Does stop start really help MPG ?

[HopeImRight]

That is my question in a nut shell.  I have now confirmed that I detest Stop/Start.  I have hired a few stop/start cars and thought that not being familiar with the car was why I did not like Stop start.  But now I know I don't --horrible.  Very very unpredictable.  BUT BUT if it helps MPG I may try to change my mind.

Has anyone got any stats on the topic please.

[Rooted]

It does if your journey mean being stationery for lots of your journey, gridlock traffic, long traffic light stops etc..

eg

Entering Glasgow from the south, or east, and it taking 45 minutes to go 8 miles, stop start is fantastic.

[GeneralPurpose]

Fifth gear, the TV motoring programme, found a saving of 10% on fuel used during a 15 mile drive across London with stop/start switched on. That's against the same car being used again for exactly the same journey, with the same measured amount of fuel with stop/start switched off. Well worth using stop/start in those conditions and also reduces pollution.

[numptie-boy]

Probably does but the tiny amount won't stop me from switching it off. Don't like it at all.

[Robertino]

I have switched it off. I think killing starter motor prematurely will wipe out those fuel savings.

[sparckzero]

Currently have start-stop on my manual Focus - works very well for the most part. I always figured it was more about reducing emissions than increasing MPG. Will be keeping it switched on in the new Fabia if the system is as smooth.

 

Have driven some automatics with start-stop too - I didn't find it as seamless as with the manual. Ended up turning it off on the last car I rented because the engine sounded like a bag of spanners every time it started...

[Bignij]

I had it on two previous Golfs and my current Octavia. I love it. The only very slight niggle which is very rarely a problem but has been for the last day or so, when it cuts in, the aircon stops. A quick dip of the clutch pedal and it restarts. I've done 80000 miles in the Octavia and well over 100000 miles in both Golfs and never had the merest hint of a problem. As for the original question, does it help mpg? I don't know 'cos I've never turned it off.

 

 

[penguin17]

I don't understand the 'I disable it to save wear' concept.  How many people have reported a starter motor failure?  I've got close to 80K miles in one car and 50-60K in another couple, with stop-start enabled.  Not a single issue.  I appreciate the system won't have an infinite number of cycles but surely it should be a mileage with 5 zero's before this is even a factor or consideration.

 

I'm also pretty certain starter motors were failing before stop-start was even available? 

 

 

Edited 19 June, 2017 by penguin17

[Rooted]

^^^  True,

exception being Skoda Fabia Mk3 probably, crap battery as fitted by Skoda and not very good regeneration so all in a pretty poor Stop / Start system.

More often inhibiting it's self than other VW Group larger vehicles with a better battery and less chance of 'Load demand too high' as one gets with a Fabia..

Allowing for the various reasons that other models inhibit Stop / Start which the Fabia also does.

Edited 19 June, 2017 by Awayoffski

[sparckzero]

1 hour ago, penguin17 said:

I don't understand the 'I disable it to save wear' concept.

 

 

 

I'm with you there. In ~12 years of motoring, I've had one starter motor go bang on me, and that was in a car without stop-start.

 

53 minutes ago, Awayoffski said:

...less chance of 'Load demand too high' as one gets with a Fabia..

 

...is this a big issue on the MK3 Fabia? How does it manifest itself?

[Rooted]

There are threads on the forum from those that have not disabled stop /start or switched off but do not need to as there type of use means that seldom does it function.

Obviously there are those that have no issues as well.

http://briskoda.net/forums/topic/430656-fabia-mk-3-stopstart

[Gerrycan]

The amount of fuel saved with stop/start will vary considerably.

I have a 2013 basic Octavia 1.4tsi manual and the version sold in Australia did not have stop/start and I can't say I miss it having driven other cars that did.

Set the consumption display to L/100 and when stationary and at tickover my consumption shows around 0.5L/hour. If my aircon is running then it will flick up to around 0.8L/hour. 

I imagine the Fabia shows the same if set to L/100km and you will get a rough idea of how much your car consumes and whether the stop/start function is worthwhile for you.

 

If I catch a set of lights I know have a long cycle, or a train crossing, or anything where I think I'm likely to be held up for a minute or more then I am quite happy to switch off the engine with the good old fashioned key and turn the engine on manually when the cross lights change. Freaks my wife out though.

[Rooted]

^^^ What sort of Ambient Temp range do you have in Australia where you drive?

 

Stop / Start is good that in you are not putting the ignition off so you have lights on in poor weather / visibility or lighting up times, 

the steering lock is not going to possibly be on, and if the battery does go lower the engine restarts.

[vc-10]

Mine certainly helps. I tend to have the MaxiDot on the 'from start' MPG, and you can really see it ticking down when you're sitting in traffic and stop/start isn't playing ball. I do think the battery is crap though, in winter it hardly ever works and even now in the summer it can be a bit intermittent. Admittedly living in Manchester I spend my life in stop/start traffic, which of course depletes the battery relatively quickly if it's constantly starting the engine. 

 

Regarding the A/C, I have the standard A/C system not climate control, and the stop/start is disabled if the fan is on 3 or 4 and the A/C is on full cold.

 

I also used to turn the engine off in older cars at long red lights, although that once caught me out! It was in my old Polo, and the battery was weak after my friend left the interior light on all night when we were at a party and the battery went flat. Anyway, I'd had the headlamps on as it was raining hard when I started the journey, and I'd forgotten that I'd left them on. Turn the engine off at the long stop light.... and couldn't start it again! Held up the A4 on the way into Bristol for a while, luckily a friend happened to drive past and I had jump leads with me. I drove straight to Halfords to buy a new battery...

[mrgf]

As with all things, there is going to be a plus and a minus... Plus, (Debatable) Amount of fuel saving, less pollution if stopped for longer periods/in tunnels etc. Minus, Battery fatigue will be considerable as starting the car is the single biggest drain on the battery... All other drains come with a running engine! Also, wear to starter motor will be a contributing factor, long term but this will most likely be ten years down the line! Simply turning off on longer stops but keeping the engine running for very small stops/short stages of movement will be better overall. Oh, Fuel consumption will increase on starting as most vehicles will use more, just to START the car again and will also cause MORE fumes to be pumped out so any gains made will be slimmer then anticipated. It is also well known that driving at slower speeds uses MORE fuel and causes MORE pollution so the so-called safer 20MPH zones are not really safer at all. More fumes at pedestrian level aside, pedestrians and indeed, other (Not me, Guv).Motorists, KNOW you can stop easier, so deliberately pull out in front or cross at inopportune intervals, safe in the knowledge you won't hit them!

Gone a little off topic there but bares a relevance too. If the car is in stop mode and someone starts to cross, technically, you are "Parked" So the pedestrian or other driver will have priority over you. You might want to debate this but a vehicle with its engine off, is NOT driving, it is stopped!

I know someone will say "Not true as I got fined when stopped, for using my phone"! To that I say, serves you right you stupid twonk!

[MickA]

I bought my Toledo as it was the best value for money. Bonus of course the stop/start = £30 VED.

 

In use, well very useful indeed if stopped long enough, irritating if only for a few seconds. I guess I've got used to it now on the journeys I do, disabling it when I know it's only going to be seconds rather than going into minutes.

[Rooted]

Pedestrians do have priority anyway in many peoples world if you are stopped with engine on or engine off.

& every car / vehicle can get across or out as long as they are not a Audi, BMW, Lexus, Jag, Range Rover etc.

 

The EU must have known what they were doing when introducing 'Daylight Running Lights' for when a vehicles ignition is on during Daytime / Daylight, 

it will mean the are Driving on the Highway when even stop stationary on the highway rather than parked sitting at the kerb side.

So useful as more EV's are going to be on the road and there will be no ticking over of engines when 'stopped' in traffic or on the road.

[threadbear]

I use stop start all the time. I am current getting well over 500 miles on a tank of diesel and my Octavia is the best car I have ever had. I now detest drivers who leave their vehicles running unnnecessarily. It is amazing how many taxis at work on the rank sit there pumping out fumes and throwing £££s away in wasted fuel and profit. 

[vc-10]

Absolutely agree with the 20 mph and speed humps destroying fuel economy- I can normally get a decent 45mpg in flowing 30 mph urban driving. Driving around London yesterday and today I've been getting around 35, as I rarely got above 25 mph and kept having to slow for speed humps. 

 

Re a car with the engine off being 'parked', that's bull. A car can be 'parked', handbrake on, driver on the phone, but engine on powering the A/C, for example, and it's definitely parked. Likewise, a car in traffic with Stop/Start (or a hybrid, which will move engine off up to 30 mph or so, or faster in some cars) is very definitely not 'parked'.

[KenONeill]

@vc-10 Your engine is off, your wheels aren't turning and your handbrake is on. You're parked!

[vc-10]

5 minutes ago, KenONeill said:

@vc-10 Your engine is off, your wheels aren't turning and your handbrake is on. You're parked!

 

So I was parked on the M3 earlier, was I?

[KenONeill]

Just now, vc-10 said:

 

So I was parked on the M3 earlier, was I?

By the strict definition of the term, yes.

[Warrior193]

26 minutes ago, KenONeill said:

By the strict definition of the term, yes.

In that case there are going to be an awful lot of infringement notices being sent out to drivers for "parking on Motorway when vehicle not broken down" aren't there?

[vc-10]

19 hours ago, Warrior193 said:

In that case there are going to be an awful lot of infringement notices being sent out to drivers for "parking on Motorway when vehicle not broken down" aren't there?

 

Exactly. Parked, to me at least, means either in a parking space or on the side of the road. Not in the lane of traffic. 

[KenONeill]

{meanwhile, back at the point}

What actually is the fuel consumption of a modern 4 cylinder engine when idling? I'm expecting any sensible answer to be in volume per unit time.