General Is ‘Economy Driving’ Worth It?
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General Is ‘Economy Driving’ Worth It?
My first contact with this idea was a Toyota Aygo 1.0 hire car that kept suggesting I should change up a gear when climbing a hill in third.
It's obviously nonsense in my opinion.
My sister on the other hand is a convert to this philosophy.
I've given up trying to reason with her and grit my teeth as she tries to drag her Hyundai i10 up a hill in fifth gear on full throttle, holding up HGVs.
I like the cycling analogy, I've used it before. It's much better to choose a low gear and keep spinning.
OK it's different on the level, or with a 3 litre diesel or something where you can rely on low end torque.
But we're not all built like 3 litre diesels.
It's obviously nonsense in my opinion.
My sister on the other hand is a convert to this philosophy.
I've given up trying to reason with her and grit my teeth as she tries to drag her Hyundai i10 up a hill in fifth gear on full throttle, holding up HGVs.
I like the cycling analogy, I've used it before. It's much better to choose a low gear and keep spinning.
OK it's different on the level, or with a 3 litre diesel or something where you can rely on low end torque.
But we're not all built like 3 litre diesels.
spidermania
Banned
Yes but only on the motorway with an automatic, cruse control on and the eco mode engaged. On flat level road.
With a manual your overdrive gear is eco mode.
The problems arise on grades up or down and most times people are still with cruse control on. The beauty of the modern day automatics like my spiders is I can manually shift down.
The other issue of course are those with manuals and most do not know when to shift up or down.
Perhaps in your country, but not in the UK.
The vast majority of UK drivers will have learned to drive in cars with manual transmissions.
But times are changing, and far fewer manual cars are sold here now compared with ten years ago.
The massive increase in EV and hybrid sales is part of the reason for that, of course.
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spidermania
Banned
Quite right, in the United States the best security to prevent theft is if the car is a manual.
He lost me @
Doesn't the ignition advance as RPM increase ?
Driving at low rpm causes more soot
And
Low rpm causes the engine to over heat
Doesn't the ignition advance as RPM increase ?
Driving at low rpm causes more soot
And
Low rpm causes the engine to over heat
his message was…Ask yourself: will the cost of repairs (engine stresses of consistent ‘labouring’ at low rpm causing premature mechanical component failure) outweigh the fuel savings of ‘eco’ driving?
Also (not covered here) is the matter of safe driving i.e. being in the right gear at the right time - what I (and I guess many here) were taught when we learned to drive, and were expected to demonstrate in the dreaded driving test
Really depends on the engine. Labouring has never been an issue for mine, it seem's to pull from under 1,000 rpm even in high gear. But it does have a huge amount of torque being a bigger turbo diesel.
I can drive economically, or not so, and you do see a big difference in mpg, and cost. So 99% of the time it's economy.
Clarkson summed it up well, M3 following a Prius going flat out round a race track, the M3 more efficient in that situation.
I can drive economically, or not so, and you do see a big difference in mpg, and cost. So 99% of the time it's economy.
Clarkson summed it up well, M3 following a Prius going flat out round a race track, the M3 more efficient in that situation.
The facts in the video are flawedhis message was…Ask yourself: will the cost of repairs (engine stresses of consistent ‘labouring’ at low rpm causing premature mechanical component failure) outweigh the fuel savings of ‘eco’ driving?
Also (not covered here) is the matter of safe driving i.e. being in the right gear at the right time - what I (and I guess many here) were taught when we learned to drive, and were expected to demonstrate in the dreaded driving test
It's made to get views, with no data just cutaways, in my opinion
Here's how I see it
Low revs don't overheat an engine
Less explosions per second, equals less heat to get ride of
Water pumps are designed to work from idle
Oil pumps are designed to work from idle,
Low revs doesn't build up carbon then mixture is controlled by the O2 sensor
Burning oil, rich mixture, does, but an engine running correctly, makes no difference, especially on modern fuels
The Italian tune up to remove carbon on these engines just isn't true, the exhaust valve is always too hot, when you strip the head down it will just have ash over it, it's impossible to get the inlet valve hot as it's constantly having cold fuel sprayed over it, accelerating hard put more blowby back into the combustion chamber, increasing build up, even at a steady 5K RPM the outer edge of the piston closest to the water jacket isn't anywhere near hot enough to burn carbon off
Low revs don't put more wear on the connecting rods
The highest cylinder pressure is at maximum torque, that when the maximum push down occurs
The only time low revs will damage an engine is if it's designed wrong or there's already a problem,
A DMF may have a harder time at low rev
compromises the safe driving issue tho
That's all a bit "from a certain point of view".
They are all equally designed to run at higher revs too, without overheating.
And maybe it's the type of car, but I've often found cars do run better and happier if used properly (not for economy).
Maximum torque is often at lower revs, so things will be stressed more there.
DMFs have no place in any car, so I view them as a design flaw.
Just as a slight aside, the satnav on the hybrid juke had a new option I'd never seen before. You had the usual fastest, shortest, but now it has the most economical. Which was different to the other, and seemed to go through the town. I'm guessing they take account of running on electric for this, and town driving is very economical if the engine isn't running.
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Mines a 1.3 Diesel Panda so not a lot of torque below 1500 rpm, though it will
pull smoothly down to tickover speed in any gear, it's so smooth that it caught
me out a few times when I first got it and wondered why it wasent accelerating.
I am not in any hurry usually so just keep up with the heard but what I do pay
attention to is coming up to stopps as in lights and junktions, if see a light is
on red I back off early with the aim of arriving just after the traffic starts moving
so you keep rolling, drive smoothly if your on and off the brakes your wasting the
fuel you just used to get up to speed,
My MPG is high but I do live out in the sticks so not driving in town all day.
pull smoothly down to tickover speed in any gear, it's so smooth that it caught
me out a few times when I first got it and wondered why it wasent accelerating.
I am not in any hurry usually so just keep up with the heard but what I do pay
attention to is coming up to stopps as in lights and junktions, if see a light is
on red I back off early with the aim of arriving just after the traffic starts moving
so you keep rolling, drive smoothly if your on and off the brakes your wasting the
fuel you just used to get up to speed,
My MPG is high but I do live out in the sticks so not driving in town all day.
I AGREE.
but That isn't ECO..
lifting off early for roundabouts and down hills,
Reading the road so you seldom use the brakes, and carry inertia is where the big gains are
I do think the "eco" button you find on cars is just for those that cant drive economically, and it effectly just desensitises the accelerator pedel.
But for the actual driving, I've often wondered if it's more economical to accelerate hard up to say 60mph, or slowly accelerate in a higher gear. The engine is probably more efficient pushing harder (less relative residual losses), and this would be for a far shorter period then the longer acceleration.
But for the actual driving, I've often wondered if it's more economical to accelerate hard up to say 60mph, or slowly accelerate in a higher gear. The engine is probably more efficient pushing harder (less relative residual losses), and this would be for a far shorter period then the longer acceleration.
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I've only used ECO in twinairs, not got it on the 500 FIRE
In my punto you can be on a flat featureless road at 45/50 mph on Cruise
Toggling ECO will give an 8 mpg Instant displayed mpg change
Performance is massively different..
When brand new you could only pull 6th gear when downhill in ECO, it would entertain 6th under full power though
With a 6 speed I do find short shifting isnt much more economic..
However the 5 speed panda TA has no "overlap" in gears.. So cannot really do that
BUT can do great MPG on a steady motorway run - 65 mph in 5th
Returned 68mpg over 100 miles of M4
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It's not from a certain point of view
It's in reply to the incorrect facts in the video
The hidden dangers of low RPM driving
Low RPM does not damage the engine
Come on, things like driving at low rpm builds up carbon and clogs the CAT.
In a modern ECU controlled petrol engine, on modern fuel, the mixture is controlled by the O2 sensor, and it simply isn't true
Here's mine 1.2 69HP
The pistons haven't been cleaned
Engine 70k miles two years driven 95% time under 2.5K RPM, mostly between 1-2K at that
It's the same as the misleading videos with title such as 5 thing you always been doing wrong, it's just click bait, not to be taken seriously
High RPM
The piston has to change direction the force required is a square of the RPMs, so doubling the RPM quadruples the force
Is the engine designed to withstand occasional high RPM, absolutely
Neither does high revs. The only thing that should overheat an engine is a coolant leak, or possible running lean.
Nothing to do with high or low revs.
Questionable, you will have more fuel and air in there to make up for the lack of revs, meaning fewer but bigger explosions.
EGR also means cooler when at high revs as it's got a cooler burn temp.
At idle there is also far less work for the cooling system to do. But a bit irrelevant as the thermostat controls the cooling, not the waterpump.
If you've ever seen an oil pressure gauge, then the pressure at idle on a hot engine is normally 1 bar or less. Usually the pressure reg controls it at not much above idle. But just because it works, doesn't mean it could be sufficient when the engine it delivering power.
Questionable for same reasons above, same power means more torque, means more force on the rods and lower oil pressure.
The reality it's far more complex, you are more likely to have higher pressures at low revs since the volumetric efficiency drops as the revs increase (you just cant get the air in quickly enough)
Again, depends on the engine, modern diesels will die if you only run them at low revs. And I always find petrol engines (not modern eco friendly ones) run better long term when given a bit of abuse.
Not agreeing with the video, just disagreeing with some of those comments you made.
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I find this all very interesting, I was raised with the notion that an engine shouldn't be 'laboured'.
Again, I have no issue with cruising along on the level under little load at low revs, it's climbing hills on low revs I understood to be the problem.
Unless this only really applies to older cars with carburetters, big end bearings that would be lucky to get to 100k miles? And doesn't apply to modern engines?
Again, I have no issue with cruising along on the level under little load at low revs, it's climbing hills on low revs I understood to be the problem.
Unless this only really applies to older cars with carburetters, big end bearings that would be lucky to get to 100k miles? And doesn't apply to modern engines?
I think this all depends on the car in question.
So both of our cars peak torque is 1500 rpm upwards...if wringing it out you're just increasing the pumping losses.
Also most manufacturers are building low rev diesel style engines so there's all sorts of allowances that get made. One of the them (or possibly actually both) has/have variable oil and water pumps so at low rpm oil/water flow to the bearings and cooling doesn't change and it stays the same as you go up the revs.
Then you have all sorts of other adjustments that in the old days weren't a thing, dual VVT, variable high pressure fuel injectors allowing multiple jets per ignition, knock detection, variable ignition timing etc etc.
As a result most engines will make themselves safe if you do something it doesn't like. Put low octane fuel in and run at low rpm on boost..it's gonna pull timing and open the waste gate to keep itself safe from LSPI.
Then you have things like variable combustion cycles...the Toyota at wide open throttle and rpm runs on the Otto cycle which has a max efficiency of 25%. Part throttle low rpm it drops onto the Atkinson cycle...with a max efficiency nearing 40% which would be decent for a diesel.
So it entirely depends what it is and if it's built for it..
So both of our cars peak torque is 1500 rpm upwards...if wringing it out you're just increasing the pumping losses.
Also most manufacturers are building low rev diesel style engines so there's all sorts of allowances that get made. One of the them (or possibly actually both) has/have variable oil and water pumps so at low rpm oil/water flow to the bearings and cooling doesn't change and it stays the same as you go up the revs.
Then you have all sorts of other adjustments that in the old days weren't a thing, dual VVT, variable high pressure fuel injectors allowing multiple jets per ignition, knock detection, variable ignition timing etc etc.
As a result most engines will make themselves safe if you do something it doesn't like. Put low octane fuel in and run at low rpm on boost..it's gonna pull timing and open the waste gate to keep itself safe from LSPI.
Then you have things like variable combustion cycles...the Toyota at wide open throttle and rpm runs on the Otto cycle which has a max efficiency of 25%. Part throttle low rpm it drops onto the Atkinson cycle...with a max efficiency nearing 40% which would be decent for a diesel.
So it entirely depends what it is and if it's built for it..
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Correct but the video says low rpm damaged the engine because the water pump isn't pumping as fast
It also says more heat is generated
Really
Not sure I understand this, the faster the piston drops the quicker the air is drawn in with it's matching fuel, it will reach a limit where it falls off again,
A diesel depends on boost
In winter a 1.2 will not kick the fans in at idle, you have to raise the revs to around 2K
The more BPM more than counters the EGR
Correct but that's not what it says in the video, I disagreed with the video
Flow not pressure is what's required, when oil can't pass through the tiny passages it's wasted as pressure, the flow is designed to be adequate at idle
What about the inertia as the pistons change direction, it's pulling something like 5000gs at higher RPMs, yes I don't know the exact figure, I used a similar engine and knocked 2000 gravity's off
At low RPM there much less forces,
The connecting rods on the 1.2 8V panda cup cars (2007) are changed for the stronger ones out of the 16V engine
Short stop start journey will, block both the erg and dpf
But even then it's not sustained high revs needed,
Just needs to get hot for long enough
Although most problems are more associated with the MAF, if it's not reading correctly the fueling is off causing more soot to build up, leeks been the most common
I done 80 miles a day 5 days a week for 10 years in both a ford 1.8 and vauxhall 1.3 rarely using high revs. Mostly at the bottom end of the rev counter, that well over 200,000 miles,
Is far as I remember the only failures were a failed alternator on the vauxhall
There's more going on here than just the engine
Higher air flow clears oil out of the inlet and of the MAP, higher fuel rate through the injectors and so on, there's no way any abuse will help with carbon build up
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