Intake plenum and 911 throttle body

[The Radium King]

Originally Posted by Ben006

And if anything happens, I can always go back to the original straight tube shape that worked great and that has nothing to do with IPD patent.
(the only reason I used a wedge on the new version is to stiffen the 3D printed part. It's not needed for the aluminum part).

well, I agree that the wedge is not required - there are some flow analyses that have been posted on this forum that show that the flow naturally splits there and there is no need for the divider.

the true problem is with the inside radii when the flow splits - too sharp a curve and the flow delaminates. so, the primary focus would be to make a plenum that has larger inside radii, as the OEM tube has a very sharp bend in it.

the other issue is that you are limited to a smaller throttle body; 67 mm on the S models. it would be nice to be able to use a cheap 76 mm throttle body take-off from a 996/997/Cayman. you need a different plenum for that, however.

the thing is, the OEM 997 plenum at $40 new meets all these needs, so the only real benefit of an aftermarket piece is to match the secondary diameters to the intake runners. That is a benefit, however, as is anything that makes it easier to install the part. with that in mind then perhaps consider the ducting between the throttle body and airbox as well, so that you can sell as a kit and add some value to your product.

personally, I think the real market is with the 996/997/Cayman guys. these cars have bigger engines and can actually benefit from the 83 mm GT3 throttle body. unfortunately, there is no OEM plenum that will drop in (the GT3 intake is configured differently) and the aftermarket stuff is at IPD prices.