17.7 LPHK isn't pretty but the QD32 wasn't too light on the juice either. Ok, let's look at all of the things that cause fuel consumption to rise.
* Larger wheels than standard. The car's designed with a certain amount of power to provide a certain acceleration through the drive train. Changing to larger tyres makes the engine work harder to do the same job.
* The higher the rpm, the more fuel used. It's simple math - low revs reduce fuel consumption. Even racing drivers do it when fuel becomes critical and they call it "short shifting". You sacrifice top-end performance for fuel economy.
* Chips increase fuel consumption. That's how they work. If yours is chipped, turn the thing off until you need the extra power.
* Traffic increases fuel consumption - there's no getting around it, either, unless you find another path or time to get to work.
* The most efficient point at which to operate the diesel engine is where the torque curve (on a torque vs rpm graph) begins to flatten out. That's the point where cruising should be done - because that's the point where the most energy is being obtained for the amount of fuel being used.
How heavy is your car?
