991.2 GT3RS Splitter Installation

This document contains information regarding the removal and installation of the 991 GT3RS front splitter.

Created by: Anthony Butay                                                                            date: 05/06/2020

Edited by: Ted Anthony                                                                                        date: 06/10/2021

Tools Required:

  1. ¼” ratchet
  2. 3” ¼” extension
  3. 5mm hex bit ¼” drive
  4. 5mm hex bit ¼” drive
  5. T30 Torx ¼” drive
  6. T25 Torx ¼” drive
  7. 8mm socket ¼” drive
  8. ¼” drive torque wrench
  9. 90* pick
  10. 3/16" drill bit
  11. Electric drill
  12. McMaster Carr Metal Cable Ties (found here)


Splitter Installation

*If any fasteners are cross-threaded, the inserts will fail.

Torque 6mm bolts to 100-inch pounds (110 dNm)

Torque 8mm nuts to 22-foot pounds (30 Nm)

Torque 4mm bolts to 36-inch pounds (40 dNm)

1. Remove large plastic panel that covers front lower part of radiators. Also remove the factory plastic diffuser pieces on each side of the car. The T30 and T25 Torx are needed for this step. The picture below shows the area where the plastic pieces are positioned. this is however not an exact image of the panels.

2. Lay splitter pieces out flat and connect the middle piece to the side piece. You will repeat the same process for the other diffuser as well.

3. Align diffuser into pocket of splitter blade. There is a machine groove for it to sit in on the other side of the splitter blade. Now we will drill the holes for the diffuser to attach to the splitter blade. Make sure there is something underneath because we will be drilling through the diffuser. Use a 3/16" drill bit. Drill all 8 holes in the diffuser. After this step is complete, bolt this diffuser to the splitter blade, and repeat for the other side.

4. Assemble diffuser together with the diffuser pieces also attached. You can also see we attached the aluminum bump stops permanently on the diffuser during this step as well. Make sure all bolts are tight, as this assembly will not come apart again.

5. Set splitter assembly aside for now as we will install a few brackets. There are 11 total brackets that we will install in this step. First attach the 2 brackets together as shown below, this is the driver side main splitter bracket, along with all of the driver bracket examples, repeat for the passenger side as well.

MANDATORY UPDATE: Splitter Reinforcement cable tie installation

  1. If already installed, remove the GT3RS splitter from the car in order to start the reinforcement process of the 991.2 GT3RS splitter. Below are the measurements from the reference slots shown in the pictures below to determine where holes need to be drilled in the splitter blade. A 7.5mm or 5/16” drill bit will be needed to drill through the splitter blades.

Splitter Diagram


Splitter shown below with holes drilled in it.



2.   Now we can set the splitter aside and move onto installing the straps onto the pedestrian bar. The                    approximate location of the metal zip ties are below. The metal zip ties (McMaster Carr P#6898K65) will          need to be fed over the aluminum bar going across the car, but underneath the plastic pieces. *not actual        zip ties shown below.



3.   Now get someone to help you reinstall the splitter or balance the splitter on a screw jack for re-                        installation. As the splitter is going up on the car, the metal zip ties need to be fed through the splitter.            Below is a picture of the splitter on the car with the zip ties fed through the splitter.



4.   Push up on the front edge of the splitter with a screw jack or other method, the goal here is to reduce the        amount of sag that the front bumper and assembly has on the front edge of the splitter. Tighten the                  straps as tight as you can, a pair of needle nose pliers can be used to help hold the mechanism as you            pull the metal zip tie tight. Then you can release the screw jack after they are tightened. Trim the metal            zip ties so there is about .25”-.5” of leftover strap past the clamping mechanism.






6. Mount the splitter onto the car to the brackets now mounted on the chassis using all of the 6mm bolts and large washers supplied. We recommend having 2 people complete this step as holding the complete splitter assembly above your head, lining up the bolts holes and starting the bolts is very challenging. Tighten down all of the 6mm bolts that are holding the splitter so that it does not want to move.

7. Now we will drill pilot holes for the front lip supports. Use a 4mm drill bit or 5/32” to drill through the lip, once the pilot holes are drilled, remove the splitter again and set aside for now.

8. Hold the metal filler piece up to the lip so that it contours to the bumper nicely. A person to hold the metal strip to the bumper while the second can pre-drill the holes in the lip with the 4mm or 5/32” drill bit. Be careful not to go through the top side of the lip. Once pre-drilled, set aluminum bracket aside and drill out all of the holes in the Lip to 5.5mm or 7/32”.

9. Place middle aluminum strip above the lip and install the aluminum center lip bracket as shown using the 4mm bolts and washers included in the kit. Tighten them down for final installation of this piece.

10. Thread 4mm studs into the aluminum side brackets as shown below in every other hole, this will help line up the brackets while getting the splitter in place. Now take each side lip bracket and get them to lay on top of the inside of the lip. With the studs protruding downward toward the ground. Make sure that the flat side of the bracket is the side touching the lip.

11. Now we will carefully get the splitter re-aligned so we can get it back on the car for final installation. When placing the splitter back on the car, be careful to not push the lip brackets off of the lip. We want to line these up and get them to feed through the splitter. Once splitter is on the car in final position and the studs for the side lip brackets are protruding, we can install all of the 6mm bolts to hold the splitter up. Now in the side lip brackets we will thread the 4mm bolts with washers into every other hole that does not have a stud in it. Get the 4mm bolts snugged down.

12. Remove all of the 4mm studs and replace them with 4mm bolts and washers. Once all the bolts are installed, the 6mm and 4mm, we can tighten all of the bolts for the final assembly. The final assembly should look like the image below.


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