The Alpina B5 Bi-Turbo Touring is the stretched M5 you’ve been waiting for

Published: 03 January 2018

► World's fastest production estate
► Uses a 4.4-litre V8
► A stretched M5, basically

Meet the new world’s fastest production estate, the Alpina B5 Bi-Turbo Touring. Designed to hit in excess of 200 mph, capable of 0-60mph in just 3.5 seconds and available for a reasonable £91,000 in the UK, the new B5 Touring is basically the stretched M5 you’ve been waiting for.

As you’d expect from Alpina, the new B5 is based on the newest BMW 5-series (G30). While a lot of the B5’s performance can be attributed to the raw power it’s been stuffed with, Alpina says the rest is down to the lack compromise in the car’s specs.

‘Our cars are for driving enthusiasts who value a blend of qualities that can only be delivered by immense attention to detail and a single-minded focus on one type of owner,’ explains Alpina’s GB’s Jonathan Noy. ‘The B5 Bi-Turbo is built with just one powertrain and one chassis specification, which allows our engineers to calibrate every component and every control system to work perfectly together without compromise.’

So what exactly is under the bonnet?

Most of the B5’s silly performance is down to the heavily modified, turbocharged 4.4-litre V8 up front. Alpina has worked its magic on the stock BMW block, adding a new wide-bore intake system, and optimised radii for better throttle response.

The engine’s forced induction system hasn’t escaped tinkering either, with the stock turbochargers replaced by a twin-scroll turbochargers in an ‘inside V’ configuration. Gas flow has been improved, while an overhauled intercooler and radiator system mean the revised unit can cope with the extra heat from its new power.

Just like the new M5, the Alpina B5 uses a four-wheel drive system for the first time,  but it will let you send up to 90% of its 590lb ft of torque to the rear wheels, so it’ll still have that tail-happy handling you’d expect. The B5 also comes with Active Rear Steering, which turns the rear wheels up to 2.5 degrees, depending on the speed and road conditions.

Just like the Mercedes AMG GTR, at low speeds the rear wheels will turn the opposite direction of the front ones, for a more responsive feel. At higher speeds, all four wheels on the B5 will turn in the same direction, increasing stability.

Elsewhere, the new B5 benefits from air suspension at the rear, replacing its standard coil springs. Of course, the exhaust note has also been finely tuned, with the B5’s advanced pipes reducing back pressure, while allowing the driver to choose from two bassy growls.

Is the Alpina B5 going to be the ultimate estate? On paper, the answer is surely yes – but we’ll be able to answer that for sure when we get behind the wheel.

By Curtis Moldrich

CAR's online editor and racing-sim enthusiast