Remus Racing Valved Axle-Back Rear Muffler / Back Box for BMW M340i (G20/G21) & M440i xDrive (G22) 3 Series 4 Series - Stainless Steel Sports Exhaust Tail Silencer, B58 OPF/GPF Compatible, Plug & Play Actuator - Part 0851201500 - 2020+

Remus Valved Rear Back Box for BMW G20 G21 G22 M340i and M440i xDrive

Unleash the B58 soundtrack and sharpen throttle response with this Austrian-made Remus rear back box. Engineered for the latest xDrive 3 Series and 4 Series platforms, this valve-controlled rear silencer adds a deeper, motorsport tone under load while remaining civil on the motorway with the flap closed. Built from premium stainless steel with a shot blasted finish, it is a direct-fit, plug-and-play upgrade that reduces back pressure and trims weight compared to the factory rear can.

Remus’ in-house development shows the complete Racing cat-back package can achieve gains of up to +19.3 hp and +43.8 Nm with around 5.1 kg saved versus stock. Those figures apply to the full system. This listing is for the valve-controlled rear silencer only.

Highlights

• Track-inspired sound with OEM-style valve control for everyday refinement
• Optimised gas flow for sharper response and reduced restriction
• Lightweight stainless construction compared to the standard rear box
• Shot blasted finish and precision fitment using factory mounting points
• Includes genuine BMW flap actuator and Y-harness for easy integration
• Handmade in Austria with a 24-month Remus warranty

Tubing size

• Factory pipe diameter: 70 mm
• Remus pipe diameter: 76 mm

What is included

Remus rear valve-controlled silencer for G20 G21 G22 M340i and M440i xDrive, supplied with additional OEM BMW actuator and Y-cable. Tailpipe finishers are required and sold separately.

Build a full system

For maximum performance and volume, pair this rear silencer with the matching components:

• Remus non-resonated Racing GPF replacement section
• Remus connection tube
• Your choice of Remus tailpipe design for G20 G21 G22

Vehicle fitment

• BMW 3 Series G20 saloon and G21 touring M340i and M340i xDrive 2020 onwards
• BMW 4 Series G22 coupe M440i xDrive 2021 onwards

Our experience

We have installed this system in-house and customer feedback has been consistently positive on tone, finish and fit. It brings out the character of the B58 without unwanted cabin drone, and the valve keeps things calm when you need it.

Fitting and support

Professional installation recommended. Book fitting with MJ Modifications in Warwickshire. Request a quote: info@mjmodifications.co.uk.

When using Racing parts such as sports rear silencers, full cat-back systems or GPF replacement sections for closed-course use, an ECU calibration can be advantageous to optimise performance and help avoid a check engine light.

Legal note

No ECE approval. Racing product for off-road and circuit use only. Not permitted on public roads.

Part number

085120 1500

Warranty

2-year Remus warranty, non-transferable.

Compatibility check before dispatch

We verify fitment before shipping. Add your UK registration or the last 7 characters of your VIN at checkout so we can confirm the correct Remus rear section for your car.

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