Review and photos by
Chris Chase, CanadianDriver.com
One might be the loneliest number, but seven surely makes for one sexy party. At least, I’d bet BMW thinks so, as it rolls out a new transmission for 2011, the seven-speed Dual Clutch Transmission (DCT) that now serves as the extra cost option in 1 Series models powered by the company’s turbocharged six-cylinder engine.
In the 2011 BMW line-up, the DCT can be ordered in the Z4 sDrive35i and 35is, as well as the 335is coupe and convertible. Lower-end versions of those cars, as well as all versions of the 3 Series sedan and the 128i, use the six-speed automatic carried over from 2010, while the 5 and 7 Series both use a new eight-speed automatic.
The DCT is the biggest bit of news for BMW’s smallest model, the 1 Series, for 2011. In North America, this little Bimmer is offered as a two-door coupe or convertible with a choice of two engines – a naturally-aspirated 230-hp, 3.0-litre six-cylinder in the 128i and a turbocharged 3.0-litre six making 300 horsepower in the 135i. Note that this motor used to be a twin-turbo but is now a single turbo engine that BMW refers to as a TwinPower turbo setup. Confusing, no?
BMW is understandably keen to show off their new toy, so my 135i Cabrio tester was fitted with the DCT. Like Porsche’s PDK, VW/Audi’s DSG/S-Tronic and Mitsubishi’s TC-SST twin-clutch transmissions, the BMW transmission is most simply described as two separate transmissions, each with its own clutch, one of which is connected to the odd-numbered gears and the other to the evens. When one gear is engaged and driving the car, the next gear is also selected so that when it’s time to shift, one clutch lets go and the second engages, for a smooth and quick transition through the ratios.
The dual-clutch transmissions offered by VW, Mitsu and Porsche are all very good, so the question is: what’s different about the way this one works? Not much, but it is an improvement over BMW’s original dual-clutch transmission, the SMG (Sequential Manual Gearbox) used in the last generation (2006-2010) M5. It was impressive for its time, but this new DCT is much better.
Like its similar counterparts, the DCT can be driven as an automatic transmission, or shifted manually. In full-auto mode, it feels like a conventional auto, shifting smoothly both up and down. Moving the shifter left into the manual gate activates the transmission’s sport mode, which holds gears longer and makes the shifts crisper and quicker. The sport button just behind the shifter allows for the same quicker shifts, but using the regular Drive mode’s more economical shift points. Official fuel consumption numbers for the 135i Cabrio with the DCT are 11.8/7.9 L/100 km; my real-world average in mostly city driving was 12.9 L/100 km.
But never mind economy. I had this car during one of the nicest weeks Ottawa had seen since the warm weather arrived, so I had two objectives: driving with the top down as much as possible, and enjoying what proved to be a terrific drive-train.
Given my choice (and my cash), I prefer a true three-pedal manual transmission, but a gearbox like the DCT is a compromise that I could see myself making. In sport-automatic mode, it makes driving the 135i surprisingly satisfying, given the lack of a clutch pedal, and it’s also a great match for BMW’s twin-turbocharged six-cylinder.
If you want to be able to hear the engine’s gorgeous exhaust note, use the transmission’s sport mode. It holds each gear longer, letting the motor spin faster – to about 3,000 rpm in normal driving – and sing louder. Do this, and you’ll find yourself actually hoping that traffic lights will turn red for you, just so you can accelerate and listen to the car some more.
Leave the transmission in Drive and upshifts come early and often; you’ll find yourself toodling along in seventh gear by the time you reach 60 km/h. That’s nowhere near as much fun, but it does highlight this turbo engine’s terrific torque curve: the 300 lb-ft peak happens at just 1,200 rpm, which means effortless acceleration without the need for a downshift, unless your right foot tells the car you’re in a big hurry.
The manual mode, by the way, works great too. Shifting can be done via the console shifter – pull back for upshifts, push forward to shift down – or steering wheel paddles. The paddles are useful as you never have to take your hands off the wheel, but they rotate with the wheel, so shifting in the middle of a turn is best accomplished with the console lever.
The engine displays a touch of turbo lag, and between that and the touchy throttle, accelerating from low speeds can create some head-tossing if you’re not gentle with the gas pedal. Same goes for the brakes, which are very strong but also grabby; smooth stopping takes practice in this car.
The suspension, while firm, isn’t punishing, which is an improvement over previous M Sport-equipped BMW’s I’ve tested. It’s possible that the convertible version of this car has softer springs to compensate for the structural strength lost without a fixed roof. Even if the suspension is a little softer the one in the 135i coupe, this little convertible still corners with enthusiasm, responding to steering inputs like a (very sexy) go-kart; the 1 Series is probably the closest thing you’ll get to a rear-wheel drive Mini Cooper in terms of right-now handling responsiveness. Even better is that the 1 Series manages to be this much fun without BMW’s active variable ratio steering.
The best way to enjoy the 135i’s engine note is with the top down. The fully-powered roof is operated via buttons at the bottom of the centre stack, and raising or lowering it takes about 20 seconds. It stows neatly, too, under a hard cover, and doesn’t take up much trunk space, either: a plastic panel in the trunk has to be pulled down to make sure the roof won’t be damaged by large cargo in the trunk, but it only intrudes about 10 cm into the space.
With the top down, things naturally get windy in the cabin, but never unpleasant, at least up front, despite the lack of a wind deflector behind the rear seats. With the roof in place, there’s more road and wind noise than in a coupe, but, again, this is one of the compromises you make with a convertible.
All four seats are usable here, though tall people will want to avoid the rear, where legroom is at a premium. With the top up, headroom is great all around, and front seat legroom is particularly impressive for such a compact car.
My tester was fitted with BMW’s M Sport package, which adds, among other perks, 18-inch wheels, an upgraded steering wheel, and BMW’s excellent sports seats adjustable six ways to Saturn and with electrically adjustable side bolsters. Beyond that, there are the usual fore-and-aft, height and lumber adjustments – all electric – and a manual seat cushion extender. These are terrific seats and well worth the $1,900 BMW charges for the M package in this car, as is the thick, grippy steering wheel.
My tester also had the Executive package, a $3,950 upgrade that includes Boston leather upholstery (red in my car), power seats with driver memory, lumbar support, comfort access, auto-dimming interior mirror, a universal garage door opener and a heated steering wheel. This last item is deleted when the M Sport Package is selected; sadly, you can have either a sexy steering wheel or a hot one, but not both.
Other extras were the $1,200 Premium Sound package including a Harmon/Kardon stereo and satellite radio pre-wiring, and stand-alone options were the double clutch transmission ($1,950) and rear park distance control for $450.
Pile all of that on to the car’s $48,500 base price, and your friendly BMW store will ask for $57,950 plus freight. That sounds like 3 Series Cabrio territory, and it is, if you choose the 328i, which makes do with the non-turbo engine; that car rings in at $57,300 before options. Add similar options to a 328i droptop – sport and executive packages and upgraded stereo – and you’ll be paying $64,000 for a car that, albeit larger, has less power and a regular six-speed automatic transmission in place of the DCT.
The Audi TTS is a fun little convertible too, but number crunchers might be dismayed: it’s more expensive at $62,000, has less power from a smaller engine (a 265-hp turbo four-cylinder), one less gear in its double-clutch transmission and two fewer seats. By that yardstick, the 135i Cabrio is a steal for anyone who can justify a $50,000-plus compact car.
BMW makes some of the sweetest stickshifts in the world and would be my choice in this car. As to me, any self-shifting transmission is a compromise made for a driver who doesn’t drive standard or prefers an automatic for running the rush-hour gauntlet. The DCT simply makes that compromise easier to accept.
Pricing: 2011 BMW 135i Cabriolet
Base price: $48,500
Options: $9,450 (Executive Package of heated steering wheel, garage door opener, comfort access, auto-dimming interior mirror, electric seats with driver memory, lumbar support and Boston leather upholstery, $3,950; Premium sound package of satellite radio tuner and harmon/kardon stereo, $1,200; M Sport package of sports seats with electrically adjustable width, M Sport steering wheel (deletes heated wheel from Executive package) and 18-inch wheels and run-flat tires, $1,900; seven-speed Double Clutch Transmission, $1,950; rear park distance controol, $450)
A/C tax: $100
Price as tested: $60,045
Crash test results
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Chris Chase is an Ottawa-based automotive journalist. He is a member of the Automobile Journalists Association of Canada (AJAC).
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