General Usefulness Of Start/Stop

[MN500]

They are the biggest cause of traffic hold ups. I love the way I'm half way to the next lights by the time the stop/start next to me has even moved, but hate when I'm behind one and you wait and wait and then finally they pull off. I doubt it has any fuel saving credentials at all.
Then there's lane assist another pointless addition to a car on a normal road, my daughter hired a almost new golf the other week. Didn't know it had lane assist.
Whilst trying to overtake a cyclist it nearly diverted here into it, frightened the life out of her. I had to work out how to turn it off so she could do it before every trip, pointless.

Your daughter ought to have indicated, after effective observations, to inform other road users including the cyclist who may glance behind, that she was about to overtake (I do assume the cyclist was proceeding). The lane departure assist wouldn't then activate diverting her towards them, and other road users would be aware of her intentions. I do appreciate the annoyance of the system when passing parked vehicles where an indication after observations isn't required.

 

[A3jeroen]

Usually lane departure systems start working if the speed is over 60 Km/h. And yes. Using the indicator as supposed means the system knows you don't go over the line accidentally.

gr J

 

[StevenRB45]

They are the biggest cause of traffic hold ups. I love the way I'm half way to the next lights by the time the stop/start next to me has even moved, but hate when I'm behind one and you wait and wait and then finally they pull off. I doubt it has any fuel saving credentials at all.

Observation is overrated in the modern era..

Nothing to do with Stop/Start just people on their phone if you're sitting in a stop/start car and the light starts to change then putting your foot on the clutch to pull away starts the engine before you can put it in gear. No reason to be left at the lights at all unless you're not looking at them. When I've driven autos braking to a stop killed the engine, releasing the brake started it.

Re. Fuel saving..

 

[rmjbn1]

Well found that man!
Good vid, with citations for scientific studies.
So about 7 seconds seems to be break-even. Good to know

 

[The Panda Nut]

They are the biggest cause of traffic hold ups. I love the way I'm half way to the next lights by the time the stop/start next to me has even moved, but hate when I'm behind one and you wait and wait and then finally they pull off. I doubt it has any fuel saving credentials at all.
Then there's lane assist another pointless addition to a car on a normal road, my daughter hired a almost new golf the other week. Didn't know it had lane assist.
Whilst trying to overtake a cyclist it nearly diverted here into it, frightened the life out of her. I had to work out how to turn it off so she could do it before every trip, pointless.

Years ago when SS was new, I experimented with my 2.2 Renault diesel. It made a 6 mpg improvement stopping the non SS engine on my 15 mile commute, with a little city running. However the engine needed to be stopped more than 30 seconds or mpg was worse when stopping and starting. SS Should give some advantage. My Panda TA SS has worked ok for 6 years. I only switch off in creeping traffic and now dont notice it. The car is ready to go by the time the clutch is at biting point. The aim of SS is city smog reduction and health benefits more than economy.

 

[StevenRB45]

Years ago when SS was new, I experimented with my 2.2 Renault diesel. It made a 6 mpg improvement stopping the non SS engine on my 15 mile commute, with a little city running. However the engine needed to be stopped more than 30 seconds or mpg was worse when stopping and starting. SS Should give some advantage. My Panda TA SS has worked ok for 6 years. I only switch off in creeping traffic and now dont notice it. The car is ready to go by the time the clutch is at biting point. The aim of SS is city smog reduction and health benefits more than economy.

I think you may have stacked the deck against stop start a bit there.

A big diesel takes a lot of electricity to get started so although you are saving fuel not idling after switching back on the electrical draw (so ancillary drag) would be higher due to the requirement of replenishing the battery while moving at low speed.

If you skip to 1 minute on this...



Apologies to those who have seen it in LL recently.

The engine is specifically stopped mid way up a compression stroke, so starter moves it quarter of turn before the ignition stroke happens.

Also it's 1.2 petrol so much less electrical load than churning over a 2.2.

There are Mazda engines that don't use the starter at all and just stop the piston at the top of the compression stroke and restart simply by firing the spark plug.

It's one of those things the tech not just a beefed up starter and battery if done properly.

Oh and just in case anyone was wondering...the Stop start in the Citroën sprang back to life yesterday after 2 weeks of semi regular use after standing for so long it was wouldn't let me put the radio on engine off in case I flattened the battery.

Because like most purpose built systems...it has a smart alternator that can charge at more than 14.4v if needed to condition the battery..or in this case the capacitor. Once they were both topped back up the 8 year old system sprang to life.

 

[The Panda Nut]

I always wonder what the break-even point is for there to be a net gain in fuel consumption and emissions?

As in, how long does an engine need to be off, to counter the extra fuel used on start-up and to recharge the battery?

I've heard 20 seconds mentioned, but never seen any sources or studies to support this.

(Plus then the extra emissions to manufacture & dispose of all them consumable DMFs ⁹

I think you may have stacked the deck against stop start a hit there.

A big diesel takes a lot of electricity to get started so although you are saving fuel not idling after switching back on the electrical draw (so ancillary drag) would be higher due to the requirement of replenishing the battery while moving at low speed.

If you skip to 1 minute on this...



Apologies to those who have seen it in LL recently.

The engine is specifically stopped mid way up a compression stroke, so starter moves it quarter of turn before the ignition stroke happens.

Also it's 1.2 petrol so much less electrical load then churning over a 2.2.

There are Mazda engines that don't use the starter at all and just stop the piston at the top of the compression stroke and restart simply by firing the spark plug.

It's one of those things the tech not just a beefed up starter and battery if done properly.

Oh and just in case anyone was wondering...the Stop start in the Citroën sprang back to life yesterday after 2 weeks of semi regular use after standing for so long it was wouldn't let me put the radio on engine off in case I flattened the battery.

Because like most purpose built systems...it has a smart alternator than can charge at more than 14.4v if needed to condition the battery..or in this case the capacitor. Once they were both topped back up the 8 ye

Yes agreed, and it was a crude test and being a bigger diesel starting must need more effort but the 6mpg was a definite. After finding out I used to turn it off more often when I could see it would be a while before moving again. It took moths of messing about to establish this Im happy to leave myn stop start to do its thing although the gains may be insignificant to me.

 

[Didge3]

I will just add to this the worst experience of S/S I've ever had which I'd totally forgotten about. It was in a 2022 Vauxhall Mokka courtesy car, I think the only reason it was terrible was due to it being an automatic.
It would cut out when at a stop with your foot on the brake, lights go green, foot off the brake, nothing happens, foot on accelerator, about a 1 second delay and then the engine starts and immediately lurches forward.
A) This is far from smooth
B) In low speed manouvering or slow moving traffic this is almost dangerous, applying even the smallest amount of throttle once the engine has cut out causes it to start and lurch forward quite aggressively.
I'm sure the system works fine in a manual where I imagine its triggered by the clutch and not the throttle.

 

[StevenRB45]

An Automatic with stop start without hybrid power is generally just awful.

It has no way of knowing if each stop is for a second or a minute.

Driven 2 one was a Transit...this was just plain awful for reasons similar to the Mokka. Although it at least started the engine when you took your foot off the brake. It still meant to had to sit foot on the brake like an absolute hoop if you wanted stop start though.

The other was a Yaris hybrid, in many ways it drove like an electric car with an occasional random engine sound from time to time.

Thankfully the Mokka drivetrain is dead and has been replaced by a hybrid that can move off on electricity alone. Given it's the same engine as the C3 in the Mokka can confirm with manual box it's fine..

 

[ZaphodB]

For people who want to ease the misery of SS on an auto, you'll find if you're stopped at lights, instead of suddenly lifting off the brake, shortly before lights go green, lift off the pedal pressure gently (but still with the brakes applied), you'll find the engine will start up on most of them.

 

[GettinBetter]

@StevenRB45 Good post #23

While the results of this video may or may not be perfect, I feel it is pretty close.

So, of late, I have been trying to get better MPG as my heavy footed driving is drinking fuel, and while I don't mind that occassionally, my trips to the petrol station need curbing.

In this respect, I have hit the ECO button and activated the Start/Stop (SS) feature.

My biggest bone of contention with SS, is that it will often stop for only a few seconds before traffic moves and you need to get going again.
So IMO a diffent style of driving is needed when using SS.

One has to decide by reading the traffic, whether the flow is about to stop, and how long for.

I personally rounded the time needed to justify stopping the engine to 10 seconds, so If I estimate the traffic is NOT going to stop in excess of 10 seconds, I keep the clutch depressed, (or employ the methods below).

For instance if you are approaching a set of traffic lights, and they have been red for some time (especially if you are familiar with the area) you will know they are about to change (and you won't get your 10 seconds).

Also (particularly in temp roadworks lights) a long queue of traffic builds up, and only the vehicles quite close to the lights actually stop, the rest just constantly crawl along moving a few meters at a time, and constantly stoping and then moving again. In this senario, I tend to drop back and choose a suitable gear that allows me to let the engine idle at the average speed of the crawling traffic. This means I don't have to keep my foot on the clutch, I don't have to keep stopping and moving off again, the SS won't keep activating every few seconds.

I still can't get MPG above 54......

 

[Greasytrucker]

@StevenRB45 Good post #23

While the results of this video may or may not be perfect, I feel it is pretty close.

So, of late, I have been trying to get better MPG as my heavy footed driving is drinking fuel, and while I don't mind that occassionally, my trips to the petrol station need curbing.

In this respect, I have hit the ECO button and activated the Start/Stop (SS) feature.

My biggest bone of contention with SS, is that it will often stop for only a few seconds before traffic moves and you need to get going again.
So IMO a diffent style of driving is needed when using SS.

One has to decide by reading the traffic, whether the flow is about to stop, and how long for.

I personally rounded the time needed to justify stopping the engine to 10 seconds, so If I estimate the traffic is NOT going to stop in excess of 10 seconds, I keep the clutch depressed, (or employ the methods below).

For instance if you are approaching a set of traffic lights, and they have been red for some time (especially if you are familiar with the area) you will know they are about to change (and you won't get your 10 seconds).

Also (particularly in temp roadworks lights) a long queue of traffic builds up, and only the vehicles quite close to the lights actually stop, the rest just constantly crawl along moving a few meters at a time, and constantly stoping and then moving again. In this senario, I tend to drop back and choose a suitable gear that allows me to let the engine idle at the average speed of the crawling traffic. This means I don't have to keep my foot on the clutch, I don't have to keep stopping and moving off again, the SS won't keep activating every few seconds.

I still can't get MPG above 54......

I don’t think 54mpg is to be sniffed at for any petrol engine really

 

[The Panda Nut]

My stop start has started playing up and after checking it seems my battery is no longer at full health. I will change it before the winter. EVerything else is normal at the moment but it only gets to 3/4 charge after a prolonged charge. CAr is 6 years and 1 month old with 27K on the clock.

 

[GettinBetter]

I don’t think 54mpg is to be sniffed at for any petrol engine really

Well TBH, I would say 52'ish is more realistic, as it goes down when I start off in the morning with a cold engine, and then also drops when doing some hills, but on the flat I can get the MPG back up again. So assuming the fuel tank is 35ltrs I can get ~400 miles per tank, which is a magic number for me.

The downside is that driving like a geriatric is hard work, so the 400 miles may never actually materialise.

My stop start has started playing up and after checking it seems my battery is no longer at full health. I will change it before the winter. EVerything else is normal at the moment but it only gets to 3/4 charge after a prolonged charge. CAr is 6 years and 1 month old with 27K on the clock.

It happens, and 6yrs is a reasonable lifespan for a battery, so theoretically you're just replacing a consumerable item.

 

[Piccolo Nero e Bella]

My stop start has started playing up and after checking it seems my battery is no longer at full health. I will change it before the winter. EVerything else is normal at the moment but it only gets to 3/4 charge after a prolonged charge. CAr is 6 years and 1 month old with 27K on the clock.

Coincidentally we're well into winter here now (though you folks might be unimpressed) and I ran my S/S while on a drive yesterday to check its performance. Restarts, with a thoroughly warm engine, occurred between 45 and sixty seconds every time so the 8yo EFB has somewhat declined. As it turned out I was passing the shop where I bought it so I pulled in and checked out a replacement. Last time it took three weeks of research and the intervention of the Australasian head of sales of the battery company to identify and source the correct battery - this time there were two options sitting on the shelf! I chose the Varta N60, the more expensive choice (Varta were not even an option back in 2017...) for $339 (about £162) installed - and that was on 'special'.

Relatively expensive I don't doubt but in OZ you can't be too picky. If it's as good as they're claiming I won't be too fussed by that!

The 'old' battery will go on the gates with the trickle charger as its still got plenty of life.

 

[steveras57]

Coincidentally we're well into winter here now (though you folks might be unimpressed) and I ran my S/S while on a drive yesterday to check its performance. Restarts, with a thoroughly warm engine, occurred between 45 and sixty seconds every time so the 8yo EFB has somewhat declined. As it turned out I was passing the shop where I bought it so I pulled in and checked out a replacement. Last time it took three weeks of research and the intervention of the Australasian head of sales of the battery company to identify and source the correct battery - this time there were two options sitting on the shelf! I chose the Varta N60, the more expensive choice (Varta were not even an option back in 2017...) for $339 (about £162) installed - and that was on 'special'.

Relatively expensive I don't doubt but in OZ you can't be too picky. If it's as good as they're claiming I won't be too fussed by that!

The 'old' battery will go on the gates with the trickle charger as its still got plenty of life.

surprised there aint a solar panel in every car roof in oz!

 

[Pugglt Auld Jock]

I've never had one where it didn't idle forever with the clutch down. The VW dsg ones seem mildly hilarious I do cringe somewhat when you hear them stop the car for a quarter of a second because you've come to halt behind someone turning right. In theory they designed for it but in practice that feels plain abusive.

Handbrake on is new on me as long as clutch is up both Toyota and Citroën stop even if you're on the footbrake. To be fair that is terrible practice but they do.

I think as with most things there are good and bad implementations, the Toyota one as you'd expect is absolutely spot on given their history in hybrid cars. Engine stop and start is instant and without any noise or vibration or flare in revs it's just suddenly at idle rpm before you've pressed the clutch to the floor. Citroën less so, the dmf (Toyota has a solid flywheel as it's a 4 pot) and the general feel is a bit agricultural and vibratey you can also hear the starter and there's times it's re-engaged the starter before fully disengaging it which sounds as awful as you'd expect.

Both do the job though...and also both have an electric coolant pump as well as standard water pump so cooking the turbo while stationary is not really a thing. Most things have them so your heater doesn't stop working as otherwise the coolant in the heat exchanger could lose all heat if you stopped for a few minutes.

Also both work after 8 years on the original battery...I say this the Citroën one currently doesn't but it's done 200 miles across about 5 days since march so the battery is crying somewhat once it's back in regular use I expect it to live again.

Re. Another line of conversation apparently the break even point is about 7 seconds re. Switching off or leaving it running. Given I've had both cars on S/S at various times for up to 5 minutes they must be saving something. Think it was engineering explained that came up with this figure by comparing idle fuel use to fuel needed to start an engine.

This is probably less on something like the Toyota where it only stops the piston in the correct place to restart and uses a reduced fuel pulse on initial fire for S/S.

Lane keeping assist? I first came across this in a rented car when visiting my daughter in the States. Didn't know you could turn it off at that time. Initially I thought it was pretty good as I found it would follow the lanes on the interstate or other multi lane highways without me even holding onto the steering wheel - that is until it didn't and gave me one hell of a shock when I almost sideswiped a big truck. On smaller country roads with variable quality marking lines I just found it a nuisance. It would tug and pull unexpectedly at the wheel. Still don't like it now my Scala has it so I just switch it off every time I start the engine. I was interested to read an article the other day suggesting the insurance companies are looking at what this may legally entitle them to do with regard to nullifying insurance if you willingly cancel a driver assist system?

Stop/start? Hmm? I'm not that convinced it saves the planet by much unless you're standing in unmoving traffic for some time - in which case, historically, I would have turned my engine off anyway. The argument around starter motors is a two pronged one in my opinion. If the setup is one with a dynamotor - where the alternator operates as a generator of electricity when running normally and as a starter motor in a start stop situation - then why not? However, if you have a traditional pre engaged starter type motor then, although they say they've "beefed" then up so cope, the increased wear and tear on the starter motor, pinion gear, and ring gear teeth is bound to be a factor. Another thing I notice with my 3 cylinder engine is that I think the flywheel is quite heavy and keeps the engine turning over for a few revs after the ignition is killed. In situations where stop start kicks in but then immediately tries to restart, for instance approaching a T junction where I think I'm going to have to stop but then realise there's enough of a traffic gap to go. The starter can kick in before the engine has completely stopped rotating and you can hear it clash with the ring gear. I've pointed it out and demonstrated it to the dealer and all they say is I'm asking it to do something it's not designed to do.

A big "thing" is made about the necessity of using an EFB or AGM type battery with stop/start systems and it would seem true that a standard "wet flooded" battery can't take the increase in duty cycle implicit with stop start and will fail early if fitted to a stop/start engine. I've no experience of AGM batteries, and avoid them anyway due to the cost and the fact I've never owned a car where one is specified. However I'm increasingly coming across the EFB type and one "feature" is becoming quite clear. Whereas the old Wet Flooded batteries would tend to give you quite a bit of warning that they were failing, often struggling on for months just, and no more, enabling a start, these EFBs seem to "fall off a cliff" when they expire. Like one day they spin the engine quite, or reasonably normally and the next they won't do more than "flutter" the solenoid. This was one of the main factors prompting me to buy my new Super capacitor Jump Starter.

For me though, there's one very big, but to most people invisible, "Elephant in the room". It's the turbo. Many more modern vehicles now have small turbocharged engines - won't get into why here - and turbos need "loving care" if they are to last. The central shaft - spindle - and the turbine blades in each end, if the engine is pulling quite hard, say going up a steep hill, will be turning at maybe 200,000 rpm, some of the latest smaller one's do even more than that. For comparison, your car's engine is going absolutely flat out at around 6,000 rpm! The actual speed is almost irrelevant, we just need to know they are going almost unbelievably fast! The central spindle is a solid one piece shaft and runs in plain bushed bearings - not ball races on the ones I've seen anyway - with dedicated oil seals at either end. The whole thing gets astronomically hot too as one side runs directly in the gasses exhausting from the engine. This heat transfers along the shaft and all that's keeping it under control is the supply of oil being pumped to the bearings. Some turbos now have water cooled cases - my Scala has one, even has a secondary electric water pump which pumps coolant round the turbo casing when the engine stops - but this doesn't cool the shaft or turbine blades, it's the oil flowing in and out which does that. So every time you stop the engine rotating the oil supply stops being pumped around and the shaft, being so hot, starts to carburise the oil next to it. This can block oil supply holes etc and allow the oil film between the shaft and bushes to break down allowing metal to metal contact. This might not seem too big an issue until you think about the spindle, spinning away at maybe 80,000 rpm even at tickover, could take 5 minutes or so to spin down to a stop after the engine has been switched off! All that time it's going to be relying on just the oil remaining in the casing and getting "super hot" probably far exceeding the temperatures it's designed to provide lubrication in. There's other stuff we could mention too, but this heat problem is the "biggy" so I just cancel stop/start every time I fire the engine up. These water cooled turbos do have one small advantage which is that, due to the water continuing to circulate after engine shut down - due to the electric supplementary water pump - they do cool down more quickly than the older type with no water cooling. One thing I've always done though, and will continue to do, is, if I've been running at speed on the motorway, or anywhere where the turbo has been working hard, and I need to pull over - so, for instance, cruising down the motorway at 70 for a couple of hours and then pulling into services - I will let the engine idle for some time, a number of minutes minimum, Usually however long it takes us to have our cup of tea on one of the Devon trips we do, and during that time the turbine on the inlet side is having cold air drawn over it and the exhaust gasses on the exhaust side will be nothing like as hot as when the engine is working to move the vehicle so heat will be drawn quite quickly out of the central core of the turbo which helps the oil enormously when you do finally kill the motor.

One final word on this. If you're engine has a turbo, don't even consider going with extended service intervals. Turbos are VERY hard on your engine's oil and breaks it down as fast as any other component in the engine. Also they are very intolerant of even the smallest bits of dirt. A new filter and change of oil - and only the highest quality oil to manufacturer spec - at least once a year or every 10,000 miles, sooner on some - is the way to go.

If this subject interests you there's loads of stuff on the web but here's a couple of "tasty bites" to get you started: https://www.turbochargersplus.com/turbocharger-oil-why-its-so-important/#:~:text=1) Oil cools the turbocharger,shaft, journal & thrust bearings. and this one: https://www.garrettmotion.com/knowl.../the-turbocharger-oil-and-gas-sealing-system/

 

[GettinBetter]

... For me though, there's one very big, but to most people invisible, "Elephant in the room". It's the turbo. Many more modern vehicles now have small turbocharged engines - won't get into why here - and turbos need "loving care" if they are to last. The central shaft - spindle - and the turbine blades in each end, if the engine is pulling quite hard, say going up a steep hill, will be turning at maybe 200,000 rpm, some of the latest smaller one's do even more than that. For comparison, your car's engine is going absolutely flat out at around 6,000 rpm! The actual speed is almost irrelevant, we just need to know they are going almost unbelievably fast! The central spindle is a solid one piece shaft and runs in plain bushed bearings - not ball races on the ones I've seen anyway - with dedicated oil seals at either end. The whole thing gets astronomically hot too as one side runs directly in the gasses exhausting from the engine. This heat transfers along the shaft and all that's keeping it under control is the supply of oil being pumped to the bearings. Some turbos now have water cooled cases - my Scala has one, even has a secondary electric water pump which pumps coolant round the turbo casing when the engine stops - but this doesn't cool the shaft or turbine blades, it's the oil flowing in and out which does that. So every time you stop the engine rotating the oil supply stops being pumped around and the shaft, being so hot, starts to carburise the oil next to it. This can block oil supply holes etc and allow the oil film between the shaft and bushes to break down allowing metal to metal contact. This might not seem too big an issue until you think about the spindle, spinning away at maybe 80,000 rpm, could take 5 minutes or so to spin down to a stop after the engine has been switched off! All that time it's going to be relying on just the oil remaining in the casing and getting "super hot" probably far exceeding the temperatures it's designed to provide lubrication in. There's other stuff we could mention too, but this heat problem is the "biggy" so I just cancel stop/start every time I fire the engine up. These water cooled turbos do have one small advantage which is that, due to the water continuing to circulate after engine shut down - due to the electric supplementary water pump - they do cool down more quickly than the older type with no water cooling. One thing I've always done though, and will continue to do, is, if I've been running at speed on the motorway, or anywhere where the turbo has been working hard, and I need to pull over - so, for instance, cruising down the motorway at 70 for a couple of hours and then pulling into services - I will let the engine idle for some time, a number of minutes minimum, Usually however long it takes us to have our cup of tea on one of the Devon trips we do, and during that time the turbine on the inlet side is having cold air drawn over it and the exhaust gasses on the exhaust side will be nothing like as hot as when the engine is working to move the vehicle so heat will be drawn quite quickly out of the central core of the turbo which helps the oil enormously when you do finally kill the motor.

I can add to this... firstly I totally agree, and do exactly the same for the following reasons.

Firstly I used to own a 7 seater Volvo back when the family was young, and after about an hour or so on the motorway (at speed) I had a core plug go on the side of the block, which promptly ejected the total contents of the coolant onto and round the engines sending a large cloud of water vapour into the car almost rendering visiblity to zero, I managed to get from the outside lane to the hard shoulder and stop in one piece. Jumped out of the car and opened the bonnet to inspect the damage, and was greeted by a vision I had never expected, and I will never forget. The turbo was not just red hot but almost white hot, something I would never have believed if I had not seen it.

Secondly, as a workshop machinist, with my own company I was asked to produce turbo bearings for a company in Christchurch, , the customer used to issue a special exotic material which I cannot remember the makeup of, but was no ordinary material, the ID & OD machining limits were extremely tight and we used a technique called burnishing and there were 6 holes from the OD through to the ID, to allow oil flow. The conversations with the client allowed me to understand the complexity and importance of adhering to stringent manufacturing limits.

With this knowledge I was able to strip and rebuild the turbo on the Volvo, as the heat had cooked the oil, and hence it was pick up by the recovery truck, and starting was never attempted untill the turbo was rebuilt.

I rarely leave the engine running these day, but prefer to drive gently prior to any motorway stops, or arrival at my destinations, as I too feel the water and oil feeds are not quite enough for my liking.

 

[StevenRB45]

I re. Turbo rpm think it's probably fine...

They "can" spin very fast but in reality unless the preceding manoeuvre was a hand brake turn into the stop after an autocross run usually it'll have been cruising off boost waste gate open down to a stop.

I'd be reasonably willing to bet between the cooled case and also the cooled exhaust manifolds that are the way these days the turbo doesn't run anywhere near as hot as they did when solely oil/air cooled.

Even cruising for long distances on the cruise control at 70 unless you're going up a long hill then immediately switch it off having screeched to a halt I'd be surprised if it caused issues. Once at a cruise it takes very little horsepower (and so boost) to maintain it and there's plenty of air flow for cooling. If anything downsized engines rely on this to generate good fuel economy.

Given nearly everything has a turbo now if it was causing issues I feel as though you'd see far more issues than you do. Very few people bother to baby turbo cars, and yet it is very rare to see the blue plume on lift off associated with failed turbo seals or even blue smoke. It's far rarer these days to see cars trailing blue at all than it was in the 80s and 90s.

 

[The Panda Nut]

I can add to this... firstly I totally agree, and do exactly the same for the following reasons.

Firstly I used to own a 7 seater Volvo back when the family was young, and after about an hour or so on the motorway (at speed) I had a core plug go on the side of the block, which promptly ejected the total contents of the coolant onto and round the engines sending a large cloud of water vapour into the car almost rendering visiblity to zero, I managed to get from the outside lane to the hard shoulder and stop in one piece. Jumped out of the car and opened the bonnet to inspect the damage, and was greeted by a vision I had never expected, and I will never forget. The turbo was not just red hot but almost white hot, something I would never have believed if I had not seen it.

Secondly, as a workshop machinist, with my own company I was asked to produce turbo bearings for a company in Christchurch, , the customer used to issue a special exotic material which I cannot remember the makeup of, but was no ordinary material, the ID & OD machining limits were extremely tight and we used a technique called burnishing and there were 6 holes from the OD through to the ID, to allow oil flow. The conversations with the client allowed me to understand the complexity and importance of adhering to stringent manufacturing limits.

With this knowledge I was able to strip and rebuild the turbo on the Volvo, as the heat had cooked the oil, and hence it was pick up by the recovery truck, and starting was never attempted untill the turbo was rebuilt.

I rarely leave the engine running these day, but prefer to drive gently prior to any motorway stops, or arrival at my destinations, as I too feel the water and oil feeds are not quite enough for my liking.

Wholly agree. I let the engine idle to allow turbo cooling. TA engines must beat oil to death. Turbo, only two big end carrying 85+ hp, pulling hard at low revs using uni air, the uniair itself must beat hell out of it too more heat and high presure. Im happy to change the oil at 5k miles or even less. Extended changes seem wholly wrong with this high tech engine, given even a small amount of thought.