Engine

Stock 1988 325iS Engine:




BMW M20B25

The German version of the M20B25 produced 170 hp (130 kW) with a catalytic converter and 171 hp (128 kW) without. It featured the newly designed "885" head featuring an open, higher-volume combustion chamber design. The new engine had an 84 mm (3.3 in) bore, and 75 mm (3 in) stroke. The redesigned pistons and combustion chambers made better power, resisted detonation better and had higher thermodynamic efficiency. It was equipped with Bosch Motronic 1.1/1.3 Adaptive fuel injection. The new 12 valve engineering gave M20B25 the name 'verschieden', meaning 'different' in German. The engine is often referred to as 'the differing one' due to the anomalous valve system. With a minor modification that adjusts the idle speed of a cold engine, the 325i fulfills Euro 2 emission requirements in Germany, resulting in a lower tax compared to Euro 1 (as of 2005).

Applications:

• 1986–1994 E30 3 Series
• 1989–1990 E34 5 Series
• 1988–1991 E30 Z1

Upgrade Engine Swap: 

BMW S50B32

The S50B32 was an evolution version of the S50B30. Power of the 3.2 L version is 317 hp (236 kW). Improvements over the previous 3.0l version include Dual Vanos operating on the exhaust camshaft as well as the inlet camshaft, increased compression ratio to 11.3:1, reduced valve stem thickness (and weight), and higher redline. This engine has a bore of 86.4 mm (3.4 in) and a stroke of 91.0 mm (3.6 in) giving a displacement of 3201 cc. It has a maximum permissible speed of 7600 +/-50 rpm, and a permissible constant speed of 7400 rpm. Power output was rated at 321 PS (236 kW; 317 hp) at 7400 rpm, with a torque rating of 258 lb·ft (350 N·m) at 3250 rpm.

Applications:

• 1996-1999 E36 M3 (except for the U.S.)
• 1997-2000 M Roadster (except for the U.S.)
• 1998-2000 M Coupe (except for the U.S.)