Johannesburg - With 441 killer-watts waiting to be unleashed, the latest BMW M5 is not exactly underpowered in our book. But just for those who like living life at the extreme of extremes, local tuner RG Motorsport has found another ‘100 horses’ in BMW’s 4.4-litre twin-turbo V8.
That’s 74kW in the metric speak that we’re accustomed to, bringing the total tally to 515kW at the flywheel, while maximum torque rises from 750Nm to 907Nm. In fact at 6000 revs, there’s still 735Nm on tap, almost as much as the standard engine’s maximum, achieved at 4000rpm.
So how fast is it now?
RGM has not run the car against a Vbox as yet, so no official acceleration numbers. But since the almost-two-tonne sledgehammer of a saloon can already hit 100km/h from standstill in 3.4 seconds in standard form, you could probably shave a few tenths off that.
How did RG achieve these gains?
A brand new RGM-Techniflow downpipe and exhaust system and an imported JB4 management system (already highly regarded for its ability to work seamlessly with highly-sophisticated electronic circuitry) are key to unlocking this fury.
The dual exhaust measures 76mm in diameter and follows the route of the original system, though wherever possible the radius of the bends are opened up as much as they can be, RGM spokesmen say.
A combination of mandrel bends (which leave interior diameter unchanged) and pre-formed sections are used to achieve this. Dozens of individual pieces of 304-grade stainless steel pipe have gone into the construction of the sports exhaust.
Sub-sections are bolted together to create the whole exhaust, which of course makes assembly a whole lot easier, as installation won’t keep you waiting.
The back end, which is a massive, pre-assembled unit with a pair of transverse silencers, continues to use the original dual-tone exhaust volume control though. This bypass function is said to create a “deep and rich” soundtrack.
How much?
It’s pretty much a grand per pony here, with the conversion retailing at R110 000, including VAT. That is, of course, over and above the R1 762 807 that you'll have to pay BMW for the car itself.