Alpina B6 Biturbo Convertible revealed

* Based on the 6 Series drop-top * 500bhp V8 twin-turbo engine * On sale by the end of the year...

Alpina B6 Biturbo Convertible revealed

Alpina has released the first details of its B6 Biturbo Convertible, ahead of the car's public debut at the forthcoming Frankfurt motor show.

The B6 is based on the 6 Series drop-top and gets the same twin-turbocharged V8 engine as Alpina's ultra-rapid B5.

It produces 500bhp at 5500rpm, and a hefty 516lb ft between 3000rpm and 4750rpm. Thats enough power and torque to take the hefty convertible from 0-62mph in just 4.8sec, and on to a top speed of 193mph. The claimed fuel economy is 25.9mpg, and the B6 emits 255g/km of CO2.

The main styling changes over a regular 6 Series are Alpina's own front spoiler, and its patented alloy wheel designs (including the Classic, seen here in the firms initial images of the car).

The early pictures also show carbonfibre detailing around the front grille. Like all Alpinas, the B6 Bi-turbo will be built on the main BMW production line, alongside regular 6 Series models.

However, Alpina offers a 'bespoke tailoring' service at its own factory, allowing customers to alter the interior trim and materials to their own specifications.

Alpina has yet to issue an on-sale date, but the company tends to reveal its models in near-production-ready form. We'd expect Alpina GB to open its order books for the B6 before the end of the year for around 75,000.