GT4 Rear Diffuser


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Installation Instructions

GT4 Rear Diffuser Overview: 
A properly designed rear diffuser not only looks great on your car, but is a very efficient way to add downforce. Using CFD software and 3D scans, the DBJ rear diffuser creates a completely flat bottom from the oil pan back to the rear of the car. This flat bottom helps reduce unwanted drag and produces downforce at the rear of the car. Although designed specifically for the 981 GT4, the DBJ diffuser also fits all 981 Caymans and Boxsters. 

The DBJ diffuser is made from CNC bent aluminum sheetmetal and is powder coated matte black. The strakes are made of durable high durometer polyurethane and have special design features to allow them to move vertically reducing the chance for fins ripping off under low clearances. These strakes can take quite a bit of beating and flex rather than crack and brake off. They can easily be replaced should anything happen due to the low clearances and track duty. 
  • 2 piece CNC bent aluminum sheetmetal design
  • Powder coated matte black
  • Covers everything behind the engine oil pan to the rear
  • 6 strake fin design with flex designed in to prevent damage and increase durability
  • Easy to replace, durable fins made out of high durometer polyurethane
  • All aluminum mounting brackets for easy installation
  • Reduces drag and creates downforce
  • CFD designed and tested
  • Road and track tested
  • Diffuser also fits 2013-2016 (981) Cayman and Boxster models (flat underbody tray section may require drilling on non-GT4 models. See installation notes
  • Overall Weight: 14lbs

    Customer Reviews

    Based on 1 review
    Saw an instant reduction in lap time

    100% recommend the product. One of the best pricing out there in the market

    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.