Originally Posted by JonnySi
Errrrmmmmm well my 325d is only meant to do 47mpg combined, but yesterday at 2 degrees Celsius I drove a 380 mile return trip to Birmingham at 75mph and it returned 54.3mpg, plus I was squeezing the throttle hard on slip roads etc.
I believe some of it is the way the 325d engine is tuned to develop torque at lower rpm, supports longer gearing, allows for lighter throttle loadings, even at sensible cruising speeds, particularly compared to the 4-pot 2.0d engines.
Would love to see a comparison of the BSFC maps/graphs for the different engines.
For the 318d vs. 325d (autos) there is virtually nothing in it for reported real world averages.