BMW S85

The S85 is BMW M’s 5.0-litre naturally aspirated V10, built from 2005 to 2010. It is the
only ten-cylinder engine BMW has ever put in a road car, it revs to 8,250 rpm, and in the
United States it powered exactly two models: the E60 M5 and the E63 M6.

What the S85 is

A 5.0-litre V10 with no turbocharger, ten individual throttle bodies and M Double-VANOS
variable valve timing. The 2006 M5 brochure lists the
specification as a “5.0-liter, 40-valve V-10 engine with M high-pressure Double-VANOS
‘steplessly’ variable valve timing”, with “10 individual throttle butterflies, electronically
controlled” and a “G-sensitive semi-dry-sump lubrication system”.

That last item is the tell. A semi-dry-sump system that responds to lateral acceleration
exists because the engine was expected to be driven at sustained cornering loads where an
ordinary sump would let the pickup run dry. It is a racing solution fitted to a road saloon,
and it is the clearest evidence of what the S85 was designed for.

One throttle body per cylinder is the M signature of the era, carried over from the
S54 six and the S65 V8 and abandoned
when the division turned to turbocharging.

Where it was fitted

500 hp on every one of the 26 specification pages we hold for it,
with 383 lb-ft of torque, a governed 155 mph and 4.5 seconds to 60 mph. The combined fuel
economy figure is 13 mpg across the range, which is the other half of the story: this is the
thirstiest engine in our records by a wide margin.

Why ten cylinders, once

The S85 arrived when BMW M was competing in Formula One, and the engine reflects it: high
revs, individual throttles, no forced induction, and peak power arriving near the top of a
range most road engines never reach. Then it stopped. The M5 that followed used the
S63, a 4.4-litre twin-turbo V8 with two fewer cylinders, more
torque and better economy.

Our own data makes the trade visible. The S85 gives 383 lb-ft; the twin-turbo V8s that
replaced it give well over 500 from a smaller engine, and do it from around 1,500 rpm rather
than at 6,100. What the V10 has instead is the top of its rev range, and that is not something
a specification table captures well.

What we do not publish

No reliability rating. The NHTSA complaint database records faults against a
vehicle, not an engine, and any figure presented as “complaints about the S85” was
produced by guessing how to divide a car’s complaints among the engines it was offered with.
The S85 is the only engine in the E60 M5, so the split would happen to be trivial here — but
the method would still be wrong, and we do not use a wrong method because it is convenient.

Common questions

How much horsepower does the S85 have?

500 hp in every US-market car it was fitted to, 2006 through 2010, with 383 lb-ft of
torque. Higher figures quoted elsewhere refer to European versions or to the limited-run
models that were not certified for sale in the United States.

Which BMWs have the S85 V10?

In the United States, the E60 M5 sedan, the E63 M6 coupe and the E64 M6 convertible. That
is the complete list. No other BMW road car has ever used a V10.

How fast is a car with the S85?

4.5 seconds to 60 mph and 155 mph, electronically limited, on the figures in our
specification data. The rev limit is 8,250 rpm.

What replaced the S85?

The S63, a 4.4-litre twin-turbocharged V8, from the F10 M5 of
2013. Fewer cylinders, less displacement, considerably more torque and roughly half again the
fuel economy.

Sources

Specification and quotations from the 2006 M5,
2008 M5 and 2009 M5
brochures in this archive. Outputs, torque, acceleration and fuel economy from EPA
certification and fuel economy data, with the source named on every
specification page.