adjustment to the lift control setting in the ECU.

Cam swaps are possible around the K24 versions, and we've seen some putting K20 heads complete with Cams on a K24 to maximize the flow into and out of the engine.

Motorsport camshafts increase the high-end rpm power range, but the car will not idle smoothly as a result, and low-end power will almost always suffer.

On a daily driver, you should strive to match your engine's power to your vehicle's usage.

You'll never have found a Motorsport and race camshaft is a pleasure to live with when on the daily commute, because the lumpy idle will make the car prone to stall and smooth driving at low rpm becomes impossible. If you are developing a track car this doesn't matter as you are in the high end of your RPM range anyway and that is where you want the power to be.

Different K24 engines respond better to more or less aggressive camshaft durations check your engine on a rolling road.

The ECU mapping and fuel pump and injectors also will make differences in the torque gains you'll make.

Extending exhaust or intake durations can alter the torque band and on most engines, the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

K20 vs k24?

These are very similar engines and there is no replacement for displacement as they say so the K24 wins. Swapping the K20 head to a K24 is a common upgrade and provides a better flowing head and more desirable camshaft profile.

The K20 head has arguably stronger valves and tolerates longer periods of high rpm driving than a K24, but the engines are very similar and share many of the same features.

Both engines would make a good base for your project, especially if you were looking to do an engine swap.

We note that the gearboxes and transmission is typically better on the k20.

If we were adding a turbo we would probably work with the K20 and lower the compression ratio slightly and raise the displacement with a stroker kit and low compression pistons.

Tuning the K24

Please watch our video which covers K24 Engine Tuning. Be sure to subscribe so you can keep up with our latest YouTube content and subscribe.

Best Engine Mods for your K24

1. Engine Tunes - engine tuning/remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives (Hondata or Apexi).
2. Reduce the RPM trigger for the VTEC to cut in, this is just like fitting a fast road cam to your engine and will give better low end power, you'll need an aftermarket ECU to accomplish this.
3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
4. Turbochargers and superchargers - forced induction is the most efficient approach to increase air supply on the K24, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains around.
5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence. The more tuned your K24 the more important this is.

K24 Tuning stages

Typical stage 1 mods often include: Remaps/piggy back ECU (Hondata or Apexi), Intake manifolds, Panel air filters, Fast road camshaft, Sports exhaust header/manifold, drilled & smoothed airbox.

Typical stage 2 mods often include: fuel pump upgrades, Sports catalyst & performance exhaust, Ported and polished head, Fast road cam, induction kit, high flow fuel injectors.

Typical stage 3 mods often include: Engine balancing & blueprinting, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Competition cam.

Can the K24 be remapped?

Mapping helps fully realize the full potential of all the modifications you've fitted to your K24 but is it possible to tune/remap the K24?

As is the case with so many Honda ECU's the earlier models can't be easily mapped, but they can in some areas be bench flashed (also depends on the ECU used) or have chip replacements but the way forward is either to use a Hondata module to provide the features you need or go fully with an aftermarket ECU. Most of these will outperform factory ECU's but make sure it has knock protection and that you get it set up properly.

Generally speaking pre facelift K24's were hard to tune/remap but there are now some solutions around now which allow red line limit raising, VTEC and timing adjustments.

A solid power gain can be had by raising the redline via an aftermarket ECU, and we've heard most people saying around 7500rpm is safe on these engines, and getting the VTEC to kick in earlier is just like dropping in a performance cam.

It will usually give you around 30% more power on turbocharged vehicles and 15% on NA (naturally aspirated) engines, but you mileage will vary depending on the modifications you've done and the condition of your engine.

It is the main goal of any engine performance tuning task to feed more fuel and air into each cylinder

The intake manifold transmits the air from the intake filter and allows it to be fed into the engine cylinders with fuel for the squish phase.

Shape and flow rate of the Intake manifold can make a noticeable improvement to fuel engine efficiency on the K24.

I usually find with most car projects that the intake manifolds are in dire need of an upgrade, although on most cars that use the K24 the manifolds are more than adequate and up to the task, even with modest tuning upgrades.

Adding a K24 larger valve kit, doing some port matching and head flowing will also raise performance, this will afford you a greater performance increase on other parts.

K24 Turbo upgrades

The more air to get into an engine, the more fuel it can burn, and uprating the induction with a turbocharger upgrade makes massive power gains in the order of taking power to 200-350hp.

NA (naturally aspirated) engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your K24.

Generally thought the K24 is pretty solid and tolerates low boost upgrades admirably well, for larger gains look to lower the compression ratio and in most cases a fuel injector and fuel pump upgrade will be required.

However, you will find all engines have weak spots which show up when tuned.

See where you'll find these restrictions and fit stronger pistons, crank and engine components to utilize the power.

It's very uncommon for individuals to spend a lot of money on turbocharger improvements for the K24, only to have the motor fail catastrophically on its first excursion after being used in anger.

Large improved turbo units typically have low end lag, whereas lesser capacity turbo units spool up faster but do not have the peak end torque improvements.

Fortunately, the turbocharger market is constantly evolving, and variable vane turbo chargers are prevalent, with the vane angle changing according to speed to reduce latency and boost top end horsepower and torque.

Twin scroll turbochargers divide the exhaust flow into two channels and direct them to the turbocharger's variably slanted vanes. They also boost the engine's scavenging ability and are nicely suited to the K24 engine, as long as you have a good quality aftermarket ECU.

Fuelling modifications on the K24

You will need to ensure that the engine is not starved of fuel so will need to ramp up the fuelling when you start going beyond 20% of a torque increase. It is important to be generous with your flow rate on the injectors.

As a rule of thumb add 20% to the flow rate when fitting an injector, which takes into account injector deterioration and gives you some spare capacity should the engine need more fuel.

The K24 intake mods

A stock K24 intake flows generally pretty well, interestingly Honda altered the profile and angle on later engines, but a decent set of headers on the intake side will help you release the power from a turbo upgrade.

Depending on the K24 version you have choose an intake upgrade that suits your power requirements of your tuned engine. Lower power versions generally leave a lot of room for improvement but the higher performance K24 engines show much less of a gain with a revised intake.

Generally speaking for the majority of standard K24 engines we see little point in adding an induction kit, with only a slight top-end improvement. Instead we would recommend you put a better flowing panel filter in the OEM airbox to maximize the return from your mods and upgrades.

A note about K24 air intake sensors

You'll commonly see there is a restriction in the air flow sensor MAP/MAF/AFM on these engines when a lot more air is being pulled into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more challenging to setup. We have a twincharger bhp and torque adding guide if you want to read more.

K24 Exhaust

You should look to boost your exhaust if the existing exhaust is actually causing a restriction.

On most factory exhausts you'll find the flow rate quite well even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Sports exhausts will certainly help air flow out of the engine but avoid an exhaust that is too large or you might just stuff your flow rate and make things worse. So generally speaking, keep to a size of 1.5 to 2.5 inches for best results.

Usual exhaust restrictions can be located the catalysts installed, so adding a better flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

Weak spots Issues & problem areas on the K24

The K24 engines are generally reliable and solid units, as long as you follow the manufacturer's service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engine's design or inherent problems, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the K24, especially when tuned, and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your Honda engine please join us in our friendly forum where you can discuss K24 tuning options in more detail with our K24 owners. It would also be worth reading our unbiased Honda tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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