BMW 3/4/2 Series G20/G22/G42 B58 Valvetronic Catback Stainless Steel Exhaust System

Engineered for BMW M340i G20 (Sedan, 2019+), M440i G22 (Coupé, 2020+), and M240i G42 (2-Series Coupé, 2022+) with the B58 3.0L inline-six turbo engine, this Valvetronic Catback Stainless Steel Exhaust System ships with its own electronic control box and wireless remote. Optimized to elevate the B58 inline-six character to its peak. Manufactured in Europe and quality-controlled by BYC Performance, the system bolts directly to the stock mid-pipe v-band.

Paired with the B58's 382 hp (M340i / M440i) and 374 hp (M240i) output, this catback stays refined and daily-friendly with the valve closed and pushes the inline-six character into a rich tonal note with the valve open. 90 mm twin exit tips are customer-selectable in Glossy Black Stainless, Polished Stainless, Matte Carbon Fiber, or Glossy Carbon Fiber.

Key Features

• Included Electronic Control Box and Remote: System ships with its own valve control box and wireless remote; integrated during exhaust installation, then valve open/close is operated via the supplied remote.
• Tuned for B58 Inline-Six Character: Mid-pipe geometry optimized for the rich tonal note of the 3.0L 6-cylinder.
• T304 Stainless Steel: Corrosion-resistant premium alloy.
• Dual-Mode Sound: Valve closed sits at OEM+ levels, valve open delivers the inline-six tonal — sporty and full.
• CNC-Bent Piping: Smooth internal surface, flow-optimized geometry.
• Customer-Selectable 90 mm Exit Tips: Choice of Glossy Black Stainless, Polished Stainless, Matte Carbon Fiber, or Glossy Carbon Fiber. Twin outlet, laser-welded detailing.
• OEM Hanger Compatible: Direct bolt-on fit to factory exhaust hangers — no hanger modification required.
• M340i / M440i / M240i Diffuser Fitment: Exit tips center in the M Performance rear diffuser cutout.

Titanium vs. Stainless Steel — This Is Stainless

This product is the T304 stainless steel variant:

• T304 Stainless Steel (this product): Durable, deeper and fuller sound tone (ideal for B58 inline-six), lifetime rust-resistance, more affordable
• Titanium (separate SKU): Noticeably lighter, sharper metallic note, heat-tint finish, higher cost
• For the B58 inline-six's full character: stainless preferred (this product)
• For weight reduction & premium aesthetic: titanium preferred

Valvetronic System — Sound Control by Driving Mode

The valvetronic exhaust integrates an electronic valve into the mid-pipe to deliver two sound characters:

• Valve Closed: OEM+ refined character — ideal for long drives, urban driving, and night use.
• Valve Open: B58 inline-six character pronounced into a rich tonal note — deep and full from the straight-six geometry.
• Remote Control: Open or close the valve at any time via the included wireless remote.

Vehicle Fitment

This BMW G20/G22/G42 B58 catback exhaust fits the following engine/trim combinations perfectly:

• BMW M340i G20 Sedan (2019, 2020, 2021, 2022, 2023, 2024, 2025) — B58 3.0L inline-six (~382 hp)
• BMW M440i G22 Coupé (2020, 2021, 2022, 2023, 2024, 2025) — B58 3.0L inline-six (~382 hp)
• BMW M240i G42 Coupé (2022, 2023, 2024, 2025) — B58 3.0L inline-six (~374 hp)
• Compatible with xDrive and sDrive trims
• Compatible with M Performance rear diffuser trim

Incompatibility Note: This catback is NOT compatible with BMW M3 G80 / M4 G82 / M2 G87 — these cars use the S58 inline-six engine (a completely different twin-turbo M engine, not B58) with different exhaust geometry, mid-pipe configuration, and hanger points. 320i/330i/420i/430i with the B48 engine require a separate catback SKU (G20/G22 B48 variant).

Technical Specifications

• Material: T304 Stainless Steel
• Configuration: Catback (entire exhaust from the catalyst/downpipe back to the tailpipes)
• Mid-pipe: B58 inline-six geometry
• Valve Control: Included electronic control box + wireless remote
• Exit Tips: 90 mm twin tips — choose from Glossy Black Stainless, Polished Stainless, Matte Carbon Fiber, or Glossy Carbon Fiber
• Sound Character: Dual-mode (valve closed: OEM+, valve open: full inline-six tonal)
• Bumper Fitment: M340i / M440i / M240i M Performance rear diffuser
• Origin: Europe

Installation Notes

Catback exhaust replacement requires lift access and professional installation. General procedure:

1. Lift the vehicle and loosen rear bumper underbody screws.
2. Release the stock catback mid-pipe v-band clamp.
3. Replace OEM exhaust hangers (rubber isolators) if worn.
4. Mount the included electronic control box in a suitable location and connect the valve actuator wiring.
5. Hang the new catback on hanger points and torque the v-band clamp (torque: 12 Nm).
6. Confirm the exit tips center in the rear diffuser cutout.
7. Pair the wireless remote and test valve open/close operation.

Care & Maintenance

T304 stainless is corrosion-resistant. Wipe polished tips with a soft cloth; avoid aggressive chemicals. If carbon fiber tips were selected, use a carbon-safe cleaner. Re-check bolt torque after first 500 km. Periodically inspect valve actuator wiring connections.

FAQ

How is the exhaust valve controlled?
Via the included electronic control box and wireless remote. The control box is mounted during installation; you then open and close the valve using the supplied remote.

How loud is it?
Calm and daily-friendly with the valve closed, noticeably fuller and more aggressive with the valve open. The B58 inline-six character is deeper and fuller.

Is it TÜV / E-mark approved?
The catback section does not include a catalyst, so emissions are unchanged. Qualifies for TÜV approval in most European markets.

Welded or direct bolt-on?
Direct bolt-on. V-band clamp + hanger system, no welding required.

Is it compatible with BMW M3 G80 or M4 G82?
No. M3 G80 / M4 G82 / M2 G87 use the S58 engine (a completely different twin-turbo M engine, not B58) with different exhaust geometry. This catback is for B58-engined M340i/M440i/M240i only.

Is it compatible with 320i, 330i, 420i or 430i?
No. 320i/330i/420i/430i use the B48 4-cylinder engine; the G20/G22 B48 catback SKU is required.

Does it fit the BMW M240i G42?
Yes. M240i G42 (2022+) is fully compatible thanks to the shared B58 engine.

Shipping time?
In-stock items ship within 1-3 business days via partner couriers. International shipping available.

Warranty?
BYC Performance offers a 12-month manufacturer warranty.

Why BYC Performance?

BYC Performance is a Turkey-based performance tuning specialist sourcing premium parts from leading European manufacturers and supplying them to the Turkish market. Our catalog includes BMW M340i catback exhausts, M440i valvetronic systems, M240i G42 exhausts, and many more high-quality performance components. All parts are built with motorsport-grade materials and undergo strict quality control.