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

The stock airbox was removed from the fender area and we installed the cone filter and block off plate.  Now ram cold air from the cars side scoop feeds the engine directly.  We got one of the silicone elbows and cut a segment and clamped it to the cone filter adaptor.

We attached the other silicone elbow to the GT3 throttle body. Then we cut an aluminum tube to the right length so we could could connect the elbows together.

Now we have a 3.25 big diameter passage from the air filter to the plenum for great flow!

The PVC line routings are somewhat different between stock and IPD.   One of the lines was blocked off with the supplied plug.

Our intake tract mods are now complete. In our next segment we will work on our cars oiling system for the engine and transmission to assure that the bearings get a good supply of oil even with increased lateral G’s and to help keep things cool even under hard track driving.


Dundon Motorsports

IPD Plenums

Fabspeed Motorsport



  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.

Leave a Reply

Your email address will not be published. Required fields are marked *