Eight spark plugs, one for each cylinder in its V8 engine.
Engine layout and spark plug count
The BMW 550i has historically used a V8 powertrain. A V8 configuration comprises eight cylinders, and each cylinder requires its own spark plug. In modern BMWs, ignition is handled by a coil-on-plug setup, meaning there are eight ignition coils and eight spark plugs in the engine bay. This configuration remains consistent across generations that carry the 550i badge, even as turbocharging or direct injection technologies evolve.
Ignition layout and access
In coil-on-plug designs, each spark plug sits beneath a dedicated ignition coil. That means eight spark plugs are positioned in pairs across the two cylinder banks, and replacement typically involves accessing each plug individually from the top of the engine. Depending on the model year and engine variant, some plugs may be more challenging to reach, which can influence maintenance approaches.
Generational context
From early E-segment 550i models to mid-generation F-series and newer G-series variants, the 550i is a V8-powered performance model. The core plug count stays at eight, even as engines have been updated for efficiency, turbocharging, or direct injection. If you encounter a different engine layout, such as a six-cylinder variant marketed as a 550i in some markets, the plug count would differ.
Maintenance considerations
When ignition service is due, plan to replace all eight plugs if you own a 550i. Direct injection can contribute to carbon buildup, which may affect plug choice or replacement intervals. Always consult the owner's manual or a BMW specialist for the exact maintenance guidelines for your vehicle's year and engine code.
Summary
In short, the BMW 550i uses eight spark plugs—one for each cylinder of its V8 engine. The standard coil-on-plug ignition layout means there are eight coils and eight plugs to service, with replacement intervals guided by your model year and engine specifications.