MK Indy RR Hayabusa | UK Review

MK Indy RR Hayabusa | UK Review


Explosive GSX1300R motor meets featherweight Indy RR base with exhilarating results By Sam Sheehan / Tuesday, September 22, 2020

If the yellow paintjob and semi-slicks weren’t enough of a giveaway, you should know that MK Sportscars’ Indy RR Hayabusa isn’t a traditional British sports car aimed at quick jaunts to the pub, or a roadster designed for touring across the continent. Far from it. This is MK’s idea of automotive madness turned up to eleven; a high-revving motorbike-engined featherweight intent on assaulting your senses with a surfeit of noise, speed and performance. It nails the brief ten times over, have no doubt about that, but then so do other bare-bone lunatics like the Caterham 620R and Ariel Atom 4. So, question is, what sets this Essex-developed machine apart from the rest?

Hayabusa. The word will either have stirred your soul or gone straight over your head. To those in the bike world, it’s a name at least as revered as the AMG M156 is on planet car; it’s the colloquial term for Suzuki’s 1.3-litre four-cylinder GSX1300R motor, infamous for its piercing exhaust note and ferocious appetite for revs. Mounted at a 10-degree angle off centre within the spaceframe chassis and fibreglass panels of MK’s Indy RR base, the first generation 1300R motor is unquestionably the Indy’s USP, but it is far from the only point of note. The Indy RR is a ground-up creation that’s less kit car (although you can self-assemble it) and more bespoke motorsport creation, with dozens of different specifications possible from that base. The one we’re driving today is about as intense as it gets.

Well, for now it is; MK has already built a turbocharged version of the Hayabusa producing over 500hp, but it expects the naturally aspirated version to be more popular for obvious reasons. 206hp (at 9,700rpm!) in a 480kg car equates to 429hp per tonne, which is 33hp better than a 992 Porsche 911 Turbo S. So it’s certainly not lacking performance. Not surprisingly, to get that high-rev bike punch to the road in a car, MK’s engineers have had to create a bespoke driveline. It starts with the jig-made spaceframe chassis, which mounts the engine off-centre so a universal joint can be attached at the same angle as the original bike drive chain, to which a prop shaft can be connected. Like the bike setup, there's no flywheel.

No less of a headache was the conversion of original bike controls to car equivalents. The throttle is now, as you’d expect, connected to an accelerator pedal, while the Suzuki six-speed sequential – with the first, neutral, second, third and so on ordering that’s typical to bikes – uses a foot clutch and hand paddles on a rocker, swapping the limbs that you’d use on the GSX1300R. You can just imagine how much fine-tuning and fiddling was required to ensure tactile and easy operation of each control. With no reverse gear, MK’s also added a separate electric motor controlled by a dash switch, which is a much cheaper but no less effective solution than the mechanical alternative. For reasons we need not explain, the reversing electric motor can only be used when the gearbox is in neutral or clutch is depressed.

Squeezing into the Indy RR’s narrow frame isn’t as difficult as you might expect because the seat is wide and there’s decent space between the steering wheel and footwell, which can be made wider still by using the wheel’s quick release mechanism. It’s certainly snug once you’re in, though, with your elbow natural falling just outside of the bodywork and no space beside the pedals for a footrest; although, with seat rails, there’s actually plenty of legroom. This car lacks a windscreen (buyers and builders can, of course, add one), using carbon deflectors to lower the air pressure in your immediate surroundings, although goggles or a helmet are advised to keep the wildlife clear of your corneas.

In fact, fully helmeted is probably wisest given the volume of this thing. The Hayabusa turns to a familiar high-pitched starter whistle and fires up with a stab of revs, before settling at about 1,400rpm. It’s smooth on tickover and while the clutch and accelerator pedal are featherweight in operation thanks to them being intended for hand use, so immediate is the throttle response that, after you’ve clicked the left paddle back to first (if that confuses you, see the aforementioned gear order), it’s actually easy to pull away without the expected stall. It’s loud. Partly because the side-exit exhaust runs only a metre or so to your left (it’d be under your elbow in a left-hand drive car), but also because Suzuki’s 1.3-litre motor is brilliantly racy at anything less than idle speed. Its motion pulsates through the chassis, so much so that the business of the chassis as it rolls over British tarmac seamlessly melds with it.

You’re actually left impressed with how much visible vertical compression there is in the double-wishbone pushrod front suspension. The right front Toyo Proxes R888 R is in clear sight, wrapped around a 13-inch Compomotive Motorsport rim that bobs up and down over bumps and compressions. But the energy doesn’t pass through the chassis, so your ride’s nothing like as bump influenced as you might expect for such a low car. Your eyes are at knee height, yet there’s enough absorption in the Indy RR to let the car flow on cambered and winding B-roads. Pick up the pace and there’s visible roll in the chassis, but with such tremendous responses from the surprisingly light and wonderfully rich unassisted steering rack, that you – rather than the car – are the limit for performance. On a sunny autumn morning, approaching the limit of those tyres takes some building to.

That’s fitting, because exactly the same can be said for the engine. Initially it feels like the gearbox is leggy, because you’ve such a wide window of revs to play with. But once you build up the confidence to explore beyond the savage delivery of its mid-range and enter the realm of utter insanity up top, the six ratios suddenly feel closely stacked. Full throttle bursts force you to kick the clutch (you can full throttle shift too) and hammer up the gears in quick succession; the motor screams towards its 10,500rpm maximum like a pin-pulled grenade. Rest assured this is a machine easily capable of quickly landing you with a driving ban if you don’t carefully pick your moments, although never does it feel out of control. Quite the opposite actually, because despite the motor’s punchy delivery, there’s enormous reserves of mechanical grip and traction. Instead of fighting wheelspin, you’re hanging on as the hedgerows turn to a green blur.

The unassisted brakes – which feature Wilwood four-piston calipers up front with soft, road-friendly pads – take some pressure before they slow the car from speed. But once you’re acquainted with the required legwork, they’ve barely believable stopping power, sending the nose ducking between its double wishbones and Toyos biting hard into the tarmac. They're so strong that MK opted against using servo-assisted brakes because the fronts would then be too easy to lock. With the unassisted setup, you can simply pick a stopping point and hammer the middle pedal to meet it. In tighter corners, there is a miniscule amount of understeer before the car settles and rotates. Otherwise the Indy RR turns on a ten pence coin and invites you to chase the throttle and play with its balance.

No car this reactive and with an engine so explosive ought to be this easy to manipulate. But because the team at MK wanted to ensure this car worked as well on the road as it does on track, that seemingly impossible aim has been achieved. Of course, buyers wanting an even more extreme package can go further, and MK suggests swapping the engine’s wet sump for a dry one, should owners more regularly be taking their cars on track. That being said, in any spec this is not an easy car to drive when compared with your usual sports machines. It remains in the company of Caterhams and Westfields for driver commitment, be in no doubt about that. Using the gearbox at low speed can be clunky – you’re often asked for a half-lifted clutch before the ‘box will engage first – and the level of commitment required to experience what the car can offer means only those serious about their driving need apply.

That’s outwardly obvious in a supercar-aping machine lacking a windscreen and doors, though. No two MK creations are the same, and it’s true that doors, glass and even a roof can be added for those after more insulation. An LS V8 model is due next year to offer more touring ability, while a turbo MX-5 engine model provides similarly mad performance to the Hayabusa with more familiar operation. So the offering is broad. But the car you see here, MK’s recently finished Indy RR, must be experienced to be believed. For reasons that centre around its mad engine but aren’t exclusive to it, this is about as scintillating as road driving can get on four wheels. For a car that you can build using a £19,995 kit yourself, that’s quite the lockdown project to get cracking on with. Even if, to be entirely honest, we’d have to spend the extra £4k and have the professionals make our one...


Engine:1,340cc, inline four, plus electric motor for reverse

Transmission:6-speed sequential, rear-wheel drive

Power (hp):206@9,700rpm

Torque (lb ft):109@6,700rpm

0-62mph:c. 3.5sec

Top speed:127mph (spec dependent)




Price:£23,995 (£19,995 for self-assembly kit)

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