The installation process might seem daunting, but Planet-9 member Voyager6 did a fantastic writeup on how he installed them on his own 981 Cayman S (seriously, if you get a chance, check out his thread on his beast of a car).
He was gracious enough to allow us to repost it on our blog for the benefit of other 981 Cayman/Boxster owners, so here's Voyager6's 981 GT4 side scoop installation guide:
Porsche 981 Rocker Panel Removal and GT4 Side Vent Cover (Scoop) Installation Procedure
By Voyager6, Copyright © 2015, All Rights Reserved.
Hosting permission is granted to Planet-9.com and CaymanRegister.org. May not be reposted to any other website without this author’s express permission.
This procedure will give step by step the process to remove the rocker panels of a 981 Cayman or Boxster and will also include the installation procedures to add the GT4 side vent covers, aka Ram Air Scoops (or scoops) or hidders. The procedure is documented, but any attempt at following the instructions are at your own risk. Steps listed may suffer minor omissions or errors.
The actual removal and replacement of the rocker panels is about a 3 on the 1 to 10 scale of difficulty. The car does not have to be on a lift and could be done with wheels installed on the ground, if you have a couple special Torx bits that can fit between the wheels and fender, but it is much easier to do with the wheels off.
Scoops with outer vent insert with pre-drilled holes and alignment studs. The latter will significantly reduce the chances of drilling holes at the incorrect location. It is highly recommended.
As spare, optionally, a couple plastic retainers in case something breaks:
- (2) 98150449700 Rocker repair kit ($13-15 each, fastener and base, fastener not available separately)
- (2) 99959141340 Fixing Clip (top rocker panel retainer) $1
- (2) 99950799940 Sill retainer clip (blue) $1
- Plastic interior trim tools (one with a V gap and angled to give pry force is best)
- 3/32” drill bit
- 3/16” drill bit
- Battery-powered drill
- T-25 and T-35 screwdriver or bits with a ¼ inch ratchet.
- Large Channel locks/ adjustable pliers
- Magnetic parts tray to hold removed screws
- Roll of painter’s tape, about 1 inch wide.
- Wide roll of painters tape
- Pen to mark tape
- Touch up paint to match your car’s exterior color.
To Remove Rocker Panel:
Jack up car at front lift point. At front wheel well area, remove T-35 screw from underside of rocker panel. It holds the wheel well liner (not shown as I removed the front liner).
Inside the rear wheel well, remove two screws in the liner that go into rocker panel. There is a nut in the general area that does not need to be removed. These screws are difficult to get to with a screwdriver, and can be removed with a proper-sized ratchet and bit. Otherwise, remove the rear wheel and the screws can be removed easily with a Torx screwdriver.
If you removed the rear wheel, put it back on and tighten the lug nuts enough to hold the weight of the car.
While car is on a jack, carefully remove eight fasteners from underside of rocker panel , between front and rear wheels.
Now, open the door and remove the outer door sill. The sill pulls outward toward the door, held by four fasteners that fit into grooves in the underside of the sill cover.
At this time, there should be nothing left other than clips that hold the rocker panel to the body. It is held by three plastic squeeze clips. You may need to pull the fender liners away from the rocker panel to fully release the rocker panel.
Reinstallation is the reverse of removal. Start at front and work backward. The only note is to try to make sure the lower 8 fasteners are fully locked (note the locked position of the slots in the head of the fasteners) and to make sure the fender liners are tucked in correctly. The fender liners have a speed nut that must go above the flange of the rocker panel (as screw will press against the rocker into the speed nut. The liner may click when put into place.
Remember to torque the lug nuts to final torque. I use 120 ft-lbs.
Ram Air Scoop Installation
This is dangerous as you have to drill six holes in each rocker panel to mount the scoops. As a result, I rate this as a 7 on a difficulty scale of 1 to 10. It is all too easy to drill holes incorrectly and leave an ugly visible hole in your rocker panel, requiring repair or replacement.
Look at the scoop edge and see the six mounting holes. They are in a raised square.
Trial fit the scoop to the rocker panel. Make sure it fits cleanly in the intended recess.
If you have Zunsport side vent grills, now is the best time to install them. They can fit under the scoop. It is recommended to bend the three mounting hooks inward to not scratch the plastic vent ring and then, when in place from behind, use pliers to bend the hooks over the ring’s back edge so the grills will stay in place.
Without the pre-drilled vent, the only hope you have is to take a large sheet of paper and wrap it around the mounting edge of the scoop, draw an outline/pattern and then cut it, leaving tabs to tape to the scoop and the rocker panel. Tape the pattern to the scoop. Then mark/punch the template/pattern where the holes should be. Place the scoop with the taped pattern on the rocker panel. I recommend using wide painter’s tape to hold the scoop firmly to the rocker panel while transferring the pattern, so the scoop won’t move on you. Recheck the scoop alignment and hole position as best you can for fitment. If you tape the pattern off center, you will put the holes in the wrong place and the scoop will not mount correctly and will leave ugly gaps at the scoop-rocker panel interface.
Now, if you did the smart thing and purchased the GT4 vent rings, things are better. Two of the holes are pre-located for you and the alignment studs will ensure repeatability and reliability of the scoop’s hole locations. You can choose to create a pattern as described in the paragraph above or use a quick and dirty way to locate the screw holes:
Take four six inch lengths of painter’s tape, 1 inch wide, and put a horizontal mark to the edge of the tape on both sides at the same location. Roll the ends up a turn or two. Affix a piece of tape to the scoop, from inside to outside, non-glue smooth side against the scoop. The rolled up edges of the tape will hold the tape to the scoop. Align the edge of the tape with the center of one of the holes. Make sure the horizontal mark you made is also at the center of the hole. This sets the approximate hole center. Repeat for all holes.
Test fit the scoop and start all six screws. Note if any are off. If so, using the 3/16” bit, auger the hole in the needed direction. Remove the screws. Hopefully you will not be so far off that the hole becomes visible at the edge of the scoop. If a hole becomes visible, your options are pretty much to continue and fill and paint the rocker after re-installation.
Install the tar-like double backed tape on the scoop, carefully aligning it. It does not take well to removal. Peel the white backing off and apply to the scoop, leaving the red backing film on the tape. Each scoop has two tape pieces. Make sure the red tabs meet in the middle. Lightly install the scoops using only an upper and a lower screw, leaving a gap between the scoop and the rocker to pull the red backing off. Note that some of the red backing film will have to be broken as the screws will wind up in the middle of the red backing film. Once off, press the scoop firmly to the rocker panel with one even motion (upper and lower at the same time) and the scoop will be more or less bonded to the panel.
Install remaining screws and tighten and the assembly is done. Reinstall rocker panel and repeat for other side.