Porsche is set to crown its upcoming Macan line-up with a fiery 370bhp-plus Turbo-badged range-topper that will establish a new performance 4x4 niche when it hits UK showrooms in October next year.In the absence of dedicated performance variants of rivals such as the BMW X3 and Range Rover Evoque, Porsche expects the Macan Turbo to carve out a niche as the fastest and most dynamic model in the class — something that it achieved with the bigger Cayenne.

The top-of-the-line Macan will be the first car powered by Porsche’s still-secret new twin-turbocharged V6 petrol engine, details of which are revealed here for the first time.

Developed in-house at Porsche’s R&D centre in Weissach, Germany, the twin-turbo V6 is understood to have a 90deg vee and a capacity of 3.0 litres. It is believed to be a variant of the 3.6-litre V6 that powers entry-level Cayenne and Panamera models.

Peak power and torque are said to be in the region of 370bhp and 400lb ft thanks to twin sequential Borg Warner turbochargers, an air-to-air intercooler system and other internal modifications, including a lower compression ratio than that of the normally aspirated 3.6-litre engine. That’s an increase of about 80bhp and 105lb ft over the non-turbo 3.6....