Board:   [WWIVnet] General Chat
Subject: Re: Vacation spots
From:    Bob Worm #81 @137
To:      R3c0n #1 @126
Date:    Thu Nov 27, 2025 02:17

Re: stop-start

I saw the most mundane argument about that on Reddit last week. A load of
people saying things like "it wears the engine less to restart it than to idle
it", that starter motors never wear out and that people who dislike stop-start
are just making noise for no reason.

I've seen experiments run looking at exactly whether it creates wear doing all
the stopping and starting - as expected it definitely does. All the special
bearing coatings, sticky oil and modifications to oil pathways help
but ultimately it is repeatedly subjecting moving parts to the highest
friction part of its cycle.

Same story with starter motors - OK, they uprated them... because they needed
to because they take an absolute kicking. I've certainly had a starter motor
die and have seen it happen on my parents' cars as well. All it means is that
you run a bigger starter harder, most likely they ran the numbers and spent
the minimum they could to keep the MTBF about the same as before, so if you
replace one it costs more.

As a side note I just had to replace the (bigger) battery on my wife's
stop-start car, which is 6 years younger than my non-stop-start car which is
still going on its original battery. Thanks to all the extra battery
management required to make stop-start work I had to have a garage do it
because I don't have the BMW-specific tool to code the new battery in.

And finally, as for making up reasons not to like it - possibly in North
America where roundabouts are pretty rare it's less of a nuisance adding half
a second or so to your launch time, but in the UK where you hit one every few
minutes it is actually dangerous. If you only have a second to join a
roundabout in heavy traffic then losing half of that to stop-start is very,
very bad.

BobW


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