This fully custom carbon wide-body Z4 is one of the most magnificent machines we’ve seen.
The basic silhouette of this car is instantly recognisable – it is, of course, a Z4. And yet, there isn’t a single original body panel there. It’s wider, meaner, more aggressive. And we’re not looking at fibreglass here. Words: Daniel Bevis. Photos: Andy Tipping.
Here’s a fun experiment for you. Take a bunch of carbon atoms, and bond them together into crystals that are more or less arranged in a line. Repeat this a few thousand times, then bundle all the strands together into a sort of tiny untwisted rope. Okay, now lay a load of these little ropes into a thermoset resin – epoxy, say, or polyester – bake for 40 minutes at 200°C (or something, consult your mum’s dog-eared Delia Smith cookbook) and voilà: you’ve just made some carbon fibre. Well, carbon fibrereinforced polymer, to be precise, although if you’re getting matey with your new creation then simply ‘carbon’ will work as a nickname.
Now you’ve got something with a very high tensile strength, low weight, high stiffness, high temperature tolerance, low thermal expansion, and high chemical resistance – all the properties you may desire for making housings for oily machinery without adding too much mass. The benefits of this miraculous weave are manifold and obvious, it hardly needs explaining why it’s so desirable to replace bits of your car with carbon fibre facsimiles.
Making things simultaneously stronger and lighter is a no-brainer. Your car will go faster and be safer. Of course, it’s also pricey – making CFRP is a fiddly process – which is part of the reason why you often see people running unpainted carbon fibre bonnets and what-have-you. It’s a badge of honour. It’s a direct link from your car to a McLaren F1, the first road car to sport a CFRP tub. And while certain manufacturers are making great advances in the field of enabling carbon fibre to be cheaper and easier to mass-produce (look at the Alfa Romeo 4C, for example, which is the first non-supercar to feature a carbon fibre tub; Lamborghini is making some exciting advances too), it’s still a evocative and aspirational material to be working with. Just look at the work of Alberto Torres of Slek Designs in Long Beach, California – he’s a man who appreciates the mystery of the black sheet and has been spellbound by its wiles for some time now. Slek Designs is an outfit that prides itself on mastering the dark art of carbon fibre custom work, promising ‘features and detailing you will not find anywhere else’, thanks to its equipment that healthily exceeds aerospace autoclave specs and a dedicated team who guarantee perfect fitment of all parts. And what better way to showcase their talents than by crafting an entire car out of carbon fibre?
Now, this kind of project requires an interesting base car for the ethos of the project to pivot around. Sure, it’d be impressive to take, say, a Toyota Prius or a Tesla Model S and replicate all of its body panels precisely in carbon fibre in order to draw commercially entertaining parallels about economy and range, but where’s the fun in that? Any chump with an autoclave can take a mould of a panel and mock up a lighter one – Slek needed to think laterally; it needed to make something truly unique. Something beyond custom. Something visually arresting. And that, in a nutshell, is what you’re looking at here.
Yes, that’s right, it’s a Z4. But not just any Z4… it’s the top-of-the-tree, full-fat Z4 M, the delicious little reprobate that came bursting at the seams with the brutal S54B32 engine – the same rampaging six-pot you’d find in an E46 M3. That’s a hell of a lot of engine to stuff into a diminutive two-seater roadster. But wait… the more observant among you may have spotted that this car doesn’t have a roof; those that have heard of #Slek-Designs
will have forged a mental association between the company and a certain Z4 Coupé that wowed the crowds at SEMA back in 2013. So what gives? Have the team taken a tin-opener to the hard-top and reworked the thing entirely? Ah, no, this is actually an entirely different car. But its inspiration came from that self-same Coupé. You see, back in 2013, Slek rolled into Las Vegas with a terrifying interpretation of the tin-top Z4 M. It had supercharged the S54, furnishing it with a loopy 570hp, and it was raising a lot of eyebrows. The modified #BMW
scene took careful note, as a truly mould-breaking (in all senses of the word) Z4 blew the established benchmarks into the weeds. This was a new world order of Z-car mischief.
Its flawlessly aligned weaves and race car cues caught the eye of one individual in British Columbia, who shall remain anonymous here for reasons of modesty. He wanted one. He wanted one badly. So he commissioned local tuning hero Flow Automotive to make the dream come true.
“To be honest, I never really liked the Z4 before this one, largely as I can’t fit in them,” shrugs Flow’s business mastermind Patrick. “But this wide-body makes it so aggressive!” Well, you can’t argue with that, can you? So why did this mystery wide-body-fancier choose this company, what’s the deal there? “Our shop does any kind of work,” says Patrick, matter-of-factly. “Restoration, performance, or even just basic maintenance. We’d love to be able to do resto or project car stuff all day every day, but the scene and market in our area isn’t really conducive to that, so we make ends meet with maintenance and service.
Although our lead tech, Hartley, is a master fabricator too…” And therein lies the rub. The truth of the matter is that if you’re after quality custom work in British Columbia, these are the lads you want to talk to. Let’s start, then, with the most obvious part of this build: that insane CFRP bodywork. “The cost of the carbon fibre body was around $20k,” Patrick explains. It’s a sizeable wedge of cash, but doesn’t that sound like good value when you consider that it’s basically a whole car shell made from scratch? Ah, but this has been done before of course, so the dimensions were already sketched out: “We delivered the car to Slek for prototyping and testing,” he continues. “There were some minor changes to redesign over its original Z4 Coupé concept, but it wasn’t as if it was starting from nothing.”
With the brutally wide panels having been lovingly hand-crafted and slathered in clearcoat to showcase the racy material, Slek itself insisted on fitting all of the panels to the car. “Slek wanted it to be absolutely perfect for SEMA,” Patrick laughs. This was very wise – with an idea as outlandish and eye-catching as this, the world would undoubtedly be keenly watching; when people see such a thing and comment that the shutlines are factory-perfect and all the weave angles match, an excitable crowd would undoubtedly beat a path to Slek’s door. It is, after all, a pioneer in the field.
With the devastatingly naughty new body in place, the Z4 M was back up to Canada for the work to continue. “We threw on an amazing big brake kit from Sparta Evolution,” Patrick enthuses. “Six-pots at the front and four-pots out back, with its innovative S-groove discs. This was followed up by retrofitting an E46 M3 coilover setup from Status Gruppe – it’s a brand that we really want to champion, because its product isn’t hugely known but should be for a company that produces such premiumquality parts.” And the next job, naturally, was to fix upon the rolling stock; after all, what kind of self-respecting show car wouldn’t be rocking the latest fashionforward rims in this day and age?
“Slek’s carbon Coupé was running gold RSV Forged wheels, and the ones the owner picked for this car are a natural evolution from that,” Patrick explains. “These wheels are more of a brushed copper, which contrasts brilliantly with the carbon fibre, and they’re wrapped in some spiffy Nitto Invos that the sponsor supplied.” The rims measure a staggering 14x19” at the rear (and a still mighty 10.5x19” up front) and come from RSV’s C|R Series, with the rear tyres offering a bonkers 345-section – plenty of rubber to harness the snorting horsepower from that revered S54 motor.
“This Z4 M’s engine is currently stock,” says Patrick, “other than the upgraded headers and a brand new air box to fit the reprofiled hood. However, a friend of the owner has an E30 that we restored and turned it into a track car for him. He’s interested in buying the S54 to swap into the E30… and has convinced the owner to look into a V10 swap for the Z4 M! It’d be a huge job, but we’d tackle it all the same.”
Regardless of powerplant – and let’s not sideline the S54, it’s still an absolute peach – this shadowy owner gets to enjoy one of the most eye-catching and talked-about Z4 roadsters the world has ever laid eyes upon. As its clearcoat sparkled under SEMA’s searing lights, nestling proudly on the Nitto stand at last year’s show while the guys from Flow buzzed around polishing people’s fingerprints away, it was surrounded by dropped jaws and camera-flashes. And that continues to be the case. An all-carbon fibre wide-body Z4 is an incredible thing. A droptop evolution to carry on the magic of the show-stopping Coupé, taking the reins and stopping the show all over again? That truly is a dream, woven from humble carbon into the roadster of the gods.
“These wheels are a brushed copper, which contrast brilliantly with the carbon fibre, and they’re wrapped in some spiffy Nitto Invos” Exterior is incredible but interior hasn’t been forgotten about, with sumptuous seats and lashings of carbon, obviously.
DATA FILE #BMW #Carbon #Z4
ENGINE & TRANSMISSION 3.2-litre straight-six #S54B32
, custom air box, #RPi-GT
stainless steel exhaust system with Helmholtz resonators, stock six speed manual gearbox.
CHASSIS 10.5x19” (front) and 14x19” (rear) #RSV-Forged
C|R Series RSF1 wheels in brushed copper with 275/35 (front) and 345/30 (rear) #Nitto-Invo
SGT-SRS coilovers, #Sparta-Evolution
front calipers, four-pot rear, #Sgroove-Pegasus
discs – 355mm front, 345mm rear).
full carbon fibre body (comprising front and rear bumpers, front wings, rear quarter panels, bonnet, doors, side skirts and bootlid), #OSS-Designs
carbon fibre seats with diamond-stitched Alcantara, carbon fibre dash inserts and trim.