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

In our last article we focused on freeing up the exhaust side of our 9A1 engine.  Now we are working on freeing up the intake side of the engine for better breathing. We are going to be using parts from Dundon Motorsports, IPD Plenums, Fabspeed Motorsport and some of our own fabrication. Porsche has many variants of the same model and different models have more or less power.  For the Cayman, the S has more power than the base model and the R has more power than either so we are going to maximize the potential of uncorking the engine. A lot of the power variation in between the models is differences in the intake, exhaust with corresponding ECU tuning tricks so we are simply doing things the same way the factory does. With our car our goal is to come close to the power output of the expensive GT-4.

Our first step is to remove the stock intake manifold plenum, runners, throttle body and airbox.

The clamps holding the runners to the plenum are removed.

All the hoses, lines, clamps, and connectors are removed from the plenum, intake and throttle body.

The throttle body is removed from the plenum and intake tube.

The vacuum lines to the dashpots that control the plenum butterflies are removed and the center plenum can be removed from the car.


  1. If the dimples in the IPD work, great, but I doubt they make a big enough difference to justify the added costs of adding them. I’d much rather them make the plenum out of a heat resistant plastic.

  2. I’m pretty sure that the dimples work, as it is well known for golf balls. My argument was about the fact that the golf ball is rotating. I guess that you could argue that in this case the dimples are located in turns and transitions (from what I can see), so the flow is rotating. I suppose at maximum intake velocity the dimples are going to have some effects. I know that they can help with fuel atomization near the injector, if you have port injection.

  3. Really looking forward to seeing how the finished project performs on track- the articles and the video released thus far for this project have been some of the most interesting at MotoIQ (all of the articles here are informative and interesting though!).

    Also, thank you Mike and the MotoIQ staff/contributors for the knowledge and information that you share here. I am a long term reader, first time poster, but I’ve read your technical articles since the days of SCC Magazine in the 90’s. I don’t keep up to date with the automotive industry as much these days, but I frequently check this site for interesting tech articles, and the stories your share. Truly appreciate the effort and dedication of all the staff/contributors at MotoIQ.

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