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BLOWN AWAYROAD TEST >> BIMOTA DB11VLX <<

We heard you coming way before we saw you, but this engine didn’t sound like anything else on the highway; it was screaming,” said the

youthful Italian police officer who’d pulled me over on the road from Misano to Pesaro in Italy. It’s a stretch I know by heart for all the likely lurking places for him and his mates to hang out holding speed cameras – which is why I’d backed off the gas on the

Bimota just cresting the hill, to save lining his coffers with a fistful of Euros. After examining my papers and finding nothing he could get the cash register ringing for, we came to the real reason he’d stopped me: “So, what is this bike?”

Well, officer, it’s the prototype of Bimota’s latest and very definitely greatest model yet in terms of performance – the supercharged DB11VLX – and when it reaches production at the end of this year, it will unquestionably be the fastest-accelerating series

production motorcycle yet offered for sale by any manufacturer. That’s thanks to the humungous 142.7Nm of torque delivered to the rear wheel at just 7750rpm by its otherwise completely stock liquid-cooled Ducati 1198cc Testastretta Evoluzione eight-valve superbike motor. Here it’s in the guise it’s fitted to the Diavel custom cruiser, which previously delivered 118.8Nm on the Bimota dyno at 8000 revs before they bolted on a Sprintex volumetric supercharger developed in Western Australia. As well as delivering

TEST ALAN CATHCART PHOTOGRAPHY KEL EDGE

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Bimota’s mental new DB11VLX is the first production motorcycle with a bolt-on supercharger

SUPERCHARGED

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that 20-percent extra dose of torque from what’s an already pretty muscular motor in Diavel guise, the Sprintex pushes peak power up to 197bhp (147kW) at the crank at 10,200rpm, a significant 19-percent lift from the normally aspirated stock engine’s 162bhp (121kW) at 9500rpm. It’s even slightly more than the 195bhp (145kW) at 10,750rpm delivered by the new 1199 Panigale R, which also comes up short in terms of muscle, producing a mere 132Nm of torque at 9000rpm!

Interestingly the Panigale is the reason for creating the new Bimota DB11VLX in the first place. “Ducati won’t supply us with the Panigale engine for installation in a Bimota model until 2015,” Acquaviva states. “So this means that, until then, for the next two years we at Bimota must use the existing 1198 Testastretta engine that already powers our DB9 and DB11 models.”

Which isn’t exactly in keeping with Bimota’s traditions of always offering its customers leading-edge engineering. “So as a way of improving the performance of that engine, we decided to supercharge it,” says Andrea. “Our Bimota DB11 Compressore will be the first production motorcycle from any manufacturer to be fitted with a volumetric supercharger, as opposed to an exhaust-driven turbocharger, with all the problems of installation, excess heat and especially throttle lag that such a system entails.”

This means the supercharged Bimota delivers a whopping 181bhp (135kW) to the rear Michelin Pilot tyre of the prototype testbike whose keys I was given for an afternoon spent exploring its incredibly intoxicating performance – even for someone like me who’s owned and ridden a Vee Two Super Squalo for five years.

The result is a more rideable and even torquier bike than my smaller-engined but more powerful (203.8bhp [152kW] at the rear wheel) 999-based device, thanks to their using the bigger 1198cc motor in Diavel guise, and a greater 20.3psi boost at 10,000rpm compared to the 8.1psi of my peakier Super Squalo. Compared to the 1198S superbike engine Bimota could have chosen, the Diavel version has various features that are more supercharger-friendly including revised cylinder head porting aimed at delivering a wider spread of power, a heavier flywheel, its compression lowered from 12.7:1 to 11.5:1 versus the 1198, and its valve overlap reduced to just 11° from 41° so as to smooth out the power delivery, to improve fuel consumption and emissions, and especially to improve low-down and midrange response.

SUPER WHAT?Supercharging (as opposed to exhaust-driven turbocharging) is a coming technology on two wheels

whose time is long overdue, seeing as how so many volume production car manufacturers have already embraced this ready means of obtaining

extra performance, as rediscovered in the past 30 years first by Lancia, then by Mercedes-Benz, Jaguar,

Cadillac, Aston Martin and BMW (via the Mini Cooper S). All without yet filtering down to a

motorcycle application, just as it took the bike world a good 20 years to adopt EFI across the

board even after this became ubiquitous in the four-wheeled world.

Using a mechanically-driven supercharger to compress the incoming charge doesn’t deliver

the same attendant problems of throttle lag, extra heat and increased bulk as turbos do, or as much of a weight penalty, but it does provide a comparable step in power. However, until recently the extra weight of the supercharger, plus the fact you had to give back some of the extra power you gained to drive it mechanically,

made supercharging unattractive for anything on two wheels, except drag racing.

But that’s all changed with the arrival of a new generation of lighter, more compact, more efficient compressors, and the technology to apply them via electronics. Turbos may still rule in the diesel car and commercial vehicle sectors, where compensating for the diesel engine’s traditional deficiencies in terms of performance while still benefiting from its miserly fuel consumption is all that matters. But with the advent of the electronic era in terms of engine management permitting engineers to govern boost via the ECU so as to vary it according to throttle opening, gear selected, rpm and road speed, all to enhance both torque and top-end performance without impacting too heavily on fuel consumption, it has to be counted as a surprise that the bike world has ignored all this – until now.

Thanks to bureaucracy and legislation, the merits of supercharging are finally poised to be exploited on two wheels as they are on four and to be truly honest, it’s about time.

Stock DB11 fuel tank as well, so you can throw the engine straight from the Diaval into

this if you wanted

Buy shares in a tyre company when you put the deposit

down on one of these

The chassis and engine are stock DB9/DB11 – the

charger has just been bolted directly on

Expect this to go up in the air under power in the first

four gears as you get on the gas

The Sprintex supercharger pushes peak power up to 197bhp (147kW) at the crank at 10,200rpm

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Finally you can legitimately say, “But it’s completely

stock, officer,” when a cop points at the supercharger

bolted to your bike

It also has lighter, stronger Vacural diecast crankcases which Bimota was eager to use for increased reliability with all that extra grunt available after adding on the Sprintex supercharger, while retaining the stock elliptical Mikuni throttle bodies, but now in the Bimota application with dual injectors per cylinder, both positioned south of the butterfly. Attached to this now is a belt-driven Sprintex compressor unit compact enough to fit between the frame rails, beneath the stock DB11 fuel tank. The entire chassis is stock DB9/DB11, and installing the supercharger entails no modification to the frame or stock Ducati engine: this is strictly bolt-on horsepower!

Crank up the starter and the blown Ducati engine already sounds pretty noisy but twist

that wrist, and it’s positively strident in the way it barks out a warning to all and sundry that this bike is on its way at warp velocity. Crank up the gas and the Sprintex-blown motor completely fulfils your expectations of urge, with wrist-yanking insistence and zero throttle lag – anyone new to riding a supercharged bike will soon learn the best way to handle this is to get it rolling off the mark, then gas it hard and hold on tight.

The ultra-distinctive whine of the supercharger at low speeds swiftly turns into a thrilling, spine-tingling scream that’s audible at almost any speed, although you have other things to worry about besides this in coping with the phenomenal acceleration from the near-as-dammit 200-horsepower V-twin motor, as the front

wheel power-wheelies in the bottom four gears. The supercharged Bimota completely lives up to its billing – this is the fastest-accelerating thing on two wheels with a licence plate, and probably on four, too. It’s an incredibly invigorating, extremely entrancing, fast-forward ride towards the horizon but a safe one, too. The Bimota chassis can handle these huge reserves of extra performance – just that you need to be careful in dialling up too much acceleration leaned hard over in turns to avoid asking too much of the rear tyre.

The Sprintex supercharger which delivers this mind-altering performance comprises twin intermeshing helical rotors – one convex and the other concave – which counter rotate without ever touching inside

an aluminium housing machined from solid billet, and thus with each rotation displace a set amount of air from the intake system to the discharge port. The design compresses the charge between the rotors and the housing. This differentiates it from other types of supercharger like the centrifugal blower which has a rotating impellor to accelerate air to high velocity, creating pressure as it backs up within the port, or the Roots-type vane blower which positively displaces a given amount of air into the discharge port, again creating pressure in the manifold as a result of overfilling the engine with air. “The difference between ours and the others is that they just blow air into the plenum chamber, whereas ours compresses the air inside the blower,”

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The ultra-distinctive whine of the supercharger at low speeds swiftly turns into a thrilling, spine-tingling scream

The supercharged Bimota’s debut at the 2012 EICMA Milan show

1. Electronic advances have made superchargers a viable power-up option2. Housing machined from solid aluminium for the supercharger’s twin intermeshing helical rotors

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explains former Sprintex R&D boss, Brook Henry. “That’s why you see the word Kompressor on the back of Benzes – the Sprintex design is similar and the great advantage is a lower discharge temperature, which creates a denser charge and greater volumetric efficiency, which is also the reason Bimota don’t need an intercooler and can run a stock Ducati radiator. But it’s important to stress that this is an entirely bolt-on package – a Bimota owner could switch the motor back to an unsupercharged Diavel engine again, if he wants.”

Interestingly, there’s quite a heavy load on the drive mechanism of a supercharger when you rev the engine up but there’s even more of a load under deceleration. It’s pretty

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Sprintex Superchargers is today a division of the Australian Automotive Components (AAC) group based in Perth, WA but was founded in Britain back in the 1980s by Glasgow-based Fleming Thermodynamics, which patented and produced the first Sprintex twin-screw superchargers. These acquired a loyal following in European automotive performance circles, and even ended up being factory fitted to TVR cars.

Brought south to England by top drag racer Dennis Priddle, Sprintex was then exported Down Under to Forced Air Technologies’ Danny Williams, who concentrated on its powerboat applications before selling the company, complete with patents, to Perth-based Advanced Engine Components (AEC), a local engineering group. Alternative supercharging applications for the WA mining industry were also developed, while Sprintex chief engineer Jay Upton has used its products for the past quarter century on a succession of drag bikes with which he’s burnt up strips around the world.

Most recent of these is the nitro-powered four-cylinder Sprintex Triumph which produces 1600bhp (1193kW) from 1400cc and is widely considered the most competitive single-gear dragbike in the world, running 45psi on the experimental Sprintex compressor it carries, and consuming two litres of nitromethane every second. “Petrol is for washing parts, alcohol is for drinking and nitro is for going racing!” says Upton, who currently holds the Australian quarter mile and terminal speed drag records (6.1sec@228mph), and is the reigning three-time Australian Top Bike Champion.

Sprintex was sold in July, 2003 to AAC – a private company founded by then-AEC directors Steve Apedaile and Tony Hamilton, who later that year purchased Vee Two Australia from Brook Henry, who has since retired from the company. Together with Upton, the duo have worked with automotive manufacturers and importers in developing dedicated supercharger kits for many different four-wheelers, and on two wheels the Harley-Davidson V-Rod and Honda VTX1800, as well as a pair of Ducatis – the S2R Monster desmodue and the 999S Testastretta-powered Super Squalo – and now the Bimota DB11VLX.

The Sprintex supercharger is a positive-displacement compressor with a patented twin-helical rotor layout which delivers lower discharge temperatures and higher volumetric efficiency. Such superchargers have long been the choice of engine builders in extreme motorsports such as drag racing and powerboating, but as most car manufacturers move towards smaller engine capacities to meet demanding emissions and economy standards, it’s now recognised that supercharging provides one of the most effective solutions for increased performance from smaller capacity engines, without the penalty of higher emissions.

AAC/Sprintex executives are banking on a similar trend manifesting itself on two wheels, with Bimota as their first motorcycle customer. “Essentially, we’re delivering bolt-on horsepower that’s environmentally friendly,” says AAC/Sprintex president Steve Apedaile. “Supercharging is great at delivering the excitement of raw power and performance – but it has significant environmental benefits, too, and these are only now being identified, with Sprintex leading the way.”

huge, because there’s pressure building up in the compressor when you back off the throttle, and on top of that you have the reverse inertia of the rotors and the gears which drive them, which you’re now trying to slow down, meaning the loads in the drive mechanism go the opposite way delivering an additional degree of engine braking. The drive mechanism on the Bimota takes the drive off a pulley positioned at the end of the gearbox shaft, then drives a belt operating another much bigger pulley which, because it’s so big in diameter, speeds up the drive without requiring a gearbox.

Instead, it’s duly geared up to four times engine speed, running up to the supercharger to drive it to deliver the boost.

The only drawback to the whole installation is the 10kg weight penalty of the entire Sprintex package – but that’s more than compensated for by the extra performance it delivers, and at a claimed 179kg dry, the DB11VLX is anyway claimed to scale just one kilo more than a Ducati Panigale R, even with the supercharger fitted. We’ll see when the final production version hits the showrooms how optimistic that figure may be.

The single most impressive feature of the Sprintex package powering the Bimota DB11VLX is the humungous torque the compressor delivers via an incredibly flat curve. Torque counts for more than power in delivering real-world performance – that’s what you really feel when you crack open the

THE SPRINTEX STORY

The single most imp ressive feature is the humungous torque the compressor delivers via an incredibly flat curve

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Main: It’s a pre-production prototype, so expect the �nished bike to look like a bazillion bucks1. Hopefully the speedo goes up to 2800km/h2. Data-logging the prototype

It is also completely content in riding along at 60km/h without overheating

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ENGINECon�guration V-twinCylinder head Desmodromic, four valves per cylinderCapacity 1198ccBore/stroke 106 x 67.9mmCompression ratio 11.5: 1Cooling LiquidFueling Athena EFI, Sprintex superchargerPower 135kW @ 9750rpm (claimed)Torque 143Nm @ 7750rpm (claimed)

TRANSMISSIONType Six-speedClutch WetFinal drive Chain

CHASSISFrame material SteelFrame layout TrellisRake 25˚Trail Not given

SUSPENSION Front: 43mm USD, diamond-like coating, fully adjustable Rear: Extreme Tech monoshock, fully adjustable

WHEELS /TYRES Wheels Cast aluminium �ve-spokeFront: 17 x 3.5 Rear: 17 x 4.5Tyres Michelin Power One Front: 120/70ZR17 (58H) Rear: 190/55ZR17 (66H)

BRAKES BremboFront: Twin 320mm discs, four-piston calipers Rear: Single 220mm disc, twin-piston caliper

DIMENSIONSWeight 179kg (dry, claimed)Seat height 800mmMax width 730mmMax height 1100mmWheelbase 1430mmFuel capacity 18L

PER FORMANCEFuel consumption Not givenTop speed Ridiculous

CONTACT & SALE INFOTestbike Bimota AustraliaContact www.bimotaaustralia.com.au 1300 869 245Colour options TBCWarranty TBCPrice TBCAus availability 2014

throttle on any bike. With supercharging, boost produces torque, but is rev-related because the faster you spin the compressor, the more boost you get, so the more torque you have, the faster you accelerate. The mapped-in refinement delivered by today’s electronics, such as the Bimota’s dedicated Athena ECU which varies the boost in accordance with such parameters as engine rpm, throttle opening, and gear selected has transformed the way supercharging is now used. I do wish there was a way of silencing this pre-production prototype’s muted scream at low revs and/or low throttle openings via a more effective blow-off valve, just to make it slightly more civilised at slower speeds.

The Sprintex-supercharged bike is completely content in riding along at 60km/h in third gear without overheating and Bimota’s VLX project

leader, Davide Comandini, says that in over 20,000km of road use and dyno time, the engine has proved totally reliable even during extended runs on continuous high boost.

If Bimota can put this bike into production while satisfying Euro 3 regulations – noise, especially – without sacrificing too much of the outrageous acceleration the Sprintex compressor delivers, it will establish a whole new performance benchmark for street-legal motorcycles, and make the Ducati Panigale, BMW S1000RR, Kawasaki ZX-10R and their like seem positively limp-wristed by comparison.

And I guarantee you, based on my own experience with the Super Squalo, that once anyone samples the thrill of riding a street-legal supercharged motorcycle, everything else will seem second best. As indeed it is.

1. Brembo: nothing but the best for a Bimota2. The chassis and suspension can handle the massive amounts of power well

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