Subaru 153ci Specs: 99.5 x 79 mm

Subaru 153ci specs: 99.5 x 79 mm (3.9173 x 3.1102 in) bore and stroke, shared by all 3 versions. Displacement, compression and factory ratings.

At a glance

Displacement	153 ci
Cylinders	4
Bore	3.917"
Stroke	3.110"
Compression	8.2–10.0:1
Advertised power	165–210 hp
Years	2003–2006

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
EJ251	153 ci	3.9173" × 3.1102"	10:1	165
EJ255	153 ci	3.9173" × 3.1102"	8.2:1	210
EJ253	153 ci	3.9173" × 3.1102"	10:1	165

Factory cars with a Subaru 153ci

• Subaru Baja: 2003, 165 hp; 2004, 165 hp; 2004, 210 hp; 2005; 2005, 210 hp; 2006, 165 hp; 2006, 210 hp

What varies across the family

Compression spans 8.2:1 to 10:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.

All are oversquare — bore larger than stroke, which favours revs over low-end torque.

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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