528i vs 328i engine sound

[acollins78]

I have a 2015 328i Gran Turismo and my in-laws have a 2015 528i sedan. They both have the 240hp turbo 4 cylinder but sound and feel completely different. The 328i sounds and feels like a 4 cylinder. The 528i sounds like a 6 cylinder and is SUPER smooth. Did BMW do anything different on this engine depending on if it was going into a 3 series or a 5 series?

[White94RX]

Nope. They should be exactly the same. Sounds like what you're experiencing is totally normal when stepping up from a 3 to a 5. Better materials, better sound insulation, smoother suspension, etc.