If you’re looking at a Honda with a K-series engine or planning a swap, the K24Z7 is a model you’ll want to understand. This article provides a detailed technical analysis of the Honda K24Z7 Engine Specs and Performance.
Honda K24Z7 Engine Specs and Performance
Known for its robust design and smooth power delivery, the K24Z7 sits in a sweet spot in Honda’s legendary K-family. It’s not the most famous, but it’s a fantastic balance of reliability and potential. Let’s break down everything that makes this engine tick.
Core Specifications and Design Overview
The K24Z7 is a 2.4-liter, inline-four cylinder, naturally aspirated engine. It follows Honda’s classic DOHC (Dual Overhead Cam) layout with i-VTEC on both the intake and exhaust camshafts. Here are the fundamental specs that define its architecture.
* Displacement: 2,354 cc (2.4L)
* Bore x Stroke: 87 mm x 99 mm
* Compression Ratio: 10.5:1
* Redline: 7,000 RPM (Fuel cut-off)
* Block Material: Aluminum with cast-in iron cylinder liners
* Cylinder Head Material: Aluminum
The engine’s “square” bore and stroke ratio (stroke is slightly longer than bore) contributes to its strong low-end and mid-range torque character. This makes it feel very responsive in everyday driving compared to some peakier engines.
Detailed Technical Specifications Breakdown
To really get how the K24Z7 works, we need to look at its components. Each part plays a crucial role in its performance and durability.
Cylinder Head and Valvetrain
The cylinder head is where Honda’s magic with airflow happens. The K24Z7 uses what’s often called “big port” heads, which are excellent for airflow at higher RPM.
* Valve Configuration: 16-valve (4 valves per cylinder)
* Intake Valve Diameter: 35 mm
* Exhaust Valve Diameter: 30 mm
* Camshafts: The intake cam features i-VTEC, which can switch between two cam profiles for economy and power. The exhaust cam has VTEC on the rocker arms for valve timing control.
* Head Casting: The most common casting number is RBB-3.
This dual i-VTEC system allows for a broad powerband. You get efficient, smooth idle and part-throttle operation, with a noticeable “kick” when the VTEC engages at higher revs, typically around 5,000-5,500 RPM depending on load.
Block, Crankshaft, and Rotating Assembly
The bottom end of the K24Z7 is built to last. It’s known for being a very strong platform that can handle significant power increases with proper modification.
* Crankshaft: A forged steel crankshaft provides excellent strength. It’s supported by five main bearings for smooth operation.
* Connecting Rods: The rods are made from powdered metal, which is strong and reliable for stock power levels.
* Pistons: Cast aluminum pistons with a slight dish to achieve the 10.5:1 compression ratio. They have two valve reliefs for clearance.
* Oil System: It uses a gear-driven oil pump, which is generally more reliable and consistent than chain-driven designs. The oil filter is in a standard, easy-to-reach location.
One common upgrade path is using the K24Z7 block with a more aggressive cylinder head from another K-series, like the K20A2, for even higher performance.
Performance Output and Dyno Analysis
So, what do all these specs translate to in real-world power? The factory ratings are conservative, as is typical with Honda. Real dynamometer readings often tell a more interesting story.
* Factory Rated Horsepower: 201 hp @ 7,000 RPM
* Factory Rated Torque: 170 lb-ft @ 4,400 RPM
On a typical dynamometer (dyno), a completely stock K24Z7 in good health will usually put down between 170-180 wheel horsepower. This “wheel horsepower” figure accounts for drivetrain losses, which is why it’s lower than the factory “crank horsepower” rating. The torque curve is particularly impressive. It builds early and stays flat, giving you a strong pull from as low as 2,500 RPM all the way to redline.
The power delivery is linear and predictable. You don’t get a huge, sudden surge, but rather a constant building of force that makes the car feel faster than the numbers might suggest. The VTEC crossover is noticeable more as a change in engine note and a renewed willingness to rev than a violent shove in the back.
Common Applications and Factory Installations
Honda put the K24Z7 in specific models where they wanted a blend of power and refinement. It was never the most common K24, which adds to its intrigue.
* 2009–2014 Honda Accord EX-L V6 Sedan Coupe (North America): This is its primary home. In these Accords, it was paired with either a 5-speed automatic or a 6-speed manual transmission. The manual version is particularly sought after.
* Some Asian-market Honda Accords: Variations of the Z7 were also used in certain international markets.
It’s crucial to note the K24Z7 is not the same as the K24Z3 found in the Honda CR-V or the K24A in the Acura TSX. While they share a family resemblance, details like the cylinder head, camshafts, and intake manifold differ.
Modifications and Tuning Potential
The K24Z7 is a favorite among tuners because it’s a great starting point. Its strong block and good flowing head respond well to modifications. Here’s a typical path for building more power.
1. Intake and Exhaust: Start with a cold air intake and a cat-back exhaust system. These “bolt-on” mods free up airflow and can yield 10-15 wheel horsepower while improving throttle response and sound.
2. Header: Replacing the restrictive factory exhaust manifold with a performance header is one of the best bang-for-your-buck mods on this engine. A quality 4-2-1 design can add significant mid-range torque.
3. ECU Tuning: This is essential to maximize gains from bolt-on parts. A professional reflash or a standalone ECU can adjust fuel maps, ignition timing, and VTEC engagement, smoothing out the powerband and adding power everywhere.
4. Cams and Valvetrain: For more serious power, aftermarket camshafts can be installed. This often requires upgrading valve springs and retainers to handle higher RPM.
5. Forced Induction: The strong bottom end makes the K24Z7 an excellent candidate for turbocharging or supercharging. With a proper tune and supporting fuel system, reliable 350-400 wheel horsepower is achievable.
Remember, when you increase power, you must also consider upgrading the clutch (for manuals) and potentially the drivetrain components to handle the extra stress.
Reliability, Common Issues, and Maintenance
Honda’s reputation for reliability is well-earned, and the K24Z7 is no exception. With basic care, it can easily surpass 200,000 miles. However, being aware of its few weak points is key to longevity.
* Timing Chain: Unlike older belts, it uses a chain. It’s designed to last the life of the engine but listen for excessive rattling at startup, which could indicate a worn tensioner.
* VTEC Solenoid Gasket: A common source of an oil leak. It’s a simple and inexpensive fix involving replacing a small gasket and filter screen.
* Oil Consumption: Some engines may consume a small amount of oil, especially at higher mileage. Regular checks (every other fuel fill-up) are recommended.
* Spark Plug Tube Seals: These can degrade over time, allowing oil to leak into the spark plug wells.
A strict maintenance schedule is your best defense. Use high-quality synthetic 5W-20 or 5W-30 oil and change it every 5,000 miles. Replace the coolant every 60,000 miles and the spark plugs every 100,000 miles or so. Listening to your engine and adressing small issues quickly prevents big problems later.
K24Z7 vs. Other Popular K-Series Engines
How does the Z7 stack up against its siblings? Here’s a quick comparison.
* vs. K20A2 (from RSX Type-S): The K20 has a higher-revving, peakier personality due to its shorter stroke. It makes less torque but feels more “racy.” The K24Z7 has a much stronger mid-range, making it often feel quicker in street driving.
* vs. K24A2 (from Acura TSX): They are very similar. The TSX engine often has slightly different camshafts and a more aggressive factory tune, leading to about 10 more horsepower. The blocks are virtually identical for swapping purposes.
* vs. K24Z3 (from CR-V): The Z3 is designed for low-end torque and efficiency in an SUV. It has smaller ports, different cams, and a lower compression ratio. It’s not a performance engine like the Z7.
For a swap, the K24Z7 block is often combined with a K20A2 head to create a “K24A2” hybrid, offering the best of both worlds: the torque of the 2.4L block and the high-RPM flow of the K20 head.
FAQ Section
What cars did the K24Z7 come in?
It was used primarily in the 2009-2014 Honda Accord EX-L V6 models (yes, despite the “V6” trim name, these specific ones had the 4-cylinder). Both sedan and coupe bodystyles with a manual or automatic.
How much horsepower can a stock K24Z7 handle?
The stock internal components are robust. With a good tune, the block and rotating assembly can reliably handle up to 300-350 wheel horsepower. Beyond that, forged internals are recommended for long-term reliability.
Is the K24Z7 a good engine for swapping?
Absolutely. Its strong block, good oil pump, and commonality of parts make it a top choice for swapping into older Hondas like Civics or Integras. You’ll need the correct wiring harness, mounts, and ECU for the swap to work properly.
What’s the difference between K24Z7 and K24A2?
The K24A2 (from the Acura TSX) typically has more aggressive camshafts, a slightly higher compression ratio, and a different factory ECU tune. The physical blocks are nearly identical, and parts are largely interchangeable, which can cause some confusion.
Does the K24Z7 have VTEC?
Yes, it features i-VTEC on the intake cam for both timing and lift change, and VTEC on the exhaust cam for timing control. This dual system helps optimize power and efficiency across the entire RPM range.
In summary, the Honda K24Z7 is a brilliantly engineered powerplant that offers a perfect mix of everyday usability, proven durability, and serious tuning potential. Whether you own an Accord with one under the hood or are considering it for a project, its blend of strong torque, smooth VTEC operation, and overbuilt bottom end makes it a truly special engine in the Honda lineup. Its not the flashiest, but its capabilities are undeniable for those who know what to look for.