The 1.5 dCi 80bhp unit fitted to the Renault Clio replaces the 1.9 dTi unit and offers class-leading carbon dioxide emissions and highly economical fuel consumption.
It puts the manufacturer in pole position in the race to produce the supermini with the lowest CO2 emissions, at just 110g/km. This is an improvement on Renault's current tax champion, the Clio 1.5 dCi 65bhp which emits 115g/km, and cleaner than its nearest rival the new Ford Fiesta 1.4 Duratorq TDCi, which emits 114g/km.
These emissions figures match or beat the 114g/km achieved by the Toyota Prius hybrid, although the diesels incur a 3% surcharge under the new CO2-based company car tax system, while the Prius receives a 2% discount.
The Clio also beats the 'green' champion Prius on average fuel consumption by returning 67.3mpg compared to the hybrid's 57.6mpg. The dCi 80 also comes out on top against the ultra-frugal diesel engine in Peugeot's 2.0 HDi Eco, which returns 62.8mpg.
The new Clio also adopts two of Renault's new automatic gearboxes. The first is the Quickshift 5 sequential gearbox which can be used as a standard automatic or as a 'flick-shift' manual.
Next in line is the more traditional Proactive automatic, which is linked to the Clio's 1.6-litre petrol engine. This makes the 0–62mph dash in a respectable 10.5 seconds while returning 38.2mpg and emitting 175g/km of CO2.
Behind the wheel
THE Renault Clio impresses immediately with the quality of its handling and the feisty performance from its new common rail diesel engine.
And it is clear Renault has gone to great lengths to soundproof the cabin from the 'clatter' that often accompanies cold diesel engines.
The engine pulls comfortably all the way up to motorway speed, although there is a pronounced whistle from the turbocharger. Like many other supermini diesels, the dCi 80 suffers from a heavy front-end caused by the weight of the engine, but this does not hamper handling.
Stepping into one of the automatics, the Quickshift 5 1.2-litre was slightly disappointing. The car will still cope admirably with the rigours of city driving and keep up with the flow of traffic on the motorway, but on more demanding roads the 'box in fully automatic mode often finds itself unsure whether to change down or stay in gear.
This flaw is accentuated by a long, ponderous gap in the gearing between first and second.
No such problems dogged the automatic version of the 1.6 16V Proactive. The car retains all of the Clio's superb handling qualities while the auto 'box is well behaved and complements the 1.6-litre petrol engine.