GT3 0-100km/h Real Time
08-07-2016, 09:22 AM
#1
GT3 0-100km/h Real Time
Have you tried real time acceleration 0-100km/h (0-62)?
I have tried a few times and couldn't get below 3,9sec (Vbox Sport).
OAT 18C, not too much wheel spin, launch control.
How about you?
I have tried a few times and couldn't get below 3,9sec (Vbox Sport).
OAT 18C, not too much wheel spin, launch control.
How about you?
08-08-2016, 02:25 AM
#4
In Colorado forget being in the 3s
. Depends on altitude, temperature, humidity, surface traction, etc. Factories and mags typically adjust performance times to ideal conditions you'll never see.
. Depends on altitude, temperature, humidity, surface traction, etc. Factories and mags typically adjust performance times to ideal conditions you'll never see.
08-08-2016, 02:23 PM
#5
Race Director
I should be in California next month, so planning to hit the drags. Interested to compare times to those I did at Bandimere (Colorado). Trying to get my dad to take his Z06 out as well! That should be epic!
08-08-2016, 02:24 PM
#6
Race Director
08-08-2016, 06:06 PM
#7
Rennlist Member
Yep.
Aero drag also drops, so it doesn't hurt top speed.
Air pressure at sea level (0) altitude is 101 MPa. For an NA engine, that means the air pressure driven air intake can add fuel and combust the air to produce 100% of rated power. The maximum power in percent drops with altitude. The power is almost the same as the (kPa A) line in this chart, with 101 kPa A producing 100% of rated power:
https://www.avs.org/AVS/files/c7/c7e...de54f87b9e.pdf
So you'd make about your rated power at just above sea level, and at altitude you'd make:
2000 ft - 95%
3000 ft - 90%
4000 ft - 86%
6000 ft - 80%
8000 ft - 74%
10000 ft - 69%
and in an airplane, 30000 ft - 30%
Note that in the chart the temperature also drops as you gain altitude. So if you are assuming you're at the same temperature, you'd do even worse.
That's both the reduction in NA engine power production and in aero drag. This is why they made superchargers and turbochargers for airplanes. They wanted to restore the air pressure and even improve on it but still get the benefit of reduced aero drag.
I live at 4400 ft, so NA cars lose about 15% of their power. That means that here, a GT3 only produces about 475*0.85 = 404 bhp. So seventy of those ponies don't make it up the mountain. Then you drop to whp after that. And dyno results typically adjust for altitude so you won't see it in a dyno chart. But turbocharged cars often simply compensate for altitude with a bit more boost. Which means where I live, a 991.2 C2S might produce more power than a 991.1 GT3.
Aero drag also drops, so it doesn't hurt top speed.
Air pressure at sea level (0) altitude is 101 MPa. For an NA engine, that means the air pressure driven air intake can add fuel and combust the air to produce 100% of rated power. The maximum power in percent drops with altitude. The power is almost the same as the (kPa A) line in this chart, with 101 kPa A producing 100% of rated power:
https://www.avs.org/AVS/files/c7/c7e...de54f87b9e.pdf
So you'd make about your rated power at just above sea level, and at altitude you'd make:
2000 ft - 95%
3000 ft - 90%
4000 ft - 86%
6000 ft - 80%
8000 ft - 74%
10000 ft - 69%
and in an airplane, 30000 ft - 30%
Note that in the chart the temperature also drops as you gain altitude. So if you are assuming you're at the same temperature, you'd do even worse.
That's both the reduction in NA engine power production and in aero drag. This is why they made superchargers and turbochargers for airplanes. They wanted to restore the air pressure and even improve on it but still get the benefit of reduced aero drag.
I live at 4400 ft, so NA cars lose about 15% of their power. That means that here, a GT3 only produces about 475*0.85 = 404 bhp. So seventy of those ponies don't make it up the mountain. Then you drop to whp after that. And dyno results typically adjust for altitude so you won't see it in a dyno chart. But turbocharged cars often simply compensate for altitude with a bit more boost. Which means where I live, a 991.2 C2S might produce more power than a 991.1 GT3.
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08-08-2016, 11:35 PM
#8
Rennlist Member
Originally Posted by ace37
Yep.
Aero drag also drops, so it doesn't hurt top speed.
Air pressure at sea level (0) altitude is 101 MPa. For an NA engine, that means the air pressure driven air intake can add fuel and combust the air to produce 100% of rated power. The maximum power in percent drops with altitude. The power is almost the same as the (kPa A) line in this chart, with 101 kPa A producing 100% of rated power:
https://www.avs.org/AVS/files/c7/c7e...de54f87b9e.pdf
So you'd make about your rated power at just above sea level, and at altitude you'd make:
2000 ft - 95%
3000 ft - 90%
4000 ft - 86%
6000 ft - 80%
8000 ft - 74%
10000 ft - 69%
and in an airplane, 30000 ft - 30%
Note that in the chart the temperature also drops as you gain altitude. So if you are assuming you're at the same temperature, you'd do even worse.
That's both the reduction in NA engine power production and in aero drag. This is why they made superchargers and turbochargers for airplanes. They wanted to restore the air pressure and even improve on it but still get the benefit of reduced aero drag.
I live at 4400 ft, so NA cars lose about 15% of their power. That means that here, a GT3 only produces about 475*0.85 = 404 bhp. So seventy of those ponies don't make it up the mountain. Then you drop to whp after that. And dyno results typically adjust for altitude so you won't see it in a dyno chart. But turbocharged cars often simply compensate for altitude with a bit more boost. Which means where I live, a 991.2 C2S might produce more power than a 991.1 GT3.
Aero drag also drops, so it doesn't hurt top speed.
Air pressure at sea level (0) altitude is 101 MPa. For an NA engine, that means the air pressure driven air intake can add fuel and combust the air to produce 100% of rated power. The maximum power in percent drops with altitude. The power is almost the same as the (kPa A) line in this chart, with 101 kPa A producing 100% of rated power:
https://www.avs.org/AVS/files/c7/c7e...de54f87b9e.pdf
So you'd make about your rated power at just above sea level, and at altitude you'd make:
2000 ft - 95%
3000 ft - 90%
4000 ft - 86%
6000 ft - 80%
8000 ft - 74%
10000 ft - 69%
and in an airplane, 30000 ft - 30%
Note that in the chart the temperature also drops as you gain altitude. So if you are assuming you're at the same temperature, you'd do even worse.
That's both the reduction in NA engine power production and in aero drag. This is why they made superchargers and turbochargers for airplanes. They wanted to restore the air pressure and even improve on it but still get the benefit of reduced aero drag.
I live at 4400 ft, so NA cars lose about 15% of their power. That means that here, a GT3 only produces about 475*0.85 = 404 bhp. So seventy of those ponies don't make it up the mountain. Then you drop to whp after that. And dyno results typically adjust for altitude so you won't see it in a dyno chart. But turbocharged cars often simply compensate for altitude with a bit more boost. Which means where I live, a 991.2 C2S might produce more power than a 991.1 GT3.
I need to move!
08-09-2016, 12:17 PM
#10
Rennlist Member
Absolute temperature at 15C is 288K, and in English units that's 59F which is 519R. (R stands for Rankine and is analogous to Kelvin but in degrees F.)
This means a drop of 29C / 52F yields a power gain about 10%. This is because 29/288 or 52/519 are about 10%. So rounding just a bit more, every 3C is 1%, and 10F is 2%.
This is why a dyno adjusts/corrects for these things in the SAE and other corrected outputs.
The impact on tire traction will be more important in a lot of practical settings.