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AMG's new S63 bi-turbo V8 limo

2010-03-02 08:23
Vehicle Specs
Manufacturer Mercedes-Benz
Model S63 AMG
Engine 5.5l bi-turbo V8
Power 400-, 420kW
Torque 795Nm @ 2 000-4 500r/min, 895Nm @ 2 500-3 750r/min
Transmission Seven-speed auto
Zero To Hundred 4.5 seconds
Top Speed 250km/h (300km/h)
It’s the beginning of the end fOR large-capacity naturally aspirated engines. We all knew it was bound to happen sooner than later though…

Mercedes-Benz’s performance tuning arm – AMG – has signalled its intent of replacing the venerable (and very vocal) 6.2l V8, which powers the bulk of Merc’s AMG fettled cars, with a new 5.5l bi-turbo V8.

AMG unveiled the new engine at the Geneva auto show on Monday.

Make it smaller, more efficient

Enthusiasts the world over will surely be asking why the decision was made to go the turbo route, especially seeing as the 6.2l V8 engine was AMG's design signature.

The reasons are simple. Large capacity performance engines are simply unable to reduce their fuel consumption and emission habits to an acceptable level within a cost (and production) effective design matrix.

Merc’s new M157 engine displaces 5.5l and sports bi-turbos, so in terms of configuration it’s very similar to the 65-Series AMGs, just lacking the additional quartet of cylinders and half a litre of swept capacity.

Although it’s very unlikely the new forced induction V8 will be able to replicate the epic acoustics of the M156 engine, it does boast better output numbers, rendering improved performance and simply staggering economy.

New engine weighs only 204kg - makes lots of power and drinks very much less fuel than the 6.2l V8.

Instead of employing variable compression turbochargers, the M157 engine’s boost regime is fed by a simple Garrett-Honeywell turbo per cylinder bank.

For a large capacity turbocharged engine compression appear a little on the high side (10.0:1), yet an AMG engineered air-to-liquid intercooler unit chills inlet temperatures down to around 90-degrees.

The new engine is based on Merc’s M278 4.6L V8, with an AMG block, sump and cylinder head. Its exhaust manifold is joined directly onto the turbocharger housing too, ensuring the shortest (most efficient) gas-exchange driven boost path possible. This is an arrangement similar to the exhaust plumbing on BMW's X5/6 M 4.4l V8 engines...

Merc’s new M157 engine will debut in the 2011 model year S63 AMG, yet the naturally aspirated displacement moniker will remain.

Geneva showcar finished in livery to pay homage to the AMG-powered 300 SEL that won its class and finished second overall at the 1971 24-hour race in Spa-Francorchamps. We doubt it will be an option.

But, more powerful too

Output figures for the new engine are either 400- or 420kW, the latter benefiting from an optional performance pack. Peak rotational force runs to 795- and 895Nm respectively. Improvements over Merc’s outgoing 386kW/630Nm 6.2l V8 are plain to see.

Curiously, for an AMG product (where performance supplants running costs in the purchasing rationale), the new S63 AMG is claimed to be 25% more efficient than the naturally aspirated V8.

The seven-speed SpeedShift transmission has a selectable ‘controlled efficiency’ program, whilst the engine ECU cuts cylinder detonation in traffic. If driven with (remarkable) restraint the new bi-turbo S63 is alleged to return 10l/100km…

These new S63 AMGs are claimed to no faster than the naturally aspirated version was, with most of the gains being made in terms of efficiency. If you think about it logically though, shifting through the SpeedShift transmission, it would be virtually impossible for the performance pack S63 (with 34kW and 265Nm more) to not be quicker than the current S63...

Expect 0-100km/h acceleration in the mid fours, and a 250km/h top speed, with the 420kW performance pack model featuring a more liberal 300km/h speed governor.

The new S63 AMG is expected to go on sale in the second half of this year.

You might not be happy about the turbos, but with more power, better consumption, SpeedShift enabled launch control and only a single differential (at the back), the new S63 AMG is still the hooligan limousine above all others.


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