Benz bets on nine-speed box
BY NEIL DOWLING | 9th Feb 2015
The nine-speed dual-clutch transmission, a development of the current seven-speed box, will arrive in Australia mid-year as standard fitment in the S-Class Coupe S500.
Mercedes-Benz Australia/Pacific product manager Gordon Jones told GoAuto that the nine-speed, which is already available in the CLS-Class range in Australia after debuting in Europe in the E-Class, will soon be rolled out to other models.
“It will then go to all models except those with a V12 engine,’’ he said.
“The V12 doesn’t need the extra gears but will move up to a seven-speed torque convertor automatic from the middle of this year, replacing the current five-speed version.’’The new dual-clutch gearbox for the S500 coupe is built in-house at Mercedes-Benz and it aims to reduce fuel consumption, emissions and improve performance.
Mercedes says the upcoming S500 coupe will cover the 0-100km/h sprint in 4.6 seconds, down 0.8 on the outgoing model. It also claims 8.6 litres/100km, significantly better than the old model’s 12.1 litres/100km.
The new transmission will be bolted to a new-generation V8 that was first seen in the AMG GT.
But it will have a much broader base and will expand beyond Mercedes and into manufacturers such as Aston Martin.
The new-generation 4.0-litre bi-turbo V8 – coded M178 – will also be used for the next C63, replacing the naturally-aspirated 6.2-litre V8.
“It will eventually go into most of the AMG range,’’ said Mr Jones.
The engine delivers 375kW and 650Nm in the AMG GT S, compared with the SLS AMG that posted 420kW and 650Nm from its 6.2-litre V8.
However, it could be capable of being tuned up to 440kW.
While it is down on power compared with the 6.2, the new V8 has specific advantages in weight, durability and size.
Aside from being more fuel efficient, it is smaller than the engine it replaces.
It has a dry sump so sits lower in the chassis for a lower centre of gravity.
In the AMG it sits 55mm lower than the previous SLS.
It has a more rigid crankcase, new forged pistons, cylinder walls with a special low friction coating and the cylinder heads are made of zirconium alloy to maximise thermal conductivity.
The two Borg Warner turbochargers sit in the centre of the engine’s V to minimise the distance from the boosters to the cylinder heads, while the exhaust end has ducting for cool air that improves low-end response.
