Unsurprisingly, the potential answers come from Germany. And while Audi has focused on pinoeering electrically-driven turbos, which have come from the motorsport world to the SQ7 and Bentley Bentayga 4.0-liter Diesel V8 engine, BMW is currently playing the numbers game.As oil-burning fans among you know, the Bavarian automaker has been offering single- and twin-turbo diesel straight-sixes for a few years now, 2016 has seen BMW engineers working to replace the otherwise fresh tri-turbo 3.0-liter oil burner with one that packs four turbochargers.As a result, the "50d" models will make a greater difference compared to their twin-turbo "40d" range mates, but what does this mean in the real world?Well, we've brought along a video that seems to provide a decent answer to this question. The footage esentially brings us a collage of dashboard instrument recordings involving the BMW 730d, the 740d and, of course, the 750d, present here in 750Ld long wheelbase form - all of them use xDrive.The three were taken to their electronically limited 155 mph (make that 250 km/h, you metric system fans) top speed on the German Autobahn. And while they were driven separately, this clip is still worthy of our attention.However, before inviting you to hit the "play" button below, there are a few things we need to set straight. First of all, the 0-62 mph (100 km/h) time of the 750Ld is actually 4.9 seconds, not 5.7 seconds as stated in the clip.Secondly, those of you who are in a hurry and want to skip right to the part where the three dashboard recordings are mixed should jump to the 4:11 point. Then there's the Launch Control part of the deal, as not all three 7-Series models seen here can turn to such stunts. Then again, how often does one use LC while driving a 7er in the real world?