Slower - cheaper? - mini 30 owner
Given the speed limits and so on, and given the speed capability of even the average small car, I reckon that even at top whack I 've probably got 50mph + of legally unuseable speed capability in my car.

So what, you might say, it's not costing you anything, but I'm guessing that I'm not actually being given it free and gratis, that at some point it did cost money to develop this, and at very least, I'm probably still being charged for the enhanced safety features to deal with it

Why do manufacturers of new cars insist on us having all this wasted capacity?

What is the benefit of it - from any perspective?

Is there an argument for "under-engineering" engines to save on the wastage and would it make cars cheaper?
Slower - cheaper? - BazzaBear {P}
If the absolute limit of possible speed in your car was the speed limit, then at that speed your car would be making a terrible noise and using lots of fuel.
In order to be economical at the speed limit the car needs to be capable of at least a decent amount above it.
Slower - cheaper? - Pugugly {P}
.................and some of us, despite the barriers, like going fast. Mind you I've been a good boy today !
Slower - cheaper? - P3t3r
If the absolute limit of possible speed in your car was
the speed limit, then at that speed your car would be
making a terrible noise and using lots of fuel.
In order to be economical at the speed limit the car
needs to be capable of at least a decent amount above
it.


lol, look at the slowest cars currently available, eg. Smart car. My car has a top speed of 89mph, but can get 60mpg (petrol) on a motorway. I certainly agree that we shouldn't need to redline our cars to reach 70mph, but I think the majority of the performance is wasted. Even at 70mph my car will is doing well under 5000rpm.
Slower - cheaper? - BazzaBear {P}
lol, look at the slowest cars currently available, eg. Smart car.
My car has a top speed of 89mph, but can
get 60mpg (petrol) on a motorway. I certainly agree that
we shouldn't need to redline our cars to reach 70mph, but
I think the majority of the performance is wasted. Even
at 70mph my car will is doing well under 5000rpm.


5000rpm!!! I can't imagine cruising at that, the noise must be terrible. My car cruises at less than 2500rpm at 70mph.
Slower - cheaper? - P3t3r
5000rpm!!! I can't imagine cruising at that, the noise must be
terrible. My car cruises at less than 2500rpm at 70mph.


Well, I haven't got a rev counter so it's hard to tell what the revs are. Actually even 4th gear at 70mph is well under 5000rpm. Even in 4th gear at 70mph the noise of the engine is acceptable, the road noise drowns out the engine noise.
Slower - cheaper? - Statistical outlier
The speed capability is a bit of a red herring.

In order to provide acceptable acceleration, and to allow a reasonable load to be carried safely (think 4 adults and luggage), there needs to be an overhead in maximum power beyond what is necessary to carry the car along at 70.

In order to provide decent economy at 70, the revs must be fairly low relative to maximum, otherwise efficiency would fall right off.

The combination provides a higher top speed than necessary, not so much by design, more by coincidence (when referring to small cars). Anyway, a car than can do 130 is pretty serious, it's certainly more than my 2.2 diesel will do (I believe).
Slower - cheaper? - DP
As well as efficiency, noise, acceleration and the overheads for load etc mentioned above there's also engine life to consider. Can you imagine how long an engine would last if it had to be driven to its limits every single day?

The answer of course is some kind of electronic speed restrictor or governor as fitted to lorries and coaches which allows unhindered acceleration up to a given speed and then reduces power to prevent acceleration beyond this point. This would be easier than ever with a modern ECU controlled engine I guess, but it wouldn't be popular. It would also be a massive pain in the backside if travelling to a country with a higher speed limit, or where speeding is not such a big deal.

Imagine having to get your car derestricted every time you go on holiday to Europe for example, and then re-restricted afterwards.

Cheers
DP
Slower - cheaper? - BazzaBear {P}
As well as efficiency, noise, acceleration and the overheads for load
etc mentioned above there's also engine life to consider.


But the limiter wouldn't solve the problem as posed by the OP. The point as stated was that money has been spent on making a car capable of say 100mph, when he doesn't require that. With a limiter, the car is still capable of 100mph, but costs even more for the fitting of the limiter.
What about a car with a ridiculously wrongly set top gear, such that it's necessarily small engine (in order to match our requirements in this thread) is totally incapable of accelerating in this gear, but it is just about capable of retaining the speed attained by the gear one lower. So, you still have to rev the nads off it to get it there, but once cruising it's sitting at low revs?
Conceivable? Of course it all falls apart as soon as you need to adjust speed at all.
Slower - cheaper? - mini 30 owner
Cheers - I haven't tested the 130 yet - maybe if I invest in a longer driveway - ha ha

I've been thinking about getting a Morris Minor Traveller lately - and saw that most of them don't exactly break any records and wondered why/how the whole speed abilty thing developed

Slower - cheaper? - Lud
I think the Minor 1000 could do about 75 but people used to wind them up to 80, and of course there were soon tweaked ones and racing ones. Seems a lumbering old thing now but in its day it was a rich young man's practical hotshoe special, like the Mini a bit later. It handled for its day too. But it had coil springs and sat taller than the original Issigonis sidevalve 850cc design, which had torsion bars and was truly sweet handling at the modest speeds it could manage.
Slower - cheaper? - mini 30 owner
I think it's a beautiful car, especially the estate/traveller.
I've read on a few other posts here about some cars which are capable of 'to the moon' mileages and I've wondered if that should be a concern with a Minor

Whether one with 80,000 on the clock is on its last legs even, or maybe because, it's taken 40 years to do it
Slower - cheaper? - Pugugly {P}
Well one thing about them, the turbo won't be knackered, they won't have been misfuelled and killed, the ECU won;t be fried, the cam belt won't need changing and the head gasket won;t blow on a whim. What price progress eh ?
Slower - cheaper? - local yokel
You can build an engine and wring all the power out of it non-stop - quite normal in racing. The engine will last one to ten hours, so it's not practical for road use. A road use car engine might go for 5,000 hours very easily, and most will last for about 10,000 no problem. To do that you have to reduce stress, for a start, and that means using the engine at probably 25% of its capability for 98% of the time.

If you want to use an engine at 90% of its capability for > 90% of the time you use very strong, and so very heavy components. That's how industrial diesels are built and used. You'd not be too pleased with the weight of the lump, and the rest of the car would be knackered before it had done the 1 million miles that the engine will last.
Slower - cheaper? - NowWheels
Well one thing about them, the turbo won't be knackered, they
won't have been misfuelled and killed, the ECU won;t be fried,
the cam belt won't need changing and the head gasket won;t
blow on a whim. What price progress eh ?


My father and his best friend both had Morris Minors in the 1940s. Some time before Dad's death, the pair of them started talking about how they used to get together on some fairly frequent basis to decoak the valves. (I'm not sure what exactly that meant, but I presume it involved some dismantling and cleabing operation).

I do count it as progress that I don't have to do that sort of chore, even if the price to pay is the risk of a less frequent major repair.

But even those Minors with the valves sound better than the poster I saw in my great uncle's grabage, dating from the 1930s. I can't recall what sort of car it referred to, but this beautifully coloured diagram showed bits all over it that required greasing every 250 miles. I don't miss that either ...

Slower - cheaper? - mini 30 owner
I quite fancy the idea of being able to maintain an engine myself.
I didn't really get into this when I was younger but the unfortunate thing is there are now no night classes in car maintenance near me - maybe none at all - could anyone maintain a modern car from home?

I think the whole 'self-sufficiency' aspect of it is very appealing.
Also, I think it would make one feel more 'plugged into' the world

perhaps I'm just being sentimental
Slower - cheaper? - Lud
You could actually. A careful and intelligent amateur mechanic can reassemble an A series engine properly, with a bit of help from a good motor factor to remachine block and crankshaft and supply the appropriate new bits, into a 'reconditioned' unit. However it is possible to do this quite badly as well as quite well. The engine will run all right but won't really last unless certain standards are maintained here and there.
Slower - cheaper? - IanJohnson
Coil springs on a Minor?

Ours was a 1971 - one of the last - and it had torsion bars (front) and leaf springs (rear).

Only car we ever had that appreciated!
Slower - cheaper? - artful dodger {P}
IIRC my old Citreon Dyane had a top speed of 68mph from the 602cc horizontally opposed air cooled engine. The acceleration was poor and it was very difficult to maintain a constant speed close to the 70mph limit as every hill slowed you down. If you have plenty of time and little money then this may be fine, but now I prefer a little comfort and acceleration.

My current diesel will cruise comfortably at 70mph at just under 3500rpm, the top speed is supposed to be about 120mph, but I have never tried anywhere near that speed as the roads are to busy and unsafe.




--
Roger
I read frequently, but only post when I have something useful to say.
Slower - cheaper? - Happy Blue!
The OP makes an interesting point and one that has been effectively put down above.

As an example I can refer to the Fiat Doblo 1.2 diesel. A sloooow car which could barely get over say 85mph at best and 0-60 was at least 20 seconds if not more. I drove one as a hire car once. I certainly improved its performance during the two weeks I had it, mainly by driving everywhere using the Italian tune up method. But it was dangerous on the open road. Sometimes, you see a situation where to brake would cause more problems and accelerating is the better option. This is certainly relevant on todays heavily congested roads. The Doblo was so slow that accelerating out of a situation was impossible, so I occasionally got myself into a problem, that would not have been a problem had the car been faster.

So, yes the car was reasonable economical, but no more so than many other vans which are faster, but potentially put me at greater risk.
Slower - cheaper? - Dyane 6 Mehari
"Doblo was so slow that accelerating out of a situation was impossible"

Accelerating out of trouble is a fallacy - no accident has its outcome improved by it happening faster. If something untoward is happening slow down, don't accelerate. Usng acceleration just increases the chances of an accident happening.

Regarding the Dyane comment above - back around 1999/2000 I used to commute around 50 miles a day up the A23/M23 in a 2CV and found that due to traffic density the lack of power wasn't a problem at all, I could easily keep up with the traffic flow. I also seemed to manage to get 70MPG - I calculated it four or five times and it always came out the same.

Terry...
Slower - cheaper? - BazzaBear {P}
"Doblo was so slow that accelerating out of a situation was
impossible"
Accelerating out of trouble is a fallacy - no accident has
its outcome improved by it happening faster. If something untoward is
happening slow down, don't accelerate. Using acceleration just increases the chances
of an accident happening.


I'll let my friend know that. She had a tree fall across her path, no chance at all of stopping in time, but by stamping on the accelerator it missed the back of the car by literally millimetres.

This: "Using acceleration just increases the chances of an accident happening." is a generalisation. I wouldn't deny that it's true in a lot of cases, but don't try to claim that you can predict every possible eventuality, and that it is true in them all.

"no accident has its outcome improved by it happening faster. " Now this is true enough, but if going faster stops the accident happening at all, then there's no outcome to worry about.
Slower - cheaper? - ffidrac {P}
Did a run from Cardiff to London & back today in the 1.0 Yaris (3 pot engine).

Watching the {MPG now} and speed I travelled at 'speeds' upto (indicated)70MPH (I KNOW it will do an indicated 95 and probably more if 'thrashed') and kept {MPG now} as high as possible. the revs diddn't go over 3500 much (redline at 6250)

Got back home and displayed the {AVE MPG} (since last fill last night) and it displayed 60.4 MPG.

If I had travelled at upto 70MPH with say 6000 RPM I would have used a lot more fuel + stressed the engine (Hey it's only small to start with!) and, probably, frayed my nerves with all the noise!
Slower - cheaper? - Garethj
Did a run from Cardiff to London & back today in the 1.0 Yaris (3 pot engine).
Watching the {MPG now} and speed I travelled at 'speeds' upto (indicated)70MPH (I KNOW it will do an indicated 95 and probably
more if 'thrashed')

Yes, the 1 litre Yaris will do over an indicated 100mph on the downhill stretches of the M4. A friend told me.

I, errr, he could only get the speedo to reach 99mph but the car gained more speed (accelerated is too strong a word) just didn't display it.
Slower - cheaper? - IanJohnson
Why do manufacturers of new cars insist on us having all
this wasted capacity?



It is actually the buying public that insist! If we didn't want them these fast cars would still be sat on dealer forecourts and old airfields. 4x4 is the same issue. All the makers do is offer us what we want!
Slower - cheaper? - SteVee
It's not just engines and mechanical components that are affected.
A car must be fitted with tyres that are capable of handling the car's top speed - even if the car will never be used anywhere near that speed. This may force compromises that you would not readily accept - especially in terms of price or longevity.

I disagree with the idea that a faster running engine is necessarily nosier or vibrates more or 'feels' worse.
It will depend upon design.
There are many engines that will rev very happily indeed and have long life. The best example perhaps is the pre-VTEC Honda VFR 800 motorcycle engine.

I do feel that many cars are engineered (and bought) as autobahn cruisers, and yet never go any where near an autobahn; which is just as silly as having a 4x4 in Chelsea really.

As for slower = cheaper, that's certainly true to a point, but buying something that is common, or common technology may also be cheaper.
Slower - cheaper? - NowWheels
It is actually the buying public that insist! If we
didn't want them these fast cars would still be sat on
dealer forecourts and old airfields. 4x4 is the same issue.
All the makers do is offer us what we want!


I'm not sure that they do, actually.

One factor is the power of marketing: all those SUVs marketed with television pictures of them roaring across deserts and through jungles is about as relevant to the average SUV-buyer as the vehicle's performance on the moon. Most of those vehicles spend more time in supermarket car parks than off-road, and the advertsing explicitly targets people's fantasies (though the same goes for other consumer products, of course).

Another factor to bear in mind is that the UK car market is haevily distorted by the high proportion of sales to company car fleets, rather than to private buyers. That leads, for example, to cars with a lot more electrical toys than are found in many other markets, because private buyers are less keen to pay lots extra for gadgets which will be expensive to maintain.

In markets where private buyers are parting with their own cash (e.g. Ireland and the Netherlands), cars are not only lower-specced, theiy are mre likely to be Japanese. When the public are doing the buying rather than having someone else buy for them, they put a much higher value on reliability.

Engine sizes also tend to be smaller in the Irish market. That may partly be because there aren't so many motorways and road tax is more heavily weighted by engine size, but it's possibily also because people are less keen to spend their own money on performance that they will never use.
Slower - cheaper? - BazzaBear {P}
Engine sizes also tend to be smaller in the Irish market.
That may partly be because there aren't so many motorways and
road tax is more heavily weighted by engine size, but it's
possibily also because people are less keen to spend their own
money on performance that they will never use.

I think it's largely down to the absolutely exorbitant insurance costs over there.
I would also say that your points about marketing might explain the reason why the punters demand these things, but they don't mean it isn't the case.
Slower - cheaper? - DP
I did some work with DoELG in Shannon on their road tax applications software and was staggered at the prices I saw.

Top band road tax (>3000cc) costs ?1300 per annum, and a typical 2.0 family car is over ?500.

Cheers
DP


Slower - cheaper? - glowplug
Doesn't this issue show up when electric cars are mentioned? The biggest drawback according to most is the limited range of say 50-80 miles. But how may motorists do far less than this everyday? There are other problems and drawbacks but if everyone that could practically use a electric car had one I reckon they'd be awful lot of them on the roads.

Steve.
---
Xantia HDi.

Buy a Citroen and get to know the local GSF staff better...
Slower - cheaper? - mini 30 owner
Very interesting replies, one of my thoughts when making the original post was whether the 'high speed capability" issue might be tied up in a progress for the sake of progress situation.

When one poster mentions the need to accelerate out of a situation I thought yes, but would I need 130 mph capability? In the few seconds of oomph my car needs is it going to use its capacity?

In the tree falling scenario, if I'd been going slower from the time I left home the tree might already be on the ground before I arrive! Alternatively, I might alrady be at my destination before it falls.

The 'manufacturers only give us what we want' argument is an old one - how do we know what we want until they give us what is possible?

What is the advantage in anybody having a car capable of more than the speed limit + 50% (just for emergencies!)

Is there any reason/point in engine manufacturers developing any faster engines at all unless and this is a big unless - the extra speed capability is an unavoidable by-product of a more-efficent/greener/cheaper engine?

I'm wondering if it's a bit like that myth of the USA spending squillions developing pens for use in space while the Russias just used pencils - like - why bother?
Slower - cheaper? - Lud
how do we know what we want until
they give us what is possible?
What is the advantage in
Is there any reason/point in
I'm wondering if it's a bit like that myth


They make cars that can't be legally used to the full in most countries because people think they want them like that, and are willing to pay for them.

But really it's just the way the automobile and its attendant industries have evolved.

I don't really like this kind of thread. I am terrified some ghastly monkey in power will read them and get ideas.
Slower - cheaper? - mini 30 owner
Ha ha - true!

It probably comes down most to what you want from the car - doesn't everything - perhaps?

Living in London - my use of a car is never going to be to get somewhere faster - train or tube will alwasy do that - sometimes even a bus

But - if you want a pleasant, leisurely trip, with no angst about spitting chavs and so on - you've got to use the car -

It actually wouldn't matter if it took me twice as long as a bus to get to the shops - it'll always be ten times more pleasant - unfortunate but true
Slower - cheaper? - Lud
I live in London too. It's true that the way they have the place set up these days it can take for ever to do what used to be a 12 or 15 minute journey. The traffic has been and is being deliberately obstructed in a number of ways.Of course there's also a lot of it. I can't imagine why everyone stands for it. Looks to me like politicians taking brutal advantage of the British citizen's endemic guilt and diffidence, for purposes that remain obscure. Heavens we're well-trained. Not sheep, more like performing sealions.

However the tube and bus aren't necessarily any quicker although of course they are for simple straight-line journeys during rush hour. I can think of several regular crosstown journeys I do more quickly in the car than by public transport, even at busy times. And as you say, it's far more pleasant. You can mutter, snarl and scream with laughter without being stared at, listen to the radio without having to wear earphones and smoke cigarettes if that is your thing.
Slower - cheaper? - Lud
My wife yesterday accompanied one of our grandchildren from one place in London to another, Like a total idiot she chose to do it by public transport. The result was that she took two hours to do a one-hour journey. Although I am sorry for her, the journey she chose to do by public transport was so downright irrational that I have a damn good mind to refer to her as SWMBO, something I have never done before. If she does anything so mad again I will.
Slower - cheaper? - Statistical outlier
I believe my car will do 126 mph. I have no intention of ever checking this, whether or not it's legal, I wouldn't want to pay for the fuel!!

However, I like having a car powerful enough to do this, as it means that I can safely overtake on the average A or B road. I spend a lot of time at the weekends heading for Wales to go to the mountains, and being able to get safely past caravans and other slow moving vehicles was a factor for me. My 2.2 diesel is very rapid from 40-70, that was a big factor in my buying decision. I don't give a monkeys about the top speed. :-).
Slower - cheaper? - Kingpin
It's about getting the balance right, suppose a 1.4 or 1.6 between 70 and 100bhp is sufficient for most needs and to accelerate safely up to and just beyond the speed limit to around 90. Over 100mph a lot of effort is wasted due to the increased drag of air against the car and I suppose there are graphs to show how much effort is required to increase up to and beyond 100mph against the wind resistance. I have noticed this on films of high performance cars inching their way towards 150mph fighting the wind resistance.
Slower - cheaper? - Number_Cruncher
Yes, drag force is given by

F = 0.5 * ro * Cd * A * V^2

with;
F - the aerodynamic drag force (Newtons)
ro - the density of air (approx 1.225 kg/m^3)
Cd - the drag co-efficient of the car (dimensionless)
A - the frontal area of the car (square metres)

A vehicle reaches its maximum speed when the tractive effort is equal to the total drag force (aerodynamic drag plus rolling resistance plus gradient load).``As the vehicle nears this speed, the surplus force (tractive effort - drag) becomes very small, and so the vehicle's acceleration diminishes likewise.

If you wished to be more philosophical about a vehicle's top speed, you might take the view that the vehicle never actually reaches the theoretical speed I mention in the above paragraph, it only approaches it assymptotically - another way of saying this is that a vehicle's top speed can only be reached after infinite time has elapsed (I suspect the petrol tank would be empty far before then!).

Another way to view aerodynaic drag is that the power required is proportional to V^3, and so, other things being equal, the mass flow rate of fuel into the engine at higher vehicle speeds, where aerodynamic drag is dominant, is proportional to V^3.

Number_Cruncher
Slower - cheaper? - Lud
**************** ***************


God how boring.
Slower - cheaper? - Kingpin
Thanks Number Cruncher for the technical explanation, as you say a vehicle cannot reach it's theoretical maximum velocity due to drag, diminishing returns.
Acceleration is the thing, feels better than outright top speed.
I remember at school in the physics lesson they had a model wooden truck on a sloping ramp attached to a ticker tape timer to measure the relationship between distance, velocity and time but that is as far as I got, I defer to your greater knowledge.
Slower - cheaper? - Number_Cruncher
>>God how boring.

Please accept my most humble apology!


Perhaps I should put my post into context. Approximately, how much extra power do you need to go at 125 mph instead of 100?
extra_power=(125/100)^3


extra_power =

1.9531

So, if you begin with a car capable of 100mph, you effectively need to bolt another engine in to get to 125!

This partly explains why when one power unit of an inter-city 125 fails , you still get reasonable performance, about 100mph, the train doesn't slow to 62.5 mph! (The rest of the explanation is that with both power units running, 125s are actually capable of closer to 150mph, but, for many reasons, they are governed down to about 128mph)

Number_Cruncher
 

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