Not certain either but I think it's related to greater cylinder pressure and/or stroke length - the former is needed due to how diesels produce combustion versus gasoline. Both will provide more torque though - though I am not sure of the 640d cylinder dimensions, so a longer stroke may not be playing a role.
Originally Posted by gehmjc21
No PCD, just regular pick up. It does give me something to look forward to. But tough none the less!
Xdrive - this may be a stupid question, but why do diesel cars produce more torque? I never quite understood that. Either way I'm just realizing torque is what you need on the highway to go? BHP, of the line?
At highway/high speeds, torque becomes less important. Of course, more is still helpful, but not as noticeable as during a 0 - 60 contest.
The Schlepper: 2011 Range Rover Sport Supercharged
2012 650i xDrive - Loved it! 2010 535i xDrive - Very competent. Too sensible? 2008 Audi S6 - Still miss the V10.
2003 Maserati Coupe - The end of an era. 2002 Maserati Coupe - Gone and mostly forgotten. 2002 MB CLK 430 - Gone but not forgotten.