installation instructions

GT4 splitter

required tools & hardware

***DBJ is not responsible for damage to you or your vehicle by installing our products. Avoid improper installations that can lead to damage by using a professional for all installations.***

TOOLS REQUIRED                                                  INCLUDED HARDWARE

4mm Allen                                                            4x    M6X12 Screws

10mm  Socket                                                        26x      M6X15 Screws

13mm Socket                                                            8x      M6X25 Screws

  T25 Torx                                                                    7x    M6X40 Screws

  T30 Torx                                                                   69x      M6 Washers

Socket wrench                                                             24x      M6 Nuts

Extensions                                                                    4x      M8 Nuts

           Pliers                                                                   7x      M6 Clip Nuts Nuts

Flat Head Screwdriver                                       2x 5/16"-18 Blind Rivet Studs                                  

3/16" Allen Key                                                   2x 5/16" x 7/8" Flat Head Screws                          

Adjustable wrenches                                                                                                    

Rivet Stud Tool for 5/16"-18                                                                                        

assemble diffusers onto splitter

Assemble the diffusers onto the splitter as shown in pictures below. The diffuser has been designed to fit onto the bottom of the diffuser as shown in the bottom middle picture. Use a M6x15 screw, (2) M6 Washers, and (1) M6 nut for each of the holes with the washers making the contact with the diffuser and splitter face. Use the screw on the bottom side of the splitter with the nut on the top side. You will need to use a 4mm allen and a 10mm socket wrench. Install all bolts by hand before tightening with tools. Be careful not to over tighten these screws and nuts. There are 24 holes in all to install both diffusers. 

remove oem front under covers

Remove the OEM front covers by removing each of the circled screws with a T25 Torx or T30 Torx set. Once all screws are removed, set aside the original screws in a safe place so as to not misplace them. 

Save the oem screws

When installing the mounting brackets later, we will need to reuse (4) B screws (shown in red), and (2) C screws (shown in blue on the right.

install m6 clip nuts

As shown in the photo above, at each of the circled locations we will need to install the (7) M6 clip nuts. For the locations circled in red, we will need to remove the OEM clip nut first. Use a set of pliers and even a flathead screwdriver for this part. When installing the clip nuts, make sure that the threads line up with the hole.

install rear mounting brackets

There are (4) rear mounting brackets that need to be installed. Using the bottom middle photo as a reference, install the rear inner brackets (circled in red). As shown in the bottom right photo, you will need to use (1) OEM "C" screw (see the previous step) per bracket. The screw should be installed by using the mounting bracket slot closest to the front of the car for both sides. Aim to center the screw on the slot. You will need to use a T30 Torx for this. Next, install the rear outer mounting brackets as shown in the bottom middle photo (circled in green). Use (1) OEM "B" screw and aim for the center of the slot in the bracket. Try to position the bracket as horizontal as possible as seen in the bottom left photo and then tighten the screw using a T25 Torx.

install main mounting brackets

The main mounting brackets will support most of the downforce generated by the splitter. In most cases (track speeds under 140mph) the main mounting brackets are sufficient to support the downforce generated by the splitter. When anticipating speeds above 140mph, it is recommended to install the internal splitter rods. Jump to the next section before coming back. Note the orientation of the main brackets above (circled in red). Each bracket is held in by (2) M8 flange nuts. The M8 studs on the front of the chassis are shown in the bottom left photo. Slide the main bracket into place over the chassis studs and install the M8 flange nuts as seen in the bottom middle photo. You will need to use a 13mm socket and extensions to reach in. Make sure the bracket is straight then torque down the flange nuts. Repeat this for the other side.

Installing the internal splitter rods

As you can see in the picture to the bottom right, the main mounts have a counter sunk hole designed to attach to the splitter rods to spread the load to another part of the chassis.

Install the included blind rivet studs (5/16"-18) on the crash bar. To create access on each side to install the rivet stud, use a 13mm socket and flat head screwdriver to remove the horns. Once removed, you will need to drill a hole into the crash bar. The hole will need to be opened to 17/32" and then a rivet stud tool used to install the stud. Although it can be accomplished with the included washers and threaded standoff, the space to work with is rather tight. We highly recommend seeking a shop with a rivet stud tool for this part of the installation.

Once the studs are installed on both sides of the chassis, attach one side of the splitter rod to the newly installed rivet studs. Tighten the splitter rod and jam nut but make sure that the rod can reach the proper location when the splitter main mounts are attached. This will take some back and forth adjustment. Once the right angle and length is achieved, it is a good time to reinstall the horns. Next, install both of the main mounts as described in the previous steps and install the rod to the countersunk hole as seen in the bottom middle picture. You will use the supplied flathead 5/16" screws and 3/16" allen key.

Install the front splitter

Now we are ready to install the front splitter. Lift the assembled splitter up and onto the car. Try to line up (1) M6x25 screw and (1) M6 washer on each main bracket before adding more screws. Using the photo above, you can determine what size screw to use for which hole. The (4) green circles use M6x12 screws. The (2) blue circles use M6x15 screws. The (8) red circles use M6x25 screws. The (7) pink circles use M6x40 screws. For all screws, make sure to use an M6 washer. Install all screws by hand first. Slide the splitter around to ensure the best fitment and positioning before tightening all screws using a 4mm allen bit. There is some room for the splitter to extend out further as all mounting holes are slots. Note: for all pink screws (M6x40) only tighten by hand. The clip nuts are mounted onto the bumper and will not bottom out. They can deform the bumper and are meant to just be tight enough to secure the air dam to the splitter. 

install diffuser tab screws

For each of the diffusers a tab extends upwards and should line up with a screw hole in the wheel well. Use (1) of the saved OEM "B" screws (see previous steps) for each diffuser. You will need a T25 Torx bit to install these. Do not over tighten these screws as you may damage the carbon fiber. The install is now complete!