BMW N63

The N63 is BMW’s 4.4-litre twin-turbo V8, in production since 2008. It is the engine
behind the 50i and 550i badges, and over its run in the United States its output climbed
from 400 hp to 523 hp without the displacement changing at all.

What the N63 is

A 4.4-litre petrol V8 with two turbochargers, direct injection and BMW’s TwinPower
Turbo branding. The 2011 5 Series
Gran Turismo brochure describes it in the plainest terms BMW used at the time: “Under
the hood of the 550i and 550i xDrive Gran Turismo is our 4.4-liter, 400-hp TwinPower Turbo
V-8 engine, with High Precision direct fuel injection technology.”

The 2011 X6 brochure lists the same unit for the
xDrive50i as a “32-valve, TwinPower Turbo 4.4-liter V-8” — four valves per cylinder,
which is worth stating only because the valve count is one of the few hard numbers BMW
printed for this engine in the sales material.

Where it was fitted

The years and outputs above come from the EPA certification records behind our
specification pages, so they describe cars actually sold in the
United States rather than the full worldwide fitment. BMW also used the N63 in the 650i
and, outside the US market, in several models this archive does not cover.

How the output changed

The N63 is one engine on paper and several in practice. Our specification cards show
the progression in steps: 400 hp in the earliest 550i, 750i and X6 xDrive50i; 448 hp in
the 2013 750i; 443 hp in the 2014–2016 550i and 750i; 456 hp in the 2019 X5 and X7
xDrive50i; and 523 hp in the M550i, M750i and M850i from 2020 onwards. The displacement
is 4.4 litres throughout.

That 123 hp spread matters when reading a used listing. A 2012 550i and a 2021 M550i
wear related badges and share a displacement, but they are separated by more than a
decade of revisions to the same basic engine, and the specification page for each model
year gives the certified figure rather than the marketing one.

What we do not publish

You will not find a reliability score for the N63 here, and that is deliberate. The
NHTSA complaint database records problems against a vehicle, not an engine: a
2019 BMW 5 Series may have a four-cylinder, a six or this V8, and the complaints for all
three sit in one bucket. Any figure presented as “complaints about the N63” has been
arrived at by guessing which bucket belongs to which engine.

What we can show is what BMW printed and what the government certified — the outputs,
the economy figures and the model years. Those are on the specification pages, and every
one of them links back to the document it came from.

Common questions

How much horsepower does the N63 have?

Between 400 and 523 hp in US-market cars, depending on model year and version. The
earliest 550i and 750i were rated at 400 hp; the M550i and M850i xDrive of 2020 onwards
at 523 hp. The steps in between were 448 hp (2013), 443 hp (2014–2016) and 456 hp
(2019).

Which BMWs have the N63?

In the United States: the 550i and M550i, the 750i, the X5 and X6 in xDrive50i and
M50i form, the X7 xDrive50i and M50i, the M850i xDrive and the 650i. The table above
gives the model years our specification pages carry certified figures for.

Is the N63 the same as the S63?

No, though they are closely related and share the 4.4-litre displacement. The
S63 is the M division’s version, fitted to the M5, M6, M8,
X5 M and X6 M, and it makes considerably more power. The N63 is the engine in the
non-M cars.

What replaced the N63?

The S68, BMW’s current 4.4-litre twin-turbo V8 with 48-volt mild-hybrid assistance,
which took over the 50i-badged cars from the 2023 model year.

Sources

Engine descriptions and quotations are taken from the original BMW US brochures held
in this archive — the 2011 5 Series
Gran Turismo and 2011 X6 brochures are quoted
above. Outputs, model years and economy figures come from EPA certification data, and
each specification page names the source for every figure it shows.