Quote:
Originally Posted by CobraMarty
For the masses, all the soccer moms and commuters, and 98% who buy the 328 especially with auto trans, and hardly rev it over 3500rpm, a single stage intake with long runners is the IM of choice.
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The 330i had (and has) its max torque at 2750 rpm, by factory torque power curves from introduction of the E90:
http://www.e90post.com/forums/showthread.php?t=218
So it is not like BMW opted for high end power for 330 with 3 stage IM, and low end torque for 3.0 lt 325/328 single stage IM.
The single stage manifold is exactly like the 3 stage with the DISA flaps missing as already mentioned.
So with single stage manifold, at all rpm ranges there are always 3 different path length between cylinder banks. So never too good but never too bad either. I think this also explains why the single stage manifold N52's don't show those dips in their torque curve, vs the pronounced dips in 3 stage intake N52s. Because the impulse air from bank one to bank two is always getting distributed between the three possible but different length paths. No productive resonance and same way no counter productive resonance is allowed.