Bavaria forever!
His other BMW is a… By Ben Miller
My 2010 HP2 Sport is not the M4’s two-wheeled alter ego. (That would be the 999cc, 209bhp M1000RR.) But it is the other BMW in my life, and there are parallels to be drawn. Both use fruity versions of classically BMW engine layouts. Both tap into decades of Bavarian performance engineering. And both are preposterously overspecified for road use, with power outputs, grip levels and suspension set-ups conceived to run flat-out between the strobing kerb paint of the world’s great racetracks.
The M4’s S58 six is made special by twin turbocharging and such lovingly crafted power and torque curves it almost feels naturally aspirated. (In doing so, it rights one of the biggest wrongs of the previous car, which dumped its turbo torque clumsily just as soon as it could generate it.)
The HP2 uses a version of BMW’s iconic air-cooled flat-twin, with its cylinder heads jutting proudly into the breeze and a torque curve like a trebuchet. It’s an odd engine choice for a bike that would compete at Le Mans but something of an anachronistic masterpiece.
When new, the HP2’s bespoke cylinder heads brought huge valves and, for the first time in an engine development story then nearly a century long, double overhead camshafts. Forged pistons and lighter conrods helped raise the rev ceiling (to 9500rpm) and power output (to 130bhp) to unprecedented levels for a flat-twin, and it remained the most powerful boxer BMW made until Motorrad – as Porsche had done with the 911 a decade earlier – introduced liquid-cooled heads. Two very BMW BMWs then, though the HP2 Sport lacks the veneer of civility the M3/M4 has developed over successive generations. It detests bumpy roads, long dull journeys, wet weather, low speeds and trac. The G82, by contrast, is such a polished all-rounder and such effortless everyday transport that I’m matching the ocial mpg figure… Must try harder.