We already know how the 2015 BMW M4 compares with a 2014 Chevrolet Corvette Stingray on a track, but how much power does the M4's turbocharged engine put to the ground? To find out, our colleagues at Motor Trend put the M4's four-door sibling, the 2015 BMW M3, on a dyno in southern California.
The 2015 BMW M3 and M4 share a 3.0-liter twin-turbo inline-six that is officially rated for 425 hp at 5500 rpm and 406 lb-ft of torque at 1850 rpm. After running the M3 on a dyno owned by K&N Engineering, Motor Trend came up with rear-wheel outputs of 379 hp at 6600 rpm and 378 lb-ft of torque at 4300 rpm.
Though the engine speeds at which those peaks occur is different than what BMW claims, rear-wheel horsepower is only down about 10 percent from what is claimed at the flywheel, and the torque figure is only about seven percent lower than BMW's stated numbers. Factoring in that some power is lost through the car's transmission and differential, MT concludes the 2015 BMW M3 and M4's power ratings are pretty much spot-on with real-world output.
For an interesting comparison, MT also brought an outgoing V-8-powered BMW M3 to the dyno session. While we knew the old BMW M3's 4.0-liter V-8 makes less power than the new turbo engine -- the car is rated at 414 hp but just 295 lb-ft of torque -- the instrumented testing shows just how much of a difference the turbocharged engine's grunt makes. As the chart below shows, the outgoing BMW M3's V-8 offered significantly less low- and mid-range power than the 2015 BMW M3 and M4's inline-six. The new cars boast more than 350 lb-ft of torque from about 3000 rpm through 5500 rpm, more than the old car's peak torque at any engine speed. That helps the new 2015 BMW M3 and M4 get out of corners and away from a stop even quicker than their predecessors.
For a more thorough explanation of the 2015 BMW M3 and M4 dyno charts, read the full story at Motor Trend.