On paper, the numbers look good. With 302hp, 296ft-lbs of torque and a length of "only" 436cm (172in), the BMW 135i sounds like it has all the ingredients to make for a zippy little package. The car is just 22cm (9in) shorter than the 335i Coupe, but slashes 0.2 seconds off the 0-60mph time, bringing it down to just 5.3 seconds - not bad considering the price. ORIGINAL ARTICLE READ FULL ARTICLE
The real gem in this car is the six-cylinder, 2979cc twin-turbo engine which is exclusive to the coupe in the 1-Series but also installed in various other performance models in the BMW lineup. Where most forced-aspiration engines need you to keep within a certain rev range in order to extract the most power from them, the BMW twin turbo has an abundance of torque from as low as 1300rpm (but the real jolt hits at 2500rpm), allowing you to push the car without being uncertain about the power band. The engine itself is not very loud, but the noise that it creates once you hit 5,000rpm is so delicious yet refined, you'll want to as wind the engine up (and the windows down) whenever you get a chance. Outstanding innovation for optimised efficiency: first-ever VALVETRONIC on a turbocharged engine.
The new straight-six power unit of the BMW 135i Coupe and the BMW 135i Convertible owes its exceptional efficiency to the first-ever combination of BMW TwinPower Turbo Technology, High Precision Injection, and VALVETRONIC valve management.
The turbocharger system following the twin-scroll principle separating the ducts for three cylinders at a time both in the exhaust gas manifold and in the turbocharger, as well as VALVETRONIC developed to an even higher standard of efficiency, contributes accordingly to the extremely spontaneous and direct response of the drivetrain. This kind of technology allows infinite adjustment of valve stroke and valve timing on the intake valves. Throttle losses in the charge cycle are reduced to a minimum and the energy contained in the fuel is put to maximum use. In conjunction with High Precision Injection likewise optimised to an even higher standard, this offers an unparalleled balance of driving performance and fuel economy never seen before in this class. The BMW 135i Coupe and the BMW 135i Convertible come as standard with a wide range of BMW EfficientDynamics technologies combined with one another in an appropriate symbiosis for each specific market, including features such as Brake Energy Regeneration, a gearshift point indicator on models with a manual gearbox, a map-controlled oil pump, final drive with optimised warm-up running qualities, as well as on-demand control of the engine's ancillary units such as the pressure-controlled fuel pump. Enhanced dynamics, greater efficiency: new six-speed manual gearbox and optional seven-speed Double-Clutch Gearbox.
Both the BMW 135i Coupe and the BMW 135i Convertible come as standard with a newly developed six-speed manual gearbox. Optimised for maximum efficiency, this high-tech gearbox features dry sump lubrication significantly reducing drag forces and completely avoiding splash losses in the interest of even greater efficiency all round. The seven-speed double-clutch gearbox with Sport Automatic featured for the first time in the BMW 1-Series makes an even greater contribution to the optimisation of driving characteristics in the spirit of BMW EfficientDynamics. The double-clutch gearbox improves both acceleration and the efficiency of these compact top-flight performers, at the same time combining this dual progress with the comfort features of a BMW automatic transmission. The seven-speed double-clutch gearbox shifts gears without the slightest interruption of power and torque and offers the driver the choice of either automatic transmission or a manual gearshift. The fast and smooth shift of gears allows unusually harmonious acceleration and helps to reduce both fuel consumption and emissions. The close, sporting increments of the seven gears ensure that the optimum transmission ratio is always available in all situations. A combination of dry sump and injection lubrication serves to further optimise the efficiency of the engine through a supreme level of oil supply. Last but not least, the double-clutch gearbox is controlled with utmost convenience either through the newly designed gear selector lever or by gearshift paddles on the steering wheel.