BMW 155720201 Cylinder Head Inline 3.0 N54B30A

( Manufacturer Part Number: 155720201 ), ( Type: Cylinder Head ), ( Material: Aluminum ), ( Vintage Part: No ), ( Finish: Unfinished )

Review BMW N54 Cylinder Head Inline 3.0 fits TWIN TURBO

The **BMW N54 cylinder head (part number 155720201)** is a meticulously engineered component from the legendary **N54 inline-6 engine**, a powerplant renowned for its twin-turbocharged architecture, direct fuel injection, and high-performance capabilities. Originally introduced in the 2006 BMW 335i, this cylinder head represents the pinnacle of BMW s mid-2000s engineering, designed to deliver an exhilarating blend of power, efficiency, and reliability. Crafted from high-grade aluminum alloy, the N54 head features a **DOHC (Dual Overhead Camshaft) design** with **four valves per cylinder (2 intake, 2 exhaust)**, allowing for precise airflow control and optimal combustion. The **twin-scroll turbocharging system** is integrated directly into the head, with each turbocharger (Garrett GT2852R) feeding a dedicated bank of cylinders, ensuring balanced boost delivery and minimizing turbo lag. The **direct fuel injection system** works in tandem with the head s precise valve timing and port design to achieve a **lean-burn strategy**, enhancing both performance and fuel economy while maintaining a rich, dynamic exhaust note.

The N54 cylinder head is further distinguished by its **variable valve timing (Valvetronic) on the intake side**, which adjusts lift and duration to optimize low-end torque and high-revving performance. The exhaust side employs **fixed valve timing**, though some aftermarket upgrades allow for variable exhaust timing (VVT) modifications. The head s **intake ports** are sculpted for aggressive airflow, while the **exhaust ports** are designed to channel exhaust gases efficiently toward the turbos, contributing to the engine s signature **high-revving, turbocharged growl**. The **spark plug placement** is optimized for efficient combustion, and the **camshafts** are precision-machined to minimize friction while maximizing valve lift. This cylinder head is a critical component in the **N54B30A** variant, which produces **300 horsepower and 273 lb-ft of torque** in its stock form, though it is widely known for its **massive aftermarket potential**, capable of supporting **500 horsepower** with proper modifications, including upgraded turbos, larger injectors, and supporting internals.

For enthusiasts and mechanics, the N54 cylinder head is not just a functional part but a **symbol of BMW s ambition in the 2000s**, balancing cutting-edge technology with practicality. However, it is also notorious for its **common failure points**, particularly **carbon buildup on intake valves**, **oil leaks from the valve cover gasket**, and **turbocharger longevity issues** challenges that have driven a thriving aftermarket for upgrades, including **high-flow heads, custom valve covers, and reinforced internals**. Whether in its stock configuration or heavily modified form, the **N54 cylinder head (155720201)** remains a cornerstone of BMW s twin-turbo inline-six legacy, offering a perfect marriage of German precision and high-performance engineering.

### **Pros and Cons of Buying a 2020 BMW 155i (N54 3.0L Twin-Turbo Inline-6, B30A Engine)**

#### **Pros**

1. **Strong Engine and Performance**

The N54 engine is a well-proven inline-six with twin turbos, delivering around **300 350 hp** (depending on tuning) and **350 400 lb-ft of torque**. It offers a balanced power delivery, making it enjoyable for both city driving and highway cruising. The twin-turbo setup provides quick spool-up, though it can be less efficient at low RPM compared to single-turbo setups.

2. **Reliability of the N54 Platform**

While the N54 has a reputation for issues (especially with oil consumption and turbo longevity), the 2020 model has seen refinements. BMW addressed some of the earlier N54 s weaknesses, such as improving oil control rings and refining the turbocharger design. A well-maintained 2020 N54 should be more reliable than older examples.

3. **Tuning Potential**

The N54 is one of the most tuner-friendly BMW engines ever made. Aftermarket support is extensive, with options for **boost upgrades, exhaust remaps, and even full engine swaps** (e.g., to an S55 or S63). This makes it a great choice if you plan to modify the car.

4. **Driving Dynamics and Handling**

The 155i is based on the F20 platform, which offers a **direct steering feel, responsive suspension, and a well-balanced chassis**. The M Sport package (if available) enhances driving dynamics with stiffer suspension and sport-tuned steering. The car handles well for its size, making it enjoyable for spirited driving.

5. **Comfort and Practicality**

The F20 chassis is spacious for a compact sedan, with decent rear legroom and cargo capacity. The interior is well-built, with **good sound insulation, a comfortable ride, and modern infotainment** (if equipped with iDrive 7). The 155i is more practical than its M240i counterpart, which sacrifices some space for performance.

6. **Resale Value and Market Demand**

BMW s inline-six engines, including the N54, still hold decent resale value, especially in tuned or well-maintained condition. The 155i is a popular choice among enthusiasts, which means parts and aftermarket support remain widely available.

7. **Cost of Ownership (Compared to Modern Twins)**

While fuel economy is not great ( 18 20 MPG combined), it is **better than a modern twin-turbo inline-4 (e.g., B48)** in some cases, especially with tuning. Maintenance costs can be higher than a naturally aspirated engine but are often offset by the car s performance and tuning potential.

---

#### **Cons**

1. **Oil Consumption and Maintenance Risks**

The N54 is notorious for **oil burning**, particularly in high-mileage examples. Even in 2020, some owners report **1 2 quarts per 1,000 miles** in severe cases. Regular oil changes (every **5,000 7,500 miles**) and using **high-quality synthetic oil** are essential. A well-documented service history is crucial.

2. **Turbo and Valvetronic Actuator Issues**

The twin-turbo setup can suffer from **turbo lag** (though less so in the N54 than in earlier N5x engines). Valvetronic actuators (which control intake valve lift) can fail, leading to **rough idle, misfires, or loss of power**. Replacement actuators are relatively inexpensive, but they can fail again if not properly maintained.

3. **Fuel Economy and Running Costs**

The N54 is **not fuel-efficient** by modern standards, averaging **18 20 MPG combined**. High fuel consumption means higher running costs, especially if you drive frequently. Premium fuel is required, adding to expenses.

4. **Transmission and Drivetrain Wear**

The **Getrag 6HP21 6-speed automatic** is generally reliable but can develop **slippage or rough shifts** over time, particularly if not serviced properly. Some owners report **clutch or torque converter issues** in high-mileage examples. A **transmission fluid flush** is recommended every **50,000 60,000 miles**.

5. **Electrical and Infotainment Quirks**

The **iDrive system** (especially in older generations) can be **glitchy or unresponsive**. Bluetooth connectivity, climate control, and other electronics may require occasional resets. The 2020 model has improvements, but some owners still report minor electrical issues.

6. **Depreciation and Market Saturation**

While the N54 holds value better than some BMW engines, the **155i is not as desirable as the M240i or newer turbocharged models**. The market is saturated with N54 cars, meaning **more competition for buyers** and potentially **lower resale returns** compared to more exclusive BMWs.

7. **Noise and Vibration Levels**

The N54 can be **loud at idle and low RPM**, especially with stock exhaust. The **valvetronic whine** (a high-pitched noise from the intake system) is a common complaint. While not dangerous, it can be annoying for some drivers.

8. **Suspension and Ride Quality**

The F20 platform is **stiffer than modern BMWs**, leading to a **less comfortable ride** over rough roads. The suspension wears out over time, and **struts, bushings, and control arms** may need replacement, adding to maintenance costs.

---

### **Ending Conclusion**

The **2020 BMW 155i (N54)** is a **compromise between performance, reliability, and practicality**. It offers **excellent tuning potential, a fun driving experience, and a proven engine** but only if **properly maintained**. The N54 s **oil consumption, turbo longevity, and fuel efficiency** are its biggest drawbacks, but these can be managed with **diligent upkeep**.

If you **prioritize performance, modding, and driving enjoyment** over fuel economy and low maintenance, the N54 is a **great choice**. However, if you **prefer a more reliable, modern turbo engine**, a **B48 (N20/N26) or newer BMW** (e.g., 135i, 330i) might be a better long-term investment.

### **Recommendation**

- You **plan to tune it** and enjoy the performance.

- You **find a well-documented example** with **low oil consumption** and **proper service history**.

- You **don t mind higher fuel costs** and **regular maintenance checks**.

- You **prefer a balanced sedan** over a sportier M240i.

- You **prioritize reliability over performance** and want a **lower-maintenance car**.

- You **don t want to deal with oil changes every 5,000 7,500 miles**.

- You **don t plan to modify it**, as newer BMWs (e.g., B58, B48) offer better efficiency and reliability.

- You **hate high fuel costs** and prefer a more economical engine.

**Final Verdict:** The N54 is a **great enthusiast s car** but requires **more attention than a modern BMW**. If you re prepared for its quirks, it s a **fantastic driving machine** otherwise, consider a newer or more reliable alternative.

Details:

Good used condition good.

part #: 155720201 prices

• $200.00-$300.00

specifications cylinderheapar:

• for models: Turbo, Twin
• for makes: Bmw
• mpn: 155720201
• type: Cylinder Head
• material: Aluminum
• vintage part: No
• finish: Unfinished

offer cylinderheapar:

• availability: In Stock
• options: Ship-to-home
• started: February 14, 2026
• quantity: 1
• sold: 0

payments cylinderheapar:

• credit card: Discover
• wallet: Paypal
• other

general cylinderheapar:

• condition: Used
• Car Truck Parts Accessories > Engines Engine Parts > Cylinder Heads

seller cylinderheapar:

• city: Raleigh, North Carolina
• # reviews: 184
• rating: 100.0%

shipping cylinderheapar:

• service: USPS Ground Advantage
• type: Fixed
• carrier: USPS
• transit: 7-11 Days
• cost: $100.00
• class: Standard

returns cylinderheapar:

• time: 14 Days
• paid by: Buyer
• policy: Returns Accepted

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