The first Sportec SPR1 I drove in 2006 was black, and had only rear-wheel drive to deploy its 802 hp. It was the sort of car that you only bring out in good weather, and tuck away again at the slightest hint of a slippery surface.

The Sportec SPR1M (M for Modified) I'm driving today is as white as the driven snow, and with a decent set of winter tires, will happily go anywhere its AWD system will allow, within the limits of its minimal ground clearance. It also has 858 hp.

Unlike many AWD road cars, Porsche's excellent all-wheel-drive system was not designed purely for traction, but rather as a performance-enhancing tool to help you deploy every one of the horses produced by its potent flat-six engines.

Unlike many tuners today who rely more on sales of bolt-ons like wheels, suspension, exhaust systems and chip tuning to boost their bottom line, Sportec is a technically based company that continues pushing the boundaries of what is possible. The engine in the SPR1M is a perfect case in point. Where most tuners would be happy to declare a genuine 800 hp that can be happily pottered around town, Sportec decided there was room for improvement.

The basic SPR1 engine spec is based on the 3.6-liter Porsche GT1 block as the factory Turbo and GT2 and GT3 cars are. With this starting point, the billet steel crankshaft is heat-treated for extra strength and installed in special bearing shells. These were deemed necessary after lubrication problems were encountered during initial dyno testing.

The lightweight pistons are tied to the crank by very light and strong titanium connecting rods from Austrian aerospace and F1 component manufacturer Pankl, which claims they will take 900Nm of thrust at 9000 rpm. The Turbo cylinder heads are gas-flowed and special Sportec camshafts fitted. Early test camshafts had issues because of the extreme loads imposed on a higher-lift camshaft rotating at these extreme revs.

Making over 800 hp requires a lot of fuel and air to be burned, so the bespoke intake manifold has one throttle body per cylinder bank, and two rows of fuel injectors. The second row kicks in at 4500 rpm on full throttle, with the ECU simultaneously cutting back on delivery to the primary set. In this mode, they overlap, each set running below maximum capability so there is still headroom. Three fuel pumps are required to supply this system.

The ECU has a very rigorous protection regime programmed into it and will reduce turbo boost at the slightest hint of trouble. In fact there are two ECUs. The factory Bosch Motronic ME 7.8 looks after the primary injector bank and the ignition, while the Sportec MFC G4.0 is given charge of the secondary injector bank, the electronically controlled throttle bodies, the electronically controlled dampers and traction control.

The evolution engine uses the same basic SPR1-style dual chamber intake plenum with balance pipe and twin throttle bodies. But further work on the flow bench led to revised internal geometry in the intake system while 15 percent smaller ram pipe diameters increase the internal air velocity for a better charge.

Because of this, there was no need to increase the boost pressure, which remains at 1.35 bar, with 1.45 bar on overboost working nicely with the 8.4:1 compression ratio. Overboost is maintained all the time you are on full throttle, rather than the 10 seconds allowed on the stock factory motor. The reason for this is simply one of heat tolerance and flow capacity, which is why Sportec ditched the factory VTG turbochargers for bespoke conventional units. The massive intercoolers, nearly double the thickness of the stock units, are significantly more efficient. The new rear wheel arches are 40mm wider on each side to accommodate them.

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