2007 BMW Z4 Review

Specifications

BMW Introduces Z4 M-Roadster and Updates Rest of Z4 Range Next Year

After denying its existence, or any plans to create it since the birth of the Z4, BMW has finally announced that it will in fact be producing an M-Motorsport version of the two-seater roadster. Officially, the model will be christened the Z4 M-Roadster (not M4), and acts as the halo to an update of the Z4 lineup, come 2006.
 
The one question that must be asked - if BMW was so persistent about the vehicle not existing, why bother to release it now? Fierce competition and stagnant sales is the answer, and in short, its what Munichs blue and white propeller is facing in the hotly contested, albeit somewhat slow roadster market segment. Lets face it, when reputations are on the line, particularly among one that creates some of the worlds finest driving machines, you cannot afford to fall behind, particularly against arch-rivals.
 
Given four years have elapsed since its launch, 2006 is just about right for a mid-life Z4 update. While theres no denying that BMWs roadster was a brilliant step forward from the slapdash Z3, which featured 80s E30 3-Series suspension components and lackluster powerplants (M-Roadster aside), the Z4, possibly due to its radical and therefore controversial styling, never managed to match up to the hype of its predecessor. An observant eye would have seen this update coming from a mile away, given the exhibition of the near production-ready Z4 Coupe Concept at Frankfurt, and now the M-Roadster variant.

As with the past M-Roadster, the new cars exterior changes are understated. Visual mods include a new front valance stylized after the M5s air-splitter, while in back the bumper integrates quad pipes and a downforce-inducing rear diffuser. A 0.4 inch drop in ride height over comparable models, and 18-inch alloy wheels round out the exterior treatment. Minor revisions to the cars body mean that it is 0.9 inches longer, 0.1 inches higher and rides with 0.07 inches extra between its wheels, but track and width remain constant.

Under its sharkish snout, the M-Roadster is powered by the existing 3.2-liter inline-six from the current M3, not the next-gen 400-hp 4.0-liter modular V8. Outputs in power and torque are unchanged at 330 at 7,900 rpm and 262 at 4,900 rpm respectively (343-hp and 269 lb-ft European specification), but placed in the Z4s vastly lighter frame it makes for an increased power to weight ratio of 241 hp/tonne compared to the M3s 218 hp/tonne (metric figures). Zero to 60 mph acceleration time is 4.9 seconds flat, with an electronically-limited top speed of 155 mph.
 
But just because the M-Roadster doesnt debut BMWs latest technology doesnt mean its not a credible sports car. Engineers have worked to make it one of the most complete sports roadsters to date by reworking the M3s six-speed manual gearbox with a shorter final drive to improve in-gear and overall acceleration. Also included is the M3s M-Variable locking differential, which has the unique ability to control power distribution by locking the rear axle for improved traction in all road conditions. Seeing as this is a true enthusiast product, the six-speed SMG sequential gearbox is not offered.

Deemed sufficiently rigid, BMW did not add additional bracing or rigidity to the Z4s body for the M model. Handling, however, has been improved by using a conventional hydraulic steering system which replaces the regular Z4s electrical assist for improved steering feel. The cars battery has been moved to the rear of the vehicle to help restore weight distribution. Minor improvements to the cars electronics include Start-Off assistance for hill starts, as well as Automatic Dry Braking which sweeps water off the discs, priming them for better wet-weather performance. The brakes themselves are lightweight units borrowed from the track-tuned M3 CSL.
 
Equally important, and not to be overshadowed, the rest of the Z4 lineup has also been updated. While the roadster is an important member of the BMW family, it has been neglected in light of the newer, bolder 5- and 3-Series. Current cars dont feature the latest engine and transmission technology, despite the fact that BMWs pride lies in producing driver-intuitive vehicles. Outclassed, and running on old technology, the base Z4s will finally receive the attention they deserve.

For 2006, the North American model range will consist of the 3.0i and 3.0si, utilizing BMWs latest 3.0-litre engine range, both of which use BMWs new lightweight magnesium/aluminum composite block. Output jumps from 230-hp to 255-hp for the 3.0si, while the 3.0i is propped up from 184-hp to 215-hp. Acceleration to 100 km/h for the former is achieved in 6.0 seconds, while the base model needs 6.6 seconds to reach highway speeds. Two lesser models, the 2.5i and 2.0i base model featuring a 177-hp 2.5 I-6 and a smaller 150-hp, 2.0-liter inline six will be offered in Europe, providing a more economical and affordable version of the fun-to-drive roadster.

Changes for the regular model Z4s include a revised front bumper with repositioned intakes, fog lamps and cornering lights, while the new coltail has been cleaned up with a less cluttered trunk lid and different tail lamps. Four ors have been added to the range, and minor interior updates of trim and accent materials keep things fresh. Mechanically, the 2.5si and 3.0si models feature a new six-speed automatic with paddle-shift, which replaces the now-retired SMG (SSG) gearbox.
 
Having just missed this years Tokyo Motor Show, the 2006 BMW Z4 and M-Roadster will make their world debut at the Detroit Motor Show this January. Prices have been announced only in Euros so far; the Z4 2.5si starts at 34,400 euro (approx. $41,500), the Z4 3.0si at 40,400 euro (approx. $48,800), and the M-Roadster at 57,900 euro (approx. $70,000) - equivalent U.S. prices will probably be slightly lower. Also, expect to see the production version of the Coupe to make its debut at the show, rounding out the Z4 lineup.