Mercedes is developing two new petrol/gasoline engines - a V6 and a V8 - that will offer more torque and improve fuel economy over their predecessors.

First off is a new, naturally aspirated 3.5 liter V6, which features a more narrow angle block than Mercedes' current V6 - 60 degrees vs. 90 degrees for its predecessor. New will be a third-generation direct injection system with piezo-electric injectors, a more efficient combustion formula, multi-spark ignition and low-friction ancillaries. All that mated to a new stop/start system can deliver up to 24 percent better fuel economy.

The numbers on the new V6: 306 PS (301 bhp / 225 kW), up from the previous 272 PS (268 bhp / 200 kW). Torque is dialed up to 368 Nm (272 lb-ft) from the former 350 Nm (258 lb-ft). CO2 emissions are 177 g/km.

The engine will be introduced in the upcoming S350 this fall and then on the CL350 a few months later.

The new 4.6 liter V8 comes with twin-turbocharging that delivers 435 PS (429 bhp / 320 kW) and 700 Nm (516 lb-ft) of torque.

The V8 will debut in the CL500 this fall too. Also with stop/start technology, it features about 22 percent better fuel economy than the previous, larger block, 5.4 liter V8 that it will replace. CO2 emissions are also a very good 225 g/km for an engine this powerful.

Please see the extensive press release below for full details.

Gallery: New Mercedes engines: 4.6-liter V8 biturbo and 3.5-liter V6 official details revealed

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