BMW 420i / 430i G22: the complete exhaust system guide

Your vehicle.

All our exhausts for this generation, version by version, are brought together on one page: BMW 4 Series G22 / G23 / G26 Valved Exhaust.

The G2x-generation 4 Series has distanced itself from the 3 Series it derives from: a bolder design, a vertical grille, a chassis set lower. In 420i and 430i form, though, it entrusts its drive to a well-behaved four-cylinder that BMW calibrated for economy and silence. Here is what you need to know before giving it another voice.

Body styles

G22 coupé, G23 convertible with fabric roof, G26 Gran Coupé with four doors and tailgate

Years

Coupé since October 2020, convertible since March 2021, Gran Coupé presented in June 2021; facelift in 2024

Engine

B48: 1,998 cc inline four-cylinder, turbo, direct injection

420i

184 hp (135 kW) and 300 Nm

430i

258 hp (190 kW) and 400 Nm at launch, then 245 hp (180 kW) and 400 Nm from summer 2021

Transmission and drivetrain

Eight-speed Steptronic; rear-wheel drive, xDrive offered from summer 2021

Rog product page coverage

All three body styles, in 420i as in 430i, model years 2021 to 2023

Three body styles for one 4 Series

BMW presented the G22 coupé on 2 June 2020, for sale from October. The G23 convertible followed, unveiled on 29 September 2020 and delivered from March 2021; it drops the retractable hard top of the previous generation for a lighter fabric roof. The Gran Coupé G26, four doors and a large tailgate, was revealed in June 2021.

Compared with the 3 Series sedan of the same period, BMW quotes for the coupé a centre of gravity lowered by 21 mm and a rear track widened by 23 mm, along with specific body reinforcements. The result is felt from the first roundabout, and the 4 Series has the stance of a grand tourer far more than of a two-door sedan. On the convertible, the fabric roof also frees up trunk space, and when open it lets far more road and engine noise through: it is on this body style that the work of the exhaust is best heard.

For the exhaust, the three body styles receive the same Rog line, brought together on a single product page. Your VIN is used to check the version, body style and model year before manufacturing starts.

420i or 430i: the power outputs

The 420i quotes 184 hp (135 kW) and 300 Nm, unchanged over the period. The 430i had two tunes: 258 hp (190 kW) and 400 Nm at its launch in October 2020, with 0 to 100 km/h in 5.8 seconds, then 245 hp (180 kW) for the same torque from summer 2021, according to the ADAC catalogue. Both rest on the same B48.

Further down, the bars show the values published on the Rog product page, version by version.

Factory 245 hp version

184 hp version from the factory

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

Rear-wheel drive or xDrive, and eight-speed transmission

When they came out, the 420i and 430i coupé were rear-wheel drive, paired with the eight-speed Steptronic automatic transmission. The xDrive all-wheel drive completed the offer from summer 2021 on both versions. On the convertible, BMW had announced a rear-wheel-drive launch in March 2021, then xDrive in July.

For the exhaust line, this choice changes nothing: the Rog cat-back starts behind the B48's downpipe and reaches the rear in the same way, whether the car is rear-wheel drive or xDrive, coupé, convertible or Gran Coupé.

The B48, a widely used four-cylinder

The B48 is the 2.0 litre four-cylinder that BMW fits across a large part of its range, from the 2 Series to the 3 Series. In the 420i and 430i, it displaces 1,998 cc and has a turbo and direct injection. On the 430i, it carries the reference B48B20B.

This engine stands out for its flexibility: maximum torque arrives early, which makes the 4 Series lively from low revs. A single downpipe leaves its turbo, carrying the catalytic converter; this is the front section of the exhaust. The cat-back starts right behind and runs along the floor to the rear bumper.

A four-cylinder more musical than you might think

A turbo four-cylinder has neither the connected song of an inline six nor the rumble of a V8, but it has a voice of its own, rasping and rhythmic, which blossoms when you let it out. On the 420i and 430i, the standard line, calibrated for comfort and for noise regulations, lets almost none of it through. The contrast with the car's design is striking.

BMW has in fact provided, in its M Sport Pro package, a sound accompaniment played in the cabin. The effect exists inside; outside, and especially with the roof open on the convertible, the car stays very discreet.

With the flaps open, the Rog line gives the B48 a full sound at start-up, a clear presence on every overtake and frank crackles when you release the accelerator. With the flaps closed, the flow passes through all the chambers of the muffler, and the 4 Series becomes as quiet as it was on delivery.

Straight pipe or resonator

The product page offers two characters, at no difference in price. The straight pipe lets you hear the four-cylinder's rasping grain without an intermediary: it is the choice of those who want their 430i to announce itself. With the resonator, the B48 gains a rounder and slightly softer voice, which suits a G23 convertible used for leisurely drives or a family Gran Coupé.

On this engine, the resonator also has the advantage of toning down the slightly dry timbre that some four-cylinders take on at high revs, while keeping a distinctly sporty line with the flaps open.

Flaps controlled by remote

On the 420i and 430i product page, the Rog line arrives with its flaps fitted and a remote, linked to a box stowed in the trunk. You open or close them with a press, and they keep that position as long as you do not touch them, whatever driving program is selected.

This operation suits a 4 Series that alternates uses: flaps closed to cross a city centre or come home late, open for a small road or an outing with the roof down.

What the product page allows

The cat-back comes in 304 stainless steel, durable against salt and damp, or in titanium, nearly 40% lighter for the same shape, whose brushed, gold and purple shades do not change the price. The tips can also be chosen: chrome Rog tips, gloss black or blued titanium, or carbon tips with the M logo, forged, black or combined with titanium; a version delivered without tips is also provided.

The front section appears on the "Manifold" line: downpipe with 200-cell sport catalytic converter, which keeps the B48's emissions control, 100-cell version, tolerated or not depending on the car and the country, or catalyst-free version, intended for the track. With the cat-back alone, the engine keeps its ECU and its power; more horsepower requires the downpipe and a remap carried out by a tuner.

Rog designs the line from the VIN of your 4 Series; your garage assembles it with clamps and gaskets, without the slightest weld or cut.

Configure your exhaust.

How the exhaust is put together

On the 420i and 430i, coupé, convertible or Gran Coupé, the Rog cat-back starts at the end of the B48's downpipe and runs to the outlets, with its pipes, muffler and flaps. The front section is limited to this downpipe and its catalytic converter, which the product page offers to replace through the "Manifold" option.

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

Three recommended configurations.

• Everyday coupé

  • Stainless steel
  • No manifold
  • Straight pipe
  • Rog remote

  For a 420i coupé that does the office commute: a four-cylinder finally present, the factory downpipe kept, and flaps you close with a press as you arrive in your street.

  View this configuration

• Convertible in the sun

  • Stainless steel
  • 200-cell sports catalytic converter
  • Resonator
  • Rog gloss black tips

  For a 430i convertible taken out with the roof down: a voice rounded by the resonator, a 200-cell downpipe that keeps the emissions control and understated tips under the bumper.

  View this configuration

• Remapped 430i

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

  For a 430i whose B48 will go to a tuner: a more open 100-cell downpipe, to be validated for your country, a clearer titanium line and carbon tips.

  View this configuration

From order to fitting.

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

Questions.

Further reading.

• All our BMW 4 Series G22, G23 and G26 exhausts
• BMW 420i to 430i F32 / F33 / F36 guide, the previous generation
• BMW 318i to 330i G20 / G21 guide, the same B48
• BMW M340i and M440i guide, the six-cylinder version
• BMW M440i Gran Coupé G26 guide