Truck & Driver UK – August 2019

(^80) Summer 2019 Truck & Driver
with the new MX11 too; we were
keen to question that assertion.
On the road
Our first trip is a Saturday
morning job running up to
Evesham with a fully laden fridge
trailer. The route is pretty flat but
the CF seems to get up to speed
relatively quickly, short gradients
are dealt with easily enough and
the truck is soon up to cruising
speed once joining the M4 at
junction 17. Also, the engine
brake is remarkably effective,
even at low revs.
Once reloaded, we elect to cut
across country to our Wiltshire
base to avoid the congestion.
Running at about 36 tonnes, the
CF450 gives a really good
account of itself on the
undulating route. It takes a bit
longer to get into top gear on
these roads but it is certainly not
sluggish, not that far behind the
performance of lower-rated
MX13 engines. Adding to the
experience is the fact the engine
note has quite a deep growl.
The TraXon gearbox really
helps get the best from the
engine, changes being quick and
generally jerk-free. The Eco
software sometimes changes up
precise control of the
valvegear and improved
engine brake
performance. A variable-
geometry turbocharger gives
better response at low revs and
boosts torque output.
From a driver’s perspective,
this technology allows an 11-litre-
class engine, when working hard,
to perform like a bigger-capacity
motor. The torque output is
increased in top gear, allowing
the engine to pull hard right
down to an ultra-low 900rpm. A
decade or so ago, this type of
performance would have only
been witnessed with a 14-litre
engine and, at 44 tonnes, we
were intrigued to see if the MX11
really lives up to these claims.
For some fleets, one of the
main attractions of the MX11
is weight reduction, saving
almost 200kg over the bigger
engine. The 450hp rating and
maximum torque of 2300Nm in
top gear (2200Nm in all other
gears) should make the latest
versions a bit more comfortable
at full weight.
TraXon ’box
The new ZF TraXon 12-speed
automated gearbox is key to the
performance of the New
Generation Dafs, with a wider
spread of ratios, much-improved
low-speed clutch control and
rapid gearchanges, the improved
software allowing the
transmission to make full use of
the increased engine output.
For more demanding
operations there is a 16-speed
TraXon option, along with a
16-speed Ecosplit manual.
Daf’s new drivelines use high
rear-axle ratios. These give
ultra-low revs at maximum
cruising speeds, with the engine
turning over at less than
1200rpm at 56mph and the
increase in torque allowing the
engine to pull harder when the
truck encounters a hill. We have
tried out this concept with the
MX13 engine rated at 480 and
530hp in New Generation XF
tractors, but were sceptical that
the MX11 could repeat the same
trick at 44 tonnes. Some modern
trucks with high overall gearing
are a pain to drive on all but the
flattest of motorways and rarely
get into top gear on many
A-roads and B-roads.
Another of the usual
downsides to high gearing is
poor engine brake performance.
Daf claims to have nailed this
Full deflector kit has adjustable top blade; plastic AdBlue tank has
a capacity of 45 litres (the aluminium fuel tank holds 430 litres). The
low-mounted cab has first-rate access yet offers great living space
for the driver, while the CF’s ride and handling are both excellent
DAF CF450