The answer depends on the model year. Not every Civic Si uses a K24 engine; some generations do, others don’t. In current production, the Si uses a turbocharged 1.5-liter engine rather than a K-series. Among past generations, the 2.4-liter K24 appeared in a specific era of the Si lineup.
To understand which engines powered the Civic Si, it helps to look at the generation-by-generation history. Honda’s K-series family includes both 2.0-liter (K20) and 2.4-liter (K24) variants, and the Si has used each in different periods. The latest Civics pivoted to a turbocharged 1.5-liter engine, moving away from K-series altogether.
Engine history by Civic Si generation
Below is a concise look at which engines powered the US-market Civic Si across major generations.
- EP3 Civic Si (2002–2005): K20A3 2.0L i-VTEC
- FK/FG Civic Si (2006–2011): K20Z3 2.0L i-VTEC
- 9th generation Civic Si (2012–2015): K24Z7 2.4L i-VTEC
- 10th generation Civic Si (2017–2021): 1.5L turbocharged L15B7 (not a K-series)
- 11th generation and newer (2022–present): continues with the 1.5L turbocharged engine (not a K-series)
These examples reflect the U.S. market, where Honda’s Si lineup has shifted over time. Engine codes and displacements vary by model year and region, but the pattern is clear: K-series powertrains appear in several earlier Si generations, while the most recent Si models use a turbocharged four-cylinder that is not part of the K-series.
What this means for enthusiasts and owners
For those considering engine swaps, maintenance, or buying decisions, the key takeaway is to verify the exact engine code for the specific model year. A 2012–2015 Civic Si is a K24-powered car, while a 2002–2005 or 2006–2011 Si uses a K20 variant, and current-generation Civics use a turbo 1.5-liter engine rather than a K-series powerplant.
Current and recent Civic Si powertrains
The latest Honda Civic Si models have moved away from K-series engines entirely. They rely on turbocharged 1.5-liter inline-four powerplants designed for efficiency and punch with forced induction, rather than the naturally aspirated or VTEC-equipped K-series layout that characterized earlier Si generations.
Summary
In short: a Civic Si does not always have a K24. The 2.4-liter K24 engine powered the 2012–2015 Civic Si in the U.S. market, but earlier Si models used K20 variants, and the current and recent Civics use a turbocharged 1.5-liter engine, not a K-series. If you want to confirm what’s under the hood, check the engine code on the block or in the vehicle’s documentation for the exact model year.