Alpina’s sparky sports coupé has broad-brush ability
Looking for a fast, comfy, 400bhp-plus coupé? Lucky you. The choices are tasty: Mercedes-AMG C63, Audi RS5, BMW M4 – and now, to be a little bit different, Alpina B4 S Biturbo. And it’s more than just different.
This B4 S replaces the old B4. It uses the M4’s straight-six-engined platform but adds a raft of changes, both visual and techy. The actual engine starts off as the same N55 3.0-litre six that’s used in regular 3 Series and 4 Series cars, but it comes with two 10 per cent larger turbochargers, a 20 per cent more efficient liquid-cooling system, a 35 per cent bigger oil cooler, and a crank that’s both forged and lighter than the standard item.
Alpina B4 S Biturbo
Engine: 3.0-litre, six-cylinder, biturbo, petrol
Torque: 486lb ft
Gearbox: 8-spd automatic
Top speed: 190mph
Fuel economy: 35.8mpg
CO2 rating: 180g/km
As a result of all that, the Alpina generates a new power peak of 434bhp at 5500-6250rpm and 487lb ft of torque at 3000rpm. That’s 9bhp and 81lb ft up on the M4. Unfortunately the eight-speed-auto-only Alpina is 90kg heavier than the automatic BMW, but the B4 S’s extra torque makes it 0.1 seconds quicker over the 0 to 62mph run at 4.2 seconds.
The suspension settings are carried over from the old B4, which means they’re still slightly softer than the M4’s. Also retained is the BMW Professional infotainment system, adding a widescreen sat-nav and all-round parking sensors. Dakota leather is a no-cost feature, with the Merino leather of the test car we’re driving here a £1285 option.
Fire up an M4 and you’ll be greeted by a guttural growl. The B4 S has a more subtle tone through its Akrapovič exhaust. You don’t get much indication of the performance potential in the default Comfort mode, but it’s hard not to be impressed by the effortlessness with which this 1690kg car moves up the road, even with the ‘box changing up at 2000rpm in normal city driving. It’ll use all eight gears too.
Put it into Sport mode however and the Alpina mods become more obvious. To the low-down response you can add a prominent and silky-sounding kick-on at 3000rpm and a burly boost forward on each change-up. The Alpina beats the M4 in how it puts its power down to the ground, too, with a more useable elasticity to its delivery compared to the M4’s more abrupt, traction-challenging style. That makes the B4 S a friendlier companion when exiting corners under power.
Having said that, the M4’s crouching stance and weight advantage do allow it to turn and stop more effectively, but the Alpina’s softer approach gives it an advantage when road creases and cracks need to be absorbed, even on its big 20-inch Alpina Classic alloys. That compliance, plus superbly weighted steering and a super-responsive gearbox (with a manual shift option via buttons on the wheel) makes it a lot easier to set a quick B-road pace in the Alpina without the will-it-won’t-it uncertainty of the M4 on slippery surfaces.
It’s an easy and rewarding drive that you can dial back to Comfort for even easier wafting if the fancy takes you. Some would call the B4 S less focused than the M4: others would call it more flexible.
The only complaint, and it’s a relative one, is the absence of high-tech infotainment. Although the BMW system has a classic simplicity about it with analogue dials that nicely fit its character, it’s nowhere near as theatrically impressive as the Audi RS5’s Virtual Cockpit.
As BMW’s M products seem to be increasingly heading down a slightly more ‘in your face’ route, the Alpina is a refreshing taste of subtlety in the performance coupé field. For ultimate hard-edged sharpness, one of the other cars mentioned here will be the answer, but if you’re happy to have a side order of relaxation along with your main meal, the B4 S is an extremely attractive choice. Not to mention a very rare one.