Project 987.2 Cayman S: Getting More Out of the Engine to Chase the GT4 Part 3

Now it’s time to remove the intake runners.

The bolts holding the wire harness to the runners are removed.

You can see the Dundon manifold runners are shorter and bigger diameter.  This changes the tuning to resonate at higher rpm as well as improves the flow.

You can see that the plenum extension for the Dundon intake runners is deeper and bigger in volume. What is interesting is that functionality of the dimples in the IPD plenum was a controversial subject among our readers yet here they are in the OEM plenum from Porsche!

The IPD plenum has more internal volume and a more aerodynamic internal shape than the OEM plenum on the right.  The plenum entrance to the throttle body is a lot bigger too.

A look at the inside of the plenum shows the dimples and just how much larger the plenum is internally.