Merc S 63 the last hurrah for 5.5 AMG V8

The S 63 AMG that launches in Australia in late October appears certain to be one of the last all-new models to be powered by the factory Mercedes-Benz tuning shop’s bellowing M157 5.5-litre twin-turbo V8.

The M157, which has itself replaced the much-loved naturally aspirated M156 6.2-litre V8 in a variety of AMG models, has reached its output limits in the S 63 AMG super-limousine, delivering a mammoth 430kW and 900Nm.

AMG chief Tobias Moers told motoring.com.au at the global launch of the S 63 AMG in Austria overnight that the engine could not deliver more power and torque without threatening reliability.

“Honestly, with 900Nm and 585hp with that engine, if I look for more than for reliability it is the end of that engine,” the 19-year AMG veteran said.

Moers shied away from further implications of that in terms of engine lifespan: “I know the answer but it is too strategic,” he said. He also refused to confirm the M157 would find its way into any all-new AMG models beyond the S-Class family.

Translated, that means it should be seen in the forthcoming AMG versions of the S-Class coupe and convertible, as well as any further updates of current models where it resides, such as the CLS and E-Class.

But don’t expect to see it in the next-generation E-Class due in 2016, or any other all-new models beyond the S-Class roll-out, which takes place over the next three years out to 2016.

Before then the new W205 C-Class arrives in 2014. But the AMG versions of that car are expected to be powered by an all-new 4.0-litre V8 essentially created by bonding two of the 2.0-litre four-cylinder turbo engines from the A45 AMG.

The 4.0-litre V8 is also expected to find its way into AMG’s new sub-SLS ‘911 fighter’, to be dubbed the SLC or GT.

The M157 first appeared in 2011 as a response to tightening fuel economy and emission regulations that encouraged downsizing and turbocharging.

It has been employed in the CL, SL, CLS, S, E, ML, G and GL models. A naturally aspirated version has powered the SLK 55 AMG since 2012.

So what could replace M157 as the mainstay engine for large AMGs? A hybridised version of the 4.0 V8  is a possibility given there is no indication AMG is developing another larger capacity V8.

Moers admitted that hybrids or other forms of electric assistance will be a part of AMG’s future.

“It’s clear depending on the segment – large SUVs, S-Class, whatever – in the future they will be assisted by electric motors… but there is no decision done, it is a discussion that must be done.”

The new-generation S 63 AMG sedan goes on sale in Australia in late October. It will be offered in both short- and long-wheelbase versions. It will continue to be rear-wheel drive only, although 4MATIC is an option for left-hand drive models for the first time.

The previous generation was sold here as a short-wheelbase S 63 and long-wheelbase V12-powered S 65 AMG. The new version of the latter model has been dropped due to lack of demand.

The new S 63 AMG short-wheelbase will be pitched in price very close to the old car at around $400,000, while the long-wheelbase version will be closer to $450,000. The S 65 L was previously a $500,000 proposition.

Watch out for our first drive impressions of the S 63 AMG coming soon.

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