Honda R-series Specs: 81 x 87.3 mm

Honda R-series specs: 81 x 87.3 mm (3.1890 x 3.4370 in) bore and stroke, shared by all 4 versions. Displacement, compression and factory ratings.

At a glance

Displacement	109.8 ci
Cylinders	4
Bore	3.189"
Stroke	3.437"
Compression	10.5:1
Advertised power	110–143 hp
Years	2006–2022

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
R18A	109.8 ci	3.189" × 3.437"	—	—
R-series (2006–2022)	109.8 ci	3.189" × 3.437"	—	113–141
R18A1	109.8 ci	3.189" × 3.437"	10.5:1	140
R18Z1	109.8 ci	3.189" × 3.437"	—	110–143

Factory cars with a R-series

• Honda Civic: 2006, 113 hp; 2006, 140 hp; 2007, 113 hp; 2007, 140 hp; 2008, 113 hp; 2008, 140 hp; 2009, 113 hp; 2009, 140 hp; 2010, 113 hp; 2010, 140 hp; 2011, 113 hp; 2011, 140 hp; 2012, 110 hp; 2012, 140 hp; 2013, 110 hp; 2013, 140 hp; 2014, 110 hp; 2014, 143 hp; 2015, 110 hp; 2015, 143 hp
• Honda HR-V: 2016, 141 hp; 2017, 141 hp; 2018, 141 hp; 2019, 141 hp; 2020, 141 hp; 2021, 141 hp; 2022, 141 hp

What varies across the family

All are undersquare — stroke larger than bore, favouring torque low in the range.

Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.

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