[GoingTooFast]

Porsche to introduce a new turbocharged flat-4 engine within the year

Porsche hasn’t built a four-cylinder engine for decades, but our sources at the automaker have hinted that the company is working on a new turbocharged flat-four engine to serve as the brand’s entry-level sports car powerplant. The powerful, yet very fuel efficient, engine is expected to debut within the next year — perhaps as soon as the Frankfurt Motor Show in September.

While details about the new boxer powerplant have not been released, the all-aluminum engine is expected to be based on the current 3.8-liter flat-six (shown above) found under the rear decklid of the Carrera S, yet with two of its cylinders lopped off. Fitted with Porsche’s Direct Fuel Injection (DFI), VarioCam Plus and a single turbocharger, the free-revving 2.5-liter flat-four will likely develop upwards of 350 horsepower and 360 pound-feet of torque as it spins towards a 7,500 rpm redline. Expect the engine to be mated to the automaker’s seven-speed Doppelkupplungsgetriebe (PDK) gearbox, with reprogrammed algorithms to make use of the engine’s impressive low-end torque. A traditional six-speed manual gearbox is still under consideration.

The new turbocharged 2.5-liter will find its home in the Boxster and Cayman. Purists need not to worry, as the smaller and lighter engine will be more powerful and more fuel efficient than the current naturally aspirated 2.7-liter flat-six mid-mounted in the Cayman/Boxster (rated at 275 horsepower and 213 pound-feet) and it will even outperform the 3.4-liter flat-six in the Cayman S/Boxster S (rated at 325 horsepower and 273 pound-feet). Expect Porsche’s yet-to-be-announced “Baby Boxster,” an entry-level model due in 2015, to also make use of the powerplant, but without the turbocharger.

Even as Porsche has dug into VW Group’s corporate parts bin for the engine in its Cayenne V6, the oil-burning powerplant under the hood of the new Cayenne Diesel and the 2.0-liter inline-four expected to power its upcoming Macan compact crossover, this all-new engine should remain a Porsche exclusive, much like its current family of flat-six powerplants used in the 911 model range.