BMW S50B30 Engine

1. Specifications
2. Overview, problems
3. Performance tuning

BMW S50 engine specs

BMW S50B30 engine reliability, problems and repair

There was also the next sports modification BMW M3 with the new body E36 in 1992. The sizes and weight of this car considerably increased. That is why the old 4-cylinder S14B25 engine couldn’t accelerate new M3 E36 for 6 sec. to 60 mph. It was decided to install larger and powerful motor. The new BMW M3 E36 engine called S50B30. It based on 6-cylinder M50B25. S50B30 filled up the M50 series (it also included a M50B20, M50B24, M50B25 and S50B32).

Engineers of the BMW Motorsport GmbH took stock the M50B25 motor and in the cylinder block installed the new cast iron crankshaft (a piston stroke 85.8 mm). Also they increased diameter of cylinders from 84 mm to 86 mm. The S50B30 rods have a length of 142 mm and increased their strength. The pistons were lighter, their compression height – 31.6 mm, and the compression ratio increased to 10.8. All this allowed to increase displacement to 3 liter. Modified the cylinder head in S50 was applied continuously variable valve timing system VANOS on the intake camshaft. New camshafts (duration 260/260, lift 11.3/11.3 mm), diameter of inlet valves increased to 34 mm, diameter of exhaust valves kept the same with reinforced valve springs. Also made the head porting. The engine got individual throttle bodies, dual mass flywheel, a new sports exhaust system and other less significant elements.
The firing order for the BMW S50B30 engines is 1-5-3-6-2-4. The stock size of fuel injectors – 240 cc/min.
The electronic control unit S50B30 engine – Bosch Motronic M3.3.
These modifications allowed to get power 286 HP at 7,000 rpm, and a torque 320 Nm at 3,600 rpm.

Because of high environmental standards, S50B30 (EU version) wasn’t delivered to the North American market (except for 45 cars). Produced other model of E36 M3 engine for the USA and Canada. This motor had S50B30 US index and based on M50TUB25. The rods length of 135 mm, and the piston compression height of 32.8 mm, compression ratio decreased to 10.5. Cylinder head S50B30 US differs 2-Stage VANOS, camshafts (duration 252/244, lift 10.2/9.5 mm), the presence of hydraulic lifters. Also these motors weren’t equipped with individual throttle bodies. As the result, S50B30 US had smaller power – 243 HP at 6,000 rpm, and a torque 305 Nm at 4,250 rpm. At the same time produced other more rare models: for E36 M3 GT produced S50B30 GT motor. Its differences in other camshafts (duration 264/264 deg, lift 11.2/11/2 mm), the modified VANOS system, the new ECU program and other innovations. All this allowed to get 295 horsepower at 7,100 rpm, a torque increased to 323 Nm at 3,900 rpm.

The highest power got from the S50B30 engine for the BMW M3-R E36 car. These models delivered to Australia market. Thanks to the modified intake and exhaust and more aggressive camshafts such motor developed the power 324 HP at 7,200 rpm, a torque – 350 Nm at 4,400 rpm.

The S50 engine used on BMW M3 E36 cars. In 1995 the S50B30 replaced by new even more powerful S50B32. The S50B30US version replaced by S52B32.

BMW S50 B30 engine problems and malfunctions

Malfunctions of this engine are similar to all BMW M50. Such as overheating, oil consumption, periodic problems with VANOS, leaks, rough idle and other. The problem with misfire practically solved. Learn the troubles HERE. S50 engines already quite old and used very actively. Today, almost all copies, are completely worn-out. Do not buy E36 M3 with S50B30 if you are not the fan of this car.

BMW S50 engine tuning

NA Tuning

BMW S50 engines is excellent naturally aspirated motors with high maximum turns and 300 horsepower for them is not a limit. Additional power can be get by buying Schrick camshafts (duration 284, lift 11.9 mm), valve springs, headers and performance exhaust system.
Another upgrade option is to buy a S50B32 cylinder head and install it instead of the stock S50B30. For this engine you need to buy a S50B32 intake manifold, Schrick camshafts 284 and valve springs. Collecting these performance parts and tune the ECU, you get about 310-320 horsepower.
For better results, you need to remove VANOS. Then you need to buy a 316/308 Schrick camshafts, tappets, springs, big valves, to make cylinder head porting, to buy a carbon airbox, fuel injectors 440 cc/min. It will untwist the motor higher than 9,000 rpm and get more than 350 horsepower.

S50B30 Turbo

S50B30 has a high compression ratio and to decrease it you have to buy CP forged pistons (compression ratio ~8.5), connecting rods Carrillo H-Beam, VAC steel head gasket and ARP studs. These performance prepare the engine with turbocharger. Then buy camshafts from M3 GT (duration 264, lift 11.25 mm), Walbro 255 fuel pump, fuel injectors 750 cc/min, boost controller, Garrett GTX35 turbocharger, turbo manifold, wastegate. All this you have to assemble and adjust ECU. If you want to make it easier, then buy a turbo kit for the E36 M3.
Those who is not require a high power likes the option of supercharger kit. On sale there are sets that increase the power up 350 to 450+ HP.

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