GrimmSpeed 2015+ Subaru WRX J Pipe/Downpipe Catted 3in

Description

Meticulous engineering meets elegant design.

With the 2015 J-Pipe, the devil is truly in the details and the product development team here at GrimmSpeed has taken the time necessary to knock each of those details out of the park. As a result, what you see here is a meticulously engineered J-Pipe with an innovative flange design, single piece construction, excellent ground clearance and fitment with superb quality and craftsmanship.

Quick Specs

• Innovative Turbo Flange Design – 1/2″ thick while retaining all OEM brackets
  
• One-Piece Tube – Ensures exact fitment, robust construction and ease of installation
• Smooth 3.5″ to 3″ Transition – Matches turbine outlet size and then reduces quickly to maintain exhaust velocity
• 100% Made in the USA – Manufactured right here in Minnesota
  
• Optimized Tube Routing – Maximize ground clearance and minimize flow restriction without modifying suspension hardware, etc
  
• Custom Stainless Turbo Studs – Replace the terrible OEM studs and nuts with these, machined specifically for use with 2015 WRX turbine outlet and our 1/2″ flanges
• Standard 3rd O2 Bung – Allows the future use of aftermarket sensors
• Grounding Strap Mount – Retains all factory functionality
• 300 Cell Metallic Substrate Catalytic Convertor (Catted Models Only) – Excellent balance of the reduced restriction of a ‘race cat’ without the stink of a 200 cell unit

Performance and Tuning

Performance of the J-Pipe was verified on our 2015 WRX using the following method. Our tuned baseline run is the same run that we used in showing the boost control performance of the GrimmSpeed 3-Port Solenoid. We then installed the J-Pipe and retuned the car, using the exact same tuning methodology to ensure consistency. This ensured a real apples-to-apples comparison between the stock J-Pipe and the GrimmSpeed unit. The results showed a gain of 26.7whp (14.1%) and 19.8wtq (9.0%) and are displayed in the chart to the left. The percentage gains should be the focus here, as this particular dyno reads very low (stock baseline was 171). From a completely stock vehicle, users can expect a gain of around 45whp (27%) and 70wtq (41%) with the installation of the GrimmSpeed J-Pipe and custom tuning. The chart on the right shows this comparison.