The success of the BMW Z3 has led to the development of the next series of sports roadsters. The Z4 was designed to address problems in the Z3 by providing a stiffer chassis and a more advanced multi-link rear suspension. Adhering to the 2-seat, 2-door configuration with very sporty looks, the Z4 was longer and wider than the previous Z3. 

It was initially introduced as a convertible model, but a sportier coupe version was later released. The Z4’s design looked more aggressive than the Z3 it was replacing. The boot and cabin were now roomier, but BMW was still able to make this car live up to its true form as a roadster.

First Generation Z4 (E85 / E86), 2002-2008

The roadster version is known as the E85 series with the later coupe variant, released in 2006, designated as the E86. Production was done solely in the US at the BMW Spartanburg facility. Interior is dressed up with good quality leather with brushed aluminium finished trims, with latter options having wood trims. Control switches and gauges are unobtrusive and very easy to use, adding to the very simple, classy design. 

Standard equipment for safety and convenience were the same as the previous late-model Z3s with, of course, the multiple options available as expected from BMW. Minor styling changes were done in 2006 together with the release of the coupe version. Standard also in all Z4s is the electric-powered convertible top that folds down in a few seconds when activated. 

When it was first released, the engine options were limited to the inline-6 cylinder with a four-cylinder version being offered in select markets worldwide for the 2005 model year. 

• 2002-2005 – 3.0i – 2.5L M54B30 (170 kW / 300 N⋅m)

• 2003-2005 – 2.5i – 2.5L M54B25 (141 kW / 245 N⋅m)
• 2003-2005 – 2.2i – 2.2L M54B22 (130 kW / 210 N⋅m)
• 2005-2008 – 2.0i – 2.0L N46B20 (110 kW / 200 N⋅m), I4 only available in Europe
• 2006-2008 – 3.0i – 3.0L N52B30 (160 kW / 250 N⋅m)
• 2006-2008 – 2.5i – 2.5L N52B25 (130 kW / 230 N⋅m)
• 2006-2008 – 2.5si – 3.0L N52B25 (160 kW / 250 N⋅m)
• 2006-2008 – 3.0si Roadster – 3.0L N52B30 (195 kW / 315 N⋅m)
• 2006-2008 – 3.0si Coupe – 3.0L N52B30 (195 kW / 315 N⋅m)
• 2006-2008 – M Roadster – 3.2L S54B32 (252 kW / 365 N⋅m)

• 2006-2008 – M Coupe – 3.2L S54B32 (252 kW / 365 N⋅m)

All Z4s used electric power steering except for the Z4M Roadster/Coupe which was equipped with a hydraulic power steering unit. Transmission options were a 5-speed auto, 5-speed manual, and a 6-speed manual gearbox. 

Second Generation Z4 (E89), 2009-2016

With the production of the E85 finishing up in 2008, the second-generation Z4 (E89) was released the following year. It was a completely new car but retained the general form of the previous. There is no longer a distinction between a roadster and a coupe as this model had a retractable hardtop, a two-piece aluminium top that takes about 20 seconds to convert a coupe to a roadster.

They were designed entirely by two female designers, Juliane Blasi for the exterior and Nadya Arnaout for the interior. Production of the E89 was moved back to Germany for this model following in the footsteps of the Z1 and Z8.

The interior was still very sporty and luxurious as could be expected from BMW. Standard equipment for all E89 Z4s included the BMW Efficient Dynamics Technology taken from the Efficient Dynamics concept “the pursuit of an enhanced, athletic driving experience while simultaneously lowering the consumption and emissions of a vehicle.”

Diesel and all-wheel-drive options, as found in other BMW series during this time, were not available in the Z4. There was no "M" variant for the E89, but an M-Sport trim was available as an option which included 18-inch alloy wheels, redesigned front and rear bumpers, sports steering wheel, M-sport seats and suspension upgrades.

• 2009-2011 – sDrive30i – 3.0L N52B30 (190 kW / 310 N⋅m)
• 2009-2016 – sDrive35i – 3.0L N54B30 twin-turbo (225 kW / 400 N⋅m)
• 2009-2011 – sDrive23i – 2.5L N52B25 (150 kW / 250 N⋅m)
• 2011-2016 – sDrive20i – 2.0L N52B30 turbo I4 (135 kW / 270 N⋅m)
• 2011-2016 – sDrive28i – 2.0L N52B30 turbo I4 (180 kW / 350 N⋅m)
• 2010-2016 – sDrive35is – 3.0L N54B30T0 Twin-turbo (250 kW / 450 N⋅m)

The Z4 sDrive35si was the top-of-the-line E89 which had an additional option to be equipped with a 7-speed dual-clutch transmission in the M-sport upgrade. The sDrive35si with M-Sport also had a computer-controlled over boost for 7 seconds on each gear shift from 3^rd-7^th gear and produces 50 N⋅m more torque during this phase.

Third Generation Z4 (G29), 2018-Present

BMW introduced the third-generation Z4 (G29) at the Pebble Beach Concours d'Elegance Show on 23 August 2018. Toyota was looking for a new powerplant to power its new-generation Supra and decided to partner up with BMW who had a reputation for very dependable inline-6 cylinders. Consequently, the new Z4 and Supra were developed together to satisfy Toyota’s needs. 

The G29 now has a more aggressive exterior and an interior bristling with BMW's new electronics. The G29 also reverted to the powered soft-top convertible as opposed to the previous generations' lightweight aluminium.

Wider kidney grilles and bigger air ducts now adorn the front, which is either black or chrome depending on the trim and option package. The BMW infotainment is now a lot easier to operate and contains a host of new features. The car lock/unlock feature also locks when you walk away from the car and unlocks when you get near to it again.

Engine options are all petrol, and no all-wheel drives are offered for the Z4 G29.

• sDrive20i – 2.0L B48B20 Turbo (141 kW / 320 N⋅m)
• sDrive30i – 2.0L B48B20 Turbo (190 kW / 400 N⋅m)
• M40i – 3.0L B58B30 Turbo (250 kW / 500 N⋅m)
• M40i (US Version) – 3.0L B58B30 Turbo (285 kW / 500 N⋅m)

The 2020 models will now also include the sDrive28i powered by a 2.0L turbocharged inline-4 cylinder producing 179 kW and an sDrive35i with a turbocharged inline-6 with power rated at 224 kW. All the engines in the Z4s' line-up feature direct injection which gives bigger output for less consumption.

Roadster for the Future

There are many roadsters now available such as the Mazda Miata, Lexus LC and Mercedes-Benz AMG GT R. The Z4 is priced somewhere between them from the base models up to the new M-sport variants. A few collectibles are also in the Z4 series and are most probably on their way to become classics. The first generation Z4s are holding up pretty well, and prices are becoming more affordable. Long term reviews are all over and once again proving dependability and practicality of these models even as daily drivers. 

If you own a Z4, especially the older ones, visit us at Carpart.com.au and see our current listing of new and premium used car parts that will help you to enjoy these cars. When you've also set your mind to sell a used Z4 or used auto parts, contact us at hello@carpart.com.au, and we will be right there to help you. 

Fred Cajulis