newton22

...in comparison to Bimmers and other luxury cars.

Check it out: http://www.dynoperformance.com/searc...563&safeid=563

Not my run, just a find online. Stock with A/C on, ran 211 rwhp and 241 rwtq. Assuming 22% drivetrain loss, thats 309 tq at the crank (Mercedes has it at 295). So our engines actually only lose about 19-20% at the wheels are far as torque goes. Either that, or Mercedes is underrating it. Not to mention, without A/C on a cold dry day, it might see figures around 215 rwhp and 245 rwtq. Maybe more.

But what I'm actually happy about:



Torque curve nearly flat from 3000 rpms to redline.



AMG guys are probably laughing at the numbers.

hbluthi

Hell yes! You think there is a chance that you got a "factory freak" though?

newton22

A what?

MarcusF

Hbluthi, that 430 dyno isn't an aberration. Unlike a number of other manufacturers, Mercedes is notorius for understating their true HP figures.

Here's one from a bone stock 2002 CLK430

newton22

245 rwhp from a stock 430 motor?? That's like 315 horsepower at the crank! And Mercedes only has it at 275.

hbluthi

A factory freak is what it sounds like. Example in vehicles I know more than most ppl about (Jeep Grand Cherokee). A 1998 5.9 liter V8 Grand Cherokke had factory freaks, where the "freaks" were faster that a lot of other 5.9L grand cherokees (5.9's were special edition btw). Understand?

Marcus, thanks man. Why would they underrate though?

MarcusF

Mercedes-Benz is well known for advertising low numbers. So are Porsche (this was especially true during the 944 turbo/951 run) and GM. When a manufacturer dynos an engine, there are a number a variables that come into play. Aside from air temperatures, and pressure, for which there formulas to correct, the question of which full exhaust system from which model car, and which air cleaner come into play. Rather than finding themselves with egg on their faces (like Ford did with their Mustang Cobra a few years ago, or Mazda and their Rx-8 when it was introduced – BTW, the brand new MazdaSpeed6 doesn’t produce it’s advertised numbers either), Mercedes-Benz advertises a conservative number so they don’t have to explain themselves later on.

This is in stark contrast to some Japanese manufacturers who are FAMOUS for lying to their customers. When running an engine on a dyno, some of these unscrupulous manufacturers do things like running the engine with NO air cleaner, NO accessories (including using an external, non-engine driven, water pump), custom headers and shorty exhaust systems that were never offered on any production car. They take that number and reduce it by some unreal drivetrain loss percentage, and pass the results over to the advertising crew. They know inflated HP numbers sell.

Here’s an article from the Detroit News that discusses the recent changes in HP ratings.

The NY Times ran a similar article a month or so ago.

Here’s a well known photo from Mercedes-Benz. Note the full exhaust, all the accessories, and the factory air cleaner.

slk55lvr

Well this explains why my 430 feels a lot faster than 275 hp I consistently beat a friend of mine in an old a8 thats supposed to be 320 hp as well, but I always assumed it was because my low-end torque was better.

hbluthi

Marcus, thanks man! Good info.

^^ No kiddin, it does feel faster than 275, a lot faster.