Opel Zafira B MPV 2006 Owners Workshop Manual page 336

REF•4
Fuel economy
Electrical loads
Electricity is 'fuel' too; the alternator which
charges the battery does so by converting
some of the engine's energy of motion
into electrical energy. The more electrical
accessories are in use, the greater the load
on the alternator. Switch off big consumers
like the heated rear window when not
required.
Freewheeling
Freewheeling (coasting) in neutral with the·
engine switched off is dangerous. The effort
required to operate power-assisted brakes
and steering increases when the engine is
not running, with a potential lack of control in
emergency situations.
In any case, modern fuel injection systems
automatically cut off the engine's fuel supply
on the overrun (moving and in gear, but with
the accelerator pedal released).
Gadgets
Bolt-on devices claiming to save fuel have
been around for nearly as long as the motor
car itself. Those which worked were rapidly
adopted as standard equipment by the vehicle
manufacturers. Others worked only in certain
situations, or saved fuel only at the expense
of unacceptable effects on performance,
driveability or the life of engine components.
The most effective fuel saving gadget is the
driver's right foot.
Journey planning
Combine (eg) a trip to the supermarket with a
visit to the recycling centre and the DIV store,
rather than making separate journeys.
When possible choose a travelling time
outside rush hours.
Load
The more heavily a car is laden, the greater
the energy required to accelerate it to a given
speed. Remove heavy items which you don't
need to carry.
One load which is often overlooked is the
contents of the fuel tank. A tankful of fuel (55
litres
I
12 gallons) weighs 45 kg (100 lb) or so.
Just half filling it may be worthwhile.
Lost?
At the risk of stating the obvious, if you're
going somewhere new, have details of the
route to hand. There's not much point in
achieving record mpg if you also go miles out
of your way.
Parking
If possible, carry out any reversing or turning
manoeuvres when you arrive at a parking
space so that you can drive straight out when
you leave. Manoeuvering when the engine is
cold uses a lot more fuel.
Driving around looking for free on-street
parking may cost more in fuel than buying a
car park ticket.
Premium fuel
Most major oil companies (and some
supermarkets) have premium grades of fuel
which are several pence a litre dearer than
the standard grades. Reports vary, but the
consensus seems to be that if these fuels
improve economy at all, they do not do so by
enough to justify their extra cost.
Roof rack
When loading a roof rack, try to produce a
wedge shape with the narrow end at the front.
Any cover should be securely fastened - if it
flaps it's creating turbulence and absorbing
energy.
Remove roof racks and boxes when not
in use - they increase air resistance and can
create a surprising amount of noise.
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