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Mercedes-Benz is preparing a new range of four-cylinder diesel engines that will be installed in various models later this year, including the C-class.
Codenamed OM651, the new 2143cc unit uses twin turbochargers, a common-rail injection system and 16.2:1 compression ratio to provide up to 20 per cent more power and fuel savings of up to 25 per cent over the engine it replaces, the OM646.
Three distinct versions of the OM651 are planned. In range-topping form, set to find its way into a n...Read the full article

So I guess this is Mercedes' follow up to BMW's 1995cc 4 cyclinder twin turbo diesel also sporting 201bhp. I haven't heard of any plans to stick this unit in the 3 series. If they don't, the Merc will be a bit of a now brainer.

That just leaves the VW group. Their existing range of 4cylinder diesels are a bit agricultural to say the least.

 

Pretty impressive figures. Don't BMW already have a ~200bhp '325d' - though I'd be surprised if it was as economical as the Merc engine as it's a 3 litre.

Plunkers:

That just leaves the VW group. Their existing range of 4cylinder diesels are a bit agricultural to say the least.

Er, VW have migrated nearly all their diesels to smoother common-rail(2.0 TDI 140PS in Tiguan etc.).

They've just launched a 170PS version of the above the same TDI engine in the Tiguan.

VW Group, Audi will by end of year/early 2009 have a 204PS two liter four cylinder diesel engine on the market - reported AutoBild 2/4/2008 - step for step with Merc/BMW.

 

A mighty "20 per cent more power and fuel savings of up to 25 per cent over the engine it replaces". What a result! Truly a huge improvement every which way and yes I agree it's very BMW going the twin turbocharged diesel route.

Mercedes top engine. the new C250 CDI, kicks out 201bhp and a whopping 369lb ft of torque giving their saloon a 0-62 of 7.7sec and combined 52.3mpg is mightily impressive too. Well done Mercedes :) 

The headline figure of 500nm of torque is slightly deceiving. The maximum torque is produced at 1800rpm and tapers off quite sharply beyond that. I have seen the engine output diagram at another website and the top of the torque band is rather narrow and steep at either end of the rpm range. I'd be interested to know the in-gear acceleration performance of an E Class saloon with this CDI engine.

What is Mercedes doing with their transmissions now? Their current 7G Tronic gearbox cannot handle high torque. I'd hate to see Mercedes to come out with these new engines only to have them coupled to the antiquated five speed autobox.............. 

Chunkster:

The headline figure of 500nm of torque is slightly deceiving. The maximum torque is produced at 1800rpm and tapers off quite sharply beyond that. I have seen the engine output diagram at another website and the top of the torque band is rather narrow and steep at either end of the rpm range.

- see below - make your own mind up. As to inability of 7G-TRONIC autobox to handle 500Nm, what about the 320CDI 3litre V6 with 510Nm already fitted?

Chunkster:

What is Mercedes doing with their transmissions now? Their current 7G Tronic gearbox cannot handle high torque.

 - Incorrect, see below:

"Automatikgetriebe ist für ein Dauerdrehmoment von 700 Newtonmetern ausgelegt." source: Daimler Technologie http://www.daimler.com/dccom/0-5-1059924-49-1063782-1-0-0-0-0-0-14972-7165-0-0-0-0-0-0-0.html

loather:

VW Group, Audi will by end of year/early 2009 have a 204PS two liter four cylinder diesel engine on the market

Im an AUDI driver and its a shame to see them once again bringing up the rear and following the herd. Why cant we have more innovation from the VW group?

BMW's Stop/Start really caught VW by suprise and it will still be at least 18 months before they start to introduce it in their range. DSG is their only real useful AND original technical achievement in the last few years.

Even SAAB now has a much more advanced version of the Haldex 4-wheel drive system which Audi tags as quattro in the A3 and TT. Yeah exactly... SAAB!

 Who were well ahead on a number of things back in the 80s but got stuffed up by GM!

Quattro369:

Im an AUDI driver and its a shame to see them once again bringing up the rear and following the herd. Why cant we have more innovation from the VW group?

Hello again Quattro369, you've really got me thinking this morning! Whether or not Audi are lagging in matters of unique pioneering technology you may have a point. After all, Mercedes/Daimler are right now considering suing Audi for infringement of their patent, Bluetec - clean up of nitrous oxides emissions from diesel engines using urea in a catalyst. Mercedes claim Audi have incorporated the technology on recent show cars and are planning market introduction before Mercedes themselves, the patent holder, on the A4 model later this summer(C/E class end of year in Europe). Mercedes licences the techology and charges around €25-45 per vehicle. Now, all that notwithstanding Audi in matters critical acclaim and sales seem to be gaining the upper hand on their two main German rivals in the prestige middle and upper segments. The new A4, whether Autocar thinks it or not, has been universally judged in its home market to be a good distance ahead of the 3 series and C class. This applies to the main petrol representative 1.8TFSI and diesel 2.0TDI. The new, electronic driver assists like lane assist and so on may be trivial but the repostioning of the front axle, engine and gearbox to give a longer wheelbase and better weight distribution more akin to a rear-driver is certainly a breakthrough for front-drive technology. Again on the sales, all-round competency point the new A3 cabriolet is rated higher than the also new BMW 1 series cabriolet as a further example. Audi have the equal of anyone's engine range with petrol direct injection and low capacity turbocharged units surpassing BMW's small, high reving but low torque 4 cyl. petrols, and finally seem to have cracked their stiff ride/suspension problems. Finally, Audi have set themselves the target of surpassing BMW and Mercedes as the no.1 prestige car maker by 2015, measured in sales numbers of course but also in covering all niches and being class-leading in key technologies. And don't forget that it is the ex-Audi boss who is now head of VW Group and Audi should therefore far from suffer when it comes to accessing latest Group technology innovations.