Fuel Misers

[Richard A Thackeray]

My Octavia is far more economical than the Panda (1.2petrol/5-speed manual)


It's a 1.6Tdi/5-speed (re-mapped)
Before/after figures shown
It's more tractable, quieter, slightly more economical


The present (Skoda) 2.0Tdi is rated at 150BHP, & 250Ib/ft, so it's not far off!


That said, I did see this 'average' figure, ona trip down the M1, to East Midlands Airport a couple of years ago (pre-mapping)
It was a 50-55MPH trip most of the way, with minimal acceleration



On sadder/scarier MPG figures
I used to have a 90CSW-V8
A genuine factory built V8, not a transplant
I once towed a twin-axle caravan to Cumbria with it, up the A65
Granted it was on LPG, so a slightly less calorific value than unleaded, but a refill-refill measurement came to 8MPG


A friend once had a 101FC, still with the (petrol) V8, & that used to see an average of 7-10MPG............... despite it being a lot lighter than a Range Rover
Granted, higher, bluffer fronted
It did sound glorious though
(my old 1969 2A Light-Weight)



Our old XKR could be persuaded to manage practically 30MPG, as I have done, driving it to Cardiff
On the other hand, in traffic, or playing 'silly buggers' has seen 5MPG
This number, or partially could describe its nature, if mistreated

 

[User33236]

A number of years ago I bought a Honda Insight (hybrid) car with the aim of being more economical. The car had a ‘game’ which allowed you to grow virtual trees on the dash if you drove in accordance with the computer’s expectations. Once you grew all the trees you would ‘level up’ and it got harder.

The annoying part was that if you ‘drove it like you stole it’ you got much better fuel economy than if you played the game.

After a couple of years I gave up and returned to ‘kill the planet’ mode and bought a Ford Mustang. Fast forward a bit, with a nasty diesel in between, I picked up my new car yesterday which claims to give great mileage due to it’s 1.2 litre Puretech engine.

The game is back on

 

[Mr Celine]

I respectfully dispute the term "antisocial".

Faced with a long hill, such as M40 northbound out of High Wycombe or the M40 "vicar of Dibley" hill southbound, I will gradually build my speed up to an indicated 75/actual 70 mph at the start. I will then choose a throttle opening that allows my speed gradually to drop to about 40mph by the top.

Going up the hill, no-one minds, because everyone accepts that people are allowed to go slowly up a hill. If, however , a lorry is just overtaking me at the top when my constant throttle opening results in acceleration again, they get really cheesed off.

I am unrepentant because I think that those of us who are antisocial enough to drive at all have a moral duty to drive as economically as possible.

Which is why I take the protestations of the haulage industry that they care deeply about fuel efficiency with a pinch of salt, when they drive everywhere on the speed limiter, maintaining 56 mph (or whatever) even up hills where it must be drinking fuel.

Why is it more economical driving slowly up a hill? Travelling up the hill from the bottom to the top you have increased the potential energy of you and your car. This increase in potential energy is the same no matter what speed you drive up the hill.
Going slowly at the top you will of course have less kinetic energy, but if that's your goal why not just drive slower all the time?

 

[Milkfloat]

I respectfully dispute the term "antisocial".

Faced with a long hill, such as M40 northbound out of High Wycombe or the M40 "vicar of Dibley" hill southbound, I will gradually build my speed up to an indicated 75/actual 70 mph at the start. I will then choose a throttle opening that allows my speed gradually to drop to about 40mph by the top.

Going up the hill, no-one minds, because everyone accepts that people are allowed to go slowly up a hill. If, however , a lorry is just overtaking me at the top when my constant throttle opening results in acceleration again, they get really cheesed off.

I am unrepentant because I think that those of us who are antisocial enough to drive at all have a moral duty to drive as economically as possible.

Which is why I take the protestations of the haulage industry that they care deeply about fuel efficiency with a pinch of salt, when they drive everywhere on the speed limiter, maintaining 56 mph (or whatever) even up hills where it must be drinking fuel.

Yes we do. In fact if you really annoyed the Police you may get pulled for ‘driving without due consideration for other road users’ although at 40mph that would be pretty harsh. Ireland has a minimum speed limit on Motorways.

Another way of looking at it is that in fact by you driving economically your overall effect is negative economic because you are causing other vehicles to brake then accelerate to get around your moving roadblock, let alone the safety implications.

 

[gbb]

I respectfully dispute the term "antisocial".

Faced with a long hill, such as M40 northbound out of High Wycombe or the M40 "vicar of Dibley" hill southbound, I will gradually build my speed up to an indicated 75/actual 70 mph at the start. I will then choose a throttle opening that allows my speed gradually to drop to about 40mph by the top.

Going up the hill, no-one minds, because everyone accepts that people are allowed to go slowly up a hill. If, however , a lorry is just overtaking me at the top when my constant throttle opening results in acceleration again, they get really cheesed off.

I am unrepentant because I think that those of us who are antisocial enough to drive at all have a moral duty to drive as economically as possible.

Which is why I take the protestations of the haulage industry that they care deeply about fuel efficiency with a pinch of salt, when they drive everywhere on the speed limiter, maintaining 56 mph (or whatever) even up hills where it must be drinking fuel.

Why is it more economical driving slowly up a hill? Travelling up the hill from the bottom to the top you have increased the potential energy of you and your car. This increase in potential energy is the same no matter what speed you drive up the hill.
Going slowly at the top you will of course have less kinetic energy, but if that's your goal why not just drive slower all the time?

I suspect Swansons point is not driving slowly up a hill...more allowing the speed to drop rather than maintaining it. Less throttle, less fuel used. The downside is your average speed is lower...but that' the price you pay for economic driving...i do the same to a degree, i drive for economy, not to maintain a certain speed. But I'd add, i wouldn't drive in a way that caused problems for other road users.

 

[smutchin]

I respectfully dispute the term "antisocial".

It wasn't my term, it was @Colin_P's own description of his own driving.

All I can say about your own description of your own driving is at least you're staying in the left-hand lane.

 

[gbb]

Does anyone inflate their tyres for economy ?
My 10 plate Astra had recommended pressures for normal, economy and heavy load conditions. IIRC, normal pressure was 30psi, economy was 36psi and heavy load was 40psi. I always run mine around 35psi. Some marginal extra wear will occur but my last fronts lasted 24k miles, so not wearing that much then.

 

[smutchin]

I hate the cars that accelerate towards red lights, or the back of a traffic queue.

Don't blame the cars.

 

[Tin Pot]

Don't blame the cars.

They’re not people once they get behind the wheel.

 

[Colin_P]

I respectfully dispute the term "antisocial".

It wasn't my term, it was @Colin_P's own description of his own driving.

All I can say about your own description of your own driving is at least you're staying in the left-hand lane.

More spin than a dose of spin a spin doctor could diagnose whilst sitting on a spinning top in a washing machine on its spin cycle.


I said it can be antisocial. And that statement was aimed at those who have insufficient spatial awareness, in fact any awareness, and are self absorbed nobber drivers.

I'm never anti social when hypermiling but excel at it in other arenas.

 

[Mr Celine]

I suspect Swansons point is not driving slowly up a hill...more allowing the speed to drop rather than maintaining it. Less throttle, less fuel used. The downside is your average speed is lower...but that' the price you pay for economic driving...i do the same to a degree, i drive for economy, not to maintain a certain speed. But I'd add, i wouldn't drive in a way that caused problems for other road users.

But if he reaches the top of the hill at 40 rather than 70 he then has to accelerate back up to 70, so uses more 'throttle' doing so. [pedant] He might have a diesel, and diesels don't have throttles [/pedant]

 

[John the Monkey]

I sometimes do a long ride without finishing all my wine gums.

 

[Nigeyy]

It's been said: I really don't think freewheeling in neutral is a safe idea, and certainly not turning off the ignition in most cars with steering locks!

I'm certainly not a fan of pulse and glide either; while it may be worthwhile trying if there were no other people on the road, one has to ask how often that happens.... And given the nature of humans, whatever you may save in fuel economy will be completely wasted by those behind you, let alone the propensity for road rage. So please, just don't do it.

Best fuel saver ideas? (and really it's just common sense)
1. don't drive at all or use a car if you can help it (may not be practical)
2. if you do drive a car, use an economical one!(duh!)
3. drive off peak hours so you aren't stuck in traffic (yeah, might not be practical either!)
4. plan accordingly or use apps that can provide least trafficky routes or traffic controls
5. obey speed limits (work out how much faster you get somewhere going 10mph faster and it can be suprizing how little time you save for the cost of aggravation, stress and lower mpg)
6. Don't be a digital driver; nice and smooth with accelerator and brakes....
7. don't accelerate to a red light (oh yes, people certainly do), brake smoothly and less firmly to try to flow along the road. Try to minimize stopping, at least in a safe manner.


I'm all for being miserly with petrol, but really safety first. I'm sure there are other points I've missed.

 

[swansonj]

I suspect Swansons point is not driving slowly up a hill...more allowing the speed to drop rather than maintaining it. Less throttle, less fuel used. The downside is your average speed is lower...but that' the price you pay for economic driving...i do the same to a degree, i drive for economy, not to maintain a certain speed. But I'd add, i wouldn't drive in a way that caused problems for other road users.

Thank you. I had assumed that driving slower up hill was common ground, and thought that the extra point i was offering was the slowing down up hill. It seems even driving slowly up hill is disputed. To those people,I offer two arguments.

First, if we drive up a given hill in a single gear, the engine will do the same number of revolutions. So what determines the efficiency is how much fuel gets injected into the cylinders each time. And, to a first approximation, that is determined by the accelerator pedal - how hard we are making the engine work.

Second, if we attempted to cycle at a constant speed up hilla s on the flat, would we end the day more or less exhausted? Human legs and car engines share some characteristics... Steve Abraham is someone who is taking the optimisation of his cycling efficiency seriously, and he often comments how other cyclists are surprised how slow he is up hill and how fast down.

Anyway, just try the same hill at different speeds in a car with an instantaneous mpg readout.

 

[swansonj]

Yes we do. In fact if you really annoyed the Police you may get pulled for ‘driving without due consideration for other road users’ although at 40mph that would be pretty harsh. Ireland has a minimum speed limit on Motorways.

Another way of looking at it is that in fact by you driving economically your overall effect is negative economic because you are causing other vehicles to brake then accelerate to get around your moving roadblock, let alone the safety implications.

My point about rejecting the antisocial label is that we don't have to accept the current, selfish, speed-driven, performance-centric culture of our roads as a given. We can and should seek to reshape our road culture in more positive directions.