BMW 4-Series Forums banner
1 - 20 of 21 Posts

·
Registered
Joined
·
339 Posts
Discussion Starter · #1 ·
So I've been doing a little research into the stop/start technology BMW has implemented on their vehicles. It looks like stop/start is more of a PITA than it may be worth...

For those of you unfamiliar with stop/start technology it shuts the engine off during idle and then restarts it during acceleration. The problem with the system is that its delayed, the car will not restart instantly there is latency of a few seconds which doesnt seem like much but consider the different possibilities. In line to make a red light, your sitting in the middle of the intersection with the car now shut off because you are "idling", you have to wait until red to turn because as per norm most people shoot through the yellow. Now you hit the accelerator to complete the turn but your 4 series doesn't turn back on right away so you're left in the middle of the intersection as oncoming traffic approaches.....

Sounds a little unsafe to me....

Besides that the system actually diminishes over time with battery life, so as the battery ages the less able it will be to support the 4 series without the help of the alternator. Especially in the winter time when the car shuts off at idle, the driver is still demanding the battery supports the heater, headlights, and radio of course.

Funnily Hyundai has come out and said that fuel savings from stop/start tech is marginal at best, Hyundai admits having difficulty obtaining a 1 mpg improvement in fuel efficiency using stop/start tech. They have all but abandoned the technology.

BMW does provide a button to switch stop start off, however it is only for the duration of your trip and it will reset each time you start the car. BMW has provided a service bulletin to dealers allowing them to make the button override the system permanently. You have to assume the 4 series will get the same treatment...

Does anyone have any experience with stop/start tech they are willing to share with us? My experience is limited to the quick test drive I took in a 3 series last week...
 

·
Premium Member
Joined
·
75 Posts
The start and stop feature does sound green and all but when it comes to real world driving on the streets I think it could get annoying after a while. And just exactly how much gas would you save by not idling? Is it enough for you to really buy in to it?
 

·
Registered
Joined
·
1 Posts
There is a solution! BMW has authorized it's dealerships to "Deactivate the Start/Stop" feature on all cars. Basically the feature defaults to "Last User Mode". I recently did this on my 2013 328i. The dealership was a bit surprised as I may have been the first. I printed out this bulletin though so it was clear.

http://www.bmwblog.com/2012/08/13/bmw-dealers-can-now-deactivate-the-auto-startstop-settings/

Now I never have to push the Start/Stop feature "off". It defaults to "off" and I only push a button if I want to use it again (which will be never)
 

·
Registered
Joined
·
360 Posts
You can turn it off if you would like. I don't remember exactly where. As jake mentioned a dealer would be the quickest way for an answer.

I don't think its dangerous. THere are many cars that have start stop nowadays.
 

·
Registered
Joined
·
339 Posts
Discussion Starter · #6 ·
The start and stop feature does sound green and all but when it comes to real world driving on the streets I think it could get annoying after a while. And just exactly how much gas would you save by not idling? Is it enough for you to really buy in to it?
Very little, Hyundai said they cant even show a 1 mpg savings with stop/start. In hybrids vehicles it makes sense because a hyb can seamlessly switch between electric and gas, but in a petrol car....

I wonder what sort of damage stop/start casues to the starter? On a trip to the market the starter motor could see as many starts as it would normally see in a week...

the 4 series will have good enough mpg without it anyways ;)
 

·
Registered
Joined
·
360 Posts
I think the downside is that the starter will wear down quicker. At least that is my common sense way of thinking. And I've always been told the start is the most harmful part of driving to the engine.
 

·
Registered
Joined
·
80 Posts
I think the downside is that the starter will wear down quicker. At least that is my common sense way of thinking. And I've always been told the start is the most harmful part of driving to the engine.
that is one of mine concerns too. Starters aren't meant to have such a strain starting and stopping that much will prematurely wear it out. unless its a different type of starter.
 

·
Registered
Joined
·
58 Posts
that is one of mine concerns too. Starters aren't meant to have such a strain starting and stopping that much will prematurely wear it out. unless its a different type of starter.
i have a feeling it's electronically controlled by a different starting unit and not the starter that would help to start the engine when you turn engine on yourself.

if it works the traditional way and it has a starter built for that, then it must be one really reliable starter.
 

·
Registered
Joined
·
3 Posts
The starter will be designed for the extra load (seems to be a view they just leave the regular starter in and then add this extra duty). That is now how things are engineered.
 

·
Registered
Joined
·
169 Posts
There is a solution! BMW has authorized it's dealerships to "Deactivate the Start/Stop" feature on all cars. Basically the feature defaults to "Last User Mode". I recently did this on my 2013 328i. The dealership was a bit surprised as I may have been the first. I printed out this bulletin though so it was clear.

http://www.bmwblog.com/2012/08/13/bmw-dealers-can-now-deactivate-the-auto-startstop-settings/

Now I never have to push the Start/Stop feature "off". It defaults to "off" and I only push a button if I want to use it again (which will be never)

@jake141 Thanks for the tip. Do you have to redo this whenever the car is in for service?
 

·
Registered
Joined
·
3 Posts
Ordered a 435xi M sport. Due Dec. Trading in a 2007 328xi which has been great (fantastic in the snow with snow tires).
 

·
Registered
Joined
·
30 Posts
Not sure about American cars, but I shut the ASS off at the dealer delivery for my 435, and it has stay off ever since.. unless I change modes to Eco and back. Then you have to reset it.

Must be programmed to last mode out of the gate now?
 

·
Registered
Joined
·
1 Posts
I just picked up my 435i on Saturday and so far I love it. First time BMW owner, switched from an Infinity G37S.
The Start/Stop is annoying so I shut it off and as others have said it will stay off unless you switch into Eco Pro mode. There is a statement in the manual that says "Certain vehicle components may experience additional wear as a result of this system". So, mine will be permanently OFF.
Ciao.
 
1 - 20 of 21 Posts
Top