bmw stop start?

utajoker · 30 May 2008 at 08:37

just from dropping my gf off at work i get behind a bus with a poster on the back " if you were using a bmw with stop start technology you wouldnt be using any fuel" or something along those lines, im quite sure it said no fuel.

so, hows that work then?

Howard · 30 May 2008 at 08:38

It turns off the engine, and restarts it when you press the clutch I believe

jamoor · 30 May 2008 at 08:39

It's annoying and isn't 100% reliable to startup IME, waste of time, also on the diesels, doesn't this ruin turbos?

Toker · 30 May 2008 at 09:10

turbos are really meant to be left idling a couple of minutes after they've been spooling before shutting the engine off

Firestar_3x · 30 May 2008 at 09:12

Personally i think its a bad idea, stop / start is always bad for an engine + excessive wear on components etc.

Joe T · 30 May 2008 at 09:23

I drove a 118d with this technology and I thought it worked really well.

Dup · 30 May 2008 at 09:25

How does it work? A friend of mine was buying his wife a new Mini with this feature (I think) and she rides the clutch. He was worried it'd cut out on her half way round a roundabout or something.

Joe T · 30 May 2008 at 09:26

Dup said:
How does it work? A friend of mine was buying his wife a new Mini with this feature (I think) and she rides the clutch. He was worried it'd cut out on her half way round a roundabout or something.

That wont happen, dont worry. The car has to be stationary.

TripleT · 30 May 2008 at 09:27

Surely a car doesn't use that much petrol when idling? How much is used to start it?

Dup · 30 May 2008 at 09:28

Joe T said:
That wont happen, dont worry. The car has to be stationary.

Ah, cool. They've probably got it by now anyway. Been a whilse since I spoke to them. Wish I could just buy cars like him. Has a new M3. 2000 miles = new tyres :eek:

Joe T · 30 May 2008 at 09:38

TripleT said:
Surely a car doesn't use that much petrol when idling?

Well, fuel has to be put into the engine to keep it turning over, so it will certainly use some.

TripleT said:
How much is used to start it?

Probably not very much at all. I would have thought the battery takes most of the strain, and the battery is only charged when the car is coasting or braking (another Efficient Dynamics technology).

I think the 62mpg (with a not too shabby 140bhp) of the 118d should show that at least some of this technology is working. The CO2 is similar to a Prius too.

Glaucus · 30 May 2008 at 10:09

Firestar_3x said:
Personally i think its a bad idea, stop / start is always bad for an engine + excessive wear on components etc.

In the past I would agree, but with modern tolerances, materials and lubrications, it's not really a problem. Not sure about turbos though as I have no idea about them.
Also as it's manufacturer fitted, they deem it to be within tolerances of what the engine/turbos/startermotor can take.

Firestar_3x · 30 May 2008 at 10:14

I suppose if the engine has an electric oil pump to keep the oil pumping around the turbo when the engine shuts down then it isn't really an issue.

With the above in place things like the starter motor is bound to wear out quicker, however how i have not idea about how much quicker, how much more efficient is the Ed model vs. the normal one?

Thomas. PLease. · 30 May 2008 at 11:48

Dup said:
How does it work? A friend of mine was buying his wife a new Mini with this feature (I think) and she rides the clutch. He was worried it'd cut out on her half way round a roundabout or something.

Was reading about this the other day and thinking about wear issues as everyone has already said.

The engine will only stop when in neutral with the clutch engaged i think?, so if you didn't want the car to stop/start you could easily just leave it in gear.

The other similar feature being introduced with stop start is the Intelligent Alternator Control (IAC), which from what i gather stops the alternator from loading the engine, and only puts load on the engine when the battery actually requires charging, as well as using the energy generated by the engine on over-run, either under braking, or downhill, to charge the battery.

Dogbreath · 30 May 2008 at 11:53

Dup said:
How does it work? A friend of mine was buying his wife a new Mini with this feature (I think) and she rides the clutch. He was worried it'd cut out on her half way round a roundabout or something.

Sounds more like an opportunity to teach her how to drive properly.

Dup · 30 May 2008 at 12:05

Dogbreath said:
Sounds more like an opportunity to teach her how to drive properly.

That was his final words on the matter. If it did cut the engine whilst riding the clutch she'd have little braking power and if she had an accident then lesson learnt hopefully. He said he's had enough of trying to get her to drive properly.

Rosbif · 30 May 2008 at 12:06

Yeah great you save all that fuel but that battery isn't going to last as long with all those additional cycles, surely?

Clarkey · 30 May 2008 at 12:10

Rosbif said:
Yeah great you save all that fuel but that battery isn't going to last as long with all those additional cycles, surely?

Indeed, starting takes a whole lot of juice out of the battery too, which will have to be replenished, using fuel..

triggerthat · 30 May 2008 at 12:13

Am sure BMW would have thought of all these concerns before hand.

fRostiE · 30 May 2008 at 12:17

Clarkey said:
Indeed, starting takes a whole lot of juice out of the battery too, which will have to be replenished, using fuel..

but the figures show that overall there is a saving as MPG's are going up not down, so it must be working.