Everyone knows about the cheap and easy GT3 front brake duct upgrade (and if you don’t, grab a set, they’re a direct replacement! P/N: 99734148392 & 99734148492), but what about the rear brakes?
Last time I was out at Sonoma Raceway I noticed my rear brakes were getting very hot. I figured it couldn’t hurt to give them a little more cooling since the 987 doesn’t come with any rear ducting from the factory.
Based on some forum sleuthing, I found some old posts referencing 997.2 rear brake ducts that may do the job with a little modification. There was no clear guide on how to accomplish this, but based on what I saw I thought it should work. And luckily, for me, it did! Below are the part numbers for each side, I believe I paid about $50 for both including shipping.
P/N’s: 99733148702, 99733148802
Here you can see the finished product installed on the car. They do require some modification to fit. The duct points directly at the rotor which is perfect.
After doing some mockups I started cutting away at the duct using a Dremel with a cutoff wheel, though you could probably get this done with hand tools as well. I tried to take off as little plastic as possible. The duct needs to be clearanced for the e-brake cable, as well as your wheel and tire. You also will need to cut off the clip furthest away from the hub as it won’t fit over the arm. I was able to retain and use the clip closest to the hub.
Finally, I drilled through the duct so I could secure it better with some additional (high-quality) zip ties. Use some needle nose pliers and roll the end to pull them as tight as possible. I have done a few track days with these on and they have not moved at all.
Check out the photos below to see what all I cut off the duct. In one of the photos I circled part of the front retaining tab, that part also needs to be removed for it to fit flat on the arm. This is perfectly mirrored for the other side.
And there you go! A cheap and effective brake duct for your 987 (and I think, 981, also) Porsche Cayman. Feel free to shoot me a message if you’ve got a question.
2 responses to “Budget Rear Brake Ducts for the Porsche Cayman and Boxster”
I’ve done two track days and I’m experiencing the same thing! Did this mod help?
Hey Tom! They definitely helped, I’ve run them for a few years and the rear brakes didn’t get nearly as hot (my front pads would still smoke occasionally without a long enough cooldown) but there’s only so much little ducts like this can do. Plus, the factory rear discs don’t have a ton of mass. They’re a great, relatively inexpensive upgrade imo. I’m currently working on a more custom ducting setup that should be even more effective, and I’ll make a post about that when I’m done too.