BMW F32/F33/F36 4″ Catless Downpipe – Straight Pipe Design for Maximum Flow, Horsepower Gains & Aggressive Exhaust Sound | Fits 4 Series Coupe, Convertible & Gran Coupe 420i / 428i Models with N20/N26 2.0L Turbo Engine (2014–2016)

Unleash your turbo’s full potential — more power, faster spool, and a rawer exhaust note with the BAVMODS® 4″ Catless Downpipe.

Your BMW’s N20/N26 turbocharged engine was built for smooth performance — but from the factory, it’s held back by one of the most restrictive components in the exhaust system: the OEM catalytic downpipe.

Stock cats choke exhaust flow, trap heat, and build unnecessary backpressure that limits turbo efficiency and power output. The BAVMODS® 4” Catless Downpipe eliminates that restriction entirely — giving your turbo the freedom to spool faster, breathe easier, and sound absolutely raw.

Engineered for Turbo Efficiency & Power

Precision-built from high-grade stainless steel and TIG-welded for durability, this 4-inch downpipe transforms both performance and sound. It’s a true straight-through design, optimized to increase exhaust velocity and reduce turbo lag — resulting in noticeably quicker spool, sharper throttle response, and a deeper, more aggressive tone.

Key Performance Benefits:

• Massive Flow Increase: 4” mandrel-bent tubing eliminates restriction for smoother exhaust evacuation and lower EGTs.
• Improved Turbo Spool: Reduces backpressure, allowing boost to build faster and sustain longer.
• Enhanced Horsepower & Torque: Gains of +20–35 HP and +30–50 lb-ft when tuned.
• Aggressive Exhaust Note: Louder, deeper, and more dynamic tone with signature turbo whistle and crackles.
• Heat & Corrosion Resistance: Premium stainless construction withstands extreme heat cycles for long-term reliability.
• OEM+ Fitment: Direct bolt-on replacement using factory mounting points and O₂ sensor bungs.

Complete Plug-and-Play Installation

This is a true bolt-on upgrade — no cutting, welding, or modifications required.

Includes:

• Precision 4” stainless downpipe
• O₂ sensor ports with pre-installed bungs
• Hardware, gaskets, and clamps for a complete install

Pair it with a Stage 2 tune for maximum power and full CEL (Check Engine Light) management.

Why Go Catless?

A catless downpipe is the single most effective exhaust upgrade for any turbocharged BMW. By removing the restrictive catalytic converter, you:

• Unleash significantly more airflow
• Lower turbo temperatures
• Improve fuel efficiency under load
• Gain headroom for higher boost levels and advanced tuning

It’s the upgrade that truly lets your N20/N26 engine breathe — transforming your daily drive into something that feels factory-plus fast and track-capable.

Performance You Can Hear & Feel

Whether you’re chasing dyno numbers or just want your BMW to sound as powerful as it looks, the BAVMODS® 4” Catless Downpipe delivers.

Expect a crisper turbo spool, sharper throttle response, and a sound that makes every pull addictive. Combine it with a tune and cat-back exhaust for full transformation.

Your turbo deserves freedom — not restriction.

FITMENT: BMW 420i (F32 Coupe / F33 Convertible / F36 Gran Coupe) – 2014 to 2016, BMW 428i (F32 Coupe / F33 Convertible / F36 Gran Coupe) – 2014 to 2016.

ENGINE COMPATIBILITY: N20B20 / N26B20 – 2.0L Turbocharged Inline-4 (Single Twin-Scroll Turbo)

For N26 SULEV models, slight differences in O₂ bung positioning or emissions fittings may require a minor adjustment during installation. Professional installation and ECU tuning recommended.

MATERIAL: High-Grade Stainless Steel (TIG-Welded, Mandrel-Bent)

Please refer to the “Fitment” section in the product description for compatibility details.