Updated: Oct 20, 2018
Last month, BMW finally showed off its long-anticipated Z4 roadster in M40i trim at Pebble Beach. However, the exact details of the power output were held back. Today we've learned that the top-trim Z4 M40i produces 382 horsepower and 369 lb-ft of torque from its 3.0-liter turbocharged B58 inline-six, which is sent to the road via an eight-speed automatic.
BMW has also introduced a base sDrive30i trim, which is powered by a 2.0-liter turbocharged B46 four-cylinder producing 255 hp and 295 lb-ft of torque also going out through an eight-speed automatic.
The sDrive30i can hit 60 mph in 5.2 seconds while the M40i takes just 4.4 seconds. Both engines offer substantial power gains over the last generation Z4: 15 hp and in the four-cylinder and 47 hp in the six-cylinder. Unfortunately, no M variant is planned, but we aren't sure why one would even be necessary. As it sits, the Z4 M40i is already faster than the non-Competition M2 around the Nurburgring.
Though it may anger some enthusiasts, the only transmission option for both engines is an eight-speed Steptronic Sport automatic transmission. If it's any consolation to those hoping for a manual, the eight-speed does feature paddle shifters and launch control - although we know that doesn't make you feel any better. BMW also says the M40i will have specific shift characteristics to match the power delivery of the straight-six engine.