BMW 209ci Specs: 92 x 86 mm

BMW 209ci specs: 92 x 86 mm (3.6220 x 3.3858 in) bore and stroke, shared by all 2 versions. Displacement, compression and factory ratings, plus rod ratio.

At a glance

Displacement	209 ci
Cylinders	6
Bore	3.622"
Stroke	3.386"
Compression	8.0–9.0:1
Advertised power	182–208 hp
Years	1985–1993

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
M30B34	209 ci	3.622" × 3.3858"	8:1	182
M30B35	209 ci	3.622" × 3.3858"	9:1	208

Factory cars with a BMW 209ci

• BMW 5 Series: 1985, 182 hp; 1986, 182 hp; 1987, 182 hp; 1988, 182 hp; 1989; 1990; 1991; 1992; 1993
• BMW 6 Series: 1985; 1986; 1987; 1988; 1989
• BMW 7 Series: 1985; 1986; 1987; 1988, 208 hp; 1989, 208 hp; 1990, 208 hp; 1991, 208 hp; 1992, 208 hp

What varies across the family

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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