| “The
3-litre Twin Turbo is as strong as an ox and
perfectly matches the smaller category of cars”
Jeroen Jongeneel, De Telegraaf
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Having already introduced twin-turbos
to great acclaim on the 3-litre diesel
found in the 335d, 535d and X3, BMW
has now developed the technology
for petrol power. And the 62 judges
from 30 countries decided that the finest powertrain introduced
in the past 12 months was the 2,979cc twin-turbo engine that
made its debut in the
BMW 335i.
The light alloy six’s use of two smaller turbos –
each supplying three cylinders with air – rather than
a single unit ensures a faster response to changes
in throttle position all the way to the 7,000rpm red line, and
also seeks to
eliminate lag.
The breakthrough engine shows
for the first time BMW’s all-new, high-
precision direct-injection system. This development maximises
performance and fuel efficiency by its precise dosing of the
air-fuel mix being fed. The piezo-injectors are located centrally
in the
combustion chamber between the inlet and exhaust valves. Direct-injection
also aids combustion chamber cooling, allowing a higher compression
ratio (10.2:1) to be employed to reduce
consumption still further.
BMW is proud of the fact that compared with eight-cylinder engines
of similar performance – 302bhp peak power, and 400Nm
between 1,300rpm and 5,000rpm – the straight-six weighs
70kg less, contributing to a fuel consumption figure of 9.5L/100km
(29.7mpg) on the EU combined cycle. Economy does not come at
the expense of performance, however: in the 335i Coupé,
100km/h (62mph) is reached from a standstill in 5.5 seconds. |
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