Stop-start, does it actually cost you more?

d2ww

Hi,
I have the automatic stop-start function on my car that is supposed to save you fuel and money. Does anyone know if there has been any independent research done on this? My own guess is that it doesn't because of the shortened life of the battery and starter motor.
Anyone any ideas?

Theboinkmaster

d2ww wrote: »

Hi,
I have the automatic stop-start function on my car that is supposed to save you fuel and money. Does anyone know if there has been any independent research done on this? My own guess is that it doesn't because of the shortened life of the battery and starter motor.
Anyone any ideas?

I've often wondered this but not sure. I have it on my f10 but always switch it off as I find it irritating.

PADRAIC.M

Depends on the manufacturer, some just added the function to a normal type battery and starter, I know with Toyota the battery is a gel type which allows it's to drain and charge over a longer lifetime than a normal battery and the starter is also a different design, do technically if you are in traffic a lot over the first year I'd say you would save more than the price to get the starter done.

MuppetCheck

Apparently the starter is beefed up to cope - I don't know how true that is. I turn it off after starting the car. If it was possible to turn it off completely I would.

evolutionqy7

I don't think there's a massive saving in fuel economy on stop and start. Maybe a tiny one...

The one area it does improve is in the city. Think of 50 cars sitting in a traffic cue...

The exhaust smell gets very stong, now if their engines are off, the exhaust fumes are not there.

That's where I see the big advantage. Of course there's very few cars with this at the moment...and majority seem to want to turn it off cause it's an inconvenience

Chimaera

I'm waiting to see what kind of trouble it causes once cars fitted with it are old enough to start running into electrical problems that hinder starting.

Some cars using this system have a starter/alternator integrated into the flywheel which can start the car much more effectively than a regular starter.

ardle1

The only claim they have is that, 'you use less fuel'....

dodzy

ardle1 wrote: »

The only claim they have is that, 'you use less fuel'....

Give it time. It'll become much more painful that the VAG "button brake" I fear. A gimmick....with another variable for failure, and no doubt, an expensive repair.

Henry Ford III

I'm on my 3rd car with it fitted. No problems with the uprated battery and beefed up starter. On a Focus 1.6TDCI it actually moves the car into a lower CO2 bracket so I've no doubt it helps economy and emmissions.

In real bumper to bumper stuff when you're stopping and starting every few yards and a few times a minute too thankfully there's a button youcan press to disable the system.

Yes it does work, you loose a noticeable amount of fuel just idling at lights in traffic etc.

Over a full tank it all adds up.

Start stop shouldn't be irritating in a manual because as soon as you pop press the clutch and change gear the engine is on and waiting.It does mean having to be in neutral.

In an automatic it can be quiet laggy.

In the Prius there is no lag at all because the motor moves the car instantly then the generator starts the engine and it's ready to go when you need it.

Bigcheeze

Deleted User wrote: »

Yes it does work, you loose a noticeable amount of fuel just idling at lights in traffic etc.

Over a full tank it all adds up.

Start stop shouldn't be irritating in a manual because as soon as you pop press the clutch and change gear the engine is on and waiting.It does mean having to be in neutral.

In an automatic it can be quiet laggy.

In the Prius there is no lag at all because the motor moves the car instantly then the generator starts the engine and it's ready to go when you need it.

Yeah was in a Prius taxi yesterday and the transition was unnoticeable. However in 4 cylinder Diesel engines the start stop is very noticeable.

Bigcheeze

Bigcheeze wrote: »

Yeah was in a Prius taxi yesterday and the transition was unnoticeable. However in 4 cylinder Diesel engines the start stop is very noticeable.

Prius has the motor and it kicks in immediately, no clutches to engage or revs to build. It's truly a pleasure to drive in traffic.

Still I think for anyone used to having the car in neutral at the lights would't really notice it, when you press the clutch the engine starts, by the time the car is in gear the engine is ready for action.

I drove my brothers 2012 Multitronic TDI with start stop and it bugged the crap out of me, and he doesn't use it at all. Drives him nuts. He loves the prius far more, in this situation lol.

corkgsxr

Diesels use pittance compared to Petrols on tickover.

Also petrols are easier to start compared to diesels. So much better suited to stop start.

corkgsxr

corkgsxr wrote: »

Diesels use pittance compared to Petrols on tickover.

Also petrols are easier to start compared to diesels. So much better suited to stop start.

It all adds up, But in reality the stop start driving itself uses a lot more fuel than idle.

I would imagine the stop start is more to reduce emissions in such conditions.

Chimaera

Without having checked into it, I wonder how the designers have ensured the engine maintains adequate oil pressure with these start-stop systems. With an engine driven oil pump, as soon as you cut the engine you lose oil pressure. So you've less lubrication on the start-up, and I'd wonder about the kind of damage this might do in the long term, especially with lower viscosity oils becoming more common too.

corkgsxr

Deleted User wrote: »

It all adds up, But in reality the stop start driving itself uses a lot more fuel than idle.

I would imagine the stop start is more to reduce emissions in such conditions.

Its time stopped that is the issue. On petrols its over 30 seconds stop and it was worth while. On diesels because its much harder to start its over 50 seconds per stop before its worthwhile.

In reality what cars need is a small battery that will allow only a few miles. So it works like the prius system. Engine doesn't start until your moving 10mph or more. That was its not starting for small movements.


The 30/50 seconds was a study done just cant find it for the life of me.

corkgsxr

Chimaera wrote: »

Without having checked into it, I wonder how the designers have ensured the engine maintains adequate oil pressure with these start-stop systems. With an engine driven oil pump, as soon as you cut the engine you lose oil pressure. So you've less lubrication on the start-up, and I'd wonder about the kind of damage this might do in the long term, especially with lower viscosity oils becoming more common too.

I think the noise you hear for a few seconds after turning your engine off. The electronic type one is a type of turbo timer. Keeps oil flowing for a few seconds

Noccy_Mondy

The craic will start in ten or more years, when these cars start to age and become unreliable, it'll stop, but the trouble will be when it comes to starting.....

Satanta

With the start stop, does it amplify issues with DPF's in diesels? More smoke is produced on start up? I always wondered about this but never took the time to investigate

mickdw

Start stop is around awhile now in vag diesels for example and I have not heard of a single issue.
Its not a great idea with a 4 cylinder manual diesel due to roughness but I don't think it's going to be a major reliability concern on aging cars as it would be quite easy to disable.

old_aussie

Drove a new mazda 6 recently, everytime the car restarted, the steering wheel had a little twitch/shimmy.

Didn't like it.

triggermortis

I have a hire car at the moment - Opel Astra Turbo - and I don't mind the stop/start apart from the fact that the air con goes off with the engine stopped, and it was 36 degrees here last week!

mickdw

triggermortis wrote: »

I have a hire car at the moment - Opel Astra Turbo - and I don't mind the stop/start apart from the fact that the air con goes off with the engine stopped, and it was 36 degrees here last week!

That's crazy.

MuppetCheck

The air con goes to a lower setting. It restarts once the car goes a certain amount over the desired inside temperature. At least that's how it worked on my Astra with climate control. You can prevent the stop start from clicking in on the Leon by setting the climate control to low and full fan.

Most of them wont kick in unless a certain number of criteria are met. A dpf regeneration, cold engine, foot on the clutch or car in gear etc will prevent it working.

R.O.R

Always makes me jump when the engine restarts by itself - usually due to the climate control.

Except for the petrol BMW's, don't think we've had issues with any cars with start/stop - caused by the start/stop system.

I don't mind the system at all - makes sense not to be using fuel while you aren't moving. Whether it saves much fuel, I couldn't say - on my daily journey it will only kick in a couple of times and that depends on traffic light sequences and how unlucky I am.

The one thing that really annoys me is on the Audi's with the Auto Hold function - someone didn't think that through properly. Audi Auto's (possibly VW as well, but we'd have more Auto Audi's) work the start/stop off the brake pedal. When you have the brake pedal pressed, the engine stops (when you are stopped obviously), but the engine re-starts when you release the brake pedal - which is when the Auto Hold function kicks in.

BMW have it sorted better on their Auto's - it goes off the accelerator, so you can sit there, not using fuel and not pressing any pedals, until you need to head off again.

MuppetCheck

R.O.R wrote: »

The one thing that really annoys me is on the Audi's with the Auto Hold function - someone didn't think that through properly. Audi Auto's (possibly VW as well, but we'd have more Auto Audi's) work the start/stop off the brake pedal. When you have the brake pedal pressed, the engine stops (when you are stopped obviously), but the engine re-starts when you release the brake pedal - which is when the Auto Hold function kicks in.

The Leon has the auto hold kicking in when it restarts. You get a jolt when you go to move off - it's very irritating in traffic and makes the car easy to stall. On the plus site it restarts itself if it does happen.

My big fear of stop start systems is oil starvation to the turbo when the engine cuts out. Probably accounted for on modern cars but I wouldn't just switch the engine off myself like stop start does.

markpb

MuppetCheck wrote: »

My big fear of stop start systems is oil starvation to the turbo when the engine cuts out. Probably accounted for on modern cars but I wouldn't just switch the engine off myself like stop start does.

I'm no expert on these things but isn't it likely that the manufacturers thought of that when they were designing and building these things? It's unlikely that, after all these years, they'll log onto boards and realise their terrible mistake.

MuppetCheck

markpb wrote: »

I'm no expert on these things but isn't it likely that the manufacturers thought of that when they were designing and building these things? It's unlikely that, after all these years, they'll log onto boards and realise their terrible mistake.

I've learned to never expect common sense design when it comes to cars. It's nice but not always the case.

jameshayes

I think I read somewhere, could have been the F30 brochure- that when the car is off for more than 3 seconds it starts saving fuel

mickdw

markpb wrote: »

I'm no expert on these things but isn't it likely that the manufacturers thought of that when they were designing and building these things? It's unlikely that, after all these years, they'll log onto boards and realise their terrible mistake.

Well using that thinking, there would be no common faults on cars at all. Sure manufacturers would have thought of all these issues however the important bit is whether their solution adequately addresses the issue.
Too many manufacturers are designing in systems that are good for the warranty period and little longer.
I don't see an issue with stop start so far but in lots of other areas, pre design is taking cash or off owners pockets.

I'd be worried about what its doing to the life of my turbo if I had it. I always let the car run for a little while before turning it off or even refill petrol etc with the engine running if I have been driving hard and then pull in for petrol straight away. Start/stop going completely against these practices.