Start/Stop...how it works.

Thanks, a very informative answer. As for the turbo, a very good point. I remember reading some while ago  it is very unwise  for example  when  having done a fair mileage and at good speed on say a motorway and pulling into a petrol station or similar,  to switch the engine off as the turbo is immediately deprived of  lubrication, but  to allow the engine to idle for a short while so as  to let the turbo  adjust to the change in circumstances.

The manual actually warns against it, too. Paraphrasing, it says you should idle the engine for a minute after a long hard run, so that the turbo can cool and adjust before the engine is cut off. Quite ironic that it's impossible to follow this advice with stop/start on the car. To be fair the turbo is additionally supplied by running coolant after you cut off the engine, and if you listen at the end of a journey you can hear the pump gently humming away for a few minutes after you've switched off the engine. This, I imagine, makes the issue moot as the car 'cools down' the turbo independently of the engine being on anyway, which ought to prevent any issues with oil burning off in a hot turbo.

Edited to add: BTW I forgot to answer one of your questions earlier. Yes, you can use VCDS to deactivate the stop/start system permanently. To be fair though, I doubt you'd want to after actually trying it. It's useful and does save a fair bit of fuel over time. My last car (a Mazda 6 tourer 2.0 petrol) had a timer that kept track of how long you'd had the engine off using stop/start, and it was showing over 30 hours after a year's driving (12k miles). That's a lot of petrol saved!

Edited 23 April, 201610 yr by Derv