View Single Post
      07-19-2008, 10:10 PM   #10
mixja
Captain
United_States
19
Rep
783
Posts

 
Drives: 2011 E90 DCT Silverstone
Join Date: Jun 2008
Location: Beverly Hils, CA

iTrader: (1)

Quote:
Originally Posted by swamp2 View Post
Nice work, very interesting. This give so much more information than silly single figures like peak hp or peak torque. Although as a single number peak hp/weight is still quite a good figure.
  • I'm assuming you used gear ratios and final drives as well as wheel size in your torque multiplication calculation?
  • The C63 AMG is a 7 speed, you are missing two gears.
  • Don't forget that the majority of the curves vs speed are not "used" in a real acceleration run. It would be good to see the curves truncated or lines added to show the lower speed/rpm portions darkened or removed.
  • I'm assuming you have seen the performance database we have here. We definitely need some more R8 data posted up here in the "database". From what I have seen for speed except low ones that are traction dominated the M3 and R8 are neck and neck. Anyone want to add those to the database?
  • As lucid mentioned the CarTest software (and other similar tools) basically do this calculation for you plus a lot more. They take into account friction, all parasitic losses (tranny, diff, axles, accessories, tires, etc. AND drag) wheelspin, vehicle weight, power vs. rpm and then simulate an entire acceleration run with ideal shifts. Cool stuff.

Yeah using gear ratios and final drive to calculate number of wheel revolutions per engine revolution, and then the wheel circumference to derive speed.

I didn't put in the other C63 gears as they aren't really relevant (I'm surprised at how tall the C63 gearing is).

Fully agree in a drag race much of each curve is not used - my comments were based around shifting at redline since this is the ideal shift point for all of the cars shown and moving to the next gear torque curve at the same speed as redline in the previous gear...