BMW
's modern turbocharged engines boast incredible performance. They match the 2JZ engine performance levels, can be easily modified, and are compatible with several aftermarket products. Some of the most popular turbocharged BMW engines are the N55 and N54.These engines are similar in design and performance. However, they also have significant differences. Jerry
looks at the differences and similarities to determine the better engine. N54 vs N55: Similarities in design and performance
Despite being different, the N54 and N55 have significant similarities. Both engines have the same compression rate at 10.2:1. They are also 3.0-liter inline-six engines with the same displacement at 2979cc and utilize 84mm and 89.6mm of stroke.
The N54 and N55 use air-to-air intercoolers to cool their charged air. Besides, they both have open deck block designs, iron cylinder sleeves, and billet aluminum blocks. Finally, both engines use direct injection, but the N55 engine is improved.
Both engines also feature the BMW proprietary variable timing system (VANOS). However, the VANOS in the N55 has an extra 15 degrees at intake and 10 degrees at the exhaust.
N54 vs N55: key differences
The main difference between N54 and N55 is the type of turbocharger used in each engine.
Its N54 engine uses twin turbos, while the N55 uses a single turbo with a twin-scroll exhaust. A twin-scroll turbocharger is a standard turbocharger but splits its exhaust housing into two.
However, the difference with other standard engines is that each set of three cylinders that fire on the same cycle has its scroll from the turbo to minimize the exhaust reversion. The twin-scroll setup allows the engine to reach its top torque with 100 fewer rpm.
According to Road Sumo
, the twin-turbo N54 has better performance than the twin-scroll N55 as it can move more air when running. It is made of two turbochargers and a pneumatic actuator, unlike the N55, which has an electronic one. In addition, the N54 uses forged connecting rods and crank, while those of the N55 are cast. This makes the N55 engine way lighter than that of the N54.
Besides, the N55 uses Bosch solenoid valves, unlike the HPI injectors used in the N54. Despite the piezo-style HPI burning leaner, the N55 injector is cheaper and more reliable.
MORE: Manhart Just Revamped the BMW M135i
N54 VS N55: Which is the better engine?
As Dust Runners Automotive Journal
explains, when it comes to reliability, the N55 fared better. The N54 is sometimes plagued by electronic water pump failures, high-pressure fuel pump problems, and issues with the fuel injectors. However, when it comes to better throttle response and lower rpm torque, the N54 offers better performance. On the other hand, the twin-turbo setup of the N54 offers better performance if you decide to modify it. However, it takes up more space and costs more than the twin-scroll setup.
If you are looking for performance or modifications later, the N54 is your best choice. However, if you want a reliable, cleaner engine, the N55 is the best choice.
The N55 is used in the 535i, 335i, X3, X4, and X5 XDrive35i
, 640i, ActiveHybrid 3 and 5, and S Bi-Turbo Edition 99. On the other hand, the N54 engine is used in the 335i, 535i, 135i, and 740i. Get quality insurance cover cheaply
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