Go the extra mile

This month the Club’s technical team share ways to help you improve your fuel economy while touring

Q How can I improve fuel economy while touring?

A High fuel cost is certainly an issue when planning trips at present. There are many factors that influence fuel economy, but the main two are weight and aerodynamics. We could say ‘buy a smaller, more aerodynamic outfit’ and there’s merit in that, but the priority for most people at the moment is to make the best of what you currently own.

Small gains come from reducing what you carry. Much bigger gains come from understanding why weight matters – mainly the influence it has on fuel used during acceleration and hill climbing. 

Where safe to do so, gentler acceleration and, crucially, using anticipation to avoid reasons to slow really help. Maintaining a high gear and steady speed is key. Where feasible, choose flatter routes, or at least try to maintain momentum up hills, anticipating things that might slow you and thus require uphill acceleration (very bad!).

With regard to aerodynamics, again there are small gains to be made from removing unloaded roof racks and not carrying items like bicycles on the car roof. The harsh fact, though, is that caravans and motorhomes will never be the most aerodynamic vehicles. So again, the key is understanding how aerodynamics affects fuel usage. While the detailed maths around this is very complex, a couple of simple principles are:

  • Vehicles with more aerodynamic shape and smaller frontal area have less drag. There’s little you can do about this for your existing outfit.
  • The faster you push a shape through the air, the greater the force, engine power and hence fuel that are required.

So the best way to address the less-than-ideal aerodynamics of leisure vehicles is easing off the speed. That doesn’t mean travelling at a snail’s pace – just 5mph makes a difference. For a 100-mile journey, 55mph instead of 60mph means arriving just 9 minutes later. Generally, the most efficient speed is 45-55mph.

To maintain a steadier, slightly slower speed with minimal hill climbing means thinking about route planning. Motorways suit this approach, but heavy traffic and trucks travelling at a similar speed to you may not result in the most pleasant journey. Pick travel times carefully. A-roads tend to mean a slower average pace, but watch out for steeper hills and, of course, junctions.

Here are a few other issues to note and some suggestions:

  • Ensure tyre pressure is correct.
  • Don’t skimp on servicing and maintenance.
  • Avoid ‘sport’ modes, but note that ‘eco’ modes can be problematic when towing; alternator output can be cut, meaning power isn’t sent to the caravan battery/fridge.
  • Keep windows shut at speed but perhaps reduce air-con use at low speeds.

We test hill starting capability during the Club’s Towcar of the Year awards but, to minimise fuel usage, you should avoid it whenever possible.

Please address your questions to: Technical Information,
Email: technical@camc.com
Tel: 01342 336611

...and quote your membership number.

Visit camc.com/advice for the best advice and support for all your touring needs.