2015 BMW M235i: Six-Cylinder Smooths Out Auto Stop/Start
by Brent Romans, Senior Automotive Editor on September 21, 2015
Our 2015 BMW M235i comes with an engine stop/start feature. To help save fuel, auto stop/start turns off the engine when you come to a stop (at a stoplight, for instance), then automatically fires it right back up as soon as you take your foot off the brake. We've had a few cars in our fleet with this feature now, including our last BMW, the 328i xDrive Gran Turismo. It received fairly positive commentary back then and it seems to work more inconspicuously on our 235i.
I'll credit that to the 235i's inline-6 engine, which fires up more smoothly than the 328i's four-cylinder. It's smooth and quiet enough that I don't mind it at all. And as Dan Edmunds tested out on our 328i GT, using auto stop/start can make a noticeable improvement on fuel economy.
How much improvement we'll get on our 235i is hard to say. Right now it's summertime, and using the air-conditioning limits how often auto stop/start engages. Plus, it's a 235i and the appeal of revving that inline-6 for fun will counter any gains we might be getting. Nonetheless, it's a worthwhile feature in my opinion.
Brent Romans, Senior Automotive Editor @ 4,848 miles