The Alpina B4 Coupe may be based on a 435i, but it’s an exercise in how to build a better BMW…

SINGAPORE — In some ways the Alpina B4 Coupe is one of Singapore’s best-kept secrets. On the surface it looks like a modified BMW, which on a superficial level is what an Alpina is.

Look deeper, though, and it’s clear that there’s a depth of engineering here that goes beyond even BMW’s formidable talent with all things mechanical. You don’t turn a 435i into a 303km/h missile with a few simple mods, after all.

That’s right, find a stretch of road that’s long and empty enough, and the B4 Coupe can turn you into a member of the 300km/h club.

The ride there is a satisfyingly thrilling one, too. Put your foot down hard, and the Alpina gets down to business right away, with the effectiveness of an assassin hurling a dagger at the laws of physics. 100km/h is coldly dispatched in 4.2 seconds, so guard your licence while you’re at it. It might be the next victim.

There’s the occasional muffled groan from the rear tyres when the Alpina’s engine does its deadly work, too. That’s because they have to withstand an avalanche of torque from the six-cylinder, now fed by two turbos (instead of the 435i’s twin-scroll unit).

At 3,000rpm is where the motherlode of pulling power comes on stream, all 600Nm of it. On its own, the resulting acceleration is enough to give your face a jolly good workout from grinning.

There’s a beautifully understated personality to the Alpina, too. It’s nearly as fast as BMW’s own M4, but much less manic and shouty. Instead, there’s a smoothness about the way it gathers speed.

The transmission shifts quickly but extremely silkily, noticeably more so than in the BMW donor car. It may be carried over from the 435i, but 20 percent of its bits have been modified by Alpina.

The suspension has had work done, too, and in a similar way it hits a sort of sweet spot between plushness and sportiness. Around bends the B4 behaves with taut precision, and maybe the overall handling is just that bit less sharp than an M4’s, but in most other situations the Alpina is much kinder to your spine.

If there’s a weakness in the Alpina’s game, it’s the brakes. They’re suitably strong, but the pedal has a spongy action to it.

Overall though, the B4 is pretty true to its Alpina roots, in that it feels like an exercise in how to build a better BMW than BMW does.

Mind you, it’s not that BMW doesn’t know what it’s doing. It’s just that production cars are built to spec. A product planner might tell the engineers something like, “Make sure the 435i hits 100km/h in less than 5.5 seconds.” The drivetrain guys duly deliver, but since no one said anything about also making the transmission smooth enough to use in a Rolls-Royce, they just don’t aim for it, and quickly move on to the next project.

In contrast, while Alpina only has about 50 engineers of its own, all they do every day is think up ways to make BMWs better.

They have a bit more leeway in terms of what the final car should cost, too, which is why the B4 is a 435i with a tuned engine, an uprated cooling system, that heavily modified gearbox, higher spec suspension, an Akrapovic exhaust with a cultured burble and so on.

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Yet, it’s worth noting that BMW and Alpina work together, and not as rivals. Indeed, BMW builds the B4 in its own factory, installing the bits specified by Alpina (even down to the car’s software).

At some point, the car is handed over to Alpina’s facility in Buchloe, about an hour’s drive from BMW HQ in Munich, where final bits like the bodykitting and interior trim are installed. Think of BMW as the B4 Coupe’s father, and Alpina as its mother.

That would go some way towards explaining the car’s good looks, too. There are the trademark Alpina stripes on the body, with spoilers and aero elements to keep it stable at top speed, but the real head-turner has to be its 20-inch wheels, and the way they wear tyres that look like they’ve been spray painted on.

At $398,800 for a B4 Coupe (and $20,000 more for the Convertible), it’s not every day that you’ll see one, and for similar money the comparatively furious M4 has to be a consideration.

But when you do spot an Alpina driver it seems more than likely that there’ll be a smile on his face. He’ll have had the experience of driving something so wickedly fast and yet so refined and understated, for one thing, but above all there’s the pleasure of knowing a damn fine secret.

NEED TO KNOW Alpina B4 Biturbo Coupe
Engine: 2,979cc, 24V, twin-turbo inline six
Power: 410hp at 5500-6250rpm
Torque: 600Nm at 3000-4000rpm
Gearbox: 8-speed automatic
Top Speed: 303km/h
0-100km/h: 4.2 seconds
Fuel efficiency: 7.6L/100km
CO2: 177g/km
Price: $398,800 with COE
Availabile: Now

Also Consider: BMW M4, Lexus RC F

TEST DRIVE AN ALPINA
Not that many 300km/h sportscars are readily available for test drives, but you can slide behind the wheel of the Alpina B4 Biturbo Coupe for a go if you’re keen. Just click here, fill out the form… and enjoy!