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2012 Porsche 911 7-speed gearbox in action +video

Tue, 06 Sep 2011

2012 Porsche 911 7-speed gearbox video below

Some of us are old enough – just –  to remember when a 3-speed gearbox was normal. And, quite often, located on the column. Cars like the Vauxhall Cresta and Ford Zephyr had them, but they now belong to a completely different world to the one inhabited by the 7-speed manual gearbox in the new Porsche 911.

So why fit a 7-speed gearbox, you may ask? What’s the point? Well, this is 2011 and we’re all a little obsessed with headline economy and CO2 emissions, and a 7-speed manual gearbox can help reduce both.

Of course, a seven-speed gearbox (and even 8-speed) are far from uncommon in auto ‘boxes. Porsche’s own PDK ‘box gets seven ratios and companies like Land Rover and BMW fit an 8-speed auto ‘box as standard. But for a manual ‘box, isn’t that just too many ratios to play with? Perhaps.

But the seven-speed ‘box in the new 911 isn’t a seven-speed ‘box in the real sense, it’s a six-speed ‘box with overdrive. Overdrive, I hear the youngsters cry. What’s overdrive? Simple – it’s a long top gear which offers no performance advantage but which cuts down the revs for motorway cruising.

Overdrive used to be achieved by fitting an additional overdrive gearbox on the back of the main gearbox, which was activated by a switch and created a ratio longer than 1:1 – lower revs for cruising but no real pulling power. That all got incorporated in the regular gearbox during the ’70s and ’80s when five speed ‘boxes became normal and, more recently, six-speed boxes.

But now Porsche has given us a seven-speed manual ‘box, which must surely be as far as manual ‘boxes are going to go? The first six ratios are a close ratio box – less revs lost during changes – with 7th gear being a long overdrive for sustained cruising with lower revs, less noise and better economy.

In practice, few will use seventh gear. Unless you’re cruising on a quiet motorway it will probably be more of a pain than a benefit. Of course, the reality may be that there will be enough torque to pull cleanly and strongly at 1500rpm in seventh gear at 75mph without having to drop to fifth or sixth. But we doubt it. And most will opt for the PDK ‘box anyway.

Still, it gives you some sort of dubious bragging rights in the pub.

(80 photos – click any thumbnail for full gallery)


By Cars UK