Maximum peformance range, diesel engines

[Daff_Duck]

What is the optimum range to change up/down gear in diesel engines so as to maximise fuel economy?

 

[[TW]Fox]

How long is a piece of string?

 

[paradigm]

Depends on the engine, the gearbox, the drivetrain, the car....

In short, your mileage may vary, so find out yourself.

 

[rodenal]

As above, varies - I get good pull from about 1750 revs to around 4250. Try that in a vag 1.9pd and you'll be wondering what happened at 3k rpm

 

[Myshra]

Anything made recently will probably have a gear indicator to tell you when to change up/down for economy purposes thanks to the EC directive from a year or two ago (not a requirement yet).