981 GT4 Splitter


981 GT4 Splitter Overview: 
Front splitters are very efficient for increasing downforce at the front of the vehicle. Designed specifically for the 981 GT4, this front splitter creates about 90lbs of downforce at 80mph (~200lbs at 120mph). This is achieved by using two main design features. First, it creates two distinct pressure regions above and below the splitter which sticks out approximately 3" to 4" from the air dam. The air above the splitter slows down as it hits the car and creates a high pressure region while the air below accelerates and creates a low pressure region. This pressure difference creates the downforce to help increase front grip! Second, there are two large diffusers just in the front of each tire. These diffusers direct airflow upwards and into the wheel well increasing the air velocity under the splitter and thus further increases the downforce produced. The diffusers produce about 20% of the overall downforce. Track tested at Laguna, this lip has no problems even on the corkscrew! 

Optional internally mounted splitter rods are included! If you intend to do endurance racing or hit tracks that go regularly above 140mph, installing our splitter rods are highly recommended. Splitter rods help distribute load on the the splitter mounts to other parts of the chassis giving the necessary support to handle the increased loads on the high speed race tracks. These rods require drilling into the crash bar. Without the splitter rods, the splitter can be operated at speeds below 140mph. 


The front splitter is constructed from pre-pregnated carbon fiber with a matte or glossy twill finish. Pre-pregnated carbon fiber ensures maximum strength and stiffness with minimal weight by avoiding excess resin during the manufacturing process. The carbon fiber sheet is then water cut to our drawings to ensure a perfect fit with your vehicle. It is stiff enough for high speeds yet flexible enough to take a beating. Should the splitter take too much damage, replacement splitter sheets are available. The two front diffusers are also created from carbon fiber formed to fit nicely on the GT4. Fits on 981 Caymans with front GT4 bumper conversions. *Wheel fender trimming required.*

Main mounting brackets are made from stainless steel sheetmetal ensuring maximum strength and stiffness. Brackets are powder coated black for durability and great looks even though they are hidden away after installation. Splitter rods are made of billet aluminum and have steel rod ends. 

  • 3.5mm dry carbon fiber 2x2 twill matte or glossy finish (stiff yet flexible enough for durability)
  • Front carbon fiber diffuser design adds ~20% more downforce than a flat bottom design
  • Heavy duty stainless steel direct frame mounting brackets
  • CFD tested and road/track proven results
  • Supports over 500 lbs
  • Optional internally mounted aluminum splitter rods for track speeds >140mph
  • 90lbs downforce @80mph
  • Helps even up aerodynamic balance for larger wing angles and upgrades
  • Overall Weight: 13lbs
  • Fits all 981 Cayman, Cayman S, Cayman GTS models with GT4 front bumper conversions with trimming of the front wheel fender liners
  • Replacement splitters at a fraction of the cost

Customer Reviews

Based on 2 reviews
Colin M
Amazing downforce...get one!

We run this splitter, along with the DBJ rear wing, in endurance racing. The grip improvement over the stock Clubsport MR is absolutely amazing. Turn in becomes so much sharper, and overall stability is greatly improved.

You need this for your GT4!

The GT4 comes from factory lacking aero in the front. To get your car really well balanced you need a splitter that can generate meaningful downforce. At your next track event, you'll notice how much better your car points and turns in.

3D Scanning & Prototyping

Each DBJ product goes through several rigorous design phases. Starting from scratch, we collect high accuracy scanned data from cars to ensure great fitment. Data is then processed and models and designs are created using CAD software. Prototyping using 3D rapid prototyping printers are used to confirm scans and fitment. Sometimes we are able to print out entirely functional parts for road and track testing. 

Computational Fluid Dynamics

Initial designs are tested using both finite element analysis (FEA) and computation fluid dynamics (CFD). Both these methods require several iterations to ensure proper performance and optimization of DBJ parts. 

Real world testing

Finally once the design is completed, we test our prototypes on the street and track! Thoroughly test driving our products helps ensure that our customers have nothing but the best experiences when it comes to installation and performance results.