how much power to go 187 mph/300 kph in a malibu? - Lateral-g Forums

deuce_454 · #1 07-11-2008, 06:03 AM

Ok i have been wondering.. How much power would it take to break 300kph/187 Mph on the autobahn on a good day??

i have done the math and with my final drive of 3.73, the gear ratio in OD: .696 my rear tire size (285/40-18) 26.976 inches i would need to turn 6030 rpm in top gear to reach 300 kph..

the rear is a 12 bolt, tranny is a 4l60e engine is 2002 LS1.. converter is a muscledrive so it can handle the torque in lockup.. and my tranny controller allows me to run WOT in top gear in lockup..

the car is as aerodynamic as a barn! its a mildly (3-inches) lowered 79 bu with suspension to handle both the speed and stopping.. i figured i could add a small lower lip spoiler and possibly a 2 inch nascar duck tail type spoiler to keep the front and rear from lifting too much.. but the less spoiler the less drag.. im not going to mount narrow tires or moon wheel covers just to go the extra 2 kph...

holschen · #2 07-11-2008, 06:55 AM

that´s a good question...
me to wants to kill myself

Quote:

Originally Posted by deuce_454

Ok i have been wondering.. How much power would it take to break 300kph/187 Mph on the autobahn on a good day??

i have done the math and with my final drive of 3.73, the gear ratio in OD: .696 my rear tire size (285/40-18) 26.976 inches i would need to turn 6030 rpm in top gear to reach 300 kph..

the rear is a 12 bolt, tranny is a 4l60e engine is 2002 LS1.. converter is a muscledrive so it can handle the torque in lockup.. and my tranny controller allows me to run WOT in top gear in lockup..

the car is as aerodynamic as a barn! its a mildly (3-inches) lowered 79 bu with suspension to handle both the speed and stopping.. i figured i could add a small lower lip spoiler and possibly a 2 inch nascar duck tail type spoiler to keep the front and rear from lifting too much.. but the less spoiler the less drag.. im not going to mount narrow tires or moon wheel covers just to go the extra 2 kph...

dave96dcm · #3 07-11-2008, 12:59 PM

I don't know the math or how to figure it out, but I would think it would be in the ballpark of 500hp, I know that it is much more aerodynaic, but a new M5 will do faster than that with 500hp.

byndbad914 · #4 07-11-2008, 06:38 PM

you would need to know the drag coefficient and I wouldn't even hazard a guess at what that car would be.

That said, I recall a C4 Vette that ran the Silver State having difficulty clearing 190mph with ~500HP so he messed with mirrors and louvers and so forth to get the car working better aero-wise. Big Red cleared it with a bit of a brick and it took over 700HP IIRC (it is up over 800HP now, but original version was something like 750HP IIRC). So I would guess with a brick like that somewhere around 700-750HP to get to 200mph.

couple links to mess with

http://www.bobnorwood.com/300%20mph%...nd%20Power.htm
http://www.trackaero.com/factors1.html

if you assume the square ft square plate, just measure nose from the ground as a rectangle, add the windshield as a rectangle and see how many square ft that is. Multiply that * 71 HP and that would be a worst estimate I would think as square plates are horrible for drag of course.

jannes_z-28 · #5 07-12-2008, 01:22 AM

I remember seeing somewhere that to double your speed you need 8 times more power.

Jan

holschen · #6 07-12-2008, 03:08 AM

weight,aerodynamics,enginedisplaysment,how wide tires u have(wider=slower),enginepower,drivetrain slip,
hmm my english is what it is ,sorry

if u wear a helmet ur speed will slow remarkably

deuce_454 · #7 07-12-2008, 02:38 PM

Quote:

Originally Posted by jannes_z-28

I remember seeing somewhere that to double your speed you need 8 times more power.

Jan

the drag increases geometrically with speed, "speed squared" so to speak,, so its double the speed = four times the power...

the eight fold is if you want to accelerate to twice the speed in the same distance....

but i see your point... do a full throttle run, record the speed and when the car is dyno´ed ill know how much power i have at the wheels at that given rpm.. and then its relatively simple math to figure out how much power i need then (assuming that it takes zero Hp to go zero Hp and not account for rolling resistance will give an over estimate of power needed)