Milltek Sport Resonated GPF/OPF Bypass | Focus MK4 ST 2.3 EcoBoost | SSXFD312
Milltek Sport Resonated GPF/OPF Bypass – Ford Focus MK4 ST
Upgrade your Ford Focus MK4 ST 2.3 EcoBoost with the Milltek Sport Resonated GPF/OPF Bypass (SSXFD312), engineered for performance-focused motorsport applications.
Designed specifically for GPF/OPF-equipped Ford Focus MK4 ST models, this premium stainless steel exhaust component replaces the factory petrol particulate filter, reducing exhaust restriction and supporting a freer-flowing exhaust system.
The resonated (quieter) design offers a more controlled exhaust note compared with non-resonated alternatives, making it an ideal choice for enthusiasts looking for a less aggressive motorsport exhaust sound.
Manufactured in the UK by Milltek Sport, this bypass is designed to connect to the original Ford OE cat-back exhaust system, allowing the factory rear exhaust section to be retained.
Key Features
Genuine Milltek Sport product – UK-designed and manufactured performance exhaust component.
Resonated design – Quieter, more controlled exhaust characteristics compared with a non-resonated bypass.
Improved exhaust flow – Removes the restrictive factory GPF/OPF for motorsport applications.
Premium stainless steel – Durable construction designed for performance applications.
76.2mm (3-inch) pipe diameter – Engineered for improved exhaust flow.
OE cat-back compatibility – Specifically designed to connect to the original Ford exhaust system.
Stage 2 ECU remap required – Suitable for appropriately tuned motorsport vehicles.
Vehicle Compatibility
Ford Focus MK4 ST 2.3 EcoBoost (2019 onwards)
Ford Focus MK4 ST 2.3 EcoBoost Hatchback – GPF/OPF equipped
Ford Focus MK4 ST 2.3 EcoBoost Estate – GPF/OPF equipped
Product Specifications
Manufacturer: Milltek Sport
Product Code: SSXFD312
Product Type: Resonated GPF/OPF Bypass
Exhaust Diameter: 76.2mm / 3 inches
Fitment: Original Equipment (OE) Cat-Back Exhaust
Construction: Stainless Steel
ECU Requirement: Stage 2 Remap
EC Approved: No
Application: Motorsport / Off-Road Use Only
Important Information
This product removes the factory-fitted petrol particulate filter (GPF/OPF) and is intended strictly for motorsport and off-road applications. It is not approved for UK public-road use and may result in MOT failure.
This product is designed for the original Ford cat-back exhaust, not a Milltek aftermarket cat-back system. Please confirm vehicle and exhaust compatibility before ordering.
Order from OC Motorsport
At OC Motorsport in Essex, we specialise in Ford Performance upgrades, exhaust systems, ECU remapping and performance tuning.
Looking to upgrade your Focus ST for track use? Contact our team for product compatibility advice, professional fitting enquiries and suitable performance tuning options.
OC Motorsport – Ford Performance & Motorsport Specialists.


