Driving Economically - 56mph Myth??

tomstickland

What do you mean by "no gas"? Do you mean with the engine turned off, or foot off accelerator?

Madiba_2

Of course, I mean with the foot off the fast pedal.

Driving around with the engine off would be silly.

tomstickland

Well, I'd take issue with your definition. The most efficient operating point for most engines occurs under some load and somewhere in the 2000-3000rpm range. Driving round "off the gas" in most situations will not be running the engine at peak efficiency. I agree that "foot to the floor" is the least efficient situation.

tinker1

So you want to go for best mpg. This is a bit dangerous but your mpg will shoot up.
Get yourself behind a lorry at 60mph and tailgate him so you are sucked along behind him with your foot just touching the throttle. Bl..dy dangerous but it works a treat for a free ride.

Stephen_Leak

According to the MPG readings (both spot and average) from the trip computer in my 10-year-old 1.8 petrol Mk.2 Mondeo, the optimum seems to be at about 50mph in 5th gear.

judderman62

Murphy_The_Cat wrote: »

jdm01, just out of curiousity is your car an auto, and if so, is it a 5/6/7 speed box. Nowt to do with your question, just being nosey

Back to your question, I don't know if 56 mph is the 'ultimate' economy speed, but if I keep to it in my car, the economy is very, very good !

MTC

so should I stop driving at 80 mph then

M4RKM

i average about 48mpg on the motorway at around 70-75mph...
i average about 45mpg on the motorway at a slightly higher speed (if i were allowed to do it)

i have no idea what my average mpg would be at 56mph, but i know i'd be out of a job if i couldn't drive at the speed limit...
cars who drive at 56mph on the motorway should only be allowd on at weekends, so not to hold other people up who have to be at 6 different places through out the day...

vikingaero

56mph was an arbitrary limit chosen to test vehicles because it equates to 90kph.

With all the theories here, there is no set formula for vehicles because each car has different drag, number of gears, engine size, engine types etc etc. I'm surprised that no-one has mentioned gearing. You can have a 6 or 7 speed gearbox but the way the manufacturer has defined the gears will affect mpg.

On A roads where you cannot overtake the 40mph dwardler I find that I get terrific mpg!

movilogo

The most optimum driving speed depends on each engine's power torque characteristics. There can never be a single optimum speed for all cars!

thescouselander

kittiwoz wrote: »

Well that's supposed to describe a typical curve but I don't know how old the figures it is based on are and it does vary between types of car. I'd expect a BMW to last well because they are known for solid build.

Obviously you dont frequent any BMW message boards then. BMWs are anything but reliable, just ask someone who has one of the recent diesel powered models whos plastic inlet manifold has disintegrated and destroyed the engine. This has happened on cars that are well under the 100,000 mile mark!