Base version will have to make do with 50 hp less.

As you may have heard by now, the next-generation Z4 roadster codenamed “G29” will top out at the M40i version as BMW has made it crystal clear it will not do a full-fat Z4 M. Now, sources close to Bavaria have managed to obtain some juicy specs about the range topper set to be blessed with a straight-six 3.0-liter engine likely inherited from the 340i. The turbocharged mill is going to deliver 335 horsepower in the base version in which the car will utilize the “B58M1” specification of the engine.

A beefier “B5801” setup of the same engine is expected to churn an additional 50 hp for a grand total of 385 hp. The bump in the amount of horsepower is likely to be complemented by an increase in torque as well, but not as significant. According to BMWBLOG, there are two plausible scenarios regarding why the same model would get two different outputs.

Leaked:

First, it could have something to do with the legislation regarding emissions standards. In other words, the lesser version of the six-cylinder engine might end up powering the Z4 M40i in Europe where there are more stringent rules. The United States and other markets where the laws are not as strict are likely to be ones in which BMW will sell its new soft-top roadster with the 385-hp punch.

As for the other possible scenario, the higher specification of the engine could be reserved for a hotter version as BMW could be cooking up something along the lines of an optional Competition Package. As with other models offered with this pack that are currently on sale, it would bring along some other improvements, such as a throatier exhaust, further tweaked suspension, exclusive wheels, lighter seats, and other miscellaneous goodies.

The Z4 won’t be all about the spicy M40i flavor as customers will still be given the possibility to opt for a lesser engine. The lineup should kick off with an s20i version providing 180 horsepower from a four-cylinder 2.0-liter engine and the same turbocharged unit is projected to push out 250 hp in the s30i model.

BMW will host the world premiere of the all-new Z4 next year and there is a good chance the M40i is going to be available right away.

Source: BMWBLOG

2017 BMW Z4 concept