The Last Emperor
A look back on the legendary #BMW-Z4M-Coupé
, the last of the naturally aspirated six-cylinder M cars. Emperor The last. If you follow the mantra that M cars should come with a naturally aspirated screaming straight-six then the Z4 M Coupé represents the last of the breed… fortunately it’s rather good, too Words: Bob Harper Photography: Steve Hall
It feels slightly odd to find myself for the second time this month writing about a car that I haven’t universally heaped praise upon in the past. Yup, the Z4 M Coupé has not always been on my list of ultra-desirable BMWs and I even remember it being the subject of a very heated argument in the office when we were selecting the cars for our Car of the Year test at the tail-end of 2006. I favoured the ‘M-lite’ 3.0si model whereas everyone else in the office thought the M Coupé should be on the short list. In all honesty I think the 3.0si is the better all-round car, certainly from the prospect of using it as a daily driver as it offers virtually the same performance as the M car, significantly better economy, a more compliant ride and much lower running costs all wrapped up in a similarly visually arresting package.
However, while that was my view then – and still is if you want to use a Z4 Coupé everyday – these days the M Coupé is starting to be appreciated for what it is: a mad, bad and brawny hot shoe – the last in the line of naturally-aspirated M cars that can trace its parentage all the way back to the original M1. Increasingly they’re becoming squirreled away as weekend cars, something to cherish and polish and then, when the mood takes you, to excite and exhilarate on an early morning cross-country dash that will have you grinning from ear to ear. The Z4 M is blistering quick – and still feels it – but it takes a strong and fully committed hand to fully tame it. To drive one quickly requires your full attention. Give it that and it’ll be hugely rewarding.
Under the M Coupé’s shapely bonnet was the last resting place for the venerable S54 straight-six, itself a development of the S50 ‘six that first saw the light of day in the E36 M3. It was a car that #BMW
claimed would never be built when the E85 generation of Z4 was created, claiming that the new Roadster was so torsionally stiff that a coupé wasn’t needed and that the regular 3.0i Z4 was so quick that there was no need for an M version. Fast forward a few years and the Z4 Concept Coupé was shown at the 2005 Frankfurt Motor Show and when we questioned one of BMW’s press bods at the time he more or less said, ‘if a BMW Concept has towing eye-covers, it’s production-ready.’ Then it was just a matter of time before the production version appeared, and at the Geneva Motor Show in 2006 the fully-fledged cars were shown for the first time with serial production starting just a month later. It wasn’t a particularly longlived M car, though, as just over two-years later it had disappeared just as quickly as it had arrived and the E85/6 generation of Zed was replaced by the less driver-focused E89 with its fancy folding metal roof, effectively killing the need for a coupé version. Of course, BMW M had form for making slightly crazy Zed cars by the time the Z4 appeared on the scene and despite the fact that the Z3 Ms were fairly deeply flawed pieces of kit they had a big following and their shortcomings could easily be overlooked thanks to their brawny characters. Quite why BMW changed its mind and decided to eventually offer the M versions isn’t fully known but perhaps the top brass wanted to have one last try to knock the Boxster off its perch, or perhaps the Zed Ms were seen as a useful way of filling the gap between the departure of the E46 M3 and the arrival of the E92 version. The Z4 Ms ensured BMW still had a presence in this section of the market, albeit with a less practical twoseater but we can’t really see it as being a fully commercial decision as with less than 5000 cars built in just over two years it’s likely the car didn’t recoup its development costs.
Knowing that the Z4 M was effectively going to be a limited production machine BMW could perhaps have been forgiven if it had scrimped slightly on its specification but by now we should know that M doesn’t generally do things by halves so the Z4 M Coupé was a fully-fettled M car. The engine was lifted directly from the E46 M3 and while it’s a familiar unit it should be remembered that it’s still an absolute peach. Double Vanos, an 11.5:1 compression ratio, individual throttle butterflies and an advanced engine management system ensured a high specific output and even today a normally aspirated engine that develops nearly 106hp per litre is something to write home about. Even within BMW M’s hallowed halls this is an outstanding achievement and betters the specific output of the later S65 V8 from the E9x M3 (including the GTS’s 4.4-litre) and even the E60 M5’s mighty S85 V10.
Unlike in the E46 M3, the straight-six was mated to a #ZF
transmission (the E46 used a Getrag unit) and the six-speed manual was the only option for the Z4; none of your fancy #SMG
gubbins here thank you very much. Naturally enough for an M car there was a limited-slip differential, BMW’s M Differential Lock, which despite being a fully mechanical item uses pressurised viscous silicon fluid to operate a multi- disc clutch to direct power to the wheel with the greatest traction. It also featured the latest version of BMW’s #DSC
traction control system along with the most up-to-date version of Dynamic Brake Control which added items such as brake fade compensation, brake standby, brake drying and hill-start assistant.
While the Z4 Ms used the same basic suspension setup as the regular production Z4 it was fine-honed by M to try to bring the best out of the car. Without a doubt the biggest change was the adoption of hydraulic power steering, as the electric setup of the normal Z4 was deemed not feelsome enough for an M car. The majority of the Z4 M’s setup was lifted more or less directly from the E46 M3 CS and it had an overall ratio of 14:5:1 which, interestingly, made it more direct than the rack that was fitted to the Roadster version of the Z4 M.
The rest of the M’s underpinnings were also beefed-up and while it still retained the basic MacPherson strut/multi-link setup of the Z4 it had a wider front and rear track, revised lower front arms and steering knuckles bolted directly to the front struts. Spring and shock absorber rates were unique to the car (and slightly stiffer than those fitted to the M Roadster) while anti-roll bars had larger diameters at 27mm and 22.5mm, front and rear respectively. At the rear there was a more heavy-duty rear subframe required to accommodate the larger M diff and there were also enhanced wheel bearings and reworked longitudinal links in the rear suspension.
That the Z4 M was going to go well was a given – it was, after all, nigh on 100kg lighter than the E46 M3 – so to ensure it stopped equally well M equipped it with the braking setup from the E46 M3 CSL with 345x28mm vented and drilled front discs and 328x28mm rears that were gripped by single piston swing callipers all-round.
Naturally enough there were exterior changes to the Z4 M and as we sit waiting for the sun to set for our cover image there’s plenty of time to take these in and while it’s perhaps not quite as outrageously distinctive as the Z3 M Coupé the Z4 version is still a stunning-looking piece of design. The beefed-up front and rear bumpers with their various cut outs and grilles for air intakes and exhausts add some much needed visual drama to the shape. The wide rear haunches seem to work particularly well with the sweeping rear hatch and with the exhaust pushed further out to the edges than in most other M cars it gives the rear end a feeling of real width and presence. The ‘Zorro’ slash in the front wings with the BMW roundels hiding the indicator side repeaters in the centre catch the dropping sun and create areas of light and dark – there always seems to be a little something extra to the shape that you’ve not seen before. Altogether it combines to create a machine that if I owned it I’d definitely have a sneaky glance over my shoulder at as I walked away after a spirited drive as the sound of hot metal ticking away to itself reminded me of the fun we’d just had.
Slipping into the cockpit reminds me of just how low these cars are and while the cabin is slightly on the snug side everything you could want falls nicely to hand. The leather-clad and M-logo’d gear knob is just a hand span away from the steering wheel, and while the latter item is nice to hold it’s perhaps not the most visually appealing item ever fitted to an M car. Instrumentation is minimal as per the standard Z4 but there’s the rev counter with illuminated segments that remind you not to thrash it from cold and an oil temperature gauge tucked away by the fuel gauge and the car’s performance potential is made clear by an 180mph speedo.
Where the Z4 M really scores over the 3.0si, though, is in the sense of occasion – a palpable sense of drama when you slip behind the wheel. There’s that dramatic view down the heavily sculpted bonnet (that the 3.0si didn’t get), and once you twist the key the straight-six sends tingles up your spine and gets the hair standing up on the back of your neck. To experience a fully wound-up S54 ‘six is a aural treat and you feel that you’re genuinely a witness to something special, and let’s not forget that it’s not something we’re expecting will be available for a long time to come with all the manufacturers following the turbocharged eco-friendly route.
The engine dominates the driving experience and you can make very decent progress without wringing the car’s neck and those sampling the car for the first time can often be caught out by short-shifting up the gearbox and even if you use 5000rpm the Z4 will be travelling very rapidly but you’ll be missing out on the best part of another 3000rpm. Hit the Sport button that sharpens up throttle response still further and use the full extent of the rev range and you’ll feel like you’re sitting on top of a low-flying ballistic missile.
You sit so much lower than in an E46 M3 that the sensation of speed is much greater and that’s before you factor in that the Z4 M is actually a quicker machine, too. 0-62mph at 5.0 seconds is 0.2 seconds faster than the M3 and 50-75mph in fourth gear is despatched 0.3 seconds quicker in the Z4, too, while over the standing kilometre the Z4 is again halfa-second quicker. Small increments, perhaps, but coupled with the low-slung Z4 and it feels like more.
This is compounded by perhaps one of the less likable aspects of the Z4 M: its ride. It’s pretty uncompromising and an M3 is more compliant and this can ultimately temper your pace on roughly surfaced roads. On first acquaintance it’s easy to feel that the Z4 M is attempting to throw you off the road and a tendency to understeer on the standard fit ContiSportContact tyres didn’t help to endow you with confidence in the chassis, but with greater familiarity it becomes clear that you can lean on the Z4 M pretty hard and it will reward the confidence you show in it. It’s a car that requires real commitment to get the best out of. Sure it’s a little rough around the edges when it comes to ultimate handling finesse but get it right and it’s hugely rewarding.
A few choice changes can also make it a better steer, too. Ditching the original equipment tyres for something with more grip – later generations of Pilot Sport work well – help to counteract that initial understeer, and the addition of a front strut brace also helps here. As standard the Z4 is fitted with a clutch delay valve and this can combine with a slightly notchy ’box to make gear changes less than perfect, but deleting it or fitting a modified one can really smooth out a jerky gear change. Many owners have also fitted 19-inch CSL rims in place of the 18-inch M Double Spoke Style 224 rims and this really does work wonders for the look of the car. If money’s no object you could fit aftermarket suspension, but ultimately when these machines start to become really collectible it will be the standard examples that will be worth the most.
When it was new the Z4 M Coupé cost a not insignificant £41,285, just a smidgen less than an E46 M3, which made it seem quite expensive when the M3 was a far more practical and almost as quick proposition. However, by the time the Z4 was discontinued its price had only risen by £1000 yet the E92 M3 that was then available cost over £50k which conspired to make the #BMW-Z4M
look like a bit of a bargain! These days prices start at around £13k for higher mile examples and rise to high £20s for really low mile examples being sold by franchised dealers.
The majority of cars fall in the mid-to-high teens bracket and represent excellent value for money. If you look after one and use it regularly but sparingly we don’t reckon you’re going to suffer much in the way of depreciation and if you hold onto it long enough you may well see values rise. Remember, only 1052 right-hand drive examples were built so rarity value certainly counts in their favour.
You could still use one every day if the fancy takes you, and bar the high cost of Inspection services there isn’t too much to worry about. The head gasket failures that afflict high mileage M3s are less of a problem with Z4 Ms as they were originally often purchased as a second car. However, I reckon you could become bored with its harsh ride, slightly cramped cockpit and brawny nature. Used sparingly, though, and every journey becomes an event, something to be looked forward to and savoured. It was the last of the line of great naturally-aspirated straight-six M cars and while it wasn’t perfect it’s still a marvellous machine to punt down a challenging bit of road. Nab one now before it’s too late.
Once you twist the key the straight-six sends tingles up your spine and gets the hair standing up on the back of your neck.
There’s a palpable sense of drama when you slip behind the wheel.
TECH DATA #2015 #BMW-Z4M-Coupé-E86
Straight-six, 24-valve, DOHC
MAX POWER: 343hp @ 7900rpm
MAX TORQUE: 269lb ft @ 4900rpm
0-62MPH: 5.0 seconds
STANDING KM: 23.7 seconds
50-75MPH (4th): 5.0 seconds
TOP SPEED: 155mph (limited)
WEIGHT (EU): 1495kg
TRANSMISSION: Six-speed manual, #LSD
STEERING: Rack and pinion
SUSPENSION: MacPherson struts (front), multi-link ‘Z’ axle (rear)
WHEELS: 8x18-inch (front), 9x18-inch (rear)
TYRES: 225/45 ZR18 & 255/40 ZR18
BRAKES: Single piston swing callipers front and rear gripping vented discs, 345x28mm (front) and 328x28mm (rear)
PRICE: £41,285 (2006)
Even today a normally aspirated engine that develops nearly 106hp per litre is something to write home about.