'Petrol efficiency experiment; an increase of 20%' blog discussion

tomstickland

Max throttle below 2000rpm looks like a pretty odd idea to me and not something I'd be keen to apply. Appalling acceleration rates coupled with loading the engine up at low revs. For most people, the way to save on fuel is to avoid erratic driving by smoothing things out and by anticipating. If you turned the engine off 1 mile before a junction and coasted up, with the car just stopping at the line, then that 1 mile would be free. Compare that with waiting until the last moment and braking as hard as possible as the other extreme.

pault123

paul.jacobs wrote: »

I tend to usually keep up with the traffic on motorway driving. SO this weekend I experimented on a 384 mile round trip. I drove between 60-65mph in the Grandad lane and kept up with lorries making very few overtaking manouvers. My trip was 40ish miles around town and 340ish motorways. I managed to get 48mpg in my 1.6litre petrol Astra which was great as I am lucky to do 38mpg on motorways. I worked out that I saved exactly £10.

The downside was that my trip was lengthend by about an hour and a half. And my leg was getting cramp as my foot was not moving as I maintaining a constant speed. I then had to make a stop during the trips and I was hobbling around for a while.

So a £10 saving and an extra hour and a half and a bit of cramp over a 384 mile trip - 27% saving

Based on personal time costing money. I think in your instance above I would rather pay the £10 more to add an extra hour and a half free time to my day and not be hobbling around.

MORPH3US

My girlfriend has just got herself a new Fiesta and neither of us have ever had electronic mpg displays before so now we are avid mpg watchers....

My gf drives slower in the car than I do on motorways and dual caridgeways etc, but i'm always trying to get her to look early at roundabouts rather than getting 1m away from the line then looking so she has virtually stopped before she knows if its safe to go.

If I look early, I can cruise (safely) over certain roundabouts at 30+ which if the limit is 30 means I don't lose any momentum = not using extra petrol....

tomstickland

i'm always trying to get her to look early at roundabouts rather than getting 1m away from the line then looking so she has virtually stopped before she knows if its safe to go.

Good plan, there's a big risk of having the car behind running into her if she stops at a clear roundabout.

bandley

When I was learning to drive 40 years ago my dad told me that it's the brake pedal that wastes fuel! Initially it souded daft, but he was right. Avoid using the brake pedal and you'll save at least 20%.

It's the same principle as looking ahead, of course. To avoid braking you have to take your foot off the gas well ahead of the hazard. This also makes for a much smoother ride for your passengers so everybody wins.

Brian Harden

John_Pierpoint

pault123 wrote: »

Based on personal time costing money. I think in your instance above I would rather pay the £10 more to add an extra hour and a half free time to my day and not be hobbling around.

Don't forget that to spend £10 you have to earn an extra 15, by the time you have paid tax and National Insurance.

(Standby for a taxation quibbler to say its 14 or 16 etc. but you get my drift).

Of course actual savings vary by the type of vehicle being driven and the fuel used. Before the AA got rid of "Petrolbusters", there used to be an interesting link to an experiment the AA carried, comparing a big Honda and a small Ford. "Thrashing" the Ford did wicked things to its fuel economy.

John

pault123

£15 hmmm I still think i'd rather pay that much more to cut a journey by 1 hour and a half and not hobble about.

For my usual shorter journeys to work, gym, shops I find ecodriving hasn't really effected my arrival times at all as of yet. Will find out the fuel consumption when the tank is empty. Not tried it out on a long journey yet.

Lorian

I drive a 2.0L petrol.

I do the same mixed motorway/A road trip a lot (70 miles)

If I drive "normally" it returns 32 to 33 mpg (sorry I don't do Litres, and the trip computer is set to imperial) If I drive "watching the instantaneous mpg" and feathering the throttle then the average is 38 to 40mpg. It's not really much slower.

HOWEVER IMHO it's really distracting to keep looking at the display!

Hefner

I do a lot of miles as part of my job, I can quite easily do 4000 miles a month which are mostly motorway / dual carriageway miles

I drive a 1.6 HDI Peugeot 307 SW and I normally cruise at about 75mph and drive a little spirited around town, which normally nets me an average of about 52mpg according to my trip computer.

After reading Martin's article I thought I'd try an experiment and cruise a little slower. For the last 1000 miles or so I've been cruising between 60mph and 65mph and my average mpg has gone up to 62mpg, that's another 10mpg! :money:

curriej99

I have just invested in a new type of engine, the 'flea-type'. Above and beyond the obvious advanages of travelling in the miniscule insect world, this new machine protocol offers advantages hitherto known only to travelling tinkers etc. What you are about to witness, ladies and gentalmoon, is finished. x