3.4l 996 intake manifold on 3.2S motor

[The Radium King]

well, the size of runners on the 996 plenum doesn't seem to be bigger than that on the 3.2, i think the difference is length - the 996 units are longer, so you will see more of a venturi effect and better cylinder fill at lower rpms. they may actually reduce max hp a bit as the increased length would be seen as a restriction at wot, but raise the overall torque curve up a bit. and more area under the curve is the goal, not necessarily the max number.

if you think about it from a porsche design point of view, the only reason the boxster runners are shorter is so they could fit the engine in the car.

[jaykay]

Originally Posted by The Radium King

well, the size of runners on the 996 plenum doesn't seem to be bigger than that on the 3.2, i think the difference is length - the 996 units are longer, so you will see more of a venturi effect and better cylinder fill at lower rpms. they may actually reduce max hp a bit as the increased length would be seen as a restriction at wot, but raise the overall torque curve up a bit. and more area under the curve is the goal, not necessarily the max number.

if you think about it from a porsche design point of view, the only reason the boxster runners are shorter is so they could fit the engine in the car.

The 996 3.4 / 3.6 left and right plenum chambers appear to have significantly more volume than the 3.2s by my eye....perhaps this yields a more consistent / higher manifold pressure giving more power. Also the entry diameter looks to be larger.

Anyone have this dimension at hand? It is probably the same diameter as the outlet of a 996 or 997 diverter tee.....recall way back when we first put 74mm TBs in and used reducers or did the stretch to make it fit with 3.2 boots.