Mercedes reveals AMG V8 tech-specs

MERCEDES-BENZ has released full technical details of its new 4.0-litre twin-turbocharged V8 engine, which will arrive under the bonnets of the next-generation C63 AMG range and Porsche 911 rivaling AMG GT sportscar.

Pumping out a meaty 375kW and 650Nm of torque, the V8 produces 100Nm and 58kW more than the C63's most staunch opposition – the freshly launched BMW M3 and M4 performance twins.

Weighing in at 209kg, Mercedes says its new engine is “the lightest in its competitive segment”, but with two fewer cylinders, the slender BMW straight-six turbo may still have the weight advantage.

The arrival of the forced-induction engine brings the end of naturally aspirated AMG engines closer, with only the SLK 55 AMG and flagship SLS supercar relying on atmospheric pressure, and their respective replacements would likely complete the turbo transition.

Mercedes' A45, CLA45, CLS63, E63, G63, GL63, GLA45, S63, SL63 and SL65 models have already made the switch to turbo power, cutting emissions to satisfy the ever tightening European emissions standards, as does the latest arrival.

Specific vehicle performance figures are yet to be released, but with the same power as the outgoing C63 AMG 507 Edition and more torque, the new engine could shave a fraction of a second from the 4.2 second zero to 100km/h dash.

The German car-maker says that extra performance will not come at a cost to the environment, and with increased thermal and volumetric efficiency the new engine will meet Euro 6 CO2 and particulate levels due to start in 2016.

Mercedes has followed BMW's lead in placing the brace of turbos in the engine's 'valley' rather than the customary position on the outside of each cylinder bank, which saves under-bonnet space but creates challenges managing the associated heat.

With a more compact unit, the engine and transmission has been mounted with a majority of the mass behind the front axle resulting in a front-mid configuration and better weight distribution.

A dry-sump lubrication system has also allowed the engine to be mounted lower, improving the centre of gravity, and at high engine speeds the two-stage oil-pump cycles the entire nine litres of oil in under 10 seconds.

The race-car derived technology also eliminates potentially catastrophic surging and oil-starvation during high-G maneuvers.

The two turbos spin up to 186,000rpm and blow through twin charge-coolers with a relatively sedate maximum boost pressure of 1.2 bar.

An undersquare bore/stroke ratio biases the engine towards low-down torque production, but despite a longer piston-stroke the 90-degree V8 manages to rev to a 7200rpm redline.

Mercedes says that turbocharging the V8 has not removed the ephemeral AMG note and a variable geometry exhaust-system keeps noise levels low while cruising, but offers a louder more noticeable soundtrack at the push of a button.

Internal losses have been minimised with a variety of low friction design features including a cylinder-bore coating that Mercedes calls Nanoslide, which also lines the inside of its Formula 1 race engines.

Much of the new engine's technology is shared with the A45, CLA 45 and GLA 45 AMG four-cylinder unit, which is effectively half of the new M178 V8.

Under the bonnet of the smaller Mercedes' the highly-strung 2.0-litre produces 265kW and 450Nm.

Theoretically, by upping the V8's boost pressure to the same 1.8 bar of the four cylinder, output could climb to around 530kW and 900Nm – power that could be destined for the forthcoming Porsche 911 competitor, the AMG GT two-seater coupe.

Arriving before the C63 AMG, the new sportscar will be furnished with 375kW and 650Nm, but a higher performance Black edition may follow as has been the case with previous Mercedes models.

Earlier this month Mercedes released pictures of the all-new sportscar dressed in green zebra camouflage with matching brake calipers, revealing more of its coupe profile and proportions but little detail.

The pictures do show large six-piston calipers gripping cross-drilled and slotted front discs, and the lurid green wrapping hides a large bonnet and side vents.

All will be revealed when the coupe makes its world debut at the Paris motor show later this year, before its expected arrival Down-Under in 2015.