[Closed] Motoring - Stop/Start - modern toss or not?

I’m not convinced with the auto stop/start thing, for the same reasons as you. It works well when everything is shiny and new, what about when it’s not? Given that my current car is now 11 years old and still drives and feels like one less than half it’s age, maybe that’s not going to be an issue for you? However, increased use of starter and battery... more expense in the long run possibly and I would imagine certainly a plug it into a something to make sure the replacement will talk to the rest of the ****ing car.

I remember my Mk1 Golf GTi had green, yellow and red lights, or something like that, for economical driving. I ignored them. Insulating tape at the time helped.

Air con? I’m all for it, generally set mine between 19 to 21 degrees for cabin temp. The fan does what the fan does. I’m learning to not having to understand how everything works and why in these ‘newer’ cars, mainly because I have little inclination nowadays to fix it myself and I don’t have the machine to plug the car into to work out which bit of solidstate kit has stopped working.

Can’t go wrong with coil, dizzy and points! 😉

It dismays me that a feature that reduces pollution can simply be turned off, dunno how the manufacturers get away with it.

As above it is a feature to stop you killing babies (as much) use it !

I thought I’d hate it and wouldn’t use it when I got new car. I spent the first week cursing it but don’t even notice it now.

Apparently they also fit seatbelts to cars now. This kind of typical nanny state type lunacy prevents you from being thrown clear of the car in a crash...

I once had a presentation from a company who set up to sell the new batteries required for stop/start tech to the aftermarket. Their business model assumed a life of 7 years for original equipment, so sales of aftermarket would begin to ramp up 7 years after stop/start was first introduced.

Unfortunately for this company, 9 years in and sales were unexpectedly poor. They realised that the factory fit batteries were in fact lasting 10 years or more.

Good for us as users. Bad for them with a warehouse full of the things.

No idea about the starter motor wear.

From a user perspective, I like stop/start in an automatic, but find it a little unintuitive in a manual (sometimes doesn’t restart immediately when you want it to).

I think the stop start thing is just a gimmick by manufacturers. I could be wrong but doesn't it use up more fuel stop starting an engine multiple times in a short distance, maybe different with modern cars but I'm sure that was the case when it first came out. Maybe a good thing if you just stop at a red light for a minute then go but on my commute I can see the lights half a mile away and maybe stop start 50 times before I get through them. Manufacturers, according to their ads, believe that there's only ever one car on the road!

Of its anything like the system in our vehicles, it will soon enough stop working mutch as the battery gets less than 100% perfect. Starter motor will have been sized with the extra duty in mind, I'd not worry about it.

The first car (ford focus 10 years ago) I had with start stop was great

The second car (ford focus 4 years ago til now) is rubbish at restating and frequently stalls - I always bypass it now

progress...…………………...

I don't think its about fuel consumption, its emissions. I turn it off for stop start traffic on dual carriageways etc, but in town it makes more sense where you may be sitting at red lights for a minute or so at a time. And thats where you don't want engines idling. Can you turn it off, or do you mean just temporarily disable it every time you start the car?

The green yellow orange lights to suggest how you are driving really are rubbish though, you can drive about and keep them the right colour but drive right up to each obstacle and hammer on the brakes. They should only go green when you are reducing speed gradually i.e. not using the brakes too much.

A hot engine restarting all the time uses less fuel than one idling. They’re not csrb fed so the injectors are off until there’s a chance of ignition.

The starters are slightly beefed up, as are the batteries, but many also use the valve train to reduce compression so the load on startup is less (fiat multiair, bmw doubleVanos for example).

It’s not new tech, VW have had start stop on some golfs since the early 90s.

Stop/start?

Do people use it?

When at lights, you definitely hear cars engines turn off but almost immediately the engines kicked into life again and the driver sits there for 5mins with their foot on the clutch..and the engine ticking over.

Very, very rarely do you come across a driver sitting at lights or roundabout with the engine off.

So, for me the feature is pointless... it’s not used IME.

My last car had it, I thought it was a fairly good feature but it did take about 10s for it to restart... and y’no when the lights have turned green and you have  “angry mob” revving the nuts off their Bimmer 1SERIES up yer arse in a state of perpetual rage... those 10s seem like a lifetime.

Glad my current car doesn’t have it...

stop/start probably going to compulsory in near future, I'd have thought. Can't have ques of traffic running their engines for nowt.

Air con is one of the best things to ever happen to "normal" cars, wouldn't be without it now. Mine's on permanently between 19-21.

Old cars were pieces of shit in comparison to new cars.

Do people use it?

Yep.

you have “angry mob” revving the nuts off their Bimmer 1SERIES up yer arse in a state of perpetual rage

Ironically we have a 1 series and the engine starts between me pushing the clutch down and before I've fully engaged first gear.

tbh, my 1961 Volvo took less than 10seconds to start and drive away from cold (with the key) so if my BMW took as long as you're saying I'd be back at the dealers.

We also have a Cooper S with the same feature and that works equally quickly.

I can't imagine why you would choose to disable it, tbh, is getting away from the lights 0.5s sooner worth sittign with an idling engine for 4 minutes?

I've had cars with it for about 12 years now. Works perfectly fine you don't really notice it most of the time as engine starts as soon as press the clutch.

Do people use it?

Yep, 99% of the time.

I turn it off at the car park barriers at work as it stops the engine just as the barrier lifts. The only other annoyance is at busy roundabouts where I may need to nip out quickly and a couple of seconds' delay makes a difference. I tend to briefly put the gearbox into sport for those moments which prevents/limits the stop/start.

ABS and Traction Control.Nanny bloody state!Whats wrong with sliding into a bus full of school children?

For a bit of balance, I love mine. It's very good.

For some traffic situations it's not suitable, like if you're going to be stopped for a couple of seconds. But then you can avoid the engine stopping if you choose.

Planning ahead and spotting those times means you can press the easy to find button to disable the system, or keep your foot on the clutch. Or plan your driving so you don't stop for a couple of seconds... 😉

I assume the starter is adequately designed for the job, just like I hope the brakes and other bits are adequate too.

And those folk who sit outside the kids' gym class for an hour with the engine running can do one.

I used it when my car had it.

For some traffic situations it’s not suitable, like if you’re going to be stopped for a couple of seconds. But then you can avoid the engine stopping if you choose.

This.  I disable mine for creeping along motorway queues, but it’s on and working all other times.  Saves fuel and pollution, why wouldn’t you?

I switch mine off every time I get in the car. I plan to keep the car long term and a starter used once per journey will last longer than one used half a dozen times a journey. I don't like the short delay if it switches off at roundabouts. I rarely drive in stop start traffic but will switch stop start on if I get stuck in a jam. No point having an engine idling when you are going nowhere.

Mrs Pondo's 8 year old Colt has it and still works fine, I wouldn't be concerned about replacing starter motors or batteries over the benefit of reduced emissions and fuel use. The GTD I used to have would start itself when the car in front started moving, which I thought was a great idea. 🙂

Here in the Antipodes, where most cars are automatic, stopping at a light can often be silent as the stop/start kicks on all the cars. Got to be a good thing hasn't it?

Does the function work better in auto vehicles? Been in taxis and Uber cars where it seemed to work fantastically, you would be hard pressed to know it was even fitted.

Works well on my V40, use it all the time.

Great tool in the never ending game of trying to keep the displayed MPG as high as possible...

I got a Peugeot Partner with one. I was dreading it, but it's really very good. I understand that the Peugeot system doesn't use the starter motor for stop/start but rather has a beefed up reversible alternator/motor that starts the engine without using the starter. As others have said, the engine has started before the clutch if fully depressed and first gear is selected so it's really not an issue. I only turn it off if I'm in creeping traffic jams where it tends to stop engaging anyway as (I assume) the battery charge drops below the threshold the ECU thinks is enough to guarantee a restart with no issues.

and a starter used once per journey will last longer than one used half a dozen times a journey

When was the last time you replaced a starter on a car?

Never had a car that started multiple times per journey. And have had faulty starter motors in work vans. So they do break. Pushing a button once to reduce wear on components seems an easy win to me.

If you never start it at all, it'll last even longer.

Except for the wear on piston rings,egr dpf , exhaust , cat , fuel pump , injectors etc etc.

Do you slow down with the clutch to save wear on the brake pads too ?

I replaced a starter motor once. It was 32 years old and ironically what killed it was lack of use rather than over use.

Wether there is an environmental benefit depends on your driving. If you do a lot of stop start driving where you're sat at a minute or two at a atime then it will be beneficial but if not then it will not be.

It dismays me that a feature that reduces pollution can simply be turned off, dunno how the manufacturers get away with it.

Because safety trumps everything. I turn it off when approaching a busy junction. The last thing I want is for the engine to die at the point i need to pull out.

Of course the starters on the cars will be beefed up to support the additional duty. Its a simple engineering problem to solve.

Does the function work better in auto vehicles?

I think it works better in manual cars to be honest. On my partners car it kicks in when stopped and in neutral and then restarts when the clutch is depressed so by the time you've actually selected a gear the engine is running. I prefer it to the way the function on my automatic works.

Surely if you need to get away in 0.1 of a second because Lewis Hamilton is coming round the A414 roundabout and you're only a point ahead of him in the photocopier sales world championship......

You can just put your foot on the clutch to keep the engine running when you're first in the queue?

In my auto (VW) it means I have to keep my foot on the brake - not sure this is nice for people sat behind me, but huh, they're only car drivers 😉
I think the VW one only works when you stop in a certain way, because a lot of the time (it seems more often lately, though I don't really drive much) the little symbol "no stop/start" comes up and the engine stays running. Bit odd. My emissions are low anyway, what with the car sat on the driveway unused.

It's seamless on my manual diesel Outlander.

It only stops the engine if the car is in neutral and your foot is completely off the clutch. The lightest pressure of your foot resting on the clutch is enough to keep the engine running at junctions and roundabouts. It's never stopped unless i've wanted it to.

It also  restarts if you so much as twitch the steering wheel.

the little symbol “no stop/start” comes up and the engine stays running. Bit odd.

That'll be because there's another system running that needs the engine, probably either heating or aircon.

My stop start disables if the cabin temperature isn't close to what is set.

The only car I've driven that had auto stop/start work very well for the way I'd be taught to drive (just like gonefishin describes above).

At the front of the queue? Leave it in gear with clutch down and handbrake on - ready to move away.
Not in the front of the queue? Take it out of gear and handbrake on - engine stops.

Given the queues of traffic standing on their brakes that one passes on their bike, I don't think many people at all drive like this.

Anyway, the stop/start worked ok. I figured the cars were designed for it and why not do just that tiny bit to reduce idling pollution?

All our cars have had Auto Stop/Start for years now. Fantastic invention, should be compulsory fit on all cars.

It dismays me that a feature that reduces pollution can simply be turned off, dunno how the manufacturers get away with it.

There's some evidence that start/ stop increases pollution. This is because it reduces the temperature of the catalytic convertor, leading to increased NOx emissions. The study I read was only for one car mind, so more research is needed.

It works on my Ford, pretty seamlessly, though I don't use it much so sometimes the system isn't available, I assume because the battery isn't fully charged. It comes back to life after a motorway run.

I never switch it off.

In my car it only works when you knock it into neutral, so roundabouts aren't an issue. The only time I would ever use it at a roundabout is if they were light controlled.

The engine has started before the clutch is fully depressed. And as its a nice petrol engine it makes a nice burble when it re-starts rather than sounding like a spanner thrown in a wood chipper

On our second Fiat fitted with it and think it’s great. Always starts quicker than you can depress the clutch so no issues there.

The main frustration is when it doesn’t stop, as noted above. The ECU thinks the battery won’t restart it, or it thinks you’re parking etc. where start/stop would be a minor inconvenience.

It is more pleasant when on the bike and you’re waiting behind a stopped engine.

Is there a generational divide here with a lot of newer tech? I see a lot of older people setting off before belting up - probably as they’ve grown up that way. Even in newer cars where auto handbrakes specifically prevent this, and you have to manually override by holding the foot brake and releasing the electronic handbrake. Why??

did take about 10s for it to restart

That sounds broken. In our Polo I can't beat it restarting however hard I try, as soon as your foot moves the clutch pedal it starts.

My emissions are low anyway, what with the car sat on the driveway unused.

There's a good chance this is linked to it not being activated. If your car sits around the battery is probably a bit low and it will disable itself.

I've never driven an auto with it, but in a manual all the concerns of it not being ready at busy junctions etc just aren't an issue, because you'd sit at the junction with the clutch in ready to pull out. Those that say they cut out at awkward times are they autos?

I don't drive the Polo that often so I do still get confused occasionally that it's gone very quiet because I forget it has it.

Out Kia Ce'ed is an auto with stop/start; works seemlessly, restarts as soon as you start releasing tension on the brake pedal long before your foot reaches the accelerator.

Just to be clear, I'm all for cutting emissions. So it'll get used.

I'm just concerned about longer term reliability and wear issues.

The air-conditioning thing boils down to how cold is it supposed to get...I suppose.
Kids, new toys etc...🙂

setting off before belting up

£60 and a chat to a nice policeman did wonders for breaking that habit for me. He was just at the end of my road.

I "had" to drive a short distance last week without a belt on because it had jammed and wouldn't pull out, felt pretty weird to bit not have it on. (I'm not That Old.

All these people worried about pulling out at roundabouts in a hurry after the stop/start has engaged: Why are you sat in neutral with the car out of gear if you're expecting to pull away at a moments notice?

It's been around for more than a decade now, if it lead to lots of issues down the road I guess we'd know about it by now.

My new (to me) car has it, it's also an auto. If I had to moan than mines a bit too keen, being an auto there's not need to put the handbrake on or anything if you drop below 2mph it cuts, even if you're not actually stopping, which also cuts the power steering, it's not been an issue yet, but moving around parked cars in the supermarket and it's cut out, it's a bit frustrating. On those busy roundabouts when there's a 20 limit and everyone feels the need to do 40 you get used to giving the pedal a bit of a tap to wake it up before you go.

I can't complain too much though, my new car is bigger, faster, auto and 4x4 (it's saloon not an SUV) and yet it's more efficient and less polluting than the last one, which wasn't bad either.

The green yellow orange lights to suggest how you are driving really are rubbish though

This does sound like modern toss..! My '11 plate has no such lights 😆

To those that say “I use it” just pull up to a junction and open your window.

Count that cars that roll up-engine stops-and immediately starts again on tick over for 5mins waiting for the lights to change.

Of the ten cars next to me this morning, 9 cut out and immediately started again.

I personally think the technology is brilliant and should be compulsory on all vehicles, but until Mr/Ms angry 1Series or MrDPDelivery bloke actually uses it.. we’ll continue to burp gas out of vehicles all day long.

if you drop below 2mph it cuts, even if you’re not actually stopping, which also cuts the power steering

that does seem a bit keen - is that how it's supposed to work, cut out every time you pause in a maneuvre?

On my car even trying to turn the wheel will restart the engine, though.

I think the stop start thing is just a gimmick by manufacturers. I could be wrong but doesn’t it use up more fuel stop starting an engine multiple times in a short distance,

Er, you are wrong. Even for a small stop at lights, it helps - I know this because when the battery's low (if I haven't driven for a week or two) or I put the blower on harder when it's just started it doesn't kick in and the fuel economy is worse.

The amount you'll save in fuel over the life of a starter motor will pay for the starter motor. The chances are older starters will fail from general age (corroding to bits etc.) rather than over-use. They are designed and tested for this use after all!

I find even at the front of the lights it's so quick to start I just dip the clutch as the light goes amber and go when it's green. No need to keep the engine running even at the front of a queue. If it's not starting immediately there's probably something up.

Had a 2009 Freelander 2 with it, started only working sporadically a few years in as it decided the battery wasn't 100%, or the ambient temperature wasn't quite right or something. When it did work it was a little annoying because it did not start quickly enough - you had to pause a moment after clutch down - and as I was used to it NOT working I didn't allow the time for it to start... Sold it last year (9 yrs old) with its original battery and original starter, the only think that went wrong on that car was a wheel bearing.

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Got a 2013 golf with it, barely notice it. Starts before clutch down and gear selected.

This had immediate and total battery failure (Moll brand) one day last year (5yrs old). Stopped as usual at a busy junction then just didn't start. No battery juice to run warning flashers or anything.

Had to negotiate someone to stop traffic and help push it out of the way. Not fun. New battery was about £70 from tayna.co.uk

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Mum has a 2015 Skoda Fabia with it. "Low battery" warning strated popping up and it turned stop start off itself last year (3yrs old) Moll brand again. I fitted a new battery to be safe.

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Overall I think its great, why sit there burning fuel polluting the air in traffic jams / queues?

Oh and these batteries weigh a tonne, so get down the local metal merchants and weigh it in for more than a tenner back.

Had SS on my Fiat for 9 years and it worked very well. If the battery is not fully charged it will keep idling or stop then restart after a few seconds but then i do lots of short journeys.

My current car has it too and it works just as well, though I turn it off on short journeys to warm the engine up. (DSG which is awful until everything is warm). Never again.

There’s some evidence that start/ stop increases pollution. This is because it reduces the temperature of the catalytic convertor, leading to increased NOx emissions. The study I read was only for one car mind, so more research is needed.

That's generally not true, especially in diesels - the flow of (relatively) cold exhaust gas at idle will transport heat out of a catalyst whereas engine off the thermal inertia in the cat with no gas flow will keep it hot. Some gasolines there is maybe an ounce of truth if the catalyst hasn't fully lit off, but stop/start will be inhibited during initial catalyst heating anyway so is a non issue.

Stop/start is a very mature feature with plenty of solid engineering around it - no reason to not use it.

The 'safety' concerns are just a non-thing: usually stemming from 'i pull up to a roundabout and it cuts out just as I need to pull out quickly' - if you NEED to pull out that quickly it's probably not safe to do so anyway, just be patient or plan further ahead.

Had it in various manual and auto cars, always liked it. Current one is a 6 year old Octavia, press break fully and the engine is off, lift slightly (e.g. getting ready to move at a roundabout) and it starts again so you’re ready to go. Nice n simple (and doesn’t take a fictional 10 seconds)

if you drop below 2mph it cuts, even if you’re not actually stopping, which also cuts the power steering

that does seem a bit keen – is that how it’s supposed to work, cut out every time you pause in a maneuvre?

I'm not sure, it's a bit too clever for it's own good sometimes. If you're travelling at say 30mph and start braking (especially if it 'sees' a car in front) it'll assume you're coming to a stop and cut (below 1 or 2mph) and 90% of the time it's right. But sometimes if say you're making your way through a busy road with car either and you have to take your turn waiting to go etc, sometimes just as you're shuffling through it'll cut, restart is about a second but there that little moment when you're still moving (very slowly) when you suddenly can't steer.

It's supposedly adaptive, either I'm adapting to it, or it to me, but this sort of stuff is happening less and less.

if you drop below 2mph it cuts, even if you’re not actually stopping, which also cuts the power steering

that does seem a bit keen – is that how it’s supposed to work, cut out every time you pause in a maneuvre?

On my car even trying to turn the wheel will restart the engine, though.

Most systems these days will cut out just before a stop if your deceleration gradient is low enough. It does help to save a fraction more CO2 and modern engines start so quickly you usually won't notice any difference ( although as mentioned above my DSG golf didn't like it when the transmission was cold...)

Cars with hydraulic power steering will generally restart if the wheel is turned greater than a certain angle, or at a fast rate of turn; this is because the engine is needed to supply the required PAS pressure. It can happen with cars with ePAS as well but generally to a lesser extent unless the battery voltage is low.

Apologies if this has been done many times.

It has.

I could be wrong

You are. I can't remember offhand the exact time where you have a net gain in start/stop over keeping the engine running, but it's in the order of a few seconds.

Stop/start is a mature technology and a lot of companies have invested a great deal of money into its research and engineering. Don't you think that someone, somewhere might've considered any potential extra wear to a starter motor / battery and compensated for that? The last time I had to replace a starter motor was in a 1977 Ford Fiesta. You don't want to "wear out" the starter motor, so you'll take additional wear on pretty much every other component in the engine instead? Bunch of luddites on this forum, I tell you. (-:

Neat thing on mine that I only noticed after about a year of ownership: the start/stop is tied in to the front parking / adaptive cruise control sensors. Stopped in traffic, if it sees the car in front move away it'll start the engine, I don't even need to go anywhere near the clutch.

Oh yeah, and,

Nice n simple (and doesn’t take a fictional 10 seconds)

If it's taking 10 seconds to start, it's broken.

That’s generally not true, especially in diesels – the flow of (relatively) cold exhaust gas at idle will transport heat out of a catalyst whereas engine off the thermal inertia in the cat with no gas flow will keep it hot. Some gasolines there is maybe an ounce of truth if the catalyst hasn’t fully lit off, but stop/start will be inhibited during initial catalyst heating anyway so is a non issue.

I was reporting on results from actually measuring exhaust gas emissions, so I wouldn't dismiss it as a non-issue. As I said, this was a single sample, so some further research is needed.

Works fine on my Passat and I'm pretty sure it improves economy (if only slightly) and of course it reduces fumes from stationary vehicles (well every little helps). My only criticism is that it doesn't work when tow bar electrics are attached (even for a bike rack).

I was reporting on results from actually measuring exhaust gas emissions, so I wouldn’t dismiss it as a non-issue. As I said, this was a single sample, so some further research is needed.

My day-job is calibrating car engine ECUs and although this is always a consideration, it almost always is a non-issue. There is always far more trouble with too-cold exhaust gas flowing through a catalyst cooling it down than heat lost from long stop-start periods. Once a catalyst is properly lit off then the thermal inertia is high enough that with no gas flowing through it will stay at temperature. Stop/start systems will generally restart the engine after a couple of minutes and the temperature lost during that time will be a small handful of degrees and then drop much more considerably when the engine is running. As mentioned, this is especially true for diesels where the idle exhaust temperature is very low, whilst a gasoline exhaust gas at idle is generally hot enough to not cool the catalysts too much.

The above isn't meant as an 'i'm right, you're wrong' - as you say it is just one report and in the report circumstances it may be true, but from experience of doing this as a job, the temp drop during stop/start is not an issue and vastly outweighed by the fact you aren't producing any emissions at all when the engine is off.

Stop/start is a mature technology and a lot of companies have invested a great deal of money into its research and engineering. Don’t you think that someone, somewhere might’ve considered any potential extra wear to a starter motor / battery and compensated for that?

And yet they continue to get it wrong. DMF, DPF, fuel injection systems classed as disposable etc.

And despite what anyone says, I'm still not sure how turning an engine on and off, particularly at lower temps can be any good for it?

I'm happy to be proved wrong,

You don’t want to “wear out” the starter motor, so you’ll take additional wear on pretty much every other component in the engine instead? Bunch of luddites on this forum, I tell you. (-:

No, I'd rather understand the consequences of half a million additional engine starts.

Its not about whats good for the engine, but they do test and design to mitigate , if you cant be convinced by the by the knowledgeable and in-industry posts above then perhaps save a couple of quid a month for the death in service starter motor , BTW they have changed in design since the old Fiesta so can cost a bit more now.

Did I miss the half a million additional starts?

Say 20 year engine life is about 68 starts every day. Is that what people are seeing?

And despite what anyone says, I’m still not sure how turning an engine on and off, particularly at lower temps can be any good for it?

Nor am I, but my lack of understanding doesn't mean it must be bad.

Say 20 year engine life is about 68 starts every day. Is that what people are seeing?

My commute on it's own has well over 60 (both ways - town, motorway, minor roads.

Nor am I, but my lack of understanding doesn’t mean it must be bad

I didn't say that. 🙂

Everything has advantages and disadvantages.
I am interested in how, in engineering terms, things have been improved.

Every day for 20 years?

Stop start engines will also have auxiliary systems designed to prevent the additional wear that accompanies constantly starting the engine up. These could include: secondary electric coolant and / or oil pumps, roller cam followers, water jacket cooled turbos.

There’s also the control software which will only engage stop/start when the engine is sufficiently warm, when the battery is above a certain charge status and when high power consumers are not required, such as heated windows, window demisting or cooling of the cabin or power steering assistance. There’s a load of thought gone into it. Shame the system on my kodiaq constantly engages just before the car comes to a halt then disengages as soon as you release the brake pedal (it’s an auto handbrake).

Stop start engines will also have auxiliary systems designed to prevent the additional wear that accompanies constantly starting the engine up. These could include: secondary electric coolant and / or oil pumps, roller cam followers, water jacket cooled turbos.

There’s also the control software which will only engage stop/start when the engine is sufficiently warm, when the battery is above a certain charge status and when high power consumers are not required, such as heated windows, window demisting or cooling of the cabin or power steering assistance. There’s a load of thought gone into it.

Absolutely - the strategy to determine when a vehicle is allowed to stop/start is pretty complex and it's not allowed if it will impact any systems that reduce emissions (e.g. during catalyst heating phases) or if ambient or engine conditions are outside of certain ranges, etc.

And despite what anyone says, I’m still not sure how turning an engine on and off, particularly at lower temps can be any good for it?

Engines really aren't that fragile. Some of the robustness tests we do are absolutely brutal and a well designed engine will survive hundreds of continuous hours of this sort of testing. Even the notion of having to 'break in' an engine isn't really a thing any more for a non-high performance car.

Thanks. 🙂

Our car (diesel Skoda Roomster) is now ten years old and while it doesn't have stop/start I can't honestly remember if it was even an option on our particular model at the time. I'm not sure how much use it would have had in that time as we live in a rural location and do very little urban driving. If the next car has it, then it has it.

Car manufacturers have a lot of data on how their cars get used so the whole starter system will have been engineered with X cycles in mind plus some contingency.

As above - I can't remember the last time I had a starter motor replaced and most of my cars have had at least 150,000 miles on the clock. Possibly the Vauxhall Cavalier I sold on in around 1995.

https://www.autocar.co.uk/car-news/new-cars/stop-start-long-term-impact-your-car-s-engine

For those turning it off, your car and it’s starter motor and battery were sized to deal with start/stop, so you’ve paid more for a more robust battery and starter and are no longer reaping the rewards of its intended purpose - to increase your fuel economy.

I wouldn't worry. Long before 2029 you won't be allowed to drive an ICE car in many built up areas anyway.

Start / stop is seamless in my EV.

The ‘safety’ concerns are just a non-thing: usually stemming from ‘i pull up to a roundabout and it cuts out just as I need to pull out quickly’ – if you NEED to pull out that quickly it’s probably not safe to do so anyway, just be patient or plan further ahead.

True in the ideal world, but we're humans and make largely emotional decisions rather than logical ones so common sense like this doesn't always play out...just like that impatient person who NEEDS to pull out into the outside lane of the motorway as soon as they join it only to get to the car in front a few seconds earlier...that impatient cyclist who runs the red light because they can't be bothered to stop or are chasing the Strava time, just like the person who just has to read that text when the notification sounds and, despite all their knowledge and understanding, pick up the phone to take a look. And in my case my concern is not me not making the gap in the traffic I wanted to accelerate into, its the person behind me thinking i'm about to go, who is looking right and is not expecting me to hesitate at the junction and rear ends me and shunts me out into the junctions. It happens every single day at roundabouts and junctions - one of the most common types of crashes. I just disable the stop start when approaching the busy junction and re-enable it once I've pulled out. All goes nice and smoothly then.

Mazda have a cool system for this. It leaves the pistons in exactly the right place so the engine can restart in half the time of other companies systems.
https://www.mazda.com/en/innovation/technology/env/i-stop/

My son is just getting used to his new 1.2 TSI Fabia Monte Carlo (learnt in a Diesel Audi A1), so has stalled a couple of times as the diesel needed next to no gas on clutch up. The stop start has actually restarted the car before you have had time to think 'Oh I've stalled'.

As a cyclist and pedestrian I appreciate the engines going dead and the fumes stopping for a while while I wait behind or next to the vehicle at lights. Good idea.

That Mazda istop tech is stunning. Proper out of the box thinking.

Some of the robustness tests we do are absolutely brutal and a well designed engine will survive hundreds of continuous hours of this sort of testing.

Mate of mine tells tales of mis-programming engine dynos for overnight runs: once they found the dyno parked in the office above the test room after accidentally telling it to hard stop a locomotive engine. Engine was having none of it. They did the same with a very expensive prototype flat plane v8. Dyno won that one. They didn’t let on to their error and the manufacturer went away and re-designed the crank.

are no longer reaping the rewards of its intended purpose – to increase your fuel economy.

... to reduce emissions.

and is not expecting me to hesitate at the junction and rear ends me and shunts me out into the junctions. It happens every single day at roundabouts and junctions

I've driven start/stop vehicles on and off for maybe a decade and this has never happened to me. If it's causing problems of this nature then there's something very wrong with either the car or your driving. I've had it cut out at the wrong time a handful of times, generally when I'm about to stop and then the lights change or some such, but it restarts so quickly that it's always been a non-issue.