BMW’s two most powerful inline 6 engines, the S55 found in the F80/F82/F87 M2 Competition, M3 and M4’s vs the S58 found in the BMW M2 G87, G80 M3 and G82 M4 are future classics. These engines are what people refer to as the modern 2JZ because they can make nearly double the factory wheel horsepower with bolt ons while maintaining the factory unopened block, factory transmission and factory drivetrain. So what exactly are the differences between these two motors? Below we’ll go in depth into each one.

BMW S55 3.0L Inline-6

• Engine Type: Inline-six cylinder
• Displacement: 3.0 liters
• Compression Ratio: 10.2:1
• Valvetrain: DOHC (Dual Overhead Camshaft), variable valve timing (Double-VANOS)
• Forced Induction: Twin turbochargers (TwinPower Turbo)
• Maximum Boost Pressure: Approximately 18.1 psi (1.25 bar)
• Fuel Delivery: Direct fuel injection (High Precision Injection)
• Horsepower Range: 425 horsepower to 454 horsepower, depending on the specific model and variant
• Torque Range: 406 lb-ft (550 Nm) to 493 lb-ft (670 Nm), depending on the specific model and variant
• Redline: Approximately 7,600 RPM
• Transmission: Typically paired with a 6-speed manual transmission or a 7-speed dual-clutch automatic transmission (M DCT)

BMW S58 3.0L Inline-6

• Engine Type: Inline-six cylinder
• Displacement: 3.0 liters
• Compression Ratio: 9.3:1
• Valvetrain: DOHC (Dual Overhead Camshaft), variable valve timing (Double-VANOS)
• Forced Induction: Twin turbochargers (TwinPower Turbo)
• Maximum Boost Pressure: Approximately 22 psi (1.5 bar)
• Fuel Delivery: Direct fuel injection (High Precision Injection)
• Horsepower Range: 473 horsepower to 503 horsepower, depending on the specific model and variant
• Torque Range: 442 lb-ft (600 Nm) to 479 lb-ft (650 Nm), depending on the specific model and variant
• Redline: Approximately 7,200 RPM
• Transmission: Typically paired with an 8-speed automatic transmission (M Steptronic)

Some notable differences between the S55 and S58

1. Displacement: The S55 engine has a displacement of 3.0 liters, while the S58 engine also has a displacement of 3.0 liters, so in this case they are the exact same size.
2. Compression Ratio: The S55 engine has a compression ratio of 10.2:1, whereas the S58 engine has a slightly lower compression ratio of 9.3:1. A lower compression ratio allows for higher boost pressure and increased power output.
3. Maximum Boost Pressure: The S55 engine typically operates at a maximum boost pressure of around 18.1 psi (1.25 bar). In comparison, the S58 engine operates at a higher maximum boost pressure of approximately 22 psi (1.5 bar). The higher boost pressure in the S58 engine contributes to increased power (horsepower and torque).
4. Horsepower and Torque: The specific power outputs of the S55 and S58 engines can vary depending on the model and variant. Generally, the S58 engine offers higher horsepower and torque figures compared to the S55 engine. The S58 engine ranges from 473 horsepower to 503 horsepower and 442 lb-ft (600 Nm) to 479 lb-ft (650 Nm) of torque, while the S55 engine ranges from 425 horsepower to 454 horsepower and 406 lb-ft (550 Nm) of torque.
5. Transmission: The S55 engine is typically paired with a 6-speed manual transmission or a 7-speed dual-clutch automatic transmission (M DCT). On the other hand, the S58 engine is commonly paired with an 8-speed automatic transmission (M Steptronic), but it does also have an available 6 speed transmission.

Both the BMW S55 and S58 engines have a significant aftermarket tuning potential, and the maximum power achievable can vary depending on various factors such as modifications, tuning methods, and supporting parts. In terms of aftermarket power potential, the S58 engine found in the newer BMW M3, M4, X3 M, and X4 M models is generally regarded as having a higher ceiling for power gains compared to the S55 engine, though both have so far made around 800whp on stock blocks, while the S58 does that with the factor turbos (which are larger than the factory turbos on the S55).

The S58 engine benefits from several advancements, including a lower compression ratio, higher maximum boost pressure, and improved cooling systems, which make it more capable of handling increased power outputs. Additionally, the S58 engine comes with some updates and improvements over the S55 engine, such as a redesigned cylinder head and higher-flowing turbos, further enhancing its tuning potential.

S55 Factory Turbo Setup

The factory turbos on the BMW S55 engine are TD04 twin-scroll made by Mitsubishi. These turbochargers are designed to work in conjunction with the engine’s exhaust gases to force more air into the combustion chamber, resulting in increased power output. The twin-scroll design helps to improve throttle response and reduce turbo lag by separating the exhaust gas pulses from different cylinders into separate paths within the turbocharger. This design allows for better energy extraction from the exhaust gases, leading to improved overall performance.

The highest horsepower rating for the BMW S55 engine is typically found in the BMW M4 GTS, a special limited-production variant. The BMW M4 GTS equipped with the S55 engine produces 493 horsepower (500 PS) and 442 lb-ft (600 Nm) of torque.

S58 Factory Turbo Setup

I am not 100% sure what model the factory turbos are on the S58, but they are made by BorgWarner.