See Photos of the 2020 BMW Z4 M40i
BMW's velvety inline-six fixes the entry-level Z4's power deficit but the M40i could still learn a few things from the mechanically-identical Supra.
It's for the best that the 2020 BMW Z4 convertible, particularly in six-cylinder M40i guise, is essentially a decapitated 2020 Toyota Supra, a car that was co-developed with the BMW and shares virtually all of its mechanical identity. Read the full story here.
The latest Supra might not be enough of a Toyota for loyalists, but it is no slouch. There's a lot of performance baked into the new platform to bolster the Z4's sports-car credentials. We'd be cool with BMW making the Z4 drive even more like the Supra.
From our prior experience with the entry-level Z4 sDrive30i, when it lost to the Porsche 718 Boxster in a comparison test, we know that the BMW is a highly athletic and agile roadster in need of better steering and either more power or less mass.
Stepping up to the M40i handily fixes the latter issue, replacing the standard 255-hp turbo four-banger with a turbocharged 3.0-liter inline-six good for 382 horsepower and 369 pound-feet of torque.
Wonderfully smooth and willing to rev, BMW's B58 six is a honey, bringing the Z4 to life with a 1600-rpm torque peak and pulling like a mule to its 6500-rpm redline.
The melody of its intake growl overlaid with the refined snarl of the Z4's exhaust, especially with the top down, never gets old, although the active exhaust system emitting pops and gurgles in the sportier drive modes seems a bit juvenile considering the Bimmer's price.
With its ZF eight-speed automatic shuffling through the gears, the Z4 M40i bolts to 60 mph in 3.8 seconds and covers a quarter-mile in 12.3, smashing the 30i model's times by 1.3 and 1.5 seconds, respectively.
At a meaty 3535 pounds, however, the M40i weighs 128 pounds more than its lesser sibling, and it's 376 pounds heavier than its key rival, the 350-hp Porsche 718 Boxster S.
When fitted with its optional seven-speed dual-clutch automatic, that Porsche is quicker than this BMW. It's also a purer sports car and comes standard with a six-speed manual.
Aided by its adaptive M Sport dampers, upgraded brakes, and limited-slip differential, as well as the optional 19-inch Michelin Pilot Super Sport summer tires (18s are standard), the hot Z4 impresses with a 148-foot stop from 70 mph and 1.02 g's of stick around the skidpad, pretty much in line with the last PDK-equipped Boxster S we tested.
Whether or not you approve of the BMW-Toyota mash-up, Munich made good on the arrangement by imbuing the best Z4 ever with a broad array of performance capabilities.
That the M40i only partially addresses the Z4's shortcomings, though, is but one of two reasons why we'd hesitate to pay its $64,695 base price, let alone our test car's $73,295 sticker. The other reason wears a Porsche emblem on its nose, even if it does cost about eight grand more to start.
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
2020 BMW Z4 M40i
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