Wagner Tuning BMW B58 300 CPSI HJS ECE Approved EU6 Sports Cat Downpipe 3.5in SS304 1.4301 (Non‑GPF/OPF) M140i M240i 340i 440i 540i F20 F21 F22 F30 F31 F32 F33 F36 G30 G31 | 500001027.HJS

Notice: This HJS 300‑cell sport catalyst down pipe for BMW B58 engines has been discontinued by the manufacturer. Most owners now opt for the Wagner 200‑cell sport catalyst for even stronger flow and response. For advice or to order the recommended alternative, email info@mjmodifications.co.uk.

HJS 300‑Cell Sport Catalyst Down Pipe for BMW B58

Part number: 500001027.HJS

Engineered for the 3.0 turbo B58 powerplant, this high‑flow performance catalyst was a favourite for sharper turbo response, reduced exhaust restriction and a richer, more engaging sound. It uses a genuine HJS Euro 6 compliant 300‑cell core inside premium 1.4301 stainless steel (SS304) with 89 mm tubing and an adapter sleeve so it mates cleanly to the factory cat‑back. Direct fit, no fabrication, OE‑style alignment and hardware locations.

Why enthusiasts chose this upgrade

• Genuine HJS 300‑cell Euro 6 ECE type‑approved sport catalyst for road use
• Large 3.5 inch tubing with reducer to the stock system for simple bolt‑on installation
• High‑grade 1.4301 stainless steel construction for heat resistance and durability
• Direct replacement for the original catalytic converter with precise OE‑like fit
• Less back pressure to unlock performance potential and improve drivability
• Faster spool and crisper throttle feel, great with software calibrations
• Lower thermal load at the turbocharger for improved component longevity
• For vehicles without petrol particulate filters only

Real‑world feedback

We have installed this setup on customer B58 builds and feedback has been consistently positive. Owners praise the improved mid‑range punch, quicker boost response and quality fit and finish from Wagner and HJS.

Vehicle fitment

• 1 Series M140i and M140i xDrive - F20 F21
• 2 Series M240i and M240i xDrive - F22
• 3 Series 340i and 340i xDrive - F30 F31
• 4 Series 440i and 440i xDrive - F32 F33 F36
• 5 Series 540i 3.0 petrol 250 kW 340 PS - G30 G31 model years 2017 to 2018

Suitable only for cars without GPF or OPF.

Fitting service

Professional installation available at MJ Modifications in Warwickshire. Request a fitting quote at info@mjmodifications.co.uk.

Installation notes

We recommend replacing the down pipe gasket during installation to ensure a perfect seal and long‑term reliability.

Compatibility check before dispatch

We will confirm fitment prior to shipping. Add your UK registration or the last 7 digits of your VIN at checkout so we can verify compatibility for your specific B58 model.

Manufacturer and warranty

Manufacturer: Wagner

Warranty: 2 years manufacturer warranty

Looking for the current best option

As this 300‑cell unit is discontinued, most customers now choose the Wagner 200‑cell sport catalyst for B58 applications due to outstanding flow, quick spool and superb fit. For product guidance, availability and pricing, email info@mjmodifications.co.uk.

Search terms our customers use

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