Auto stop/start when towing with an automatic

IanHCharles replied on 27/09/2019 22:24

Posted on 27/09/2019 22:24

I have a diesel BMW 2L 3 series automatic that has automatic stop/start.  It's the first car with this function that I have driven when towing.  Should it be switched off when towing

ocsid replied on 22/02/2020 07:04

Posted on 21/02/2020 15:21 by Boff

Haven’t factory fit towbar, but the electrics are fully coded. Into the system.   It still stop starts but subjectively I would say less often. 

And I still don’t get what the big problem with stop start is anyway?

Posted on 22/02/2020 07:04

I can't see it can be argued "Stop start" is a healthy thing of any ICE but undoubtedly it is for the local environment and I am sure that is the motivation for its adoption.


In most normal situations the vehicle will be already in a low power generation state, before stop starts becomes particularly active, i.e. into urban slowing traffic as opposed to be at full tilt then abruptly be stopped.


So, as said, in that situation even if not desirable mechanically, it is less of a "big problem".


Towing must change things in a negative direction, as the machinery will always be lugging near twice the solo use mass. A spin off is this there will be twice the waste heat to dissipate, from the cooling, from components, out of the turbo and from the exhaust. At the same time there is no change in the ability to dissipate this ( e.g. no road speed), only calling in the fan or fans.

So in most vehicles without electrically pumped cooling systems, when we stop the engine the blocks heat soaks as do other critical things, here particularly the turbo's hot end bearings. Plus the transmission, in the traffic will have been in slip mode, not locking up so again getting quite hot, and with a stopped engine without a means to shed much of that.


Things are much worse if the engine has been really pulling and then goes into stop mode, e.g. hauling up a hill then running into backed up traffic or a "tee" junction where the vehicle stops moving.


Overall I don't see Stop start as a mechanically healthy thing to be doing, and towing it just gets worse.

rayjsj replied on 22/02/2020 10:06

Posted on 21/02/2020 15:21 by Boff

Haven’t factory fit towbar, but the electrics are fully coded. Into the system.   It still stop starts but subjectively I would say less often. 

And I still don’t get what the big problem with stop start is anyway?

Posted on 22/02/2020 10:06

Agree with the Above.

As has been said , the problem with it , is, if Towing. fridge and leisure battery charging is interrupted, if a turbo diesel, overheating of Turbo bearings and overheating of  Transmission fluid all of which can be which can be very expensive.  Turn it off, if it doesnt turn off automatically because you are towing.   Common sense really.

 

Oneputt replied on 22/02/2020 11:34

Posted on 22/02/2020 11:34

For some reason when using stop/start when stop is activated it knocks out my sat nav which is a pain

Vulcan replied on 22/02/2020 11:34

Posted on 22/02/2020 11:34

In my opinion the system is badly thought out, it should only activate when the handbrake is applied. This would alleviate the annoying habit of idle drivers sitting with their foot on the brake dazzling the driver behind at night because they are too lazy or ignorant to use the handbrake as required.

ocsid replied on 22/02/2020 11:45

Posted on 22/02/2020 11:34 by Vulcan

In my opinion the system is badly thought out, it should only activate when the handbrake is applied. This would alleviate the annoying habit of idle drivers sitting with their foot on the brake dazzling the driver behind at night because they are too lazy or ignorant to use the handbrake as required.

Posted on 22/02/2020 11:45

How would redesigning Stop start to work via the hanbrake alleviate drivers holding on the foot brake?

That bright brake light issue is a feature of using an automatic, surely.

However, I can't ever see that going away, many will feel safer to be themselves holding the vehicle, and others never thought of its side effect.

Tinwheeler replied on 22/02/2020 13:04

Posted on 22/02/2020 13:04

"That bright brake light issue is a feature of using an automatic, surely"

Why do you think that? Autos have handbrakes just as manuals do and they have a 'N' position.

Vulcan replied on 22/02/2020 13:14

Posted on 22/02/2020 11:45 by ocsid

How would redesigning Stop start to work via the hanbrake alleviate drivers holding on the foot brake?

That bright brake light issue is a feature of using an automatic, surely.

However, I can't ever see that going away, many will feel safer to be themselves holding the vehicle, and others never thought of its side effect.

Posted on 22/02/2020 13:14

Why would you keep your foot on the brake if the handbrake is on? The fact that it is a feature of using an automatic does not mean that you cannot use some common sense and good manners by not dazzling the driver behind and complying with the Highway Code.

ocsid replied on 22/02/2020 13:18

Posted on 22/02/2020 13:04 by Tinwheeler

"That bright brake light issue is a feature of using an automatic, surely"

Why do you think that? Autos have handbrakes just as manuals do and they have a 'N' position.

Posted on 22/02/2020 13:18

Because so many driving an automatic leave it in "D" with a foot on the brake, for traffic lights, bumper to bumper  driving.

Not that they have to, but very much what I observe happens. Sit in bumper to bumper moving traffic, it appears all but endemic that is the adopted driving style where a move is thought immenent. Otherwise would Vulcan have raised it as an issue?

JVB66 replied on 22/02/2020 13:49

Posted on 22/02/2020 13:14 by Vulcan

Why would you keep your foot on the brake if the handbrake is on? The fact that it is a feature of using an automatic does not mean that you cannot use some common sense and good manners by not dazzling the driver behind and complying with the Highway Code.

Posted on 22/02/2020 13:49

I am sure that in this area ,and others with a lot of stop/start traffic ,there are not the amount of auto box cars that sit in traffic with their foot on the brakes ,in the creeping traffic, manual box car drivers do the samesurprised

 

Tinwheeler replied on 22/02/2020 13:52

Posted on 22/02/2020 13:18 by ocsid

Because so many driving an automatic leave it in "D" with a foot on the brake, for traffic lights, bumper to bumper  driving.

Not that they have to, but very much what I observe happens. Sit in bumper to bumper moving traffic, it appears all but endemic that is the adopted driving style where a move is thought immenent. Otherwise would Vulcan have raised it as an issue?

Posted on 22/02/2020 13:52

Your first para applies equally to drivers of manual cars but they keep two feet on the pedals.

Vulcan did not raise the issue specifically in respect of auto drivers but about lazy drivers in general. The auto aspect is your take on things.

I drive a manual and an auto and treat them both the same. Handbrake on and gear lever in neutral/N.

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