D-DAY FOR VOLVO
A new generation of D4 and D6 engines and drives is crucial to the success of
almost every new motorboat between 30ft and 50ft. We take them for a spin...
olvo Penta has revamped its
entire range of D4 and D6
diesel engines in a bid to
deliver more power, increased
reliability, improved effi ciency
and lower running costs. It has
also launched a new Duoprop sterndrive leg
as well as a new engine management system
and redesigned throttles.
The changes represent the most
comprehensive refresh of its four and six
cylinder diesel drivetrains since their launch
in 2005, and with more than 100,000 of them
sold to date the stakes could hardly be higher.
So what has changed and how should that
benefi t customers?
THE NEW ENGINES
First and foremost is extra power. The most
powerful D4 now delivers 320hp (up from
300hp) while the punchiest D6 now offers
480hp (up from 435hp). The latter is reserved
for shaftdrive and IPS applications only,
although a new 440hp DPI sterndrive package
still represents a 70hp uplift over the previous
top of the range sterndrive unit. All the
lower-rated models also get a 10% horsepower
boost across the range.
With no change to either the capacity or
footprint of the 3.7-litre D4 and 5.5-litre D6
engine blocks, the extra power is largely down
to new superchargers and turbochargers as
well as upgrades to the engine management
and fuel injections systems. The high-pressure
common rail injection system now operates at2,000 bar (up from 1600) for more precise
control of fuel delivery and combustion.
This also improves fuel economy by between
1% and 7%, with the largest gains at the
lower horsepower ratings.
Although the new 440hp and 480hp
D6 variants will be welcome news forA B O V E 85% of the components on the D4 and D6 are newNEW TECHV