Even though Citroen does offer some pretty good petrol engines it still expects well over 60 per cent of sales to be diesel. The 1.6-litre four-cylinder unit does have plenty of poke for town driving and thanks to some good sound insulation doesn't make too much of a racket. On longer drives that engine really starts to prove itself, thanks not only to its high torque output at low revs but also its fuel efficiency. We know to always take manufacturer's quoted fuel economy figures with a pinch of salt but Citroen really has made this engine work well.
Citroen C4 Cactus 1.6 BlueHDi 100 came equipped with the 99bhp turbocharged 1.6-litre diesel Blue HDi occupying the space beneath the bonnet. It is a relatively refined unit. The lengthy gaps between the ratios of the 5-speed manual gearbox coupled to the mediocre output ensure that fairly quiet and relaxed progress can be made. The engine has to be worked quite hard to get the best from it and inclines and hills require frequent changes of gear. More vigour lower down the rev range than the 187lb ft at 1,750rpm as supplied, wouldn’t go amiss, and a sixth gear would have probably provided more punch around town as well as lowered the engine speed on motorway journeys – further improving fuel consumption. According to official figures, the C4 Cactus as tested could complete the 0-62mph sprint in 10.7 seconds – so you should never feel vulnerable pulling out of busy junctions or blending into motorway traffic.
This isn’t to say that the 100 HDi isn’t still frugal. It manages to achieve around 62mpg in tests. Admittedly, this is some way behind the 83.1mpg that is officially claimed and we suspect you would need to drive downhill on every part of your journey with a following tail wind to get anywhere near this figure.