Six-Cylinder Smooths Out Auto Stop/Start - 2015 BMW M235i Convertible Long-Term Road Test

Edmunds.com

Six-Cylinder Smooths Out Auto Stop/Start - 2015 BMW M235i Convertible Long-Term Road Test

As with many new BMWs, the 2015 BMW M235i comes with an engine auto/stop start feature. It's unobtrusive and helps save gas.

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kirkhilles1

I still think that's a crazy feature to have for a mechanical device that isn't designed to be turned off and on so frequently. This is where an electric motor really shines.

veedubber86

kirkhilles1 said:

I still think that's a crazy feature to have for a mechanical device that isn't designed to be turned off and on so frequently. This is where an electric motor really shines.

Isn't it designed to be though?

allthingshonda

veedubber86 said:

kirkhilles1 said:

I still think that's a crazy feature to have for a mechanical device that isn't designed to be turned off and on so frequently. This is where an electric motor really shines.

Isn't it designed to be though?

Kinda. They all have more robust starters than normal but frequent cycles will cause the starter to fail sooner than a car not equipped with start/stop. They also don't tell you that all those starts require the use of expensive AGM batteries.

meckser

allthingshonda said:

veedubber86 said:

kirkhilles1 said:

I still think that's a crazy feature to have for a mechanical device that isn't designed to be turned off and on so frequently. This is where an electric motor really shines.

Isn't it designed to be though?

Kinda. They all have more robust starters than normal but frequent cycles will cause the starter to fail sooner than a car not equipped with start/stop. They also don't tell you that all those starts require the use of expensive AGM batteries.

No, the more robust starter with atuo-start-stop will fail at the same rate as a regular starter on a regular car. BMWs have had AGM batteries long before auto-start-stop.

stever

Not very often in other words. Can't remember the last time I had to replace a starter, and I'm old enough to remember when there was a generator shop in every small town where you'd get them rebuilt.

allthingshonda

Ford says the starter in F 150's equipped with auto start stop are good for approximately 150,000-240,000 cycles. If longevity wasn't a concern I don't think Ford would've gone through the trouble of testing the life cycle of the starter. And although BMW has been using AGM batteries for a while, start stop systems are migrating to more mainstream cars where those owners have never had to purchase such an expensive battery.

dlrodgers

it's a 10% improvement at best folks(I believe Edmunds said 9.6% actually)I would prefer to leave car at idle thank you