Review: Mini Cooper SD Convertible

22 April 2011

Mini Cooper SD Convertible front

This is the first open-topped car I’ve reviewed for GreenMotor.co.uk and I have to say it feels pretty good. The sun is shining, it’s not too hot, I’m bowling along a dipping and twisting Somerset B-road, and the wind is tousling my hair in a pleasant but not overly blustery fashion. And to keep my conscience as clear as the skies, the trip meter is showing consumption firmly on the frugal side of 50mpg. What’s not to like?

Alas I only have the car for an hour or so, so I can’t do a proper consumption test. But presuming the figure I’m seeing is vaguely correct, it’s all the more surprising as I’m driving the biggest-engined soft-top in Mini’s line-up, the 2-litre Cooper SD Convertible.

Externally, it looks identical to its petrol powered counterpart, the Cooper S Convertible. There’s the same scoop on the bonnet, which looks purposeful but is actually just decoration. There’s the same double-barrelled exhaust. Only the badges are really different, with the addition of that final D, signifying that I’m running on diesel.

Mini Cooper SD Convertible badge

Under the car’s curvy clamshell bonnet, Mini has squeezed a 2-litre turbodiesel borrowed from the BMW 118d. It’s fit for 143bhp and 305Nm. By comparison, the 1.6-litre petrol Cooper S offers up 184bhp and 260Nm. The plain Cooper D, meanwhile, can muster 112bhp and 270Nm.

The petrol S Convertible wins if hurling yourself at the horizon is your thing, galloping to 62mph in 7.3 seconds – the SD requires 8.7 seconds, which is still pretty quick for this class of car. The ordinary Cooper D soft top brings up the rear in a respectable 10.3 seconds

Where the SD does win is at the fuel pump nozzle, achieving official combined cycle scores of 62.8mpg and 118g/km, substantially better than the petrol Cooper S’s 47.1mpg and 139g/km. At average April 2011 pump prices the SD would cost about £300 less to fill up over 10,000 miles. The slower Cooper D beats both at being miserly, returning 70.6mpg and 105g/km of CO2, thus saving another £100 or so over 10,000 miles.

All of the above numbers are based on official consumption figures – your mileage will vary. Fuel costs seem certain to rise further, however, which will widen the gaps to an unguessable extent. Slightly more predictable is that you’ll struggle to haggle much off the purchase price of a new Mini. Here the Cooper SD looks less tempting, starting at £21,130 before the inevitable option packs. That is £735 more than the S and a very noticeable £2,820 more than the D Convertible. So there are no free lunches here.

Insurance costs favour the diesels – at 30 out of 50, the Cooper S Convertible ranks seven groups higher than the Cooper SD and 11 groups higher than the Cooper D soft top.

Mini Cooper SD Convertible rear

Back on today’s leafy lanes the Cooper SD feels fast but not blazingly quick. I can tell it’s a diesel, even though the BMW-built unit is smooth and keeps most of its rattle and clatter to itself. It’s refined at low revs, aside from a slight vibration that I can’t really feel through seat or wheel but which sets the rear-view mirror dancing. The engine note turns gruff and coarse through the middle of its rev range, but up near the 5,000rpm red line the note changes again and becomes quite musical.

I wouldn’t normally explore the region near the rev limiter – it’s not good for economy – but it’s an alarming easy place to visit in the SD. This is a great car for overtaking, zipping from 50 to 75mph in 7.1 seconds in fourth gear. There are six gears on offer, but pick third to zip past a slow-coach and you’ll quickly run out of revs and need to change up.

Everything else about the car is as per the familiar Mini recipe. It corners like a jackrabbit, bounces over bumps, communicates, entertains and cramps your legs.

The Convertible feels marginally more softly sprung than the Cooper SD hatch, but the difference may be down to wheel sizes and tyre profiles. Soft in the Convertible is a relative term – a slightly different level of rigidly firm.

The interior is beautifully but quirkily built. Switches all move with precise perfection but are scattered in the strangest places. The electric window buttons aren’t on the doors – heavens no, they’re hiding down below the ventilation controls in the centre stack. Similarly, to select sport mode, grope for the button you can’t see that’s lurking on the far side of the gearstick.

Mini Cooper SD Convertible interior

Perhaps the sport button is hiding because it doesn’t actually do anything. It’s supposed to enliven the throttle and steering response, but it’s so subtle I honestly can’t tell the difference.

The sport button shares its hidey hole with a button for switching off the automatic stop-start, a fuel-saving system that works reliably and mostly unobtrusively. The engine cuts out smoothly when the car is stationary in neutral, and starts again promptly as the clutch is dipped to select first gear. A stopped engine means no power steering, though, and it can take a noticeable moment for the assistance to come back to life as you set off. You’ll only feel this if you come to a stop with a fair amount of lock already applied.

The soft top opens and closes in about 15 seconds, and offers one-finger operation with no manual latches to fiddle with. It can be operated at up to 20mph. All four windows will dance up and down as part of the roof palaver, seemingly with a mind of their own, presumably ensuring they keep well clear of the roof’s scissoring struts. There’s also a helpful centre-console switch for raising or lowering all the windows at once. The front section of the canvas can be opened or closed like a sunroof, if you so choose, which is a nice option for those in-between days.

The folded roof piles up on the rear deck and cuts a little into the centre mirror’s picture of the world. Roof up, the car can feel a little claustrophobic, exacerbated by the dark cloth lining, and over-the-shoulder visibility is predictably poor. The view in other directions is great, however, with the Mini’s characteristic upright screen and slim pillars making it hard for anything of consequence to disappear from view – a rarity these days.

Overall the Mini Cooper SD Convertible is a highly desirable little car but it is quite pricey. A Cooper D offers much of the same experience for a lot less – less initial outlay, lower running costs and fewer grams of CO2. The Cooper SD offers intoxicating speed, but I can’t help feeling the cheaper, slower Mini is the one to go for.

Mini Cooper SD Convertible, roof up

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