Is this the year when new technology usurps the enthusiast’s preferred mechanical hardware in the fine-handling stakes? We find out by pitching BMW's i8 against the Porsche Cayman GTS and BMW M4
Richard Bremner Autocar
15 October 2014

A trio of rear-drive cars here, two of them with your enthusiast’s preferred mechanical hardware, the third with something quite radical and no less promising for that.

BMW’s M4 coupé is a traditional front-engined, rear-drive machine powered by a 425bhp twin-turbo 3.0-litre straight six, and the Porsche Cayman GTS is mid-engined and propelled by a naturally aspirated 335bhp 3.4-litre flat six.

The BMW i8, however, is twin-engined, the 228bhp 1.5-litre turbocharged triple sitting behind its cabin boosted by a 129bhp electric motor driving the front wheels to make the plug-in hybrid, carbonfibre-bodied i8 all-wheel drive.

The i8 is new to our Handling Day, but previous editions of the Cayman and M3 have been front-runners or outright winners. So although these three are far from the most potent cars here, two of them have very positive form.

Despite its driveline, this M4 is far from old-school in detail make-up. Its gearbox is the optional M DCT seven-speed dual-clutch automatic and its engine is turbocharged for the first time in the model’s history. It revs to 7600rpm and delivers a resonant rumble under load that certainly builds the excitement.

But not as much as the BMW’s behaviour near the limit, its body tilting towards oversteer that often trips up its on-track pace. That’s fun, but as one tester said: “It can be quite annoying because it compromises the car’s ability to get into a corner. You can find yourself busier than you were expecting before the apex and in a way you might not always appreciate.”

On the other hand, the suppleness of dampers that allow some close-to-the-limit roll also enable the M4 to soak up Castle Combe’s often unhelpful dips, crests and mid-bend bumps with less disturbance than some of the other cars here, although the Cayman and i8 are calmer.

Some testers complained that the M4’s gear ratios weren’t ideally suited to Combe circulating duties, but for the most part there was praise for a powertrain that delivers substantial thrust with a minimum of fuss and a potent soundtrack.

The BMW’s dynamic crudities are less intrusive than the mildly wayward Jaguar F-type coupé’s, incidentally, but present enough that you feel slightly short-changed. The original E30 M3 (and BMW must be sick of reading about this car) was far less fast but provided better balance and a lot more high-precision control.

And that’s what you get from the Cayman, as well as the intriguing swivel-about-the-centre turn-in that you enjoy in the best mid-engined cars. Its reactions are measured enough to avoid twitchiness, allowing you to lean on it until it produces controllable oversteer that’s rewardingly straightforward to control. ‘Measured’ captures the character of much of this car, its confidently precise way with bends, its unflustered absorbency of bumps, its secure braking and evenly delivered acceleration making this an easy car to drive fast and a forgiving one, too.

However, this doesn’t mean that it’s not exciting, especially for one tester, who complained that it was too easy to tip the Porsche into oversteer. But most marvelled at the Cayman’s balance, not only in chassis terms but as a complete car. “What can’t this thing do?” asked one. “The only reason the Cayman S didn’t get my vote last year is because it lacked that final hard edge when you really wanted it. The GTS has that and also improves every component on top of it.”

Despite its 335bhp, ‘measured’ often describes the performance, too, the Cayman’s fuel-eking gearing making third practically a 100mph ratio, with three more to go. Absurd, and it takes the edge off its grunt.

On the road, this makes it a bit less of a thrill than you’d think until you learn to work the lower gears, doubtless to the detriment of economy. But that’s when the tactile rewards really flow and the Cayman emphatically underlines its credibility as a properly sorted piece of driver’s kit. It’s also very civilised. With the fire of lower gearing, it would be close to perfection.

Fire is what you think you’re going to get from the i8, with its satisfyingly dramatic, supercar looks. It may be the unlikely wearer of an eDrive badge, but the little three-pot sounds at least twice as big as it really is and, together with the electric motor, allows the i8 to get going pretty smartly.

This dramatic machine looks like a  mid-engined car and duly behaves like one on track, with the impression of a chassis pivot point not far forward of your seat. It turns in well and, in contrast to the early reports from its launch, understeer is not  an issue. It will oversteer readily enough on a trailing throttle, too, before transitioning smoothly to gently run wide.

Your enjoyment of this behaviour is somewhat spoiled by a steering wheel that feels unpromisingly light unless you’re in Sport and, regardless of mode, this turns out to be the numbest rim here. But the wheel does shuffle encouragingly over camber changes. Fulsome brake feel has also been neutered by the i8’s electronics, although there’s no doubting their effectiveness. And while we’re whining, the instruments are near unreadable at speed despite their trick graphics.

The brakes’ scope for recharging the BMW’s battery pack in track conditions appears to be limited, though, the battery charge sinking to a solitary segment’s worth within a couple of hours of intermittent use. Which doesn’t mean that the electric motor turns dormant; the battery always retains enough charge to power the front wheels when necessary, BMW’s aim being to provide consistent handling regardless of circumstance.

However, what you won’t get is the overboost that a semi-charged or fully charged battery pack would provide. To restore that, you’ll need a session of less committed action to allow the battery power to regenerate. Or a mains recharge.

A less frenetic drive will allow you to enjoy the BMW’s near-languid suppleness over bumps, its motion over these surfaces integral to its sophisticated allure. So is the sound of that engine – the unaware will be amazed to hear that it’s shared with the Mini – whose racey downshifting blips are satisfyingly timed. This BMW is quick, too, but feels less so at higher speeds, its progress dulled by eco-oriented gearing.

All of which makes the i8 a more intriguing machine on the road, where its twin engines usually function at full strength and its sharp handling and supple ride gel in a manner that makes you dream of long-distance drives. The disappointment of the steering is less evident here, and you get the pleasure of uncovering what it’s up to via the information displays. “A complete enigma, better on road than on track but not entirely out of its depth here,” concluded one tester.

The i8 offers many rewards, but the best of them are not found on a race circuit. Its more traditional sister, the M4, is of far less complicated character, almost too much so on the track, where its lively rear end denies it some of the delicate driftability of M3s past. Still, there’s little wrong with its powertrain, although some yearned for the previous-generation M3’s normally aspirated V8.

You won’t be doing much yearning in the Cayman GTS unless it’s for shorter gearing; the Porsche is the most complete, and completely satisfying, driver’s car of our trio. “Beguiling controls, velvet-smooth powertrain and a forgiving ride make it great on the road or track” was one summation, and that just about nails it.

Lap times

BMW i8 – 1min 19.4sec 

Porsche Cayman GTS – 1min 17.4sec

BMW M4 – 1min 16.8sec

Britain’s Best Driver’s Car 2014

Click on the links below to read each section of Britain's Best Driver's Car 2014, followed by the crowning of this year's overall champion as decided by our eight judges.

The supercars – Ferrari 458 Speciale vs McLaren 650S vs Porsche 911 GT3

The V8 muscle cars – Chevrolet Corvette Stingray vs Jaguar F-type R coupé vs Vauxhall VXR8 GTS

The misfits – Alfa Romeo 4C vs Ariel Atom 3.5R vs Renault Mégane RS 275 Trophy

The verdict – Britain's Best Driver's Car 2014 is crowned

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Our Verdict

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