carl

Bought a BMW 320 Cd for the missus. It has 150bhp at present. A bit more power would be nice, but not at the expense of economy. Currently we're getting around 40mpg in mixed driving, which is some way off the 49mpg extra urban figure that's quoted in the brochure.

Lots of the chipping companies (e.g. Tuningbox, Van Aaken) claim their chips increase mpg in "real world driving" as well as increasing power. I can see this as being possible, because the engine will have been tuned at the factory to give the best figures for the official government mpg measures (urban, extra urban, combined) which are not necessarily representative of real driving.

So has anyone fitted one of these and noticed an mpg improvement in real world driving?