BMW 435i N55 Turbo Downpipe – High-Flow Sports Cat or Catless Decat (De-Cat) | 3"/76mm Front Pipe | F32 F33 F36 4 Series Coupe/Convertible/Gran Coupe | Stage 2 Remap Ready Exhaust Upgrade | Cobra Sport

High-Flow Catted or Catless Turbo Downpipe for BMW 435i N55 | F32 Coupé, F33 Convertible, F36 Gran Coupé

Unlock serious performance and sound from your BMW 4 Series 435i with this Cobra Sport turbo downpipe upgrade. Available as a high-flow catted unit or a decat option, this front pipe delivers freer exhaust flow from the turbo outlet to the centre section, reducing back pressure and sharpening throttle response.

Built with 3 inch 76.2 mm tubing, it replaces the restrictive OE catalytic converter between the turbocharger and mid pipe. The result is faster spool, a deeper, sportier note and the headroom you want for Stage 2 tuning and remaps on the N55 engine.

Why choose this upgrade

• Big flow gains from the turbo to the centre section with 3 inch 76.2 mm pipework
• Choose catted for a high-flow solution or catless for maximum track performance
• Crisper throttle, improved turbo response and a richer, more purposeful tone
• Ideal foundation for Stage 1 and Stage 2 software on the N55
• Direct fit for F32, F33 and F36 435i models
• Supplied with gaskets and fittings for a straightforward install

Fitment and compatibility

Designed for BMW 435i with the N55 engine across the following chassis:

• F32 435i Coupé
• F33 435i Convertible
• F36 435i Gran Coupé

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Real-world results

We have fitted this setup on customer cars at MJ Modifications and the feedback is consistently positive. Owners love the improved urgency, stronger mid-range and deeper exhaust character without unwanted drone when paired with a suitable system.

Road legality and important notes

Catless/decat option: sold strictly for motorsport and off-road use only worldwide.

Sports catalyst option: replaces a factory emissions device and is not EC homologated. It may not meet current emissions regulations for road use in your area. Please check local laws before purchase.

Installation and support

Professional fitting available at MJ Modifications, Warwickshire. For a fitting quote or to book, email info@mjmodifications.co.uk.

What’s included

• Downpipe assembly in 3 inch 76.2 mm tubing
• Gaskets and all required hardware

Watch: Sports Cat vs Decat

Understand the differences between a high-flow catted downpipe and a decat option in this quick explainer.

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