Honda Accord buyers may think they’ve outgrown cars like the Civic Type R, but for 2018, the Accord sedan shares more engine parts with that millennial-baiting hot hatch than with anything else in the Honda lineup.
Lift the hood of the 2017 Civic Type R and the 2018 Accord 2.0T, and you find nearly identical turbocharged 2.0-liter inline-fours, both part of the new Earth Dreams family. Granted, they may not look the same: One has an engine cover in snazzy red and carbon fiber, with HONDA proudly embossed in contrasting silver letters; the other is generic black plastic. But beyond their displacement, nearly everything that makes up a modern engine is shared: the exhaust manifold built into the cylinder head, the air-to-air intercooler, the sodium-filled exhaust valves, variable exhaust-valve lift and timing (VTEC), intake and exhaust camshaft phasing, a two-piece water jacket, the turbo’s electric wastegate, and pistons with internal cooling channels. The 9.8:1 compression ratio is equal on both cars (the Accord’s engine runs less boost, thereby avoiding devastating knock when burning regular gas). How, then, can the same engine feel snappy and high-strung in the world’s fastest front-wheel-drive production car around the Nürburgring, yet refined and smooth in a mid-size family sedan"

Chief powertrain engineer Terunobu Kunikane told us that a major differentiating part is the Accord’s smaller-diameter turbocharger. While this lowers the...