To add Fiat has a system that has 2 runners going to each cylinder and a butterfly valve of sorts that regulates flow between them.
One runner is long for torque, and the other is short for upper end power.
They call it a multi air system IIRC.
I don't like the stock design.
The plenum is far too small. and the runners are about 2 inches (overall length) too long and have odd bends in them when they don't need to be.
I'm basing my opinions on how the sr20det manifold is designed.
same displacement, about the same power. The theta has a higher compression, so it should be making more torque, and CVVT to make it more efficient.
Which doesn't really show in comparison.
And I don't recall any manufacturer designing their manifolds like this, pretty sure with good reason.
Last edited by AKGC; 04-10-2013 at 05:39 AM.