Best valved exhaust for BMW M140i F20 / F21

Your vehicle.

All our exhausts for this generation, version by version, are brought together on one page: BMW 1 Series F20 / F21 Valved Exhaust.

The M140i closes a chapter: after it, the 1 Series moved to front-wheel drive and the four-cylinder. It therefore concentrates, in a compact, what BMW does best with an inline six-cylinder and rear-wheel drive. Let us begin with it, before talking about its exhaust.

Body styles

F20 five-door, F21 three-door

Launch

Summer 2016, replacing the M135i; end of production in 2019

Model years covered

2017 to 2019; for 2016, VIN check

Engine

B58: 2,998 cc, inline six-cylinder, one twin-scroll turbo

Factory output

340 hp (250 kW) at 5,500 rpm; 500 Nm up to 4,500 rpm

Transmissions

Six-speed manual with rear-wheel drive, until 2018; eight-speed Steptronic Sport automatic

Drivetrain

Rear-wheel drive, or xDrive with the automatic transmission

Factory exhaust

Exhaust with a car-controlled valve, two outlets

The last six-cylinder 1 Series

BMW launched the M140i in summer 2016, in place of the M135i, on the basis of the five-door F20 and three-door F21 1 Series. It keeps the architecture that is rare in its category: longitudinal engine at the front, rear-wheel drive, inline six-cylinder under the hood. At the end of 2017, the range received a new dashboard and instrumentation taken from the 2 Series.

In 2019, the F40 1 Series took over, with a transverse-engine architecture and a four-cylinder, all-wheel-drive M135i. The M140i therefore remains BMW's last compact to combine rear-wheel drive and a six-cylinder, a combination the category no longer knows.

Three or five doors, the mechanics are identical: same B58, same transmissions, same Rog exhaust. Our product page concerns cars from 2017 to 2019; if yours came off the line in 2016, send us its VIN first, and we will confirm in writing what we can do.

340 hp and 500 Nm

The M140i's B58 delivers 340 hp, or 250 kW, at 5,500 rpm, and 500 Nm available very early, up to 4,500 rpm. From a standing start, BMW quoted 4.8 seconds with the manual transmission, 4.6 seconds with the automatic and 4.4 seconds for the M140i xDrive. Sports-car figures, in a car that keeps five seats and a proper trunk.

Compared with the M135i it replaces, the M140i gains in power and adds 50 Nm of torque, with a more recent engine, with a higher compression ratio and boost pressure. The bars below show the factory values from our product page.

Stage 2: published figures with the front section and an ECU remap carried out by a tuner.

Manual, automatic, rear-wheel drive or xDrive

With rear-wheel drive, the M140i was delivered as standard with a six-speed manual transmission, fitted with an automatic double-declutching function on downshifts, and the eight-speed Steptronic Sport was offered as an option. The manual disappeared from the catalog around summer 2018. The xDrive version, heavier by about 65 kg, existed only with the automatic transmission and was not sold in all markets.

For the rear exhaust, none of these combinations justifies a different product page: whatever the transmission, whatever the drivetrain, with three doors as with five, the M140i receives the same Rog exhaust, and its VIN is used to confirm this before manufacture.

The B58 under the hood of a compact

The B58 lines up six cylinders for 2,998 cc, with twenty-four valves, direct injection and a single twin-scroll turbo: the gases from cylinders 1 to 3 and those from cylinders 4 to 6 arrive there through two separate ducts, for a turbine that responds sooner from low revs. It made its debut in the 340i F30 before spreading to a good part of the BMW range.

At the turbo outlet leaves the downpipe, which contains the catalytic converter: that is the front section. Further back, the cat-back passes under the floor to the rear, with its mufflers and its valve. It is this second part that shapes the voice of the car; the Rog exhaust replaces it first.

The voice of a big BMW in a small one

An inline six-cylinder has a sound that the four-cylinders of the category cannot imitate: a round, continuous rumble at idle, then a song that brightens and turns more metallic as the revs climb towards the limiter. In a compact, it is a rare signature, that of a higher-segment sedan slipped under the bodywork of a sporty small car.

With the Rog exhaust open, the M140i rumbles from start-up, climbs in one stroke to the limiter and lets the exhaust crack when you lift off, especially when the automatic transmission downshifts in Sport mode. With the exhaust closed, the compact resumes the discretion that makes it a sleeper appreciated by its owners.

The standard valve and what holds the B58 back

As standard, the M140i's exhaust has a valve controlled by the car's electronics, which regulates its opening according to the driving mode chosen. Around it, bulky mufflers, sized for the occupants' peace and the noise limits, hold back most of the six-cylinder's voice.

The result: from outside, the factory M140i lets only a small part of its six-cylinder's temperament show. A valved exhaust reverses the logic: closed, it routes the gases through all the chambers of the muffler and keeps a level close to the factory one for setting off early or driving a long time on the highway; open, it offers them a direct path, and the B58 is finally heard.

Your valve or the Rog remote

The product page offers two systems. The Factory option provides on the exhaust the place for your BMW valve: your garage transfers it there, and the mode chosen, from Eco Pro to Sport, carries on deciding. The Rog option delivers the exhaust with our valves already fitted, a remote and its trunk control unit: what you decide with a button stays as it is until the next press, regardless of the mode engaged.

On a compact that often serves as an everyday car, the remote has an advantage: you choose the M140i's voice without changing its behavior, keeping for example Comfort mode and valves wide open on an empty road.

Tips, straight pipe or resonator

On the M140i product page, the tips are part of the configuration. Three Rog finishes are included at no extra cost, chrome, gloss black or blued titanium; three carbon finishes with the M logo, forged, black or combined with titanium, are offered as an option. An exhaust delivered without tips also remains possible.

For the sound, two characters are open to you, at the same price: the straight pipe, which keeps the B58's raw grain and its cracks, or the resonator, which gives the six-cylinder a rounder and slightly softer voice, welcome if the M140i also does the weekday journeys.

Front section, material and fitting

As a "Manifold" option, the product page adds the B58's downpipe: 200-cell sport catalytic converter, which leaves emissions control in service, 100-cell catalytic converter, accepted or not depending on the car and the rules of your country, or catalyst-free version, designed for the track.

With the cat-back alone, the M140i keeps its 340 hp and its mapping: the exhaust changes its voice, not its power. The extra horsepower comes from the downpipe, provided a tuner then rewrites the engine management. 304 stainless steel stands up to winter salt; titanium, about 40% lighter for an identical layout, is chosen in brushed, gold or purple, always at the same price.

Your exhaust is made to the VIN of the M140i, then fixed by your garage with clamps and gaskets, without the slightest welding.

Configure your exhaust.

How the exhaust is put together

On the M140i, three or five doors, our cat-back follows on from the B58's downpipe and runs to the two outlets, with its pipes, its mufflers, its valves and the tips of your choice. The downpipe, catalytic converter included, forms the front section; on the product page, it is added with the "Manifold" option.

Each choice explained in detail, from sound to material: How to configure your exhaust.

Three recommended configurations.

• Everyday sleeper

  • Stainless steel
  • No manifold
  • Resonator
  • Factory valves
  • Rog gloss black tips

  For a five-door M140i that is driven every day: the factory front section stays, the six-cylinder takes on a rounder voice, and the valve still obeys the mode chosen.

  View this configuration

• Weekend three-door

  • Brushed titanium
  • 200-cell sports catalytic converter
  • Straight pipe
  • Rog remote

  For an F21 M140i that goes out on the back roads: more breath and presence, emissions control kept, and the B58's song freed at the press of the remote.

  View this configuration

• Prepared rear-wheel drive

  • Titanium
  • 100-cell sports catalytic converter
  • Straight pipe
  • Carbon tips with the M logo

  For a rear-wheel-drive car you plan to have remapped: the 100-cell downpipe lets the turbo breathe, titanium lightens the rear, and the carbon tips with the M logo sign the car.

  View this configuration

From order to fitting.

VIN, manufacture, delivery, fitting and warranty, step by step

Questions.

Further reading.

• All our exhausts for BMW 1 Series F20 and F21
• Our exhausts for the B58 six-cylinder
• Guide to the BMW M135i N55 F20 / F21
• Guide to the BMW 340i B58 F30 / F31