It's a turbo! BMW reveals M3 and M4 engine details

It's a turbo! BMW reveals M3 and M4 engine details
The 2015 BMW M3 sedan and M4 coupe will have a twin-turbocharged inline six-cylinder engine that makes about 430 horsepower and 369 pound-feet of torque. (BMW)

Look out M3 fans: a turbo is coming.

Confirming what had long been rumored, BMW announced Wednesday the next generation of its venerated M3 sedan (and M4 coupe) would indeed use a turbocharged engine for the first time in the model's history.

The duo are mechanically identical. However, for the first time, BMW is positioning the 4-Series coupes as slightly more upmarket from their 3-Series sedan brethren, similar to what it's done with the 5-Series sedans and 6-Series coupe models.


When M3 and M4 cars debut at the 2014 Detroit Auto Show in January, they'll have hiding under the hood a (deep breath) 3.0-liter, twin-turbocharged, direct-injected, inline six-cylinder engine. It will make approximately (BMW's words) 430 horsepower and 369 pound-feet of torque.

That's a gain of 74 pound-feet of torque and 16 horsepower from the current model, which uses a naturally aspirated V-8. The engine is remarkably high-revving, capable of up to 7,500 RPM, BMW said.

Also noteworthy is both the new M3 sedan and M4 coupe will come standard with a six-speed manual transmission. While such a DIY gearbox may seem like a no-brainer for a car whose legacy is steeped in driver-oriented performance, many brands are switching entirely to automated transmissions. This is largely because dual-clutch transmissions offer quicker shifts and acceleration.

Drivers who prefer such a setup will have the option of a seven-speed dual-clutch transmission on these M models.

BMW didn't disclose fuel economy ratings, but did say the new models would be 25% more efficient than the current generation. For comparison, a 2013 BMW M3 coupe with a manual transmission is rated at 14 mpg in the city and 20 mpg on the highway.

Some of these weight savings undoubtedly came from the cars' lower curb weight. While BMW didn't disclose the exact number, the automaker did say the M4 coupe would be "less than" 3,300 pounds, and about 176 pounds lighter than its predecessor.

Some of these weight savings come from the increased use of carbon fiber and aluminum for various components throughout the cars. The M3 sedan will now come with a carbon fiber roof panel, while the coupe will continue to do so. Of course, swapping out a larger V-8 for a more petite, albeit turbocharged, inline six-cylinder engine also helps save pounds.

The design of these cars hasn't been officially revealed, though you'll remember that BMW had an M4 Coupe Concept on display at the Quail Gathering during Monterey Car Week in August. Expect the production model to look essentially the same.

The cars will be sold as 2015 models, and should officially make their first auto show debut at the Detroit Show in January.