lmao

[CrAz3D]

AWD cars are engineered to run. 

Also, think about this, 4 wheels moving the car vs. 2 wheels moving the car?  Which is gonna get you to XX speed faster?  This is OF COURSE assuming you're a good enough driver to not spin your tires when starting.  You have same weight, same power (- the little bit lost for the AWD), same wind & all.  Since there is 4 wheels moving the car there wouldn't be less static friction, but the static friction would be broken by twiec as many wheels, making it that much easier to accel.

[quasi-modo]

How would there be less static friction? How would there be less friction at all? By nature there would be more friction w/ awd... it has more moving parts so there is going to be more friction, that means energy is removed from the system by the friction.

[CrAz3D]

WTF, I never said there was less, I said there WOULDN'T be less, but that there would be twice as many ground contact points BREAKING the static friction.

[quasi-modo]

Whoops, misread. I am sorry about that.

Ideally you do not wan tthe cars tire to overcome the static friction with the road because if they do that means they are sliding. You want them to roll. If a car overcomes that static friction with the road it would be spinning its back wheels, if it overcomes the friction while breaking or turning it is sliding. Then you just have friction. But you do want all of the gears, axels, bearings, etc to break their static friction and be able to overcome their normal friction as easily as possible and with awd that means you have more surfaces rubbing.

some kinetic energy for the hell of it.
1/2mv^2(final)J  = 1/2mv^2J + μ*cos(σ)*d*mg
No potential because I would have to put gravity, em, and spring potential on there and that is too much typing

[UserLoser.]

You loose some power, but since there are 4 wheels pushing you along instead of two, it will seem as the car accelerates easier...I think.  Grok, where are you, your AWESOME Volvo is AWD you said... explain this to us

Volvos are awesome?

[CrAz3D]

I didn't really think static friction would be what I wanted to say, but I don't know what it would be.  "W/e force it takes to get the auto moving to begin with" force, there, I'll call it that.

Volvo's are nice cars, nicer that what I drive.  I mean you can find BETTER, but a Ford Focus or something isn't gonna beat it out

[quasi-modo]

I didn't really think static friction would be what I wanted to say, but I don't know what it would be.  "W/e force it takes to get the auto moving to begin with" force, there, I'll call it that.

Volvo's are nice cars, nicer that what I drive.  I mean you can find BETTER, but a Ford Focus or something isn't gonna beat it out

Well the energy put in to getting the car rolling is going to has to overcome friction and static friction of the parts, which awd has a lot of. So you are loosing more mechanical energy from the engine before that energy gets to the wheels because of friction so if you want to go head to head with a car that has less static friction in its parts to overcome you are going to supply more chemical potential energy (fule).

AWD offers a higher coef of static friction with the road because it has 4 surfaces touching rather than 2. This means it is not going to peel out so much and when the coef is lower because of a slick road or something you still haver a higher coef then you would with two wheels. It is better for breaking and accelerating on wet roads. The reason it is not better for this on dry roads though is because of above, you loose that extra energy due to friction on the inside of the thing and you really do not need that higher coef on a dry road because the coef is high enough.

ps: Can anyone prove that more weight does not help you on a slick road? Our prof canceled out normal force somehow and I forgot what he did. It was a long time ago and I forgot what he did.

[CrAz3D]

I think it would depend if you already have some traction...because in my truck I fishtail on pavement ALOT easier than in my Jeep.  Both weigh about the same (this is a sation wagon Jeep thing)

I think we need a physics phd dude & an mechanical engineer

[dxoigmn]

Well to disprove quasi-modo I'll give an example.  Porshe 911 Turbo.  All-wheel drive. 0-60 in 4.2 seconds.  Slow acceleration?  I think not.  Gas guzzler?  Yes.

[Grok]

You loose some power, but since there are 4 wheels pushing you along instead of two, it will seem as the car accelerates easier...I think.  Grok, where are you, your AWESOME Volvo is AWD you said... explain this to us

Volvos are awesome?

Yes.

[quasi-modo]

Well to disprove quasi-modo I'll give an example.  Porshe 911 Turbo.  All-wheel drive. 0-60 in 4.2 seconds.  Slow acceleration?  I think not.  Gas guzzler?  Yes.

A porshe is a porshe.... That is like saying a ferrari has awd and it is still fast... well of course it is. If you had them same engine, body, gear rations, all else equal I mean, but the thing was rwd it would accelerate faster and have a higer top speed. I am not saying cars with AWD are slow. I am saything that AWD is wasteful and that if the car were in RWD it would be faster then it currently is.

[quasi-modo]

I think it would depend if you already have some traction...because in my truck I fishtail on pavement ALOT easier than in my Jeep.  Both weigh about the same (this is a sation wagon Jeep thing)

I think we need a physics phd dude & an mechanical engineer

My truck fishtailed a lot too. Its got a light rear end so therefore a low normal force. But I wish someone could prove that that does not effect how much you slide... I think it does but my prof somehow was able to prove it does not.

My truck is now dead.... flew into a tree. I hydroplaned and had to avoid another car and then I got traction when I was sideways and spun around and went off the road, and when I hit the curb it poped me into the air and I hit the tree  The truck was only worth 2 grand... but I still loved it.

[CrAz3D]

You said having more weight doesn't affect traction..... I'm confused now

[quasi-modo]

You said having more weight doesn't affect traction..... I'm confused now

It confuses me too. My professor managed to work it out and cancel out the normal force. I forgot exactly how he did it. I think I am going to have to ask him how because it does not make sense to me either. Since w = n and n * coef is your friction.

[Grok]

Well to disprove quasi-modo I'll give an example.  Porshe 911 Turbo.  All-wheel drive. 0-60 in 4.2 seconds.  Slow acceleration?  I think not.  Gas guzzler?  Yes.

A porshe is a porshe.... That is like saying a ferrari has awd and it is still fast... well of course it is. If you had them same engine, body, gear rations, all else equal I mean, but the thing was rwd it would accelerate faster and have a higer top speed. I am not saying cars with AWD are slow. I am saything that AWD is wasteful and that if the car were in RWD it would be faster then it currently is.

You're limiting your usefulness of power to straight-line speed.  Consider fun curvey roads and hills.  That Porsche and my Volvo would unquestionably benefit from AWD in a race on such terrain.  Consider that in street racing, as well, you don't always start on track-like conditions, and often have loose pavement, dirt, tiny rocks, any number of things that take away from traction in one or more wheels.  The computers in the Volvo take 500 readings per second of the suspension and make corrections of power to the wheels that need it and can use it (the ones that are not slipping).

During the hurricanes back in October, I was driving down Interstate 95 at 80 mph and there were cars stopped everywhere, and the occasional one in the ditch of the median.  At this one place I hit 8 consecutive puddles that completely crossed the road, and the car steered perfectly along the road, only slowing slightly as it hit each body of water.  A RWD car likely could not handle it.

So go ahead and enjoy your RWD car in perfect dragstrip conditions.  For daily driving, I have more power to the road than you will the rest of the time.  In average, impromptu, street-racing-at-the-next light, my Volvo is even with a BMW M3 despite the M3's 0.4s better 0-60 time on the track.