2019 BMW Z4 M40i Prototype Review: BMW Breathes Life Into a Forgotten Droptop

On a postcard-perfect day in the Provence region of France, we agree to keep our phones tucked away in our bags. In a convoy, we pass through the security gate of the former Michelin, now BMW proving ground in Miramas and wind our way to a garage on the other side of the enormous facility. Our hosts are a small handful of immensely friendly, obviously proud, and enthusiastic engineers responsible for bringing the BMW Z4 convertible back to our roads next spring. They’ve been at it for five years—or three years before the last Z4 disappeared from our showrooms after the 2016 model year. Why? BMW’s not-so-secret arrangement with Toyota to co-develop a coupe-only Supra sports car in exchange for valuable, forward-thinking battery and hybrid technology was too good to pass up.

Impressions of Scale

Feeling a bit like stowaways or spies, we catch our first glimpse of a pair of near-production-spec Z4s in full camo—including black interior shrouds. Having only seen the same spy photos as you, we were rather giddy at the prospect of meeting them in the metal—and they are noticeably larger than the previous-gen hardtop convertibles. Impressions were confirmed as the car’s project manager, Andreas Ederer, shared some key specifications with us. The new Z4 will sport a soft top instead of a hard-panel convertible top that eats space when stowed. Compared to its predecessor, trunk space grows from 8 cubic feet (only with the top up) to a generous 9.4 cubes regardless. Also, the new Z4’s wheelbase is 1.1 inches tighter; however, the front track has been widened by 3.6 inches, the rear by 2.2 inches. In terms of dimensions, the new car is 3.2 inches longer, 2.8 wider, and 0.5 taller. It doesn’t sound like much, but it’s quite noticeable. For perspective, the 2019 Z4 is nearly the size of a current-model Mercedes-Benz SL-Class (except in length and wheelbase), but it’s much larger than the SLC-Class.

Field of Dreams

Somewhere in that field in Miramas was a 15-turn handling course we’d use to evaluate the new Z4. Before that, though, we had to learn the track. Led by driving dynamics engineer Florian Dietrich driving an M4, we first get behind the wheel of an M240i coupe, and then an M2, and attempt to keep up on the fast course. Florian was quick—right out of the pit lane—and not in a daring, catch-me-if-you-can sort of way. Rather, it was the kind of confident speed that merely demonstrated he’s put in perhaps thousands of laps in dozens of cars on this track. I imagine it’s something akin to showing up the first day of Riders Academy at Valentino Rossi’s private Motor Ranch thinking you’ve gotten in over your head. For us, the hard part was that there were no signposts, landmarks, cones, or anything but red/white curbing at the apexes in what otherwise was waist-high golden grass. After two hot laps and one cool-down lap in each prep car, we learned a couple of things. In a nutshell, the M2 had a fighting chance of keeping up with Florian in the M4; the M240i, not so much. Also, we could finally go mostly flat in the fast bits where Florian was clearly confident and demonstrably quicker.

Some Hardware

Finally, I hop into the Z4 test car. I could see that the car was close to production ready. The black-and-white camo wrap didn’t cover the door jambs, and the blue paint I saw there looked flawless. Some plastic surfaces still lacked graining, but the steering wheel, shifter, a new digital instrument panel, next-gen iDrive controller/touchscreen display, and center console (what I could see of it) were fully functional and seemed to be finished. Similar to the 3.0-liter twin-scroll single-turbo B58 I-6 in the M240i (335 hp/369 lb-ft), the B58 in our Z4 M40i is torque-rich and more than powerful enough to propel the Z4. However, we were shocked to learn that this version of the B58 in the new Z4 makes nearly 50 horsepower more, at 382 hp and 369 lb-ft of torque in U.S. spec. European cars will be downrated to 335 hp due to new particulate filters on “petrol” cars. Reportedly weighing just under 3,400 pounds, or nearly 100 fewer than the 2011 Z4 sDrive35is we last tested, the new Z4 should feel lighter on its toes. It was also heartening to learn that this Z4 routes power through a BMW-tuned ZF eight-speed automatic before it reaches the standard electronic M differential. It’s like the front third of a hopped-up M2 and the rear two-thirds of a current M5, if you think about it. With 255mm front and 275mm rear Michelin Pilot Super Sports beneath it all, good tidings were afoot.

Track Time Revelations

In Sport mode with Dynamic Traction Control (DTC) engaged, we set out on the chase again. For the first time since I’d arrived, I felt like I had a fighting chance against Fast Florian. It only took one blast down the straight and two corners to realize that the Z4 M40i is a genuine sports car. Its rorty exhaust note sounds better than that of an M240i but not as racy as an M2’s. I could sense the stiffness of the chassis, the weight being low and chuckable. The multimode dampers handled the rapid changes in direction, and the EPS steering was responsive and precise. I didn’t detect any of the BMW Active steering gremlins that make it difficult to predict steering input on corner entry/exit where the ratios change with vehicle speed. The balance is neutral but leans toward oversteer with an aggressive throttle. Also, the way the Z4 puts power down, especially on corner exits, was clearly due to the excellent tuning of the differential. (Later, Florian rode beside me with a laptop he used to tweak the differential’s settings. With the differential in “open” mode, the unloaded inside wheel would spin, causing chassis twitches that needed a dab of oppo to correct. This made it difficult to sustain a quick pace around the circuit. There were dramatic advantages with the stock Sport setting.)

In Sport drive, the transmission felt responsive, too, though not as much as some cars with the same ZF hardware and certainly not to the degree of an M5 in its most aggressive setting. There might be some more software tuning left in the Z4’s autobox, but to really keep up, I had to shift manually, either with the paddles or by knocking the stubby shifter. The large steel brakes never faded, and the firm pedal familiar to BMW faithful never went soft. As with the best sports cars, it was easy to find the ABS at the far end of the pedal’s travel and back off slightly to maintain full control. After I parked the Z4, I mused to our hosts, “Compared with either the M240i or even the M2, I wasn’t working nearly as hard to keep up. Did you slow down, or was the Z4 really that much better?” One of the BMW reps confessed in a hushed tone, “The Z4 is actually quicker around here than the M2.” OK, mind blown. I wasn’t expecting that. If the Z4’s reported weight and power specs bear out and genuinely compute to 8.9 pounds per horsepower, then it does have an advantage over the M2’s 9.6 lb/hp figure. Suffice to say that when properly equipped (and driven), the forthcoming 2019 Z4 M40i will be a worthy adversary to the Audi TT RS, Porsche 718 Boxster S, and Mercedes-AMG SLC 43 with a similar mid- to upper $60K price tag. Did you see that coming?

The Road Drive

As if the track drive weren’t reason enough to be convinced of the Z4 M40i’s abilities, our hosts had also carved out an hour’s drive on public roads. For this portion of our program, I sampled Comfort mode, which was too soft for track duty. With the exhaust muted and the top down, it was truly comforting to motor around the French countryside and easy to carry on an in-depth conversation with BMW’s vice president of customer orientation, driving dynamics, press support (and driving instructor for internal BMW certification), Jos van As. It was encouraging—and only a little surprising—to learn that Jos is a huge fan of the Ford Mustang Shelby GT350R and is intent on finding a way to import one to Germany. These BMW Dynamics guys are real car guys. The bumpy-road portion he had selected was smoothed out by the Z4’s needle-valve adjustable dampers. Having spent an entire year in a long-term 2017 BMW M2 with fixed/firm springs and shocks, I truly appreciated the Z4’s Comfort mode. There were several occasions to pass slower traffic (which we did with ease), plenty of hairpins and city streets, even a short blast of highway. The Z4 felt immensely competent and controlled throughout. Its bandwidth is exceptional thanks, in large part, to the cohesive tuning of all the various parts and within their respective and distinct modes. BMW got it right.

The First (Real) Look

Before we left, a final, especially jolly host, Albert Maier (driving dynamics), had one more reveal for us: two undisguised Z4s, one in deep red paint on a lift and one bedecked in a matte silver paint job. We soon learned why the car felt so stiff. There are multiple braces and an integral aluminum (not plastic) belly pan at the front of the car that not only delivers good aero but is securely bolted in such a way as to also add actual structure and rigidity. Does the car look like the BMW Z4 concept revealed at Pebble Beach? Sadly, no. Imagine that car but with most of the dramatic edginess removed, almost certainly due to production/stamping realities. The front fascia lacks the concept’s pronounced cheeks and deep cooling ducts. The doors are less sculptural, but the rear comes closest to the concept with narrow LED taillamps and the horizontal gesture. Also, what contours remain on the production car largely get lost in glossy paint. Like the concept, the matte paint does a far better job of showing off the car’s sculpture and shadows, and BMW told us it will be available for about triple the cost of a metallic color. Ouch. The concept’s old-school double-cowl treatment behind the headrests is replaced with more common roll hoops and a flat deck. Inside, there’s no two-tone interior treatment, and the steering wheel is humbler, but the rest of the center stack/console remains.

The End and a Beginning

As the eager Z4 team probed us for our opinions at the conclusion of this exclusive event, it became clear that we had very little criticism regarding the 2019 BMW Z4 M40i. “The concept looked edgier, but the way it drives? I don’t think I’d change a thing. Maybe the shift speed in Sport mode could be sharpened up a bit?” Not satisfied to present a mere incremental successor to the Z4, this team has produced a car that will be reviewed as a sports car among the very best in its segment. As with other recent BMW releases and rereleases, it appears that BMW has gotten its groove back. We couldn’t be happier for them—and for us. Thank you, BMW, for the opportunity and for the surprises along the way.