How is power "dialed back" on cars?

Question

In the latest issue of motor trend, they have an article on the upcoming 08 mecedes c63 amg. They say, i quote "Power output dialed back to 450 hp and 443 pound feet" Yet the same engine in the black series clk63 gets 500 hp. Motor trend also says it will be "child's play" to get it to the 500 hp mark. How do they do that? and How can you get it back to the 500 hp mark? Thanks

The thing is the both the black series clk63, and the c63 amg are rated by the epa at the 13/20 mpg. I understand adjusting curves, but that usually eirther gets you better millage, more torque, or horspower, so where are the blacks 50 hp going in the c63?

Answer 1

They adjust the ecu mapping.

They tune the fuel mapping so that less fuel is brought into the peak RPM zone, resulting to less power in that range. This should give the engine less HP and Torque.

You can have it removed by retuning the ECU or put the aftermarket chip made by tuners such as Brabus or Clarksson. Just my 2 cents...

Answer 2

In modern engines it is done with the programming in the engine controller. Presumably in this case they wanted the gas economy and lower pollution of the less powerful output curve and may also have wanted to have the high horsepower engine be unique to that model.
To change it back probably involves reprogramming an EEPROM which would be child's play for someone with a lot of expertise and $50,000 worth of equipment.

Answer 3

To be specific, all these expensive high-perf cars are "drive by wire". That means your accelerator pedal is not actually connected to the throttle. So the computer can just close the throttle back on you any time it wants. Simple.

Here's the historical footnote: On some older cars that had traction control, which weren't "drive by wire", they took a different approach. They would first retard the timing. Then, if that wasn't enough, some cars would deactivate cylinders. If that didn't work, the ABS system would go to work applying the brake on one wheel.

Answer 4

simple,programed by computer,no matter,all have rev limter,only going to turn so many rpm,it is done by changing map,timing etc.same thing as going to parts store and buying a hopped up computer,its alwaysadds more hp and stuff,but also there goes your warrenty!!!!

Answer 5

hello,, computers run everything and they are programable,motor trend should have explained that ,read it again.