Question...
- Thread starter Shannon
- 7 comments
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Nope, not at all.
It has to do with wieght distribution and weight movement(there's another term for it, but I don't remember it).
Most cars on the road are front engined. Making the front wheels drive the car puts the wieght of the engine over the drive wheels. This helps in traction. A FF car will go a lot better than a FR car in the snow and on wet pavement. For an example, use my family. It's snowed here twice(bigger, road covering snows). My dad could drive the Probe(FF) or the RX-7(FR). The Probe has wieght over the drive wheels, and goes a lot better then the RX(trust me on this, even with posi-traction and 50-50 wieght distribution the RX is all over the place, I've been there). In the snow, accelerating around a turn or on a banked road is hard. In an FR car, the back tends to slide out easily, while in an FF car, the fronts might push, but you will get more speed and more control in FF then in a FR car.
Why there isn't alot of power in FF cars is partly cause of size and space, and the other reason is that FF cars get to a point where the power is unable to be effectively transfered to the road because of the wieght transfer under acceleration. On any car(or even bicycles for that matter), when you accelerate the front of the car raises up and the back drops down. So at rest, a RX-7 has 25% of the wieght on each wheel. Hit the gas, and the numbers change, to lets say 15% on each of the fronts and 35% on each of the back. Input cornering and you get the inside front wheel really light, and the outside rear wheel pretty heavy.
So if you make a FF car really fast, acceleration will be interrupted by a loss in traction.
Like my bro's MX-6GT or Probe GT(about 180HP, 200+FT LBS). We've raced many people, some times around corners(at a stop light with a double left turn onto another road). While cornering that inside wheel loses traction and spins. This is also in part to, simply put, Subaru's AWD slogan inverted(creating the phrase "from the wheels that grip to the wheels that slip"). Power tends to go to the place of least resistance, only corrected by a traction control system, such as a locked differential or electronicly controlled system, that forces power to be outputed through the drive wheels equally.
And I now realise that this post is pretty damn long, so I'm done. Hope it makes sense to you Eddy.
It has to do with wieght distribution and weight movement(there's another term for it, but I don't remember it).
Most cars on the road are front engined. Making the front wheels drive the car puts the wieght of the engine over the drive wheels. This helps in traction. A FF car will go a lot better than a FR car in the snow and on wet pavement. For an example, use my family. It's snowed here twice(bigger, road covering snows). My dad could drive the Probe(FF) or the RX-7(FR). The Probe has wieght over the drive wheels, and goes a lot better then the RX(trust me on this, even with posi-traction and 50-50 wieght distribution the RX is all over the place, I've been there). In the snow, accelerating around a turn or on a banked road is hard. In an FR car, the back tends to slide out easily, while in an FF car, the fronts might push, but you will get more speed and more control in FF then in a FR car.
Why there isn't alot of power in FF cars is partly cause of size and space, and the other reason is that FF cars get to a point where the power is unable to be effectively transfered to the road because of the wieght transfer under acceleration. On any car(or even bicycles for that matter), when you accelerate the front of the car raises up and the back drops down. So at rest, a RX-7 has 25% of the wieght on each wheel. Hit the gas, and the numbers change, to lets say 15% on each of the fronts and 35% on each of the back. Input cornering and you get the inside front wheel really light, and the outside rear wheel pretty heavy.
So if you make a FF car really fast, acceleration will be interrupted by a loss in traction.
Like my bro's MX-6GT or Probe GT(about 180HP, 200+FT LBS). We've raced many people, some times around corners(at a stop light with a double left turn onto another road). While cornering that inside wheel loses traction and spins. This is also in part to, simply put, Subaru's AWD slogan inverted(creating the phrase "from the wheels that grip to the wheels that slip"). Power tends to go to the place of least resistance, only corrected by a traction control system, such as a locked differential or electronicly controlled system, that forces power to be outputed through the drive wheels equally.
And I now realise that this post is pretty damn long, so I'm done. Hope it makes sense to you Eddy.
- 15,799
Ah! Thanks Maz!Originally posted by MazKid
Nope, not at all.
It has to do with wieght distribution and weight movement(there's another term for it, but I don't remember it).
Most cars on the road are front engined. Making the front wheels drive the car puts the wieght of the engine over the drive wheels. This helps in traction. A FF car will go a lot better than a FR car in the snow and on wet pavement. For an example, use my family. It's snowed here twice(bigger, road covering snows). My dad could drive the Probe(FF) or the RX-7(FR). The Probe has wieght over the drive wheels, and goes a lot better then the RX(trust me on this, even with posi-traction and 50-50 wieght distribution the RX is all over the place, I've been there). In the snow, accelerating around a turn or on a banked road is hard. In an FR car, the back tends to slide out easily, while in an FF car, the fronts might push, but you will get more speed and more control in FF then in a FR car.
Why there isn't alot of power in FF cars is partly cause of size and space, and the other reason is that FF cars get to a point where the power is unable to be effectively transfered to the road because of the wieght transfer under acceleration. On any car(or even bicycles for that matter), when you accelerate the front of the car raises up and the back drops down. So at rest, a RX-7 has 25% of the wieght on each wheel. Hit the gas, and the numbers change, to lets say 15% on each of the fronts and 35% on each of the back. Input cornering and you get the inside front wheel really light, and the outside rear wheel pretty heavy.
So if you make a FF car really fast, acceleration will be interrupted by a loss in traction.
Like my bro's MX-6GT or Probe GT(about 180HP, 200+FT LBS). We've raced many people, some times around corners(at a stop light with a double left turn onto another road). While cornering that inside wheel loses traction and spins. This is also in part to, simply put, Subaru's AWD slogan inverted(creating the phrase "from the wheels that grip to the wheels that slip"). Power tends to go to the place of least resistance, only corrected by a traction control system, such as a locked differential or electronicly controlled system, that forces power to be outputed through the drive wheels equally.
And I now realise that this post is pretty damn long, so I'm done. Hope it makes sense to you Eddy.
Moment of Inertia: an object will rotate around an axis determined by the center of gravity. If that object is unevenly balanced (FF cars), it will rotate around the off-centered center of gravity (which in an FF car, will be the way you probably want to turn). If the object is evenly balanced (FR), the object will rotate around the true center of the object (which will probably spin you out).
http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html
The other problem with FF cars is torque steer. This happens because the FF drivetrain takes up a lot of space, leaving less room for the engine. An easy way to get around this problem is mount the engine sideways. This then creates an issue with uneven length axles to the front wheels:
0--#----0
[...'0' are tires and '#' is the engine output.] Since the axles are not even, the tires will not spin at the same rate. Put a lot of power to these wheels and dump the clutch and the car may want to take a turn towards the long axle (it's turning slower, and the short axle faster; path of least resistance, remember?). This also makes the steering wheel squirm in your hands, giving you an uncomfortable feeling about the car.
Similar things happen during high-speed cornering.The easiest way to combat this is with a limited-slip differential.(*) This basically reverses the trend of "path of least resistence". But that's often expensive, and the cheaper way is to simply use less powerful engines.
(*)http://www.howstuffworks.com/differential.htm
- 209
There's another major afctor, too, and that's torque steer.
In factm ever since the CV joint was created (neccessary in order to use the fornt wheels to steer and power the vehicle), manufacturers have nee battling torque steer. It has only been in the last 10 years or so that it's really been under control. If you had an old Escort or something with 250hp, it would be nearly undriveable from a stop.
Basically, torque steer is a side effect from driving the same wheels you use to steer. The rotational movement of the wheel acts like a gryoscope. If you've ever held a gyro while it's sipping, you'll notice it wants to pull to one side. The wheels try to do the same thing, in a way. The more power you put to them, the more they want to pull. Next time you drive a hi-po FWD car, try flooring it without holding the wheel (okay, only try this in an empty lot). It will jerk all over the place. That's torque steer.
You try to put a 500hp V8 in a car with stock manufacturer front suspension & axles, you will literally rip the wheels off.
In factm ever since the CV joint was created (neccessary in order to use the fornt wheels to steer and power the vehicle), manufacturers have nee battling torque steer. It has only been in the last 10 years or so that it's really been under control. If you had an old Escort or something with 250hp, it would be nearly undriveable from a stop.
Basically, torque steer is a side effect from driving the same wheels you use to steer. The rotational movement of the wheel acts like a gryoscope. If you've ever held a gyro while it's sipping, you'll notice it wants to pull to one side. The wheels try to do the same thing, in a way. The more power you put to them, the more they want to pull. Next time you drive a hi-po FWD car, try flooring it without holding the wheel (okay, only try this in an empty lot). It will jerk all over the place. That's torque steer.
You try to put a 500hp V8 in a car with stock manufacturer front suspension & axles, you will literally rip the wheels off.
- 209
Heh, yes, yes I did.
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