Diesels are meant to be run within a very small rpm range. Their powerbands
http://www.diesel-cold-air-int ... -results-Duramax-Dyno.jpg. Diesels are meant to resist changes in RPM over differing loads. Hence why they are compression driven.
Diesels are not meant to 'be run through the gears' and accelerate quickly. They tend to have larger, and heavier engines and internal components, to handle the massive amounts of torque they produce, part of the reason why they have such a low max RPM.
Will diesel get you better drivability? Maybe if you enjoy shifting all the time while accelerating because they are peaky with short powerbands. Will you have to shift going up hills? Probably not because this is what a diesel is designed for. Will you have to shift to pass someone on a single carriageway? Probably, when you run out of RPM. You will not have to shift to get into the powerband because you are probably already cruising in it.
If diesels did have such wonderful and wide powerbands what would be the need of having 16 or 32 gears in a lorry then? Surely if there was plenty of power available through the whole rpm range that 1/2 that would be needed? Don't tell me these diesels are different than car diesels, both run the same fuel and operate under same laws of physics...
FTR the pug had a powerband of about 1500. Anything before 1500 was useless, and while it did have a rev limit of 4500 the 1500 leading up to it was useless and flater than the bonnivlle salt flats. This gave me a whopping 1500 RPM to work with...
Now my petrol car.. I get max torque at 2200, sooner than the diesel in fact, My torque doesn't even start falling off until 4400 (all 250ft-lbs) by then I am well into my power which starts showing itself at about 3500. Max power is at 5200. Then from there they both slide off to a 6125 redline.
If I do my math right that leaves me with a powerband nearing 4k. Almost the maximum rpm of virtually every diesel.
Newer diesels will probably have a little larger band, but not 4k...