DON’T FREAK, IT’S BOOSTED M-POWER

With the aesthetics of the chassis addressed, focus shifted to the engine bay. Although BMW’s M division tuned the inline six-cylinder S54 engine to produce a respectable 333 naturally-aspirated brake horsepower, Estudillo wanted to increase the output of the engine to complement the aggressive GTR exterior. To more than double the engine’s output would require fortification of the engine along with some sort of power adder. After searching for a solution, the opportunity to purchase a Horsepower Freaks (HPF) Pro Built engine presented itself. This complete longblock assembly featured HPF third-generation forged pistons and connecting rods mated to a factory crankshaft. HPF also ported and polished the cylinder head for improved volumetric efficiency before securing the head and block together with ARP L19 head studs.

To pressurize the cylinders, this engine setup relies on an HPF Stage 2.5 turbo system. An HPF ceramiccoated manifold channels the exhaust gasses to the inlet of a Precision Turbo & Engine PT6766 turbocharger to generate boost pressure. From the compressor discharge, a custom hard pipe forces compressed ambient air through a HPF front-mount intercooler. Then the air charge rushes through the polished HPF intake manifold for distribution into the stock individual throttle bodies. To provide chemical intercooling and permit more aggressive ignition timing, an HPF water/methanol injection kit was also plumbed in. This E46-specific kit positions a factory-looking black plastic tank in place of the stock intake filter housing on the front of the shock tower, while a specially designed bracket positions the water/methanol pump and the controller harness beside the factor fog light port. This plug-and-play system is regulated by the HPF engine management system, to ensure proper tuning maps are selected when the system is activated. With the water/methanol system activated and race-fuel in the tank, the M3 spun the rollers of the Dynojet dynamometer to a peak output of 755 horsepower and 615 lb-ft torque at 23 psi boost pressure.