What Are The Differences Between Honda’s K20 And K24 Engines?

Honda K20 and K24 inline four-cylinder engines have powered a number of popular Honda and Acura automobiles, such as the Accord, Civic, Integra, and RSX, just to name a few. While those cars rolled off the assembly line with Honda power under the hood, it’s not uncommon to find these engines powering cars from other brands. 

As far as engine swaps go, Honda K-series swaps can rival Chevy LS swaps in popularity. The engines are plentiful, dependable, and have deep aftermarket support, making them attractive options for people looking to instill more power in older Honda cars, BMW E30s, Datsun 510s, Miatas, and Nissans. You can even get K-series crate engines that will give you serious horsepower for your money.

The 2.0-liter K20 engine debuted under the hoods of Honda automobiles in 2001. Honda followed up the K20 with the 2.4-liter K24 for the next model year. The K24’s increased displacement came from increasing the four cylinder’s bore to 87 millimeters and stroke to 99 millimeters compared to the K20’s existing 86-millimeter bore and stroke dimensions. The longer stroke length also necessitated a taller cylinder, stretching the deck height from the K20 engine block’s 8.3 inches to 9.1 inches for the K24. Thanks to the all-aluminum construction of both engines, the larger K24 only weighs nine pounds more than the 403-pound K20.

While Honda’s K-series engines are generally held in high regard, there are many different K20 and K24 variations. Options for the K20 engine range from the K20A and K20A2 to the later-model K20Z1. Honda K24 engine options are no less complex, with variations from A to Z as well.

From the factory, K24 engine variants produced a range of output from 160 horsepower at the low end up to 206 horsepower and 182 pound-feet of torque from the K24W7 found in 2015-2020 Acura TLX models. The smaller K20 engine produced at least 156 horsepower, but the most powerful production variant is the K20C1. It was first available in the U.S. as part of the 2017 Honda Civic Type R, and it had 316 horsepower and 295 pound-feet of torque. That extra power came from the fact that the K20C1 is turbocharged, and Honda never produced a turbo K24 engine variant.

K20 engine builders report safely building in excess of 1,000 horsepower with the stock crankshaft and up to 1,400 horsepower with upgraded components. Adding a turbo to a stock K24 can get you up to about 500 horsepower, and it also benefits from upgraded components, helping it output as much as 1,600 horsepower. With that much potential for power, it’s no surprise people are swapping the K24 into about any engine bay you can imagine. The K24-powered Ferrari by Stanceworks is one example, and although the engine is a great fit for a Ferrari, a K24-swapped Mazda Miata might be an even more perfect sports car.