2.5l I4 ohv tbi
wet manifold tuned for a set rpm range
shrouded valves in cylinder head
counter balancing shafts
2.5l 60v6 ohv mpi
mpi intake(can be tuned better then a wet intake manifold)
cylinder head valves are less shrouded due to mounting
No balancing shafts
possibly better camshaft specs
2.5l I6 dohc mpi
due too the change in camshaft layout, valves have to be canted at an angle in order to be efficiently activated; resulting in less valve shroud
longer intake manifold.
no balancing shafts
ps. there are alot of things that can change an engines efficiency
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