BMW calls its latest 2.0-liter four-cylinder engine B48, and the new single-turbo six is the B58. The B48 cars get 30i suffixes and the B58s say 40i on the back. And if you really want to get down into code numerology: the B48 replaces the N20 four and the B58 supersedes the N55. Here's where they're headed next year:
2 Series: 230i and M240i
For the small Bimmer, the 228i and M235i names are replaced by 230i and M240i models. In these applications, the four-cylinder makes 248 horsepower and 258 lb-ft of torque and the M-ish six makes 335 hp and 369 lb-ft of torque. The 2 gets other updates for 2017 as well.
3 Series: 330i sedan/wagon/Gran Turismo and 340i Gran Turismo
For 2016, BMW put the 335-hp B58 six in the 3 Series sedan only. That engine spreads to the 340i Gran Turismo for 2017, and the N20 in the 328i is replaced by the B48 for 330i models in all body styles. There's still no six-cylinder wagon, and the 320i sedan keeps its N20 engine. Diesel sedans and wagons keep both the 328d name and the 2.0-liter four they had before. Trivia: The 330i name is being recycled – it was used on the E90 most recently.
4 Series: 430i and 440i
Every 4 Series – including coupe, Gran Coupe, and convertible models – gets a new engine for 2017. Woo! And both engines will again be available with or without xDrive all-wheel drive. Woo. And no, that's not an official BMW photo above.
BMW hasn't shared information on its 2017 crossover lineup, but we expect the X1, X3, X4, X5, and X6 will get new engines where applicable. And then there are the 30i and 40i models that already existed and won't be getting these new engines. The 330e iPerformance plug-in hybrid sedan already has the B48 four-cylinder. And the 540i, 640i, and 740i continue with a version of BMW's last-gen six.
Got that all straight? Yeah, neither do we. And expect updates once the details on the 2017 crossovers are shared.