This article was first published in the 2011 BMW Car Club Magazine
The BMW Z4 M Coupe and Roadster were the last of the old-school M cars, it was an enticing recipe that has all but disappeared from modern alternatives.
Unlike its predecessor, the BMW Z4 M was always going to be a part of the Z4 range from the start and this time the differences between the Coupe and Roadster variants were minimal, you could have your M car kicks with the roof up or down. Both body styles were released in 2006 and utilised the 252 kW S54 3.2-litre inline-six that had done duty in the E46 M3 and final variants of the Z3 M (albeit in detuned form).
The Z4 M was a class-leader in terms of straight-line performance but could be a handful in the corners if you didn’t know what you were doing. The intrusive traction control system was best left off for quick progress and the granite hard ride could concertina your spine over bumps. So, it may not have had the refined road manners of the E46 M3 or its more direct mid-engined Stuttgart rival, but for some that was what made the Z4 M so desirable in the first place. Being designed as a convertible from the off meant that the Roadster was actually a little lighter than the Coupe, it had softer shock settings and a slightly slower steering rack, but don’t confuse it for a boulevard cruiser, both M cars were clearly intended to be driven with enthusiasm.
The Z4 M signalled the end of the naturally aspirated inline-six engine for the M division, its hydraulic power steering has long since been dropped in favour of electrical systems while the traditional six-speed manual transmission is the exception rather than the rule these days. There have certainly been some great M cars since the Z4 M, but its particular recipe is no longer on the menu at BMW. If that is something you lament, then this characterful little modern classic may be just the thing.
BMW Z4 M Engine
The S54 engine was a known quantity by the time it came to be used in the Z4, early issues like failing Vanos units and conrod bearing failures had been largely resolved. A handful of Vanos failures have been noted by some owners but regular oil changes can greatly reduce this occurring. It is also worth it to get the rod bearings done if the car has done big mileages or you aren’t sure of its service history.
The 2,000 km oil change was considered crucial on these engines as the ‘running-in oil’ needed to be changed to prevent undue wear but this theory has not really proven to result in damaged engines on cars that had their first oil changes done after this point.
Rough running can sometimes be traced down to a dirty idle control valve and the hard suspension can actually lead to the engine mount bolts breaking. Stronger replacement items are available from specialists. Aside from bolting on a supercharger there is not much to be gained in tuning the highly-strung S54 motor, CSL-style carbon intakes and a remap add a few kW and enhance the intake noise but the cost is rarely worth it. If the car you are inspecting has been modified in some way, be sure to check that it has been done by a reputable specialist.
BMW Z4 M Gearbox
The six-speed manual transmission was a different design to the unit used in the E46 M3 and while it is strong with few issues, owners have complained of an obstructive shift quality which can slow down cog swapping when in a hurry. Changing the gearbox oil can usually alleviate this.
Suspension and Brakes
The Z4 is a hard riding car, Roadsters had slightly softer suspension settings but both variants can deliver bone-jarring progress over uneven surfaces. Uprated springs and shocks have been found to improve both the ride and handling. Bushes and springs can give issues from as little as 80,000 km so some owners have upgraded the standard setup on higher mileage cars.
The brakes are off the M3 CSL and are more than enough for fast road use, harder pads are recommended for track use.
Bodywork
Rust is rare but can rear its corrosive head around the bootlid and if the Roadster’s drain holes get clogged the interior can become damp. Keep an eye out for accident damage, the tricky on-the-limit handling has caught out many unwary drivers, sometimes resulting in a sideways exist off the road.
Interior
The interior is a mix of quality leather and materials as well as some rather hard plastics around the doors and dashboard that can show wear and tear rather quickly. Check that the window slots into its rubber grooves without issue. The cockpit is a tight fit for taller drivers, more so on the roadster (with the roof up of course).
Some cars came fitted with an infotainment screen but the options you really want are the PDC and cruise control. The first to avoid dings when backing into a parking bay and the second to avoid speeding fines when driving on the highway.
Model History
2003: BMW E85 Z4 launched
2006: Z4 M E86 Coupe and E85 Roadster introduced. 252 kW 3.2-litre inline-six, manual transmission and LSD standard. Roadster features slightly softer suspension setup
2008: Last Z4 rolls off the line
Production numbers:
Roadster LHD: 4,466
Roadster RHD: 921
Coupe LHD: 3,529
Coupe RHD: 1,052
Which Z4 M To Buy
The BMW Z4 M in either Coupe or Roadster form offers an exhilarating drive that is markedly different to anything you would experience in a modern sports car. It rewards good drivers and bites inexperienced ones; the hard suspension can be uncomfortable on less-than-perfect road surfaces, and you won’t fit much in the boot of either variant. On the right road, though, the Z4 M’s strengths shine through and there is little else out there that can deliver this much fun at the price.
After just two years in production a total of 5,387 Roadsters and 4,581 Coupes were built, this makes the Z4 M cars rarer than their Z3 equivalents, yet despite this the older car enjoys a big price premium in today’s market. The Roadster may have been more expensive when new, but the Coupe is generally found to be trading at a premium these days and low mileage cars can sometimes command silly prices.
We wouldn’t be too fussed about higher mileage cars as long as the service book has all its stamps, multiple owner cars are less desirable and cars with a few track days under their belts may need more thorough inspecting for wear and tear.
BMW Z4 M Specifications
3.2-litre inline-six
Power: 252 kW
Top speed: 250 km/h (limited)
0-100km/h: 5.0 sec
