Swapping a Honda K-series engine (K20, K24, etc.) into a chassis that did not come with one originally. Most common in older Civic and CR-X chassis.
K-swap is the modification of fitting a Honda K-series engine (most commonly the K20A2 or K24) into a Honda chassis that originally had a different engine. The K-series replaced the older B-series and D-series Honda four-cylinders in the early 2000s. K-series engines are larger, more powerful, more refined, and have superior aftermarket support compared to the engines they replaced.
The most common K-swap targets are first and second generation Civics (CRX, EF, EG, EK, DC2 Integra), where the original B-series or D-series engines are replaced with K20A2 or K24 engines from RSX, Civic Si, or Element donors. The result is an older chassis with significantly more power and modern engine reliability.
K-swaps require engine mounts, axles, wiring harness, ECU, and various other components. Companies like Hasport, K-Tuned, and Hybrid Racing produce dedicated swap kits. A complete swap typically costs $5,000 to $10,000 in parts plus labor.