BMW S55
BMW S55 (2014-2020): specifications, reliability, common problems and every car that has it.
- Displacement
- 3.0 L
- Layout
- Inline-6 twin-turbo M petrol
- Power range
- 405–444 hp
- Produced
- 2014–2020
The S55 is the M division’s 3.0-litre twin-turbo inline-six, built from 2014 to 2020.
It is the first turbocharged M3 engine, and the one that took the M3 and M4 from 425 hp
to 444 hp in the M2 CS.
What the S55 is
A 3.0-litre straight-six with two turbochargers, direct injection and M TwinPower Turbo
branding. The 2015 M3 brochure introduces it as the
range’s headline technology: “Experience a new dimension of driving enjoyment and
efficiency with innovative BMW engines featuring M TwinPower Turbo technology.”
The 2016 M2 brochure describes the same family of
engine as “torquey and extremely refined”, driving the rear wheels through an optional
seven-speed M Double-Clutch Transmission — though the 2016 M2 itself used the
N55, and the S55 arrived in that car only with the M2
Competition of 2019.
Where it was fitted
| Model | US model years | Output |
|---|---|---|
| M3 (including M3 CS) | 2015–2018 | 425 hp |
| M4 (Coupe, Convertible, GTS) | 2015–2018 | 425 hp |
| M2 (Competition, CS) | 2019–2021 | 405–444 hp |
The M2 entry is the one that trips people up. The M2 of 2016–2018 has the N55; the M2
Competition from 2019 and the M2 CS have the S55, in a lower state of tune than the M3 and
M4 at 405 hp, rising to 444 hp in the CS. Our
specification pages carry the certified figure for each model year
separately, which is the only reliable way to tell them apart.
What we do not publish
No reliability score. NHTSA files complaints against a vehicle, not an engine,
and any number offered as “complaints about the S55” comes from splitting a car’s
complaints between engines by guesswork. We publish the certified outputs, the economy
figures and what the brochures said.
Common questions
How much horsepower does the S55 have?
425 hp in the US-market M3 and M4, 405 hp in the M2 Competition and 444 hp in the M2
CS. The M4 GTS was rated higher still.
Which BMWs have the S55?
The F80 M3, the F82 and F83 M4, and the M2 Competition and M2 CS. The plain M2 of
2016–2018 does not — that is the N55.
Is the S55 the same as the B58?
No. Both are 3.0-litre inline-sixes, but the B58 is the
volume engine of the 40i cars with one turbocharger, and the S55 is the M division’s
twin-turbo unit with a closed-deck block and its own cooling and oil systems.
What replaced the S55?
The S58, from the 2021 M3 and M4.
Sources
Quotations from the 2015 M3 and
2016 M2 brochures held here. Outputs and model years
from EPA certification data.