BMW S50B30 engine

Characteristics

Average fuel consumption for the E36 M3 is 11.8 liters per 100 km in the city, 8.4 liters per 100 km on the highway and 9.1 liters per 100 km in the mixed cycle.

Oil consumption can reach up to 1000 grams per 1000 km. Recommended engine oils include viscosities 5W-30, 5W-40, 10W-40 and 15W-40. The volume of oil in the engine is 7.0 liters. It is recommended to change the oil every 7000-10000 km.

The operating temperature of the engine is approximately 90 degrees Celsius.

The resource of the S50 engine on the factory data is not specified, but in practice it can be estimated at more than 400 thousand kilometers. The tuning potential of this engine can reach 1000 horsepower without loss of resource, and adding power up to 320 horsepower is also possible.

The S50 engine was installed in the BMW M3 E36.

Reliability, problems and repair of the BMW S50 B30 engine

With the release of the new E36 body in 1992, BMW introduced an updated version of its M3 sports car. The increase in size and weight required a more powerful engine than before, and so the decision was made to install a new powertrain. The new engine for the BMW M3 E36 was called the S50B30 and was based on the M50B25 inline six-cylinder engine.

Engineers from BMW Motorsport GmbH took the standard M50B25 motor and made a number of modifications. A new cast iron crankshaft with a piston stroke of 85.8 mm was installed in the cylinder block, and the cylinder bore was increased from 84 mm to 86 mm. S50B30 connecting rods became longer (142 mm), their strength increased, pistons became lighter, their compression height increased to 31.6 mm, and the compression ratio increased to 10.8, which increased the working volume to 3 liters.

The cylinder head in the S50 was significantly modified: VANOS system was introduced with continuously variable valve timing on the intake shaft, new distributors (phase 260/260, 11.3/11.3 mm lift), valves were replaced (diameter of intake valves was increased to 34 mm, exhaust valves remained the same), stiff valve springs were installed, and the cylinder head porting was performed. The engine also received a 6-throttle intake system, dual mass flywheel, new sports exhaust system and other improvements.

The control system for the S50B30 was the Bosch Motronic M3.3.

These modifications resulted in 286 hp at 7000 rpm and 320 Nm of torque at 3600 rpm from 3 liters of displacement.

It should be noted that due to strict environmental requirements, the described version was not delivered to the North American market (except for 45 cars), and for the U.S. and Canada was offered another version of the M3 E36 engine under the index S50B30 US, based on the M50TUB25. The characteristics of this motor were slightly different: power was 243 hp at 6000 rpm and torque was 305 Nm at 4250 rpm.

In addition, there were other modifications, such as the S50B30 GT for the E36 M3 GT, with an output of 295 hp at 7100 rpm and 323 Nm of torque at 3900 rpm, as well as the most powerful version of the S50B30 for the Australian market, which developed 324 hp at 7200 rpm and 350 Nm of torque at 4400 rpm.

The S50B30 engine was used exclusively in the BMW M3 E36. In 1995, it was replaced by the more powerful and voluminous S50B32. The S50B30US version was replaced by the S52B32.

Problems and advantages of BMW S50B30 engines

Benefits

The motor is designed in such a way that the car owner feels all the advantages of a sporty atmospheric, but at the same time did not lose anything in the convenience and comfort of daily driving.

The s50 model looks much more attractive against the background of its prototype m50. This powertrain has an excellent safety margin and shows itself perfectly during operation at high rpm. The intake valves are 52mm by 28mm, which is larger than the m50’s 50mm by 25mm intake valves. Thus, the capacity of the cylinder head of this motor is greater than its predecessors, the m50 and m52 models, by 10-15%.

S50 is equipped with the Vanos system, which has a continuous change in the intake shaft timing within 80-122 grams. In comparison, the m50 has two fixed positions.

The use of stiffer springs and one-piece pushrods than the prototype allowed the motor to rev around 8,000 rpm. The installation of a throttle on each of the available cylinders improved throttle response. Specially shaped intake ports allowed for increased cylinder fill during high rpm operation. The good volume of the intake receiver smoothed out pulsations, resulting in equalized fill across the cylinders.

Disadvantages

The main breakdowns inherent in this type of unit include:

• overheating;
• leaking;
• causing air inflow at the inlet valve;
• increased oil consumption; RPM instability;
• problems with Vanos.

That is, the faults that occur during the operation of this engine are similar to the breakdowns characteristic of the entire 6-cylinder series of M50 motors. In addition to the above-mentioned malfunctions, the car “heart” was also inherent in the problem with trolling, which was practically solved by the manufacturer.

Due to the fact that the production of the power unit was discontinued back in the early 2000s, now cars with such engines are practically not purchased for quiet driving. This is due to the significant wear and tear of the “heart” installed in such cars. If the purchase for some reason is necessary, you should pay close attention to the condition of the purchased vehicle and its “heart”.

Tuning the engine BMW S50B30

Crossmembers

BMW S50 engines are excellent revving atmospheric engines, but 300 hp is not the limit. Additional power can be obtained by purchasing Schrick camshafts (284 phase, 11.9 mm lift), valve springs and installing a straight-through exhaust. The second option could be to buy a S50B32 cylinder head and install it instead of the stock S50B30, it is worth buying a S50B32 intake, Schrick 284 camshafts and valve springs. With the firmware, this will give about 310-320hp.
For more output, you need to remove VANOS (there are corresponding kits), then buy Schrick 316/308 camshafts, pushrods, springs, enlarged valves, do a porting of the cylinder head, buy an airbox, 440 cc injectors. This will spin the motor above 9000 rpm and get over 350hp.

S50B30 Turbo

The stock S50B30 engine has a high compression ratio and to lower it you will need to buy CP pistons (~8.5 compression ratio), Carrillo H-Beam connecting rods, VAC steel cylinder-head gasket and ARP studs. This will prepare the engine somewhat for supercharging. It would be good to buy camshafts from M3 GT (phase 264, lift 11.25 mm), Walbro 255, injectors 750 cc, boost controller, turbine Garrett GTX35, westgate, make a manifold to the turbine, flash the brain. As an option, you can look for ready-made turbo kits.

Those who do not need high power, may like the option with a compressor. There are both new and used kits on sale, increasing power from 350 to 450+ hp.

MOTOR RATING: 5