Valved Exhaust System for BMW M240i B58 G42 3.0T (2021+)
Configuration
BMW M240i B58 G42 Valved Exhaust System (2021+)
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 |
The BMW M240i G42 exhaust in detail.
Many choose the M240i G42 as a smart alternative to the M2: the same compact footprint, a 3.0-litre B58 inline-six, 374 hp and 500 Nm (392 hp, 540 Nm since 11/2025). Only G42 coupés, built since 2021, appear on our page. The previous-generation M240i F22, the four-cylinder 230i G42 and the M2 G87 have their own pages.
This coupé has everything going for it except its voice: a particulate filter and oversized silencers, imposed by regulations, lock down an engine with a naturally round tone. The Rog valved cat-back, or valve exhaust, sets it free; when open, the valves let through a generous bass note at idle, a smooth climb and crisp crackles, with no tiresome resonance. When closed, they give the M240i the discretion expected of an everyday coupé.
No cutting required: heavy-duty band clamps, gaskets and around two hours for an equipped workshop, with the system built to your VIN. You keep the factory control, which lets the drive modes decide if the car has factory valves, or you take the two-button Rog remote.
On this turbocharged B58, the “Manifold” option sells the downpipe, the catalysed pipe that follows the turbo and the main restriction after the silencer; without an ECU remap, it brings sound and a little lightness, not horsepower. The 200-cell variant leaves the G42 coupé with complete exhaust gas treatment, in line with its road use, while the 100-cell one is accepted or not depending on the car and the rules in your country and the decat version is reserved for track use. The cat-back comes in 304 stainless steel with a full tone, or in titanium around 40% lighter, with three finishes.
BMW M240i B58 G42 3.0T exhaust specifications.
| System type | Valved cat-back (valve exhaust), built to your VIN |
|---|---|
| Vehicle and chassis code | BMW M240i G42 coupé |
| Engine | B58, 3.0-litre turbocharged inline-six, 374 hp and 500 Nm (392 hp, 540 Nm since 11/2025) |
| Years | 2021+ |
| Materials and finishes | 304 stainless steel or titanium; titanium in brushed, gold or purple |
| Valves | Factory drive modes or the Rog remote |
| Front section (option) | Downpipe with 200-cell or 100-cell catalytic converter, or decat |
| Fitting | Clamps and gaskets, no welding, about 2 hours on a lift |
| Manufacturing and delivery | Made to order, 20 working days, free delivery |
| Warranty | 3 years, parts and workmanship |
Questions about the BMW M240i B58 G42 3.0T exhaust.
Does the M240i G42 system also fit a 2024 model year?
Yes, the page covers G42s built since 2021; send the VIN and we check compatibility before starting manufacturing.
Does the M240i G42’s B58 respond well to an ECU remap?
Very well, once the downpipe is fitted: the published Stage 2 figures for the M240i G42 are 440 hp and 620 Nm, while the cat-back alone works with the factory map.
The modified M240i G42 coupé has to go through its inspection: what precautions should you take?
With the valves closed, the coupé returns to a volume close to when it left the factory; the cat-back alone and the 200-cell downpipe keep the catalytic converter active, the 100-cell is accepted or not depending on the vehicle and your country’s rules, and the decat version is reserved for track use.
Do the M240i G42 and M2 G87 share the same system?
No: the M2 G87 gets the S58 and a dedicated system, shown on its own page, whereas this one is designed for the M240i G42 coupé and its B58.
Why is the M240i G42 so discreet from the factory?
Because its particulate filter and bulky silencers, dictated by emissions standards, smother the inline-six; our cat-back leaves those standards intact on the engine side and simply puts you back in control of the volume thanks to the valves.
BMW M240i B58 G42 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 M240i B58 G42 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 M240i G42: unleashing the B58, the complete exhaust system guide
The M240i G42 is a worthy heir to BMW's compact coupés: rear-wheel drive, a 374 hp (392 hp since 11/2025) B58 and a compact footprint. Many buyers pick it as the smart alternative to the M2. Only one thing is...
In detail
Rog Advisor
A question about this exhaust?
Fitment, sound, catalyst, valves, delivery: the answer comes straight away, with your configuration in context.
The Rog Advisor is an automated assistant trained on our product pages and answers. For an important decision, write to us: we confirm by e-mail.
Unsure about your configuration? Talk to us before you order. We know your car. Write to us at contact@rogmotorsport.com: we reply in writing, in English, within 24 hours. Email us
Reviews imported from our previous system and translated from French; verified purchases carry the badge.
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.
-
Finishing
Material, elevated.
The finish reveals the character of the metal. Stainless steel or titanium, depending on the options available for your vehicle.
-
Assembly
Every part in its place.
Components are assembled and adjusted. On valved systems, the mechanism is fitted, set up and tested.
-
Inspection
Check. Then approve.
Geometry, welds, connections and gas flow: the key points are inspected before shipping.
-
Shipping
Ready to join you.
Reinforced packaging protects your exhaust in transit. The final step before giving your vehicle a new voice.
Customer builds
Your videos & photos
The Rog lines fitted on our customers' vehicles, in real conditions.
- Builds
- 500+
- Brands
- 28
- Satisfaction
- 4,9
The journal
News & advice
Best valved exhaust for the BMW M2 G87
Which valved exhaust for a BMW M2 G87? The options compared (sound, material, valves) and the Rog system made to...
Read the articleBest valved exhaust for the Audi RS3 8Y
Which valved exhaust for an Audi RS3 8Y? The options compared (sound, material, valves) and the Rog system made to...
Read the articleBest valved exhaust for the Mercedes-AMG A45 / A45 S W177
Which valved exhaust for a Mercedes-AMG A45 or A45 S W177? The options compared (sound, material, valves) and the Rog...
Read the articleExhaust rules: what changes in 2026 and 2027 (Euro 7, noise cameras, MOT)
Euro 7, new-car noise, noise cameras, MOT and vehicle inspection, and models: what really changes in 2026 and 2027 for...
Read the articleChanging your exhaust: what inspections and approvals cost in 9 countries
What the periodic inspection and the check of a modification cost after changing your exhaust, in 9 European countries: official...
Read the articleIs a cat-back exhaust legal in Ireland? What the NCT checks.
A cat-back leaves your factory cat, sensors and OBD as they are; valves closed, very close to stock, valves open,...
Read the articleSports exhaust (sportsummuti) in Estonia: what the tehnoülevaatus checks.
The sound you choose, a discreet car when it matters: what a Rog valved exhaust gives you in Estonia, how...
Read the articleSports exhaust in Latvia: tehniskā apskate and the CSDD noise limit.
The sound you choose, a discreet car when it matters: what a Rog valved exhaust gives you in Latvia, how...
Read the articleNo article matches this search.
All articles