Well there are lots of factors involved, the main one is probably the type of daily journey you do. I am fortunate in that I have only a small amount of urban driving, and that is with few stops, and a long enough motorway drive to warm up the engine properly.
Other factors are:
* Top motorway cruising speed, since aerodynamic drag is the greatest consumer of fuel when you are motorway driving
* Aerodynamics, the A2 has a CD of 0.28 - 0.25 depending on model. I also installed aero components to try to improve this.
* Weight (the A2 has an aluminium chassis not steel)
* Tyre pressure (must always be >= recommendation, never below)
* LRR tyres
* Current temperature (at the moment my mpg has dropped dramatically thanks to winter)
* Windspeed & direction - driving into even a gentle headwind on the motorway will reduce your mpg
* No short journeys!!! Your fuel efficiency is only good once the engine has fully warmed up.
* RPM. I spent £1400 on a gearbox upgrade in order to reduce my RPMs on the motorway. I also drop the car into neutral on gentle downhills etc (but keep it in gear if you need to slow down or it is a steep hill).
Yes I see from the official stats that the A2 has better cruising consumption than the Polo and yr 6th gear presumably makes it even better. Am not entirely convinced by the neutral thing though because that might cause more fuel to be used keeping the engine ticking over, rather than letting the car's momentum achieve this?
>Am not entirely convinced by the neutral thing though because that might cause more
>fuel to be used keeping the engine ticking over, rather than letting the car's
>momentum achieve this?
While it's true that neutral uses some fuel to keep spinning, whereas in-gear uses no fuel, the problem is that when you are in-gear you are engine-braking and hence slow down quicker (due to the friction etc of keeping the engine spinning at high revs). So the total energy loss is greater in-gear than in neutral. Hence if you want to slow down (engine-brake), in-gear is best. But if you want to keep moving, then neutral is best.
Looks like tickover is very economical these days. From following another link. Did always strike me as a bit weird, those people who coasted with clutch in or in neutral....! But maybe their time has come!