Stone Exhaust BMW B48D Catless/Decat Downpipe (G20 G21 G22 G23 G26 G29 Z4) for OPF/GPF – 320i 330i 420i 430i 20i 30i – SUS304 Stainless – A218E

BMW B48D 2.0T de-cat front pipe for OPF and GPF cars - Stone Exhaust - A218E

Unlock sharper response and a stronger soundtrack from your G series BMW with Stone Exhaust’s high flow turbo outlet pipe. This straight through de-cat front section is designed for OPF and GPF equipped petrol models running the B48 four cylinder, delivering reduced back pressure, quicker spool and a deeper, motorsport inspired tone. Built from SUS304 stainless for long term durability and precise fit, it is a direct bolt-on upgrade that transforms drivability and pairs perfectly with performance software.

Why it stands out

• Engineered for BMW B48D 2.0T applications - G20 and G21 320i and 330i including xDrive, G22 G23 G26 420i and 430i, and G29 Z4 20i and 30i OPF and GPF models.
• Free flow de-cat design that reduces exhaust restriction for faster turbo response and improved mid range pull.
• SUS304 304 grade stainless construction for strength and corrosion resistance in UK conditions.
• 7 axis CNC bending for excellent roundness and smooth internal transitions that maintain gas velocity.
• Dual cross welding and mechanical direct spot welds at critical joints for reliability at the turbo flange and high temperature areas.
• Correctly positioned oxygen sensor boss to promote stable lambda data feedback.
• Direct fitment using OEM style connections - no cutting, no extra fabrication.

Real world feedback

We have fitted this part to customer cars and our own demonstrators with consistently positive results. Expect crisper throttle, earlier boost and a richer exhaust note that still sounds refined on the motorway. Owners looking for a premium cat delete front pipe for B48 powered G series cars rate Stone for quality, fit and finish.

Stone Exhaust manufacturing detail

Using 3D scanning and reverse engineering of OEM components, Stone models the ideal tube diameter, bend radii and routing for the B48D platform. Flow, heat and pressure zones are simulated and refined before production to maximise performance and fitment accuracy.

• Up to 98 percent roundness maintained through tight bends for consistent cross section.
• Crisscross and overlapping weld technique improves penetration and joint strength.
• Mechanical spot welding delivers repeatable, precise seams.

Vehicle fitment - B48D OPF and GPF petrol

BMW Z Series

• G29 Z4 sDrive 20i and 30i

BMW 3 Series

• G20 and G21 320i
• G20 and G21 330i and 330i xDrive

BMW 4 Series

• G22 420i and 430i including xDrive
• G23 420i and 430i including xDrive
• G26 420i and 430i including xDrive

Part number

A218E

Installation and support

Professional fitting is recommended. MJ Modifications in Warwickshire can supply and install this part and advise on OPF and GPF compatibility, mapping and aftercare. Request a quote at info@mjmodifications.co.uk.

Manufacturer

Stone Exhaust

Warranty

Stone Exhaust 2 year warranty.

Emissions notice

Laws vary regarding aftermarket exhaust components that remove or alter catalytic converters or particulate filters. Check and comply with local regulations before purchase and installation. For off road and motorsport use where permitted. The purchaser is responsible for legal compliance.

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