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

shelovestobuystuff

pault123 wrote: »

Surely were talking 0.5% fuel saving when talking about not having your radio on and your headlights on in the winter? I would hate to turn my radio off and I like having my headlights on when its dull and rainy, there must be a point where were taking saving fuel a bit too far

*edit* busabus's post is exactly what I was getting at 50% saving from no radio seems ridiculous. Its such a low drain appliance vs revs, and driving flow on petrol consumption.

I was definately not suggesting that anyone turns off headlights in the winter,that would be stupid and very dangerous,I was just trying to show how electrics alter fuel consumption.:eek:
Having electrics on affects the revs too.Sit in your car,start it up but dont go anywhere ,switch on your electrics one by one and see and hear what the rev counter does.Even without driving anywhere the engine has to rev harder as its driving the alternator harder to compensate for all the power you are taking from the battery.
I also know that listening to music whilst driving can alter the way you drive without you realising.People who listen to music when driving are distracted and generally drive faster.Diferent styles of music will have different effects on drivers behaviour obviously.Having the radio off then probably altered the drivers behaviour so a smoother more steady,probably slower driving speed will have helped the drop in fuel consumption too.
Another factor could be a change in the quality of the fuel supply.
Lots of factors,but electrics is one of them.

harryhound

Then you fall asleep, drive off the road and save the rest of us having to pay your pension.

tomstickland

The power drain of the radio is far too small to make a 33% reduction in fuel consumption.

Personally I drive just as fast with the radio off as on, though when I was caught speeding on the motorway at 00:15am I was being a bit motivated by a Tony Du Vit mix on the radio.

tomstickland

Olz wrote: »

Driving economically is all about reading the road well ahead, and as Martin states road safety benefits too. I was taught the 'police system' of car control which utilises 'gears are for going and brakes are for slowing.
Some people are taught to drive by changing gears down in sequence to slow the car for a junction. This is not how to drive, it is how we learn to use gears when we are taught to use the clutch. We learn to drive after passing our test!
Using your head and slowing for the 'feature' and sometimes not even using the brakes but maintaining momentum will not even cause you to lose journey time. It is also cheaper to replace brake pads than it is to buy a new clutch.

I'm pretty sure advanced driving instructors will go on about being the correct gear for the situation and vehicle speed. Say you're approaching some sweeping bends on a A road in 4th, then it might be worthwhile changing into 3rd, then easing off to slow the car slightly without using the brakes at all, then being in 3rd gear ready to put some power down on the exit. If gears are for going then you want to be in the right gear ready to go when the time comes to go. Brakes are better for slowing though since they work on all 4 wheels rather than generally two.

Poppycat

I like to think I am a careful driver and adhere to speed limits and conditions etc, I dont pretend to be perfect.

Now thats out of way, I have for many many years tried to save money on driving and no braking hard, accelerating off etc.

But one thing does concern me when you do all that and adhere to the speed limits I get a lot of tail gaters, and idiots who want to overtake you and for what? so that they can be in the car in front and gain a few secs in front I find driving on occasions very stressful and very trying, mainly tiring because I concentrate a lot when I drive to be alert for any problems should they arise.

wireguided

Hi, I always drive like you did during your experiment. I am a truck driver, so all fuel costs are mine. I also drive an Alfa Romeo Gtv, but last week managed to get 495 miles out of a 60 litre tank. When my fiance has the car she can only get about 350 miles out of a full tank.

So, keeping an eye on your driving style is worth it.

tomstickland

Poppycat wrote: »

Now thats out of way, I have for many many years tried to save money on driving and no braking hard, accelerating off etc.

But one thing does concern me when you do all that and adhere to the speed limits I get a lot of tail gaters...

If there is a lot of traffic and you slowly accelerate away from lights you are likely to cause frustration, since following traffic doesn't know that you are conducting a fuel saving process; they'll just assume that you belong to the hard of thinking who take approximately 10 minutes to notice a light has turned green. Bear in mind that brisk acceleration is not wasteful. It's unecessary braking and acceleration that is throwing energy away. If you accelerate smartly and then travel at the speed limit, say with speedo a few mph over the limit and then someone tailgates then it's their problem.
However, in the last 10 years there has been a proliferation of speed limits, many of which seem to make little sense, so you'll find that 80% of traffic goes faster in some situations and you will quickly end up with tailgaters. I'm thinking of some roads near me where they've turned a 40 limit into a 30 and most traffic seems to continue to travel at 38-40 indicated like they did for the previous 15 years. There are also several sections of straight A road where a 40 limit has been extended a mile out into countryside.

pault123

tomstickland wrote: »

since following traffic doesn't know that you are conducting a fuel saving process;

HAHA I like that

curriej99

i have been reading various takes on economy methods and an interesting one i read is that accelerating hard and keeping the revs as close to 2000 RPM is the most economical method of driving. If you look you will notice that your vehicle is doing 56mph when your engine is at 2000 revs in fifth. This is regardless of vehicle apparently, and is something to do with making the vehicle look economical on paper. What i do is accelerate hard to about 2500 rpm, then change up a gear, at which point the revs drop to about 1500 rpm. i repeat this up through the gears until i am in fifth at 2000 rpm, at 56mph, and try to stick to that. It is boring though, and i find myself drifting up to about 80 quite easily!

paul.jacobs

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