BMW tuning specialists AC Schnitzer have transformed a BMW Z4 by fitting a mighty 430 hp triple-turbo diesel engine for a one-off 300 km/h supercar.
Named the ACZ4 5.0d, this machine started as a BMW Z4 sDrive 23i (E89) from which the petrol-fuelled heart was removed and replaced with the M50d powerplant, upgraded from 381 hp and 740 Nm torque to a thumping 430 hp and 840 Nm.
Transmitting all this power, the standard manual gearbox has been replaced with an 8-speed automatic with pedal sports shift, through to rear axle gear and limited slip differential from the BMW M3 (E92).
The result is eye-popping performance with the AC Schnitzer ACZ4 5.0d sprinting from 0 to 100 km/h in just 4.5 seconds, topping the 300 km/h mark, and at 1:37.22 min – according “Auto Bild sportscars” – is the fastest diesel on the Sachsenring.
This car would cost € 113,965 but it is not for sale: the AC Schnitzer ACZ4 5.0d is a concept vehicle produced to customer specifications as a technology platform for AC Schnitzer product development. Conversions to brakes, suspension, body, interior and wheelset are part of the AC Schnitzer retail range for the Z4 model series, all homologated and available via BMW dealers.
There’s more to it than just more muscle, with weight cut by 131 kg despite the much heavier M50d engine so that it turns the scales at just 1469 kg. Swapping the electro-hydraulic metal folding roof and boot lid for CFC mouldings saved 90 kg, another 19 kg went by fitting a 4 kg lightweight silencer. A further 25 kg was saved in the wheelset – based on the AC Schnitzer forged alloys Type VIII – with 9.5J x 19 inch rims shod with 265/30 R 19 tyres.
The dynamics of the ACZ4 5.0d have also been optimised with racing suspension, fully adjustable in both compression and rebound stages, while also lowering the Z4 bodywork by 30 mm combined with the lightweight high performance braking system on the front axle.
Drag is cut by the aerodynamic conversion with carbon front spoiler, two carbon sports fenders, two bonnet vents, a two-piece rear spoiler and the carbon rear skirt insert.
And the interior completes a very special car with trim elements in orange, and carbon racing bucket seats embroidered with the ACZ4 5.0d logo, were all specially made. Aluminium pedals and foot rests, and floor mats complete the transformation.