Milltek Large Bore Downpipe Hi-Flow Sports Cat - BMW 428i F32 - SSXBM977

Milltek Large Bore Downpipe with integrated Hi-Flow Sports Catalyst for BMW 428i (F32). Direct factory fitment when paired with Milltek Cat-Back Exhaust System. Mandrel-bent T304L stainless steel construction with CNC-formed catalyst housing delivers increased flow over OEM restrictive units.

Larger diameter core expands exhaust gas velocity and reduces backpressure, unlocking additional power and torque. Hi-Flow catalyst maintains street-legal emissions compliance while allowing full acoustic character expression. Stage 2 ECU remap required to extract peak performance and recalibrate fuel delivery.

Fitment:

• BMW 428i F32 (2014-2016)
• Requires Milltek Cat-Back System for complete fitment
• Uses OEM exhaust hangers — no modification required
• Stage 2 tune mandatory

Hand-finished welds and TIG construction throughout. This downpipe unlocks the full potential of your F32 when combined with proper engine management.

Designed and manufactured in the UK with 40+ years of performance exhaust heritage. Tested at the Nurburgring.

Specifications

• Pipe diameter: 76.2mm (3.00")
• Off-road / competition use only. Not legal for use on public roads in the US.

Fitment

• BMW > 4 Series > F32 428i Coupe (Automatic Gearbox, without Tow Bar, None xDrive & N20 Engine Only) > 2014 to 2016
• BMW > 4 Series > F32 428i Coupe (Manual Gearbox, without Tow Bar, None xDrive & N20 Engine Only) > 2014 to 2016

• Free US shipping on orders over $250.
• Free pickup at our Dallas shop, usually ready within 24 hours.
• Unused parts can be returned within 30 days. Tunes, opened electronics, merch and installed parts are final sale.
• Want it installed? Book the install at thegbmotors.com.

Full details are on our shipping and returns page.