Is using auto start-stop bad?

WellKnownSid

uncreative wrote: »

Wait..What??? your S/S cuts out the engine on the motorway? Ours only cuts out at traffic lights or when you have physically stopped. No way would I have the engine cutout on the motorway - surely thats not right??

Why should my car treat the M6 different to any other road? And creeping downhill, it won't restart unless speed is > 18mph or the brake vacuum needs a top up.

Stop start leaves ancillaries like power steering and other services running safely... Meaning you could actually cover some distance with no engine.

That's why manufacturers call it "micro-hybrid".

neilmcl

mttylad wrote: »

SS is bad if you have a Fiat Punto like I do.
I'm on my 3rd battery, they only last about a year as it knackers them up pretty quick.

Ideally I'd like to disable it completely.

Sounds to me like an overall issue with your car or the batteries you keep buying if they're only lasting a year.

My last 3 cars have had SS and I've never had any battery issues other than having to buy a new one on my second because the previous owner had removed the OEM one and fitted a cheap, unsuitable, standard battery.

DUTR

uncreative wrote: »

Wait..What??? your S/S cuts out the engine on the motorway? Ours only cuts out at traffic lights or when you have physically stopped. No way would I have the engine cutout on the motorway - surely thats not right??

It doesn't cut out at all!
You have to hold the brake for about 2 seconds for the engine to return to a standby status, whether this be at traffic lights or where the traffic is not moving for some time this could include a heavily congested motorway if there has been an accident ahead, some cars you have to hold the brake for the engine to remain stopped. Once the brake pedal is released the engine restarts, in the case of my car as the accelerator pedal is touched the engine starts.

uncreative

sorry DUTR I quoted you earlier but meant to quote wellknown sid!

GabbaGabbaHey

facade wrote: »

I read once in the comics that BMW were fitting a system that basically ran the battery down when moving, by disabling the alternator, and only charging the battery if it fell below say 50%.
They then used the alternator as a regenerative brake, by switching it on when the fuel was cut off = coasting downhill, or when the brakes were applied. This represents an increase in efficiency, as some of the kinetic energy that would have turned to heat in the brakes becomes electrical energy in the battery.

Don't know if it got to production or not though..

It most certainly did. My 2012 M3 has it - BMW call it "Brake Energy Regeneration" - more details here: http://www.bmw.com/com/en/insights/technology/technology_guide/articles/mm_brake_energy_regeneration.html

prowla wrote: »

Keeping your foot on the clutch is bad for the clutch.

Oh no it isn't. The only possible downside is wear to the throw-out bearing, but I have yet to hear of anybody ever having to replace one. What's bad for the clutch is slipping it.

Zandoni

GabbaGabbaHey wrote: »

It most certainly did. My 2012 M3 has it - BMW call it "Brake Energy Regeneration" - more details here: http://www.bmw.com/com/en/insights/technology/technology_guide/articles/mm_brake_energy_regeneration.html

Oh no it isn't. The only possible downside is wear to the throw-out bearing, but I have yet to hear of anybody ever having to replace one. What's bad for the clutch is slipping it.

It is very bad practice to sit with your foot on the clutch when stationary, it most defineately will cause damage to the release bearing if done to excess.

reeac

GabbaGabbaHey wrote: »

It most certainly did. My 2012 M3 has it - BMW call it "Brake Energy Regeneration" - more details here: http://www.bmw.com/com/en/insights/technology/technology_guide/articles/mm_brake_energy_regeneration.html

Oh no it isn't. The only possible downside is wear to the throw-out bearing, but I have yet to hear of anybody ever having to replace one. What's bad for the clutch is slipping it.

I once had to replace a graphite throw-out bearing on an old Wolseley 1500. It was worn down to the point where the trunnions were catching on a rotating part of the clutch causing a rhythmic noise.

reeac

neilmcl wrote: »

You not heard of the principle of "marginal gains". SS is just a one part of the overall ECO packages included with new cars, taken as whole can make significant differences.

Yes, I guess that it's the converse of Pareto where you concentrate first on the big effects where there's more to be gained - in the present context that would be driving style e.g. minimum use of brakes.

victor2

I heard from a mechanic that the Ford "EcoBoost" engine fitted in some Fiestas is a turbo charged engine and the turbo of course runs at high speed and gets very hot. The stop/start on that engine also stops the turbo without allowing it to idle and cool down. It does this repeatedly in typical city driving. As these engines are getting older, there are reports of the turbo casing cracking due to the build up of temperature and inadequate cooling in stop/start city driving. That is a very expensive repair...

DUTR

victor2 wrote: »

I heard from a mechanic that the Ford "EcoBoost" engine fitted in some Fiestas is a turbo charged engine and the turbo of course runs at high speed and gets very hot. The stop/start on that engine also stops the turbo without allowing it to idle and cool down. It does this repeatedly in typical city driving. As these engines are getting older, there are reports of the turbo casing cracking due to the build up of temperature and inadequate cooling in stop/start city driving. That is a very expensive repair...

Did this same mechanic tell you that supermarket fuel is different to other forecourts?