Valved Exhaust System for BMW M340i B58 G20 / G21 3.0T (2019+)
Configuration
BMW M340i G20 / G21 Valved Exhaust System (2019+)
Valves
Operated by remote control, factory-paired.
Estimated at 0.50 m from the outlet, 45°, 2,000 rpm with a warm engine. Allow ± 2 dB depending on the engine and measuring point. A 3 dB difference is audible in a direct comparison; 10 dB sounds roughly twice as loud.
Configuration guide
Sound intensity with the valves open, on a scale of 0 to 10.
| Configuration | Intensity |
|---|---|
| Decat downpipe + Rog cat-back | 10/10 |
| 100-cell sports catalytic converter + Rog cat-back | 9/10 |
| 200-cell sports catalytic converter + Rog cat-back | 8/10 |
| Rog cat-back only, factory catalytic converter retained | 7/10 |
| Factory exhaust, for comparison | 3/10 |
Rog Advisor
A question about this exhaust?
Fitment, sound, catalyst, valves, delivery: the answer comes straight away, with your configuration in context.
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The BMW M340i G20 / G21 exhaust in detail.
This page is for the BMW M340i G20 saloon and G21 Touring built since 2019: both body styles take the same system. Under the bonnet sits the B58: a 3.0-litre inline-six with a single twin-scroll turbo and direct injection, delivering 374 hp and 500 Nm (392 hp, 540 Nm since 11/2025) very early and holding them across a wide band. It is the M Performance version of the 3 Series, built to be driven every day, and your system is made to its VIN.
The BMW inline-six has a round, even song that turns more metallic at the top of the rev range. On the stock M340i it arrives muted, kept at a distance by an exhaust tuned for passenger comfort. The valved Rog cat-back reverses the balance: with the valves open, a start-up that announces itself, a crisp climb through the revs and clear crackles on the overrun; with the valves closed, the saloon becomes as discreet as on delivery day, in town as on the motorway.
Nothing is welded or cut: high-strength band clamps, gaskets that are guaranteed leak-free, and about two hours for an equipped mechanic. The valves respond either to the factory control, if your G20 has it, or to the two-button Rog remote, independent of the drive mode.
On this turbocharged B58, the restriction that counts after the silencer is the downpipe, the pipe that runs from the turbo and contains the catalytic converter. This page offers it under the “Manifold” option; only the 200-cell version keeps the B58’s original emissions control. Fitted without an ECU remap, it brings sound and a little weight saving, not horsepower. The system comes in 304 stainless steel, robust with a full sound, or in titanium around 40% lighter, in brushed, gold or purple.
BMW M340i B58 G20 / G21 3.0T exhaust specifications.
| System type | Valved cat-back (valve exhaust), built to your VIN |
|---|---|
| Vehicles and chassis codes | BMW M340i G20 saloon and G21 Touring |
| Engine | B58, 3.0-litre turbocharged inline-six, 374 hp and 500 Nm (392 hp, 540 Nm since 11/2025) |
| Years | 2019+ |
| Materials and finishes | 304 stainless steel or titanium; titanium in brushed, gold or purple |
| Valves | Factory valve control if the car has it, otherwise the Rog remote |
| Front section (option) | Downpipe with 200-cell or 100-cell catalytic converter, or decat |
| Fitting | Band clamps and gaskets, no welding, about 2 hours on a lift |
| Manufacturing and delivery | Made to order, 20 working days, free signed-for delivery |
| Warranty | 3 years, parts and workmanship |
Questions about the BMW M340i B58 G20 / G21 3.0T exhaust.
Can my M340i Touring G21 take this system?
Yes. The G20 saloon and the G21 Touring take the same Rog system: same B58, same rear section, same clamp-and-gasket fitting. Your VIN is only used to confirm the model year before manufacturing.
Does the M340i need an ECU remap after fitting?
Not for the cat-back: the ECU stays stock and the B58 keeps its 374 hp (392 hp since 11/2025). If you add the downpipe, an ECU remap at an approved tuner turns it into power; at Stage 2, the published figures are 440 hp and 620 Nm.
BMW M340i B58 G20 3.0T with a Rog exhaust: what should you know about vehicle inspection?
With the valves closed, it sounds very close to stock. Cat-back alone or 200-cell downpipe: the catalytic converter still does its job. With the 100-cell, the answer depends on the car and local regulations; the decat version is kept for the track.
Stainless steel or titanium for an M340i?
304 stainless steel is the safe choice, with a full, round sound. Titanium costs a little more, weighs around 40% less for the same design and takes on a clearer note at high revs, with three finishes to choose from.
How long before I can drive with the system?
The system is made to order: allow 20 working days from confirmation to delivery, with free, tracked delivery. After that, around two hours in the workshop at the garage of your choice.
BMW M340i B58 G20 / G21 3.0T: Does a valved exhaust system drone?
No. With the valves closed, the gases flow through the whole rear silencer and the cabin stays calm at a steady speed. Our Rog exhausts are designed to avoid drone. Learn more: Why our systems stay calm on the motorway.
BMW M340i B58 G20 / G21 3.0T: straight pipe or resonator?
On this model, two characters at the same price: the straight pipe for the raw sound of your engine, unfiltered, or the resonator for a rounder and slightly softer voice. Either way, the exhaust stays fully sporty. Learn more: Exhaust resonator: what does it do? Straight pipe or resonator, which sound to choose.
Rog expert guide
BMW M340i G20 / G21 and M440i G22 / G23: the B58 in saloon and coupé form, the exhaust guide
M340i G20 saloon or M440i G22 coupé, the recipe is the same: the B58, a 3.0-litre turbocharged inline-six with 374 hp and 500 Nm (392 hp, 540 Nm since 11/2025), in BMW M Performance models built for everyday use. Their...
In detail
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Rog presentation film: choosing your vehicle, Standard or Equal Length design, stainless steel or titanium, Z-Pipe, controlled valves, titanium and tip finishes, and support from choosing your configuration through to shipping.
THE Rog CRAFT
Our process.
From the first bend to the last check. The same care at every step.
-
Design
Designed for your vehicle.
Geometry matched to your model, carefully studied bends and precise mounting points. Everything starts with accurate design.
-
Manufacture
Crafted with precision.
Tube bending, part fitting and TIG welding: every joint receives the same care.
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Finishing
Material, elevated.
The finish reveals the character of the metal. Stainless steel or titanium, depending on the options available for your vehicle.
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Assembly
Every part in its place.
Components are assembled and adjusted. On valved systems, the mechanism is fitted, set up and tested.
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Inspection
Check. Then approve.
Geometry, welds, connections and gas flow: the key points are inspected before shipping.
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Shipping
Ready to join you.
Reinforced packaging protects your exhaust in transit. The final step before giving your vehicle a new voice.
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