Anything to save a penny .. what do you think ?

Bigmuz7 · 18 September 2009, 19:31

I realised today that there is a dude up our street that drives a 3 series 57 plate BMW that whenever he comes to a stop at a junction, or a set of traffic lights switches off his engine

I mean stroll on,.. I'm all for being a bit greener and recycling and all that ,.. but I reckon he'll be keeping his dealer busy with starters and batteries for a while,.. is it just me or do you think he's mad and totally counter productive ? or will he actually do some good what with modern electrics etc ?

JSP · 18 September 2009, 19:35

I was once told you use more fuel stopping and starting the engine like that?

chris123 · 18 September 2009, 19:44

I suspect it is the car doing it, rather than him:

http://www.bmw.com/com/en/insights/t...tart_stop.html

The technology has been around a few years now on various makes, so presumably any issues have been ironed out.

Cheers

Chris

Bigmuz7 · 18 September 2009, 20:28

Jeeee .. I didnt know that

I wonder if it really does any good

willk · 18 September 2009, 20:33

It may be an urban myth, but I understood that this kind of thing was de rigeur in Switzerland?

Steve_B · 18 September 2009, 20:35

Stopping your engine manually, is only efficient if the stop is for longer than 21secs. There in lies the problem, how do you know? If it's a traffic jam, maybe. At traffic lights you know well, yes. In other cases,looking at your watch could be more of a distraction and you might end up with a motoring offence ..... Look at petition thread

codprawn · 18 September 2009, 21:19

Quote:

Originally Posted by chris123

I suspect it is the car doing it, rather than him:

http://www.bmw.com/com/en/insights/t...tart_stop.html

The technology has been around a few years now on various makes, so presumably any issues have been ironed out.

Cheers

Chris

Yes and no - really bad idea in my opinion - I turn the engine off at certain lights because I KNOW how long they will take - the car doesn't!!!

I am suprised the government haven't banned them as they admitted recently that they deliberately bugger around with traffic lights so people waste more fuel and they get more money..........

Bigmuz7 · 18 September 2009, 21:31

Quote:

Originally Posted by codprawn

I turn the engine off at certain lights because I KNOW how long they will take - the car doesn't!!!

It said it restarts whenever you put the clutch in

HUMBER P4VWL · 18 September 2009, 21:38

My mate has it on his 1 series. Better mpg than his older slower one one!! Unnerving at first but then becomes unnoticeable. You are right it only stops in neutral then starts as soon as you dip the clutch.

codprawn · 18 September 2009, 22:53

Quote:

Originally Posted by Bigmuz7

It said it restarts whenever you put the clutch in

I know it does - I have driven one - but it doesn't do much good turning the engine off for say 27 seconds. I only turn the engine off if I know it will be longer than a minute!!!

Leapy · 19 September 2009, 08:15

Quote:

Originally Posted by codprawn

I am suprised the government haven't banned them ..........

I thought you were against the nanny state?

Leapy · 19 September 2009, 08:24

The official fuel consumption and emission tests that produce the figures we see in brochures and the like - but which none of us can actually achieve - have significant periods of idle meant to replicate a typical driving cycle.

Manufacturers have discovered that having the engine switched off for these periods, rather than just idling, cuts both advertised emissions and fuel consumption and so shows them in a better light.

This is where I can get on my hobby horse...does the fuel saved pay for the environmental cost of more technology and more complexity and more parts and more all else?

Just don't get me stated on hybrids

What's the environmental cost of producing/dragging around the place when they're flat/disposing of all those sodding 200kg Li-ion battery packs?

My neighbour has a Lexus petrol 4x4 hybrid that does no more mpg than my Disco 3 diesel. What's the bloody point?

JSP · 19 September 2009, 09:42

Quote:

Originally Posted by Leapy

My neighbour has a Lexus petrol 4x4 hybrid that does no more mpg than my Disco 3 diesel. What's the bloody point?

Coz Hybrid is the new form of the GTI/SRI 'cool' badge. Your cars just not cool if it doesn't say it on the back.
Daft init?

eilean mor · 19 September 2009, 19:11

I'm busy replacing my volvo, and looked at the one that does this start stop stuff, as its got the 'supposed' best fuel efficiency - the point which made it useless for me was the towing limit - on the same car/ same engine - its 1450 with the 'manual' - and only 800 with the start/stop - the info being tucked away in the technical bits and pieces.

chris.

Bigmuz7 · 19 September 2009, 19:58

Quote:

Originally Posted by eilean mor

its 1450 with the 'manual' - and only 800 with the start/stop - the info being tucked away in the technical bits and pieces.

That doesnt make sense ?

I thought it was all about chassis and body design ?

tinker · 20 September 2009, 17:39

Think the new Freelander has it as well.

Leapy · 20 September 2009, 17:56

Quote:

Originally Posted by tinker

Think the new Freelander has it as well.

The manual Freelander does...not the auto: much more difficult to engineer

Simon B · 20 September 2009, 19:41

So if you made a 200kg Li-ion flywheel that you could use to bump start the petrol engine you'd really be quids in. I'm looking into LPG injecting my latest scrap-heap-challenge vehicle.

John Kennett · 21 September 2009, 10:59

Quote:

Originally Posted by codprawn

I am suprised the government haven't banned them as they admitted recently that they deliberately bugger around with traffic lights so people waste more fuel and they get more money..........

Do you have a reference for that?

9D280 · 21 September 2009, 13:16

Quote:

Originally Posted by Leapy

The official fuel consumption and emission tests that produce the figures we see in brochures and the like - but which none of us can actually achieve - have significant periods of idle meant to replicate a typical driving cycle.

Or, depending on how you drive & your "personal drive cycle", make the offiicial numbers look realy small. I do a LOT of motorway driving, and if I donlt do Illegal speeds, I make my car's official figures look laughable. To replicate the official numbers I have to tow the rib!

The Euro drive cycle is there as a benchmark. A bit like crash tests. The car is fired at an EU approved deformable barrier bolted to a 200 tonne concrete block at 40 % offset at exactly 90 degrees incidence ...... Like there's a lot of them travelling on the M6!

Quote:

Originally Posted by Leapy

This is where I can get on my hobby horse...does the fuel saved pay for the environmental cost of more technology and more complexity and more parts and more all else?

Hang on. To get through the emissions tests these days, all cars use engine management. The already have starter mortors & a vast array of sensors to tell the brain what it's doing. All that "complexity" boils down to a few (!) more lines of software in the ECU.

Bear in mind that with a warm engine & engine management you get EXACTLY the right amount of fuel at the right time, and the power to the starter (that will need to be generated by the engine to recharge the battery) will be cut instanly the engine fires, so I suspect the "21 second" rule of thumb is well old hat, because when you start, I bet your foot is on the RH pedal, you don't kill the starter immediately.......

Also there are stystems out there where the alternator & starter are morphed into one unit, so you get a weight saving too.......

[QUOTE=Leapy;316881]
Just don't get me stated on hybrids

What's the environmental cost of producing/dragging around the place when they're flat/disposing of all those sodding 200kg Li-ion battery packs?

Spot on!