2020 BMW Z4 vs. 2019 Porsche 718 Boxster

Detailed Review, Specifications & Comparison

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Safety

The Z4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 718 Boxster doesn’t offer pre-crash pretensioners.

The Z4 has standard Post-Crash Braking, which automatically apply the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The 718 Boxster doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.

The Z4’s optional lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane. The 718 Boxster doesn’t offer a lane departure warning system.

To help make backing safer, the Z4’s optional cross-path warning system uses wide-angle radar in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The 718 Boxster doesn’t offer a cross-path warning system.

The Z4’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The 718 Boxster doesn’t offer a driver alert monitor.

Both the Z4 and the 718 Boxster have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, rearview cameras, available blind spot warning systems and rear parking sensors.

Warranty

BMW pays for scheduled maintenance on the Z4 for 2 years and 26000 miles longer than Porsche pays for maintenance for the 718 Boxster (3/36,000 vs. 1/10,000).

There are over 82 percent more BMW dealers than there are Porsche dealers, which makes it much easier should you ever need service under the Z4’s warranty.

Reliability

To reliably start during all conditions and help handle large electrical loads, the Z4 has a standard 800-amp battery (900 M40i). The 718 Boxster’s 450-amp battery isn’t as powerful.

From surveys of all its subscribers, Consumer Reports’ December 2018 Auto Issue reports that BMW vehicles are more reliable than Porsche vehicles. Consumer Reports ranks BMW 3 places higher in reliability than Porsche.

Engine

The Z4 has more powerful engines than the 718 Boxster:

Horsepower

Torque

Z4 sDrive30i 2.0 turbo 4-cyl.

255 HP

295 lbs.-ft.

Z4 M40i 3.0 turbo 6-cyl.

382 HP

368 lbs.-ft.

718 Boxster 2.0 turbo 4-cyl.

300 HP

280 lbs.-ft.

718 Boxster S 2.5 turbo 4-cyl.

350 HP

309 lbs.-ft.

718 Boxster GTS 2.5 turbo 4-cyl.

365 HP

309 lbs.-ft.

718 Boxster GTS 2.5 turbo 4-cyl.

365 HP

317 lbs.-ft.

Fuel Economy and Range

On the EPA test cycle the Z4 gets better fuel mileage than the 718 Boxster:

MPG

Z4

Auto

sDrive30i 2.0 turbo 4-cyl.

24 city/32 hwy

M40i 3.0 turbo 6-cyl.

24 city/31 hwy

718 Boxster

Manual

2.0 turbo 4-cyl.

21 city/28 hwy

S 2.5 turbo 4-cyl.

20 city/26 hwy

GTS 2.5 turbo 4-cyl.

19 city/25 hwy

Auto

2.0 turbo 4-cyl.

22 city/29 hwy

S 2.5 turbo 4-cyl.

21 city/28 hwy

GTS 2.5 turbo 4-cyl.

20 city/26 hwy

Transmission

The BMW Z4 comes standard with an automatic transmission, for driver comfort, especially in the city. Automatic costs extra on the 718 Boxster.

An eight-speed automatic is standard on the BMW Z4, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the 718 Boxster.

Tires and Wheels

For better traction, the Z4’s optional front tires are larger than the largest tires available on the 718 Boxster (255/35R19 vs. 245/35R20).

The Z4’s standard 255/40R18 rear tires provide better handling because they have a lower 40 series profile (height to width ratio) that provides a stiffer sidewall than the 718 Boxster’s standard 45 series tires.

Suspension and Handling

For better handling and stability, the average track (width between the wheels) on the Z4 is 3.5 inches wider in the front and 2.6 inches wider in the rear than the average track on the 718 Boxster.

The Z4’s front to rear weight distribution is more even (49.9% to 50.1%) than the 718 Boxster’s (45.5% to 54.5%). This gives the Z4 more stable handling and braking.

Chassis

The design of the BMW Z4 amounts to more than styling. The Z4 offers aerodynamic coefficients of drag from .29 to .31 Cd (depending on bodystyle and options). That is lower than the 718 Boxster (.31 to .32) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the Z4 get better fuel mileage.

As tested by Car and Driver, the interior of the Z4 sDrive30i is quieter than the 718 Boxster S:

Z4

718 Boxster

At idle

48 dB

54 dB

Full-Throttle

82 dB

88 dB

70 MPH Cruising

70 dB

75 dB

Passenger Space

The Z4 has 3 cubic feet more passenger volume than the 718 Boxster (52 vs. 49).

Cargo Capacity

With its convertible body style, valet key and remote trunk release lockout, the Z4 offers cargo security. The 718 Boxster’s non-lockable remote release defeats cargo security.

Ergonomics

The Z4 offers a remote vehicle starting system, so the vehicle can be started from inside the driver's house. This allows the driver to comfortably warm up the engine before going out to the vehicle. The climate system will also automatically heat or cool the interior. The 718 Boxster doesn’t offer a remote starting system.

Unlike the driver-only memory system optional at extra cost in the 718 Boxster, the Z4 has standard driver and passenger memory, so that when drivers switch, the memory setting adjusts the driver’s seat, outside mirror angle, climate settings and radio stations and the front passenger seat also adjusts to the new passenger’s preset preferences.

The Z4 offers an optional heads-up display that projects speed and other key instrumentation readouts in front of the driver’s line of sight, allowing drivers to view information without diverting their eyes from the road. The 718 Boxster doesn’t offer a heads-up display.

If the windows are left open on the Z4 the driver can close them all from a distance using the remote. On a hot day the driver can also lower the windows the same way. The driver of the 718 Boxster can only operate the windows from inside the vehicle, with the ignition on.

The Z4’s rain-sensitive wipers adjust their speed and turn on and off automatically based on the amount of rainfall on the windshield. This allows the driver to concentrate on driving without constantly adjusting the wipers. The 718 Boxster’s standard manually variable intermittent wipers have to be constantly adjusted.

The Z4’s sun-visors swivel front-to-side to block glare from the side windows. The 718 Boxster’s visors are fixed into the windshield header.

The Z4 has a standard dual zone air conditioning allows the driver and front passenger to choose two completely different temperatures so people with different temperature preferences won’t have to compromise. This makes both the driver and front passenger as comfortable as possible. Dual zone air conditioning costs extra on the 718 Boxster.

The Z4’s optional Parking Assistant can parallel park by itself, with the driver only controlling speed with the brake pedal. The 718 Boxster doesn’t offer an automated parking system.

© 1991-2018 Advanta-STAR Automotive Research. All rights reserved.

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