Hoovey689

iTrader: (16)

Mercedes-Benz details new variable-displacement V8 for SLK55 AMG

Balancing power and economy is a tricky business, especially for Mercedes-Benz and its in-house performance division, AMG. On the one hand, a buyer's conscience demands improved fuel economy and reduced emissions. But on the other, AMG knows what its customers really want is pure, unadulterated muscle.

Eventually, that dichotomy is expected to amount to the exclusive use of turbochargers across the AMG range, allowing the German automaker to reduce displacement while increasing output. But in the meantime, Affalterbach has found another solution: cylinder deactivation.

The latest AMG powerplant, labeled M152, is based closely on the M157 engine that already powers the new CL63 AMG and its four-door counterpart, the S63 AMG. What makes this engine different, first of all, is the removal of the twin turbochargers. It also makes use of a new air intake, cylinder heads, valve drive, oil system, crankcase and, most importantly, a Formula One-derived cylinder deactivation system that allows it to run – when so selected – on four pistons when conditions don't require all eight. Click through the jump to continue reading.


A variable exhaust system also plays a key part. Under low revs, the exhaust flaps are closed. At 2,000 rpm they start to open in increments – 15 percent, 30, 50 and finally, completely open at full throttle. At 3,600 rpm, the extra cylinders fire up, giving the driver the full surge of power and noise when desired, but a drive more respectful of the environment around it when not.

The bottom line is 415 horsepower and 398 lb-ft of torque from 5.5 liters – a considerable improvement over the 355hp and 376 lb-ft offered by the engine it replaces – but with a whopping 30 percent decrease in fuel consumption.

The engine will be deployed exclusively (at least for now) in the new SLK55 AMG, which will remain the only V8 option in the segment (compared to the likes of the BMW Z4, Porsche Boxster and Audi TT) when it debuts at the Frankfurt Motor Show this September.

http://www.autoblog.com/2011/07/21/m...for-slk55-amg/

Stormwind

It's about time this kind of technology makes it into production other than MB's own V12. I would really like to see this go into every MB engine even the none AMGs and V6. They can even take this further by shutting off 2 more cylinders at a stop, this keeps the alternator and ac running while using very little fuel and they can get rid of the current stop/start none sense.

DustinV

This technology was already available on the W220 S500 and its CL equivalent. I believe it was optional and not many were sold indicating that at that time the market simply didn't care or saw it as a gimmick.

Now, with more stringent fuel economy and emission ratings over the horizon, people are willing to accept this technology in cars.

Jewcano

iTrader: (4)

I wish this could be implemented into current cars at an acceptable rate. I'd love to get 30% greater fuel economy.