Stone Exhaust BMW B48D Catless Downpipe for G20 G21 G22 G23 and G29 Z4 OPF Models
Unlock serious performance and sound from your BMW B48D engine with the Stone Exhaust catless downpipe. Designed for BMW G20 G21 320i and 330i, G22 G23 G26 420i and 430i, and G29 Z4 20i and 30i OPF models, this premium turbo downpipe maximises exhaust flow, reduces back pressure and sharpens turbo response. Expect a crisper, more aggressive exhaust note and faster spool compared to the restrictive factory catted downpipe, all with precise OEM-style fitment.
At Nforcd we have fitted and used this Stone Exhaust B48D catless downpipe ourselves and for customers, and the feedback is consistently excellent for fit, finish, sound and performance. If you are searching for a BMW B48 catless downpipe, BMW 330i downpipe, BMW 320i downpipe, BMW 430i downpipe, BMW 420i downpipe, BMW G20 G21 G22 G23 downpipe or Z4 20i 30i downpipe for OPF and PPF models, this is the proven upgrade.
Why choose the Stone Exhaust B48D catless downpipe
- Catless downpipe for BMW B48D engines in G20 G21 320i and 330i, G22 G23 G26 420i and 430i, and G29 Z4 20i and 30i OPF models
- One piece CNC bent design for smooth, uninterrupted flow
- Unique flex section engineered to handle extreme heat and prevent cracking
- Crisscross and overlapping welds strengthen the turbo flange for durability
- Machine and robotic welding for precision, penetration and repeatable quality
- Reverse engineered with 3D scanning for exact OEM fitment
- 100 percent direct bolt-on to factory turbo and exhaust connections
- Developed in-house with flow velocity measurement and 3D simulation to optimise gas speed, thermal zones and pressure
R&D and manufacturing detail
Stone Exhaust engineers 3D scan OEM components to understand flow paths, pipe diameters, bend angles and routing, then iterate with simulation to remove restrictions and hot spots. The result is a highly efficient B48D downpipe that enhances exhaust efficiency beyond typical aftermarket offerings.
Built on a 7 axis CNC bending machine, the tubing maintains up to 98 percent roundness with only 25 percent outer bore wear at 180 degrees. This precision helps prevent airflow obstruction and reduces weld fracture risk. Combined with direct spot welding via mechanical arms, the final product achieves an accuracy error under 0.025 mm and delivers reliable performance at the turbo-to-downpipe interface where temperatures can reach 800 to 1100 degrees Celsius.
Compatibility
Engine: BMW B48D
- BMW Z4 G29 20i and 30i 2019+
- BMW 3 Series G20 G21 320i 2019+
- BMW 3 Series G20 G21 330i and 330i xDrive 2017+
- BMW 4 Series G22 420i and 430i 2020+
- BMW 4 Series G23 420i and 430i 2020+
- BMW 4 Series G26 420i and 430i 2020+
Suitable for OPF and PPF equipped models.
Part number
A218P
Brand and warranty
Manufactured by: Stone Exhaust
Warranty: Stone Exhaust 2 year warranty
Dimensions and weight
Dimensions: 70cm x 20m x 18cm
Weight: 2.21 kg
Professional fitting
Want it fitted professionally in the UK Find us at Nforcd in Warwickshire. Email Sales@nforcd.com for a fitting quote and availability.
Emission notice
Various U.S. states and the U.S. federal government have individual laws regulating the use of aftermarket exhaust parts and systems, especially as those parts and systems modify, remove, or replace original equipment catalysts. Please consult the appropriate laws in your area before installing any aftermarket part or system on your vehicle to ensure compliance with all applicable laws. The purchasers are entirely responsible for informing themselves of the applicable laws where the products are to be used and to comply with those law.
Search keywords
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