TRWeiss1

iTrader: (20)

Wow, he actually PM'd you over that? Some people on this forum REALLY need to grow up.

no_more_rice

I have limited patience with fools who post bullshit and call it a "fact". These simple minded power-to-wait ratio claims in the racing kills section need to stop, it's all complete nonsense. You can't some grade school power to weight "equation" in a lame attempt to try to predict how much power you need to beat a 700 hp single turbo Supra from 100-150 mph - that's garbage science, and I'm calling it out every time.

no_more_rice

By exclusion (in your moronic "formula" from the previous page) they are not taken into account! Duh! The two vehicles involved in this highway street race do not have the same frontal area, Cd, tire size, etc?? Furthermore, contrary to your post, Speed DOES matter, because drag starts to increase EXPONENTIALLY at higher speeds. Get a clue before you post bullshit.

no_more_rice

Now this is FACT

Road load horsepower is the power required for a vehicle to maintain a constant speed on a level road. It is the sum of the powers required to overcome the car's rolling resistance, and aerodynamic drag.

Rolling Resistance

Rolling resistance includes power train losses, wheel bearing losses, and power losses in the tires. Of the three, tire rolling resistance is the greatest, and so dominant that the other losses may be disregarded for first-order approximations.

The force of tire rolling resistance in radial-ply tires for passenger cars tend to be about 1.2% of the car's weight at 30 mph (48 km/h), increasing to about 1.6% at 70 mph (113 km/h), when properly inflated. For a 3000 pound car these equate to roughly 35 and 50 pounds of force at 30 and 70 mph, respectively. Under inflation or excessive weight increase tire rolling resistance considerably.

Aerodynamic Drag

The force of aerodynamic drag is a function of a car's shape (Coefficient of Drag), size (frontal area), the square of it's speed, and (to a minor extent) its altitude. For a mid-size sedan this equates to about 20 and 90 pounds of force at 30 and 70 mph, respectively.

Modern cars have drag coefficients (Cd) ranging from 0.30 to 0.50 (with pickups and SUV's being somewhat higher). To give some idea of what these number mean, here are typical Cd's for some other objects: an airfoil, 0.05; a ball, 0.10; a narrow (30°) cone, 0.34; a wide (60°) cone, 0.51; a square flat plate, 1.17; a parachute, 1.35.

Road Load Horsepower

Horsepower is a measurement of a force applied at a speed. Both rolling resistance and aerodynamic drag are calculated in terms of force. At any chosen speed, these forces can be resolved into horsepower requirements. If the car can supply that amount of power to the wheels, then it can maintain that speed. Total road load horsepower for a typical mid-size sedan is about 15 hp (11 kW) at 50 mph (80km/h).

Since rolling resistance force is not a function of speed, then rolling resistance horsepower (a function of speed) increases proportionally with speed. Since aerodynamic drag force is proportional to the square of the car's speed, then aerodynamic drag horsepower increases proportionally to the cube of the car's road speed.

It is generally accepted that, on a typical car, its rolling resistance and aerodynamic drag become equal at about 50 mph. So at twice that speed the aerodynamic drag is about 4 times the rolling resistance.

JSmith0101

iTrader: (6)

Calm down, hoss.

Scorpio Antares

Dang, your car is still nasty.... no matter how you put it, that GTR was definitley high boost pushing his car to the limit... if you throw up the boost and put in some V-power lol, youll take him no problem...

and dang, that S2JZ is beast!!!!


need more races

BoostCrzy

I am actually the one who tuned that GTR.......at the time it was making 715whp on my Mustang dyno...