171mph

Does anyone have this? In latest Car&Driver in the Nissan GT-R review they cite this magazine.

Apparently the GT-R creates 186lbs of downforce (F&R) at 186mph. Porsche 997 turbo creates 60lbs of rear downforce at same speed and i think it said a little lift at the front.

OldGuy

The Gt3 approaches negative lift with the exhaust vent in the front. I dont know what the forces are in the back

LERA GT2

I posted this acouple of months ago with the same question:

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Here is an excerpt of PORSCHE 911 Story by Paul Frere, relating to negative lift or down force for the 996 GT2:

“Porsche claims that a front down force of 2.2 kg and a rear down force of 7.5 kg at 200 kph (124 mph) are produced. Corresponding forces at 300 kph (186 mph) would be 5 and 17 kg respectively”.
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They do not mention at what level or degrees of wing. Is it published anywhere for GT2 & GT3 wings?

C.J. Ichiban

from my old physics classes I remember that a big part of lift/downforce is the length/surface area of the wing from front to back- and it seems like those race cars always have really long wings that even trail off pretty far past the edge of the car, just like retractable flaps on those jumbo jets we always fly on. There are some pretty esoteric calculations and ratios to assume downforce but unless porsche or another race team actually releases wind tunnel figures, we probably won't actually know without a bachelors degree in math.

Ferrari likes to use the underbody to create it's downforce, by sucking wind through the bottom, the air rising over the car actually pushes it down. maybe the issue on downforce with our porsches is that the cars are too smoothly shaped to create real downforce without resorting to winged appendages.

to be real honest- 5 kg and 17 kg don't really do much for me in the wow department compared to 186lbs of downforce on the gt-r, but even still the new viper ACR is supposed to have 1000lbs at 150mph or something. one cars marketing blitz said that it would actually grip upside down in a tunnel because of so much downforce- saleen maybe?

excessive downforce creates real problems with top speed which is why companies like Ruf that build 220mph rt12s don't always want MAX downforce on their designs, you have to have a ton of HP to overcome that- even the veyron in "top speed mode" actually retracts the rear spoiler to make it more slippery.

it's all a big mess. just set your wing to high angle and pray that you stick when you're going fast. amen.

hesperus

hahahaha!!! AMEN brother!!!