Hybrid mega-test part two: Does diesel do it better?

The Honda scores the most points for ride comfort, too. Both cars deal with undulating surfaces with more than enough fluidity and composure, but where the Mazda can at times trip and slap its way over ruts and divots in the road (more so at low speed), it’s the CR-V that best keeps its occupants at arm’s length, rounding off impacts in a more mature, genteel manner. The Mazda fights back with a superior sense of handling dynamism: its excellently weighted steering provides confidence-inspiring accuracy through bends, while its slightly more focused chassis and suspension tune make for a more immediate and engaging rate of response.

Based on the above observations alone, I dare say the average punter, who isn’t too fussed about whether or not their next family SUV is the most dynamically involving car of its kind, would probably be sizing up the Honda as the winner of this test.

The problem is, none of the above strengths or weaknesses is really a product of either car’s selected powertrain. And when you examine the means through which the Mazda and Honda both generate their motive power in order to answer the question of whether ‘self-charging’ petrol-electric hybrid systems have what it takes to usurp diesel, things get a bit more interesting.

In terms of straight-up usability, the superior torque of the Mazda’s 2.2-litre diesel engine lends it a more effortless and urgent sense of in-gear acceleration. The instant torque-fill afforded by the CR-V’s electric motor means it isn’t far behind at all, but a comparatively muted throttle response hampers the Honda’s effectiveness in this regard.

Admittedly, in more relaxed town environments, the CR-V is the quieter and smoother of the two on part-throttle. But hit the kick-down switch and the Hoover-like racket that erupts from the CR-V’s engine bay as its single-speed auto aggressively flares the engine’s revs does undo its previous efforts somewhat. It’s just not quite as zen as the Mazda in this regard – and mechanical refinement hasn’t always been the calling card of the CX-5’s Skyactiv-D engine. Certainly not in previous encounters we’ve had, anyway.

So in terms of civility, performance and usability, it would seem diesel remains on top for now – if only just.

There isn’t much in it when it comes to fuel consumption, either. A 15-mile economy run on the Longcross test track at typical A- and B-road speeds narrowly ended in the Honda’s favour: its trip computer showed 51.9mpg versus 50.9mpg for the Mazda. Taking fuel tank size into account (57 litres for the CR-V, 58 for the CX-5), the difference in theoretical maximum range is a mere two miles. Of course, in town the Honda would be likely to outperform the Mazda, but the reverse is probably true once you hit the motorway.

What about company car tax, the area where one might think the electrified hybrid should really stand out? Well, from April, when the new, stricter WLTP-based system comes into force, someone who falls into the 40% income tax bracket would be in for a monthly saving of just £5 by opting for the Honda. Now, a saving is a saving, but that ain’t much. A yearly subsidy of a single tank of fuel doesn’t really seem like a dramatic enough saving to see diesel knocked off its perch.

So where does this leave us? Well, the introduction of WLTP emissions tests and the effect they’ll have on how company car tax is calculated hasn’t really done the conventional hybrid powertrain any favours – at least not the one fitted to the Honda. Under the outgoing NEDC system, there would be a bit more daylight between the two, with the saving borne out of opting for the hybrid amounting to £94 per month for someone in the 40% tax bracket.