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Yes, but dont forget the extra traction given by having all 4 wheels pull the vehicle.

The numbers are there, argue with them all you want not me.

The rwd is lighter, pulls off the lien faster, and even (barely) crosses the 1/4 mile line faster.

The awd starts off much slower, but pulls a higher 1/4 mile speed (not time, speed, as in mph)

Slow start + higher finished speed = faster acceleration down the line somewhere.

I dont feel like debating.

I'll give one more example then you can believe me or not, it doesn't really affect me:

If I get on a bicycle and pedal as hard as I can, then attach 300 lbs worth of dead weight to the back of the bicycle and pedal as hard as I can. Do you think I'll be faster with the 300 lbs of dead weight?

The laws of physics can't be broken. Force = mass x acceleration.

Or in other words Acceleration = Force / Mass

If mass increases and force stays the same, acceleration decreases.



This post has been edited by Jabberwocky on Oct 26 2004, 10:02 PM

Your absolutely right.. but lets add one more important part into this equation.

More traction = more force.

You could add the power to the rwd vehicle, that the awd vehicle loses through its drivetrain (becasue this is the cost of awd along with the weight), but the rwd still wouldnt have as much traction in comparison.

you can believe me or not, as i said, argue with the numbers.. not me.

Added: Haha crap man, this must be good stuff, 1001 views already. Looks like we have some good ass debates jabber

This post has been edited by sidewaysgts on Oct 26 2004, 10:58 PM

The problem with traction is that it's kind of an "x" variable. There's no such thing as more traction than traction, you have it or you don't. And that's dependent on too many things like hp/torque, weight, tires, clutch, LSD, driver ability, etc. That's why turbo 240's on open differentials and street tires are all over the place in the quarter. Of course an AWD will accelerate faster, but give the the same 240 slicks and a LSD, and the numbers will change. Will it be faster than the AWD? Maybe, maybe not. . .

So its up to whether or not AWD traction can compensate for the weight in a certain situation against a certain car. I think most everyone has good points from different views.

You guys are looking at this all wrong. Of course a FWD Eclipse will be faster then a AWD Eclipse, that is if both cars were bone stock. What your failing to look at is the power...it totally fails to drive the AWD drivetrain and tires to its maximum potential. Mod both cars to 400hp and the AWD will rip the FWD Eclipse in both the 0-60 and quarter mile.

Same thing goes for the Porsches. 300hp is right at the line on driving a AWD system to its limit. The RWD car will keep up. Now take a look at the 996 Turbo AWD and RWD Porsches. The AWD runs a 3.94 0-60, while the RWD runs it in a 4.3. Quarter mile the AWD runs a full 0.2 seconds faster, that is two cars.

On the street, AWD is ridiculous. I ran a couple modded EVOs and STi's from a dead stop...they blow me out the hole! Then Ill grab 3rd gear and fly past them. It would take a RWD car on slicks to keep up with the traction of a AWD car from a stop. Even the AWD Pikes Peak Celica ran a 9sec quarter mile on a drag strip, and that was on rally dirt tires! As long as it has those front wheels pulling it, that intially doubles the contact patch for acceleration. Traction is what it boils down too...you can do the math, contact patch of 4 tires w/ 400hp vs contact patch of 2 tires w/ 400hp. To be the fastest is placing that 400 horses of power through the tires and keeping it in constant contact with the ground with out slipping...RWD will always have a harder time of doing this, and once it slips just alil bit, it will be slower. As long as the power is there to drive everything to the limit, AWD will always win.


From a roll, weight is meaningless(AWD or RWD wouldnt make a differance)...if both cars have the same exact wind resistance, the one with the most power will win. This is just like in physics class. Take a fat 200lb kid and 85lb kid, and put them both on a swing. It will take more force to push the fat kid then it would the skinny kid...BUT once they are in full swinging motion it will take the same amount of power to keep them both in a even swinging motion. If you want to accelerate the swinging motion, apply the same amount of force to each and they will still swing the same.

This post has been edited by 1slowsupra on Oct 27 2004, 07:33 AM

Most cars do not have trouble putting down power once you get it rolling. You can push the gas all the way down once you get going. So from a roll, the force vector actually stays the same. What happens as the eclipse get modded is that the increase in lateral accleration doesn't offset the advantage of the launch. Neither car are traction limited once they get rolling, so the FF eclipse pull harder due to a better power to weight ratio, modded or not. A=F/M again.

The quarter mile example is just flawed you are assuming both cars are the same distance to the goal when they hit 100mph. A stock neon and a corvette hit it, and you mark the spot where each car gets up to 100mph, it will not be the same spot because that means that they are neck to neck.

Weight is not meaningless from a roll. The amount of kinetic energy required to accelerate an object to a certain speed depends on mass. K = M x V^2

Or energy = mass times velocity squared
If it took the same amount of energy to accelerate or decelerate a heavy object vs a light object, then me chucking a paper ball at you should hurt the same as me chucking a rock at you. Try actually pushing the fat kid on a swing when it is going, you'll need to push harder.

Most of this is common knowledge and very simple physics. No offense, but if you have trouble understanding a simple junior high level physics equation like F = MA, then maybe you should do some reading (not ricer mags either).

If you still don't believe me. Go down to your local drag strip and tell people that awd sucks at launching but acclerates harder to make up for it. Just remember I told you so when people start laughing their asses off at you.

This post has been edited by Jabberwocky on Oct 27 2004, 08:09 AM

Anyways, AWD is faster. I guess you just like arguing, when I actually thought i was agreeing with you. We can sit here for years breaking down every detail. Which it seems you want to get into. Ive been to the track and see it all first hand and experianced it myself.

I was not speaking of acceleration or deceleration. I am talking about a object "already" in motion(like both cars traveling 120mph). Drop two objects from a plane, 10lb weight and 5lb weight...they will both fall at the same speed. It wont take more energy to move the 10lb weight faster when it is already in motion...double the force on both and I bet you the 10lb weight will not pull ahead of the 5lb weight, it will still be even. Acceleration is completely different.

This post has been edited by 1slowsupra on Oct 27 2004, 08:56 AM

Oh well.

FYI though, weight always matter, whether is it during braking accleration or cornering.

Man I feel like I'm in school. This thread could use some Cliff notes at this point. . .

I've said everything I could say, and I've tried to be as clear as possible.

i was never copmaring the distance of the cars at 100 mph, nor have i said they were the same. obviously the car who reaches 100 mph faster will have more distance to vocer to the 1/4 mile line.

In terms of the porsches (and ive said this before) The rwd ocne it hits 100 has 1.6 seconds, the awd has .9

The awd has less time once at the same speed, and still pulls out of the 1/4 mile -faster- then the rwd porsche. If that doesnt prove that its accelerating faster, i dont know what will.
___

Added oh ya as for what supra said, start adding more power at the awd is goign to always win thing.

Thats just becasue as you add more power, the weight disadvantage because less of a handicap, and at one point will even become a advantage. More weight means more mass over the tires which will mean youll have even more traction.

THink of weight reduction as an example. Take one pound from 20 pounds, not much of a difference, take 1 pounds from 2 pounds thats a 50% difference.

As you start adding more and more power, the power:weight ratio gap closes.

This post has been edited by sidewaysgts on Oct 27 2004, 11:12 AM

for those that needs convincing about the potency of AWD on the track, just look at the history of touring car races.

When the R32 came out, it BLEW THE DOORS off every other Gr.A car PERIOD. it ran circles around E30 M3s and Sierra Cosworths even tho the R32 was prolly heavier by a mile.

Then in the mid 90s you have the Audi A4 who dominated BTCC w/ the Quattro before the system was banned and they had to go FF. A4s had to carry penaly weights and they STILL won by a landslide.

Most recent "balance of scale act" is on the RS6 that are racing in the SCCA WC series. Quattro again and now they have a TON of restrictions placed on em to "level the playing field". (it's in this month's GRM)

The only reason why you DON'T see open wheelers using AWD system is trying to package everything in while keeping drag to a minimum (and weight). Weight isn't as critical when it comes to saloon racing as the drivetrain makes for a lower percentage of the entire vehicle, thus using an AWD system has more positives than it does downside.

weight is -not- the concern of many open wheeled racers. F1 being a perfect example, there is a minimum weight requirment and f1 cars often are -way- below that, and actualy have to -add- weight to the vehicle, like adding depleted urnaium to the bottom of the chassis. a awd system would help then be closer to this.

The thing is the straight line acceleration would be pretty useless, f1 courses are tight and passing directly isnt easy. the understeer it would bring into the corners would bea big disadvantage as well. The guy following your ass into the corner (becuase you were on someone elses ass) could easily just pass you on the inside as soon as your understeer started to show.

too bad its banned from so many races hough

This post has been edited by sidewaysgts on Oct 27 2004, 12:04 PM

Who needs AWD when you can do this? Yay for power wheelies.

lol

This post has been edited by Nick on Oct 27 2004, 12:32 PM

Jabber, you've been crystal clear and absolutely correct. Some people need to take some physics courses.

However, it is dependant on power as 1slow says.

Given equal weight, for low-power cars (75-125WHP or so) FWD is going to rule because less drivetrain loss and not enough torque to really spin the wheels. For medium power cars (125-250 whp) RWD will win due to better traction than FWD combined with less drivetrain loss than AWD. For high power the AWD comes into its own due to the traction it offers and the lesser importance of its added weight. All this is strait line speed from a dead stop of course.

MR layouts like in open wheel racing are a whole 'nother ball of wax; the low drivetrain loss and weight of a FF with the traction and balance of a FR. In F1 they avoid AWD due to the drivetrain loss primarily, although Lotus ran a turbine powered AWD car in 1971. It had 150 HP on all the other cars though... and still never completed a race.

it sure is a concern.
there is a reason why they are WELL below the weight limit.

the POSITION of their ballast affects the handling of the car TREMENDOUSLY. the more ballast they have to put on to get to that minimum weight figure the better.

if you've ever raced karts competitively, you'll know what i mean.

there's also the question of packaging AWD into an open wheeler w/o having detriment effects on aerodynamics.

straight line acceleration uselss in F1? try telling Jarno Trulli that when he got his doors blown off of him by Juan Pablo on the OUTSIDE of turn 3 at Hockenheim this year.


road racing is just drag racing between corners

I never said straight line acceleration was useless I meant its pretty difficult to -pass- on the straights from what i have seen, just due to a lack of room to do it in, thats all.

And from what ive seen abou the weight they add, its usually undert he legs of the driver forward to bring the weight oft he car to, or as close to 50:50 as they can (they can actually make damn good use of thise weight distribution)

Theres many reasons not to use awd for f1, i was just hitting some i was told by people who have done cart racing (none in f1 though from what i know, so it may not count.. haha), and youve obviously made some good points yourself.

___

Back to the subject: I feel this topic has been pretty damn hot so far, i think it deserves to be pinned for now unless i find it useless or something later...

damn this thing got a sticky?

I think its a good comparison of all the drivetrains now, not just awd vs fr. not -too- often good info and a good debate like this happens.

Well, after all thoses 5 pages of debates, i have one small detail i want to add. The weight shifting that occur when accelerating don't affect each drivetrain the same. For exemple high power FR can lift their front end from sheer acceleration, but won't happen in an FF or AWD (unless the AWD has disabled the front wheels traction). FF don't loose that much grip accelerating, it's more they don't GAIN any. By their suspension geometry and the fact the car get pulled, the rear can't sink much under acceleration and the front is very unlikely to lift (so the grip remain mostly even). And last, the AWD weight distribution remain mostly even under acceleration as not as much weight can move in the back due to the front pulling it.

Thats true but keep in mind theres a reason -why- FF cant get their front up and their back down.

They can not accelerate fast enough, plain and simple. Give them more power and their front tires are just going to slip and fight for traction.

The faster you accelerate the more weight transfers off the front and to the rear, so you have less and less force pushing, or holding the front tires down to the ground...it becomes a loosing battle the more power you put out on FF

My point was that no matter how much acceleration you put on an FF, the front can't lift off the ground, not even a little (try to picture an FF front lift off like an high powered FR). That's regardless of the tyre's grip, it's impossible. The rear might sink a little but that's all. Also i'm pretty sure even an high powered skyline can't lift it's front (as long as it's not FR). But it's a common problem for high powered FR.

This post has been edited by Rayp on Oct 29 2004, 05:52 PM

if the car has double wishbone rear on an FF, the designers theoretically COULD factor for some anti-squat.

tho of course just how much would of course be limited by the overall packaging (aka size of the car)

Well, i'm pretty sure they do.