CCXR wtf?

Discussion in 'European Cars' started by ging, Mar 4, 2007.

  1. 0-100 mph in 4.5 seconds? it wishes. Even on slicks it would probably be in the low fives (this is optimistic that it can get the power down with such light weight, the veyron's enormous weight helps it with traction and it has awd).
  2. #27 26y4u, Mar 8, 2007
    Last edited by a moderator: Apr 25, 2016
  3. hmm, its not spot on actually. it tends to be a little over-generous on acceleration i think.

    the frontal area is not required to run the simulation, but you can optionally enter the data for more accuracy.

    heres the enzo and s7. it cant predict data for cars with more than 6 gears as its quite an old program, so no veyron. although i could just miss out 5th or 6th gear i suppose.
  4. there is a shitload of other parameters that you can enter as well, but i normally keep them constant for all the cars, these are:

    air temperature: 65F
    barometric pressure: 29.38 in.Hg
    humidity: 55%
    elevation above sea level: 0ft
    headwind/tailwind: 0mph
    road incline/decline: 0ft

    manual shift time: 0.5s
    manual engage time: 0.2s
    auto shift time: 0.3s
    auto engage time: 0.1s
    manual maximum clutch slip time: 5.0s

    engine free decel. rate: 2000rpm/sec
    bog down decel. rate: 4000rpm/sec
    wheelspin decel. rate: 500rpm/sec
    manual clutch slip decel. rate: 250rpm/sec
    auto transmission slip accel. rate: 750rpm/sec
    auto transmission wheelspin accel. rate: 250rpm/sec

    coeffecient of static friction: 1.00
    coeffecient of kinetic friction: 0.85
    coeffecient of rolling resistance: 0.013
    tyre expansion factor: 0.020% per mph
    hot tyre pressure: 35psi
    tyre tread to section width ratio: 90%
    wheel + tyre weight: 45lb

    minimum engine speed: 700rpm
    0hp engine speed: 600rpm
    turbo start speed: 3000rpm

    mechanical losses - auxiliries: 2%
    mechanical losses - manual trans.: 6%
    mechanical losses - auto trans.: 8%
    mechanical losses - differential: 4%
    mechanical losses - axels and shafts: 5%
    mechanical losses - torque converter: 3%
    clutch slip losses: 10%
    auto trans. slip losses: 15%

    center of gravity from bottom of car: 30%
  5. Do you know what it uses for Sref if you don't enter one?
  6. enter what? a frontal area? it requires the drag coefficient Cd, and i presume it somehow predicts the frontal area
  7. But there are cars with low Cd but high S. Like those old Volvos...
  8. That's what I'm asking... What number does it assume / "predict"
  9. Precisely. Frontal area can be drastically different from car to car. Like take the frontal area of a Mk1 VW Scirocco versus say an Audi A8... the Scirocco will have a much smaller frontal area and even if it has a higher drag coefficient, it may still be "more aerodynamic". I'm sure you know this, but for others reading:

    Drag (force) = 1/2 * rho * Cd * A * v^2

    Power = Force * velocity, so:

    Power to overcome drag = 1/2 * rho * Cd * A * v^3

    rho = density of fluid object is passing through (air for cars obviously)
    Cd = drag coefficient
    A = frontal area (for cars, this changes definition depending on the shape)
    v = velocity
  10. im not sure how it works, i didnt write the program <A BORDER="0" HREF=""><IMG BORDER="0" SRC="pitlane/emoticons/wink.gif"></A>

    how do you calculate a cars' frontal area?
  11. I know, I was just adding some thoughts to the physics behind the program so folks reading would start to understand (hopefully).

    The frontal area is the area projected onto a flat surface by the car looking at the front of it... a better explanation may be that it's the cross-sectional area (looking at the front of the car) at the car's widest point. The only way to get frontal area is to get manufacturer's data or start taking a bunch of measurements. <A BORDER="0" HREF=""><IMG BORDER="0" SRC="pitlane/emoticons/smile.gif"></A>
  12. maybe the program could take an approximate "guess" at the frontal area, as you have to enter width, height, ground clearance, Cd and a few other things
  13. i think it probly would assume the car is a bloc with the height and width unless you tell it otherwise
  14. How do you copy paste from cartest? doesn't seam to work with the print screen button.

    Edit: don't know why i quoted you.
  15. That's probably it.
  16. I’m well aware of the fact that Christian created the company my friend, I have been In contact with Koenigsegg several times during the years, but that’s beside the point.

    But Bard Eker invested in Koenigsegg for some time ago now, and he owns something like 40-50% of the company now.
  17. I look forward to this.
  18. You can enter the frontal area yourself.

    Curious thing however is that when i put in the Veyron with a CD of .36 which it in top speed mode is claimed to have and a frontal area of 2,00 square meters it got nowhere near 400km/h.
  19. Could be. Note: CD has absolutely nothing to do with area.
  20. is 2m the veyrons frontal area?

    the veyron is a strange beast. the engine could actually be developing more than 987bhp at high speeds due to the sheer volume of air rushing into the engine. try giving it like 1050 hp or something, although this would mess up the accuracy of its low speed acceleration
  21. No idea if that is it's frontal area, just took a guess seing as most cars are swerving around that number.

    First i took it with the grearing which it aproxamatly has, shifting into 6th gear at 320km/h

    0-100km/h - 2.6 sec
    0-160km/h - 5.4 sec
    1/4 mile - 10.1 @ 228.2km/h
    1000 meters - 18.1 @ 299.3km/h

    With gearing to over 400km/h with a drag of .36 and 2.0 square meters frontal area i only got to 385km/h with 1040hp.
    when i lowered the frontal to 1.8 (which i doubt it has seeing as a VW Lupo if i'm not mistaken has a frontal area of 1.94m2) meters it got to 402km/h.
    Then i lowered the cd to .34 and it got to 410km/h.

    Edit: just noticed that the koenigsegg CCX has a frontal area of 1.87 m2.
    With the cd of .30 and frontal are of 1.87m2 cartest calculated a top speed of 404km/h for the Koenigsegg CCX.
  22. 2.2!
    0-100 4.5 ahahahahah
    400m 9,7 @152 !!!!!!!!
    is a jet! you are crazy my dear....

Share This Page