1. Certainly no significant improvement below 50mph, above about 60mph aerodynamic drag increases much more quickly, depending on how aerodynamic the car is, gearing, & at what revs the majority of the torque is produced by your engine (see if you can find a power & torque graph for your cars engine).
Here's a couple of graphs showing aerodynamic load vs speed giving you a rough idea.
http://www.speed-wiz.com/graphs/aero-drag-graph.htm http://www.kasravi.com/cmu/tec452/ae...ehicleAero.htm
And TBH anything below 55mph is impractical/inconsiderate on any BUSY motorway/highway as trucks would have to pass you causing ques & slowing down other traffic, at least on 2 & 3 lane ones anyway.
Anyway, basically you want top gear with the lowest revs that is still IN the main torque 'curve'.
2.Gradual build up for diesels (they have no throttle plate), short low rev 'bursts' of about 3/4 throttle for petrols with a conventional throttle plate (electric or mechanical).
Although be aware some petrols don't have a throttle plate either so those might be better with a gradual build up (although they still produce a vacuum in the cylinders, that's what wastes power).
Also bear in mind theirs no point quickly building up speed if you've gotta slow down several seconds latter!
3. I hate people who slow down & speed up on motorways! Grrr lol. Letting your speed drop by not giving more throttle going uphills will improve MPG vs steady speed (whether manual or cruise control) but it's a PITA to everyone else!
For steady speed, cruise control is better as it naturally won't let you overspeed downhill. Although with any auto you may well have to manual select top gear to stop the stupid box downshifting unnessacarily (as my 325 did!). Obviously don't let the revs drop too low going off the torque curve (re earlier comment).
MMUK
Don't forget on most autos you can manually select gears. Although if you did that all the time it would kinda defeat the point
.
Btw most stress occurs on the clutch during pulling away as its (naturally) slipping, or in rough gear changes. Once the clutch is fully engaged it makes no difference how much throttle you give it (assuming it's not slipping due to being oil contaminated, worn out or its max torque limit being exceeded by large torque increases from remapping excessively etc).
I really wouldn't worry about the torque going through your gearbox, lol. Unless you know it's on its last legs, is an inherently weak box or again the engine has had a large torque increase then it won't make any significant difference to box life avoiding peak torque.
Linear Mode
