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-   -   Saving fuel in a car by not using brakes (https://www.pprune.org/jet-blast/448931-saving-fuel-car-not-using-brakes.html)

Parapunter 16th Apr 2011 09:02

No judgement Whirls, just acute observationzzzzzzzzzzzzzzz.:}

Whirlygig 16th Apr 2011 09:24

Yeah, very cute. Let's face it, your observation applies to everyone who posts on Jet Blast. :8

Cheers

Whirls

Lord Spandex Masher 16th Apr 2011 09:43

I always find the extra effort required to gain a couple of miles a gallon takes the fun out of driving a precision engineered motor properly.

Besides, everybody knows that you need to drive quicker to get to the next petrol station before your fuel runs out.

ATNotts 16th Apr 2011 09:52

Why Miles per Gallon?
 
Thread deviation, but why do we in UK still talk about mpg, and as an alternative Litres/100km?

We don't buy fuel in gallons, and so a mental mpg calculation isn't so easy, and we don't measure distance in km!

Whats wrong with miles per litre? Thats how I check my consumption (usually around 11 miles per litre in a Skoda Superb).

Returning to the thread, surely the simplest way to minimise fuel consumption is a light right foot, on both peddles.

islander539 16th Apr 2011 09:59

It's all to do with acceleration sense - the ability to vary the speed of the car according to existing road and traffic conditions, without the use of the brake. :ok:

Cacophonix 16th Apr 2011 10:21

I would have thought that the accident that will inevitably ensue through consistently not using one's brakes will ensure fuel saving while the car is being repaired or scrapped.

One wonders about kinetic energy recovery systems though. Could such systems actually result in fuel economies if used sensibly to reduce the amount of power required to reaccelerate after slowing down or would their weight negate any value they might add?

Tarq57 16th Apr 2011 10:39

It's the sort of anticipation mentioned several times through the thread, of when to reduce power early so as to maybe avoid having to stop that reduces the need for braking. So, avoiding braking is not about avoiding braking, in this context; it's about driving so that less braking is required.

Conversely, I've found it is usually better, especially in traffic, to jockey for position so as to be numero uno at the lights, or a tunnel, or any other place where passing is difficult or unsafe, so as to be able to drive at a nice steady speed, which means briefly using a bit more gas to save it in the long run. Most other drivers are slow away from the lights, or very slow in corners, or indecisive approaching roundabouts, or behave as though they have never operated a car in a bit of rain before. Staying with them often means staying in 2nd or 3rd gear. (This is in NZ. Home of the crap driver.)

Of course, being numero uno away from the lights presents a much more attractive view of the wide open space ahead, and therefore makes it difficult to keep the foot at best economy setting, so it's best just to let the car accelerate to the speed the car wants to go at.

It would simply be disrespectful to the car not to.

Tarq57 16th Apr 2011 10:42

@Cacophox, the prius (small "p" intentional) has a system where the first pressure on the brake pedal turns the motors into generators, causing the battery to recharge (albeit briefly) as the vehicle is slowing.

Horrid beast of a thing to drive, though. Test drove one, once. Once too often.

forget 16th Apr 2011 10:58

The idea that ECUs shutting off fuel flow on the overrun is the best way to minimise consumption has been proven wrong - but I can’t remember who did it. Just trust me. :)

The argument was – on the overrun with engine braking the fuel flow drops to zero. However, engine braking usually (so they found) slows the car more than optimum, so at some stage during deceleration it needs a manual squirt from your right foot. This squirt was found to use more fuel than if you’d knocked the car into neutral in the first place, and coasted on tick-over. And the fuel savings more than made up for any other (generally perceived) wear and tear.

I coast in neutral sub-consciously now - and my 523i is on the original discs after 170,000 miles – and it’ll give 36MPG on A roads in normal traffic.

My Mk ll Zodiac (happy days) had an overdrive with a built in freewheel. And the Rover 105 Series had a manual free wheel. There must have been many more.

G-CPTN 16th Apr 2011 11:00


Originally Posted by Cacophonix
I would have thought that the accident that will inevitably ensue through consistently not using one's brakes

It's about awareness, not only about what features are upcoming, but, especially, in anticipating what other vehicles will do (and where they might appear from).
If you drive as if you have no brakes, then when you are forced to use them you will be in a better position anyway . . .

Cacophonix 16th Apr 2011 11:07


It's about awareness, not only about what features are upcoming, but, especially, in anticipating what other vehicles will do (and where they might appear from).
Fellahs (I guess) I was attempting to be droll! :ok:

Agree with all your points and attempt to drive like that unless I am listening to ZZ Top when I seem to be be driving on the accelerator and the brake all the time.

Parapunter 16th Apr 2011 11:30

Oooh, bit of a judgement there Whirlz.:=

Tankertrashnav 16th Apr 2011 11:33

Used to live in Paris and loved to watch the Parisian attitude to fuel economy/brake wear.

Sit at red light (rev up a bit to keep right foot in practice).

Watch light turn green - hit horn one nanosecond later on assumption guy in front hasn't moved off yet.

Race to next set of lights a couple of hundred metres down the boulevard. Dont get out of second gear.

Hit brakes at the last possible moment (the light will inevitably be at red).

Repeat process.

Always fancied owning a brake/tyre fitting centre somewhere in Paris!

yotty 16th Apr 2011 11:38

Tanker... I had some fun on the Boulevard Peripherique! :eek: Capetonian why is it not advisable to coast? I do it a lot and get 60 mpg from my 90hp TDI golf..?

vulcanised 16th Apr 2011 11:52

Of course, with an automatic (which I have) you tend to use the brakes more frequently because of much less engine braking.

The upside is that you can do a lot of 'coasting' and make savings that way.

Windy Militant 16th Apr 2011 11:53

Years ago a friend of mine was a Star rider instructor. This was in the days before CBT was introduced for Motorcyclists. There was IFRC a three stage syllabus Bronze, Silver and Gold which took the rider from basic to advanced standard. One exercise they used was to ride without the use of brakes. The idea being that it taught you how to judge your speed into the corners better and by using the correct approach speed meant smoother riding and better control.
The other technique used to teach anticipation was to ride without stopping or rather if you could balance the bike not putting a foot down in the designated section then you'd pass.
My mate developed a theory of Zen riding, I believe in America it's called "the Pace" The idea is that every road has a rhythm, become one with the road and you make the best progress for the least effort.
The best example of this for me was at Aberdare park road races watching a character called Bill Swallow on a 1950s Velocette keep ahead of Carl Fogarty on a 1980s 500cc Two Stroke that had just come back from the Isle of man TT.
The redoubtable Mr Swallow used conservation of energy to keep ahead of a machine that was three times more powerful for two out of the four laps and it took a serious amount of effort on the part of Mr Fogarty to get past.
I've used this in my own little way on the Cromwell road recently, catch the lights just right and use the right speed and you sail through on green all the way down, seriously annoying the Porsche driver using the thrash and brake method as you pass him at the lights, while he tries to overcome inertia and get rolling again. Brute force will always win out, but with a bit of thought you can make life easier on your self, your vehicle and your wallet and not be that much slower over the ground ;)

Whirlygig 16th Apr 2011 11:56


Oooh, bit of a judgement there Whirlz.:=
Not at all; just,as you say, an observation. ;) Why not try saying, "ha, ha, very funny". :p

Cheers

Whirls

Cacophonix 16th Apr 2011 12:02


The best example of this for me was at Aberdare park road races watching a character called Bill Swallow on a 1950s Velocette keep ahead of Carl Fogarty on a 1980s 500cc Two Stroke that had just come back from the Isle of man TT.
The redoubtable Mr Swallow used conservation of energy to keep ahead of a machine that was three times more powerful for two out of the four laps and it took a serious amount of effort on the part of Mr Fogarty to get past.

rans6andrew 16th Apr 2011 13:14

one way of increasing economy by using the brakes somewhat less is to take all bends at a higher speed. Why slow to 30 if you can comfortably get around the bend at 40 or even 50?

It is fairly easy to anticipate how much the car in front will slow for bends, after following them for a few minutes, then you can take your foot off the loud pedal before they brake and then be catching them up as you round the curve. As they accelerate away afterwards, let them go away a bit so that when they brake again you have anticipated. You will have saved a lot of loud pedal use and still be just as close to them at the end of the road.

If taken to extremes it will start to impact on your tyre cost so don't overdo it.

Works for me.

Rans6


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