'How much further can you go on a tank of petrol?' blog discussion

davidjwest

I've been keeping a spreadsheet with this kind of information on it ever since I got my current car last year. It's a Mondeo diesel, 2.0 engine and I've had a best ever 855 miles to a tank of fuel that equates to 9.5p a mile. I'm averaging around 60 mpg at the moment, mainly motorway miles.
The new Shell diesel appears to be the best fuel from what I've used. Wouldn't be much good in a petrol car obviously!
My car has cruise control that helps quite a bit and it makes the commute to work easier as well, especially in the annoyingly long stretch of 50 mph average speed cameras on the A1 near Leeming.

My total "pence per mile" cost including everything (including depreciation) works out at 24p a mile, but I do quite a high mileage (36k annually approx).

Katie-Kat-Kins

In my diesel clio I manage over 55mpg on my usual runs, complete with my heavy right foot, and stop start rush hour traffic. If I'm trying to be economical I can manage over 65mpg.

I would highly recommend an small engined diesel car to anyone wanting to reduce their motoring costs. The fuel costs more but is outweighed by the improved mpg. It requires less frequent servicing than my last petrol car too!

I have tried shell fuelsave diesel, and I did find my trip computer showing slightly better results. I haven't done a proper scientific comparison, just noticed my average mpg was up a little. Probably not worth paying more for but if it is the same price as elsewhere then it would be worth going for.

fatpiggy

I do around 60 miles a day, just over half of which is on motorway, then the rest is semi-urban and near-enough city centre (Manchester). Alot depends on whether it is school term time or not, so at the moment I'm doing 40mph on one road which might be first gear, 5mph in term-time I drive a 1 litre petrol Yaris which does just over 400 miles on a full tank (about £41 at today's prices) (6 days driving, from full to warning sign coming on which gives me about 35 miles left in the tank) in the winter and nearly 500 miles on the same tank in the summer months when fuel vapourisation is better. It doesn't seem to make much difference to consumption when I drive 350 miles in one go to visit family in Cornwall with long periods on the motorways. I have always driven "sensibly", ie smooth acceleration, slow braking, good stopping distances etc because that is how I was taught! Periods of idling in traffic jams don't seem to make any noticeable difference to fuel consumption.

I have never owned a car which has cost me so little to run. Yes, it cost a bit to buy (3 years old from a main-dealer) at £5500 but since then, apart from tyres, wiper blades etc. I have replaced one shock absorber, one throttle cable and tonight a garage is going to fix the loose heat shielding around the exhaust pipe. The car is a 51 plate, has now done over 154000 miles and still has the original clutch (!!) battery, exhaust and everything else. A friend services it for me once a year which is much cheaper than using a garage (he is a proper qualified mechanic). It started first go right through the awful winter (minus 16 on a couple of mornings) and coped brilliantly with 10 inches of snow, chugging happily past those spinning their wheels fruitlessly. I love my Freddy!

tomstickland

Patjan wrote: »

Much good advice in all these posts! But the real secret is not having a lead boot on your right foot. Accelerate gently (no more than 2000 revs in each gear up to your final gear), anticipate your braking thus braking gently, and remember: open windows and sunroofs, air conditioning, incorrect tyre pressures, etc., will all increae your fuel consumption.

There's nothing wrong with vigorous acceleration.
It's throwing the momentum away by braking or accelerating up to an obstacle that's the waste.

jeferey

I've got a 6 seater Honda FR-V 2.2 diesel and average over 50mpg using hypermiling techniques.
The best full tank I had was over 620 miles on 51.5 litres for 57mpg
I have been careful with fuel use for quite a few years but have only been hypermiling for the last 3. The manufacturer's official figures for my car are 44mpg on the combined cycle and I always BEAT this by 10 - 30% (unless there's loads of snow then I match it).
The daft thing is I usually get where I am going in roughly the same time as it would have taken me before but I feel less stressed and have saved money on fuel to boot.
My cost per mile works out at about 10p but would be 12p if I didn't hypermile.

JohalaReewi

tomstickland wrote: »

There's nothing wrong with vigorous acceleration.

There is. The faster the acceleration, the more fuel you burn.
It's all tied in to Force = mass x acceleration.

So 0 to 60 in 10 seconds uses less fuel (for the same mass) than 0 to 60 in 5 seconds. But it takes longer which is one of the tradoffs you have to make. You can reduce mpg a lot by accelerating gently, going slower and using the brakes less, but you will increase the time taken to do the journey.

Oneday77

Most of the techniques for fuel saving are part of the IAM Skill for Life course.
I have found since I strted and subsequently passed that my fuel consumption has reduced considerably.
Not only that I feel more confident on the road and pre-empt the ineptitide of many drivers.

Martin as a Money Saving Future is there any chance that you could show how people save by being IAM members? Now that I have passed I know I get reduced car and strangely enough home insurance. On top of reduced fuel consumption and wear & tear on my car. IAM surety guarantee to beat insurance prices and in many cases give things like free no-claims discount protection. You do have to keep your IAM membership alive £30 a year.

I must note that I am not in any financial way affiliated with the IAM.
Since my wife sat it last year and myself this year 'I am' just a very keen advocate of it.

a-ztech

Oneday77 wrote: »

Most of the techniques for fuel saving are part of the IAM Skill for Life course...I must note that I am not in any financial way affiliated with the IAM.
Since my wife sat it last year and myself this year 'I am' just a very keen advocate of it.

You could say "I am an IAM's driver" :rotfl:

lhogg65

Oneday77 wrote: »

Most of the techniques for fuel saving are part of the IAM Skill for Life course.
I have found since I strted and subsequently passed that my fuel consumption has reduced considerably.
Not only that I feel more confident on the road and pre-empt the ineptitide of many drivers.

Martin as a Money Saving Future is there any chance that you could show how people save by being IAM members? Now that I have passed I know I get reduced car and strangely enough home insurance. On top of reduced fuel consumption and wear & tear on my car. IAM surety guarantee to beat insurance prices and in many cases give things like free no-claims discount protection. You do have to keep your IAM membership alive £30 a year.

I must note that I am not in any financial way affiliated with the IAM.
Since my wife sat it last year and myself this year 'I am' just a very keen advocate of it.

Interesting as my partner started an IAM course 2 years ago & was told by his instructor to drive up to the speed limit wherever possible (& presumably safe to do so). This led to so many arguments with him doing up to 60mph on country roads which I didn't feel comfortable with and also he alleges he was also told the "2 second rule" is no longer relevant due to improved braking technology. Bad instructor or OH not telling the whole truth?:undecided

Not sure of my average mpg but rarely rev above the 2000 mark and agree entirely with the priciple of braking smoothly through the gears, perfected over years of towing a horse trailer (with a horse inside). It does cause some hairy moments when crazy drivers zoom up behind; some people seem to rely on other people's brake lights to tell them when to slow down. And I follow the 2 second rule...:)

Also agree it's so much less stressful to drive at 60 on the motorway-just wish some drivers would keep to the left & not hog the middle lane at this speed!!!

tomstickland

JohalaReewi wrote: »

There is. The faster the acceleration, the more fuel you burn.
It's all tied in to Force = mass x acceleration.

So 0 to 60 in 10 seconds uses less fuel (for the same mass) than 0 to 60 in 5 seconds. But it takes longer which is one of the tradoffs you have to make. You can reduce mpg a lot by accelerating gently, going slower and using the brakes less, but you will increase the time taken to do the journey.

It's greater acceleration but for a shorter period of time.
The net momentum change is the same.
The amount of work done on the vehicle is the same.
Most engines operate more efficiently when under a decent amount of load.


http://wikicars.org/en/Hypermiler

When running in traffic, a brisk (but not full throttle) acceleration, followed by an off throttle attempt (see previous) will be much more effective than gentle acceleration.

Using lower speeds will help because drag forces are proportional to speed squared.

Less braking will help because it's throwing away momentum as heat.