Mercedes engineers have developed a V6 powerplant for the SL 350 that brings the sporty qualities of the new SL generation right to the fore. The term "sports engine" could not be more apt: through a process of meticulous engineering, the Stuttgart specialists have further enlivened the temperament of the six-cylinder unit, enhancing its dynamic response dramatically. The engine responds instantaneously to movements of the accelerator pedal and can rev up to 7200 rpm in order to make full use of its power reserves in certain driving situations. Compared to the previous 3.5-litre engine, the output has been boosted by 16 per cent to 315 hp (at 6500 rpm), while the peak torque has been increased by 10 Nm and now stands at 360 Nm. This powerplant accelerates the new SL 350 from 0 to 62 mph in a mere 6.2 seconds, making it 0.4 seconds faster than the outgoing SL 350.
In this case, however, the extra power does not come at the expense of fuel economy: with a consumption figure of 28.5 mpg, the new SL 350 has not only improved power but also increased fuel economy by 1.1 mpg.
The sporty character of the V6 power unit is also clearly audible. Its powerfully sonorous sound is the result of meticulous work carried out by sound designers. So these specialists also contribute to the sporty driving pleasure. In this respect, the standard-fit seven-speed automatic transmission also has an important role to play: on the one hand by allowing fast multiple downshifts when accelerating, on the other hand by providing a new double-declutching function that is activated during manual downshifts. As well as producing a sporty sound, this function also enhances comfort and safety as the double-declutching equalises the rotational speeds of the crankshaft and transmission. This set-up gives the driver the advantage of even more harmonious gear changes. Plus there is a noticeable reduction in load-change reactions.
The flagship engines in the SL line-up remain the eight-cylinder unit in the SL 500 developing 388 hp and the V12 powerplant in the SL 600, which develops 517 hp thanks to its twin turbochargers. The Mercedes engineers also worked meticulously on these models to further improve fuel consumption by 3%.