Stone Exhaust BMW F-Series N20 2.0T Catless Downpipe | DeCat/De-Cat Front Pipe | Turbo Outlet Straight/Test Pipe (Catalyst Delete) - F20 F21 F22 F23 F30 F31 F32 F33 F36 - 120i 220i 228i 320i 328i 420i 428i - A205P

Stone Exhaust Turbo Outlet Pipe for BMW N20 2.0T F-Series | Track-use de-cat front pipe upgrade

Transform throttle response and turbo spool on your BMW N20 2.0 turbo with this race-spec catalyst delete front pipe from Stone Exhaust. Engineered for the F-Series 1 Series, 2 Series, 3 Series and 4 Series, this high-flow turbo outlet pipe replaces the restrictive factory catalytic converter section to free up exhaust velocity, sharpen boost response and deliver a deeper, more purposeful soundtrack.

Built using advanced 3D scanning, precision CNC bending and robotic welding, the Stone Exhaust system offers exact fitment, outstanding durability and a clean, smooth internal bore for optimum gas flow. We have installed these units for years and the results are consistently excellent. Customers repeatedly praise the flawless fit, premium construction and the way the car feels more eager through the rev range.

Highlights that set it apart

• Direct swap for the OEM front section on BMW N20 2.0T engines across F20, F21, F22, F23, F30, F31, F32, F33 and F36 platforms
• Suitable for 120i, 220i, 228i, 320i, 328i, 420i and 428i applications
• Designed to reduce back pressure for improved turbo efficiency and a richer exhaust tone
• Unique flex joint to help protect against cracking under extreme heat cycles
• Crisscross and overlapping weld technique to reinforce the turbo flange under high thermal load
• One-piece mandrel-style bends for uninterrupted flow and fewer potential weak points
• Robot-assisted welding for consistent, high-penetration joints and long-term strength
• True OEM-style alignment for a hassle-free install

Engineering you can rely on

Stone Exhaust employs 3D flow analysis and reverse engineering to optimise diameter, routing and bend geometry. The internal surface is exceptionally smooth, minimising turbulence and weld intrusion for maximum exhaust-gas efficiency from the turbine outlet onward.

R&D and 3D scan workflow
Factory components are digitised to examine routing and pinch points, then simulated for gas speed, heat and pressure zones. The team iterates until the most efficient, durable solution is achieved for the N20 2.0T architecture.

7-axis CNC bending
Aerospace-grade bending keeps up to 98 percent roundness with only 25 percent outer-bend wear at tight 180-degree turns, maintaining cross-sectional area and reducing stress. Tolerances are exceptionally tight at approximately 0.025 mm for a precise, rattle-free fit.

Reinforced flange and robotic welds
The turbo flange area endures extreme temperatures. Stone’s overlapping weld pattern increases width and penetration, while direct spot welding by robotic arms ensures uniformity, strength and longevity.

Compatibility

Engine: BMW N20 2.0 turbo petrol

1 Series

• F20 120i, including LCI
• F21 120i

2 Series

• F22 220i, 228i, 228i xDrive
• F23 220i

3 Series

• F30 320i, 328i, including xDrive and LCI variants
• F31 320i, 320i xDrive, 328i, 328i xDrive, plus LCI

4 Series

• F32 420i, 420i xDrive, 428i, 428i xDrive
• F33 420i, 428i, 428i xDrive
• F36 420i, 420i xDrive, 428i, 428i xDrive

Part number

A205P

What our customers say

We have fitted many of these at MJ Modifications and feedback is always positive: tight tolerances, no drama during installation and a noticeable step-up in response and sound quality. If you want a premium N20 turbo outlet upgrade that fits right and performs, this is the one to choose.

Warranty

Backed by Stone Exhaust with a 2-year warranty.

Professional fitting

Want it installed properly first time? Book fitting with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Important note

This product is a de-cat track component. For motorsport and off-road use only where permitted. Check local regulations before purchase and installation.

Photos

Video

BMW F36 N20 420i complete exhaust sound

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