martinbo
Staff member
Yes chonkoa, when entering into a discussion around primary balance - a V12 is far better balanced than an inline 4. Hence the reason that most inline 4 cylinder make use of balancer shafts to smooth out the inherent vibration.
This inherent imbalance of the inline 4 is why we very seldom see displacements of higher than 2.0 litres in an I4 engine - bigger components carry more weight, more inertia and the magnitude of the forces causing vibrations is amplified.
Hence: 2.5 litre 5 pot Volvo inline engines and 2.5 litre Boxer 4's in the Subaru range. (In the case of the latter, the engine is counter-balanced by the opposing pistons across the horizontal axis but is imbalanced longitudinally.) Flat-sixes and straight-sixes are particularly well-balanced, hence it's not uncommon to see displacements of higher thatn 500cc per cylinder in straight and inline sixes. Examples of which are the 3.8 litre 911 flat-six at 633cc per cylinder and the 4.0 litre straight six from TVR with 665cc for each pot.
This inherent imbalance of the inline 4 is why we very seldom see displacements of higher than 2.0 litres in an I4 engine - bigger components carry more weight, more inertia and the magnitude of the forces causing vibrations is amplified.
Hence: 2.5 litre 5 pot Volvo inline engines and 2.5 litre Boxer 4's in the Subaru range. (In the case of the latter, the engine is counter-balanced by the opposing pistons across the horizontal axis but is imbalanced longitudinally.) Flat-sixes and straight-sixes are particularly well-balanced, hence it's not uncommon to see displacements of higher thatn 500cc per cylinder in straight and inline sixes. Examples of which are the 3.8 litre 911 flat-six at 633cc per cylinder and the 4.0 litre straight six from TVR with 665cc for each pot.
