Forester commissioned

I drive a Subaru Forester automatic with cruise control. Having been widowed recently, I'll possibly change to something smaller at some time in the future. What effect on petrol consumption does an automatic gearbox have, and does cruise control use more petrol than not having it?

Asked on 25 January 2010 by TF, Dalry

Answered by Honest John
In town, losses through a torque converter automatic use 10% - 20% more fuel than a manual. But on the motorway the higher overall gearing of the auto means it can actually be more economical. Cruise uses more fuel by maintaining the car’s speed up inclines when a driver might lift off, then by arresting the car’s speed down inclines when, unfettered, the engine would otherwise use very little fuel.
Similar questions
I have identified three cars that meet our needs of automatic gearbox, ease of access, cruise control, aircon, economic petrol engine due to low usage (max 5000 miles pa). They are the KIA Venga, Ford...
I want to buy a used car. My budget is £6000. Could you please tell me the choice of cars I could have with the following specifications? Fuel economy of 45- 50mpg, automatic gearbox, cruise control and...
More than once in your column I've seen complaints by readers that cruise control is a fuel waster. I was always under the impression that cruise control allows the engine management system to select the...
Related models
Very useful off-road yet an enjoyable car-like drive on tarmac. Looks and feels classier than its predecessor. Well built. Owners rate it.
 

Ask Honest John

Value my car