General Info. - 323is, 323iC With New M52 B25 Engine
Group 00Maintenance
and General Hints
Bulletin Number
00 75 97
Woodcliff Lake, NJ
November 1997
Product Engineering
SUBJECT:
323is (coupe) and 323iC (convertible) General Information
MODEL:
E36 with M52 B25 engine
General Information:
With the 1998 model year BMW introduces two new variants of the familiar E36 coupe and convertible models.
These models designated 323is and 323iC will replace the existing 318is and 318iC. The 323 models carry over the same standard trim levels and available options as the four cylinder models they are replacing.
Additionally, side impact air bags are now standard equipment on all 1998 E36 models (excluding the 318ti and Z3).
The major change incorporated in the 323i model is the introduction of a smaller displacement M52 six cylinder engine. This engine is based on the design concept of the already familiar and proven M52 B28 engine currently used in the 328i and 528i models.
The engine displacement is actually 2.5 liters which deviates slightly from the new models 323i identification badge.
The new M52 B25 engine develops 168hp (125kw) at 5500 rpm with a maximum torque output of 181 ft. lb. (245 Nm) at 3950 rpm.
The new M52 825 engine has a few differences and unique specifications compared to the M52 828 engine.
The cast iron cylinder block is the same component used on the M52 828 with an 84 mm bore (1).
The block also incorporates a hole and a mounting boss (2) on the left rear side, as on the M52 828, used for mounting the RPM / reference sensor for the MS41.1 control module.
A cast iron crankshaft is used with 7 main bearings which conform to the triple color code classification.
The new crankshaft, connecting rods with a length of 140 mm (M52 828 = 135 mm) and redesigned pistons provide a stroke of 75 mm compared to the 84 mm stroke of the M52 828 engine.
The M52 825 engine uses the MS41.1 engine management system manufactured by Siemens which includes the following features:
^ Ignition Control
^ Fuel Injection Control
^ Running Losses Fuel Control
^ Secondary Air Injection Control
^ Idle Speed Control
^ Oxygen Sensor Heating
^ Purge Control
^ Main Relay / Fuel Pump Relay Control
^ VANOS Control
^ Exhaust Flap Control
^ ASC Control (ignition / injection)
^ A/C Compressor Control
^ EWS II Drive Away Protection O8D II Fault Monitoring
New quad electrode platinum spark plugs designated NGK BKR6EQUP or Bosch FGR7DQR are used in the M52 B25 engine which feature four non adjustable electrodes.
The new platinum spark plug has an increased service life as outlined in the applicable Service Maintenance Checklist.
The exhaust system used on the 323i models incorporate stainless steel exhaust manifolds and a single catalytic converter which provides one pre cat and one post cat oxygen sensor.
The rear silencer has a single pipe connection which leads to a Y pipe connection at the rear silencer. The active rear silencer incorporates the same electro-vacuum unit used on the 328i. (This design rear silencer system is used to reduce noise in the low and mid range power bands without performance reduction in the high engine speed range.)
Technical Data - 3 Series M52 Engines