FWD Vs. RWD Vs. AWD
#31
![Post](images/icons/icon1.gif)
2.5 G is defo downforce related (and car weight), but even cars with a small front/rear lift at 200 km/h(like an Impreza MY00) can corner upto 1.2 G in the dry (see Sport-Auto tests).
Should look it up as it's explained in "Drive to Win", but wasn't this to do with the fact there's not only mechanical but also chemical locking ?
Should look it up as it's explained in "Drive to Win", but wasn't this to do with the fact there's not only mechanical but also chemical locking ?
#32
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
you can get on the power earlier with RWD as you can do this before all the major cornering is done
![EEK!](images/smilies/eek.gif)
#33
![Post](images/icons/icon1.gif)
![Big Grin](images/smilies/biggrin.gif)
In a straight line, yes, because the car would be lighter.
What about understeer?
Absolutely spot on
Because they're lighter.
If so, are you saying that this therefore makes it faster? If so, are you saying only in a straight line? If so, are you saying that the likes of Lotus, Ferrari, McLaren, etc are only interested in straight line performance?
Come on Claudius, put a bit of weight behind your arguments rather than taking pot shots at me from behind my statements.
All the best
Simon
#34
![Post](images/icons/icon1.gif)
claudius
Unfortunately, you clearly just do not understand what's going on. Could you give us some idea of what experience / expertise you have to bring you to this conclusion?
Some of the most respected and successful vehicle manufacturers and motorsport companies in the world will be VERY interested to hear this revelation.
Can you explain WHY this will happen, rather than just stating that it will?
Cheers
Simon
This is just plain wrong! You dont get any front grip in a RWD and if you would accelerate as early as with an AWD, you would go straight!
Some of the most respected and successful vehicle manufacturers and motorsport companies in the world will be VERY interested to hear this revelation.
Can you explain WHY this will happen, rather than just stating that it will?
Cheers
Simon
#35
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
Hi Simon ![Big Grin](images/smilies/biggrin.gif)
What I'm saying is that given the same entry speed into a corner, if I floor my former M3 before the apex, it will understeer.
If I do the same thing in my Evo, the front diff locks up and pulls me into the direction I indicate.
![Big Grin](images/smilies/biggrin.gif)
What ABOUT understeer? Are you saying that putting power to the fronts will reduce understeer? I hope not.
If I do the same thing in my Evo, the front diff locks up and pulls me into the direction I indicate.
#36
![Post](images/icons/icon1.gif)
I reckon that when you corner, you're using all the available grip of the front tires, and only part of the grip of the rear tires.
Imagine a car with similar geometry both front and rear, same suspension, 50/50 perfect weight distribution. Now imagine it cornering - what side would break traction first? I guess the front tires will, as they have to cope with more combined force. That means they both effecitvely brake (due to being in an angle relatively to the cars direction of movement) and provide lateral grip (which I believe is the same between the fronts and the rears..?).
The grip of the fronts is almost fully utilized by the cornering forces (which is operating in two planes), hence they have very little longitudinal grip left availiable for propelling the car forward.
RWD will just power the rears which aren't nearly as used as the fronts are and got lots of longitudinal grip left, while AWD will make the front break grip and FWD will be the worst..
So Simon, for putting an Impreza sideways - an Impreza specifically - without active differential tricketry, i.e. a standard 99 GT, you have to first reduce traction at the rear to the point of almost oversteer, like using flick or trail braking and then apply power? You can't just power oversteer like in a RWD?
Imagine a car with similar geometry both front and rear, same suspension, 50/50 perfect weight distribution. Now imagine it cornering - what side would break traction first? I guess the front tires will, as they have to cope with more combined force. That means they both effecitvely brake (due to being in an angle relatively to the cars direction of movement) and provide lateral grip (which I believe is the same between the fronts and the rears..?).
The grip of the fronts is almost fully utilized by the cornering forces (which is operating in two planes), hence they have very little longitudinal grip left availiable for propelling the car forward.
RWD will just power the rears which aren't nearly as used as the fronts are and got lots of longitudinal grip left, while AWD will make the front break grip and FWD will be the worst..
So Simon, for putting an Impreza sideways - an Impreza specifically - without active differential tricketry, i.e. a standard 99 GT, you have to first reduce traction at the rear to the point of almost oversteer, like using flick or trail braking and then apply power? You can't just power oversteer like in a RWD?
#37
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
Just because of the weather, lack of experience on a bend and that the road may not be clean, does that mean that you drive your AWD car as though you are on a rally?
![Smile](images/smilies/smile.gif)
I said AWD is probably better / easier for the inexperienced driver in real world conditions.
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
![Smile](images/smilies/smile.gif)
#39
![Post](images/icons/icon1.gif)
Claudius
We're talking about vehicle dynamics, not your "former M3".
Maybe your front tyres were less than perfect, baybe the suspension geometry was off, maybe you weren't driving it properly, who knows. That is hardly the evidence you should take to base an argument on.
roee
Agreed 100%. Did I say something that made you think otherwise?
Cheers
Simon
We're talking about vehicle dynamics, not your "former M3".
Maybe your front tyres were less than perfect, baybe the suspension geometry was off, maybe you weren't driving it properly, who knows. That is hardly the evidence you should take to base an argument on.
roee
Agreed 100%. Did I say something that made you think otherwise?
Cheers
Simon
#40
![Post](images/icons/icon1.gif)
Claudius
I take the advice I give (and in-fact any advice given) on scoobynet very seriously. There is nothing worse than hearing some advice from someone who seems to know what they're talking about and taking it as gospel only to find out it was innacurate or just completely wrong.
It is even worse if people make decisions based on that advice. This is why it is not always "just banter", sometimes people are reading this stuff to learn something.
All the best
Simon
I take the advice I give (and in-fact any advice given) on scoobynet very seriously. There is nothing worse than hearing some advice from someone who seems to know what they're talking about and taking it as gospel only to find out it was innacurate or just completely wrong.
It is even worse if people make decisions based on that advice. This is why it is not always "just banter", sometimes people are reading this stuff to learn something.
All the best
Simon
#41
![Post](images/icons/icon1.gif)
Cladius,
Before the apex you haven't built up enough lateral forces to use much of the overall grip of the rear tires.
Therefore, if you accelerate at this stage your won't be able to break the traction of the rears. You then just cause a severe weight transfer backwards which will load up the rear tires with grip but won't do any good to the fronts.
But that's only a guess. I haven't driven much except FWD![Smile](images/smilies/smile.gif)
Before the apex you haven't built up enough lateral forces to use much of the overall grip of the rear tires.
Therefore, if you accelerate at this stage your won't be able to break the traction of the rears. You then just cause a severe weight transfer backwards which will load up the rear tires with grip but won't do any good to the fronts.
But that's only a guess. I haven't driven much except FWD
![Smile](images/smilies/smile.gif)
#42
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
Are you honestly trying to tell me that the cream of all performance cars are reduced in weight enough (meaning stripping everything on the car that is not necessary) that they would even reduce the performance of the car (which is what you are saying it would do) by making them RWD instead of AWD just so it can be lighter?
![Wink](images/smilies/wink.gif)
Therefore, it will feel slightly faster to people who mainly go straight (those M numbers and dual carriageways that get mentioned here all the time
![Stick Out Tongue](images/smilies/tongue.gif)
In addition to that, a good RWD such as an M3 always slightly let the back out in curves and can be very easily controlled with the throttle. That makes journalists or people on here say that they are more "rewarding" or that you need to be a good driver etc to be fast in them. So there's another reason: so that people (like potential customers testing the car) can easily reach the limits of the RWD under acceleration and think they're good. If they made the high performance cars AWD, many wouldnt be able to reach the limits easily...
#44
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
Before the apex you haven't built up enough lateral forces to use much of the overall grip of the rear tires.
Therefore, if you accelerate at this stage your won't be able to break the traction of the rears. You then just cause a severe weight transfer backwards which will load up the rear tires with grip but won't do any good to the fronts.
Therefore, if you accelerate at this stage your won't be able to break the traction of the rears. You then just cause a severe weight transfer backwards which will load up the rear tires with grip but won't do any good to the fronts.
You need to transfer some weight to the front, ie flick the car a little (or a lot
![Big Grin](images/smilies/biggrin.gif)
#45
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
We're talking about vehicle dynamics, not your "former M3".
Maybe your front tyres were less than perfect, baybe the suspension geometry was off, maybe you weren't driving it properly, who knows.
That is hardly the evidence you should take to base an argument on.
![Smile](images/smilies/smile.gif)
#46
![Post](images/icons/icon1.gif)
Exactly! That's why a RWD would understeer.
You need to transfer some weight to the front, ie flick the car a little (or a lot depending on corner etc) and then power out without as much angle and lack of traction as you would get in a RWD.
You need to transfer some weight to the front, ie flick the car a little (or a lot depending on corner etc) and then power out without as much angle and lack of traction as you would get in a RWD.
Flicking the car around is creating a virtual corner apex.
I can promise you a plain AWD without active differentials would understeer even more than the M3. If you're talking about Evo with AYC, i don't think it's a fair comparision.
#47
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
I take the advice I give (and in-fact any advice given) on scoobynet very seriously. There is nothing worse than hearing some advice from someone who seems to know what they're talking about and taking it as gospel only to find out it was innacurate or just completely wrong.
It is even worse if people make decisions based on that advice. This is why it is not always "just banter", sometimes people are reading this stuff to learn something.
It is even worse if people make decisions based on that advice. This is why it is not always "just banter", sometimes people are reading this stuff to learn something.
But I guess you also meant me. Again, please excuse me for talking crap about suspension settings first, and now about AWD being better than RWD. I shall probably get one of those fantastic M3 or Modena things (with a tubi stile exhaust for that AWESOME
![Roll Eyes (Sarcastic)](images/smilies/rolleyes.gif)
#50
![Post](images/icons/icon1.gif)
Claudius
Take a step back a minute here. You came on to this thread (As you have done on a number of threads I've contributed to) with
icons and comments like "that is wrong".
There is no need to get upset when someone simply offers science and substantial experience to prove your blanket statement innacurate.
As you will probably have also noticed on one of the other threads I mentioned, I was thrilled to have learned something new from a member who knew something about suspension dynamics that I didn't.
Text books are very useful, and I've read a few, but my knowledge comes from years of experience as a test / development driver for some of the leading manufacturers / motorsport companies in the world.
Is it not possible that I may actually know a bit about what I'm talking about?
All the best, and kind regards
Simon
Take a step back a minute here. You came on to this thread (As you have done on a number of threads I've contributed to) with
![Roll Eyes (Sarcastic)](images/smilies/rolleyes.gif)
There is no need to get upset when someone simply offers science and substantial experience to prove your blanket statement innacurate.
As you will probably have also noticed on one of the other threads I mentioned, I was thrilled to have learned something new from a member who knew something about suspension dynamics that I didn't.
Text books are very useful, and I've read a few, but my knowledge comes from years of experience as a test / development driver for some of the leading manufacturers / motorsport companies in the world.
Is it not possible that I may actually know a bit about what I'm talking about?
All the best, and kind regards
Simon
#52
![Post](images/icons/icon1.gif)
surely if you take out the LSDs, then the turbo, some of the brakes, etc, there will be a point where I'd rather have an M3!
Take a typical AWD car without that gadgetry (even though useful gadgetry
![Smile](images/smilies/smile.gif)
Cars with active differentials are actually neither RWD or AWD, they're both. Like saying a Golf V6 is a good representitve of AWD kind, while it's definitely not. A standard Impreza is, however.
Speaking of gadgetry, the M3's DSC would surely eliminate the understeer you experience when powering before the apex. Not different than using AYC.
If AWD was so good, why manufactorers mess so much with the drivetrain for getting good handling? Why isn't that needed in RWD?
#53
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
There is no need to get upset when someone simply offers science and substantial experience to prove your blanket statement innacurate.
![Smile](images/smilies/smile.gif)
As you will probably have also noticed on one of the other threads I mentioned, I was thrilled to have learned something new from a member who knew something about suspension dynamics that I didn't.
Text books are very useful, and I've read a few, but my knowledge comes from years of experience as a test / development driver for some of the leading manufacturers / motorsport companies in the world.
Is it not possible that I may actually know a bit about what I'm talking about?
Is it not possible that I may actually know a bit about what I'm talking about?
Talking about driving experience, I have talked about this with professionnal drivers who have won national and international rally championships and they seemed to agree with me.
I think that we do not talk about the same types of roads or something. Or maybe I'm just plain stupid in addition to being a dumbass? I would really appreciate if you could tell me in simple words
![Smile](images/smilies/smile.gif)
#54
![Post](images/icons/icon1.gif)
OK..
I think your misunderstanding comes from limited exposure / experience. You are looking at 2 isolated instances. Your M3 vs Your Scoob, both with You driving.
I am not saying you are thick or a crap driver or anything even slightly relating to that. I was just saying that your statements were incorrect.
A good way of showing the difference between cars being driven well and what a difference that makes is to look at a mixed track day.
If the drivers are average, all the scoobs, etc will eat the lotus, porsche, caterham guys alive.
The reason for this is that it takes very little skill to drive a scoob to 70% (let's say) of it's ability. The same amount of skill however could probably only muster up 45% (again, let's say) of the ability of a caterham. This does not mean that a caterham is slower, it just means that the average driver can't exploit it.
The last rally I did was the xmas stages. We won our class by a country mile and finished well ahead of evo's, scoobs, escort cosworths, etc, etc and we were driving an old RWD sierra cosworth with a stage 1 road chip in it. This does not mean that my cosworth is faster than the evo's, it just means that I was able to exploit my car's abilities more than the competition.
If your driving style suits AWD, then AWD is probably better for you. This does not mean it is more performant.
All the best
Simon
I think your misunderstanding comes from limited exposure / experience. You are looking at 2 isolated instances. Your M3 vs Your Scoob, both with You driving.
I am not saying you are thick or a crap driver or anything even slightly relating to that. I was just saying that your statements were incorrect.
A good way of showing the difference between cars being driven well and what a difference that makes is to look at a mixed track day.
If the drivers are average, all the scoobs, etc will eat the lotus, porsche, caterham guys alive.
The reason for this is that it takes very little skill to drive a scoob to 70% (let's say) of it's ability. The same amount of skill however could probably only muster up 45% (again, let's say) of the ability of a caterham. This does not mean that a caterham is slower, it just means that the average driver can't exploit it.
The last rally I did was the xmas stages. We won our class by a country mile and finished well ahead of evo's, scoobs, escort cosworths, etc, etc and we were driving an old RWD sierra cosworth with a stage 1 road chip in it. This does not mean that my cosworth is faster than the evo's, it just means that I was able to exploit my car's abilities more than the competition.
If your driving style suits AWD, then AWD is probably better for you. This does not mean it is more performant.
All the best
Simon
#55
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
Hmm...
So what's the big deal about driving a RWD?
On my favorite (twisty) road, I can keep the throttle open much longer than with the M3, or at least without sliding too much. And I always braked very late with the M3 (often getting the back to step outwards), to get enough weight to the front to get it in and have always accelerated as early as possible.
With my Evo, I do the same thing but I can accelerate a lot earlier and have traction.
Am I drawing the wrong conclusions from this fact? And first of all do you agree with it? I dont think you are trying to fool me, so there must be something I'm missing.
So what's the big deal about driving a RWD?
On my favorite (twisty) road, I can keep the throttle open much longer than with the M3, or at least without sliding too much. And I always braked very late with the M3 (often getting the back to step outwards), to get enough weight to the front to get it in and have always accelerated as early as possible.
With my Evo, I do the same thing but I can accelerate a lot earlier and have traction.
Am I drawing the wrong conclusions from this fact? And first of all do you agree with it? I dont think you are trying to fool me, so there must be something I'm missing.
#56
![Post](images/icons/icon1.gif)
Claudius..
How can you be sure you were accelerating as early as possible?
Remember the evo deals with much of the driving for you with the AYC.
I'm not sure what conclusions you're drawing. I think you may well be just applying that experience to the rest of the world, and taking your evo as being the way all AWD cars handle, and your M3 as being the way all RWD cars handle?
I agree that you did what you said you did. I do not agree that this means AWD cars handle better than RWD cars.
Try re-reading what has been posted here. It's all down to tyres.
All the best
Simon
On my favorite (twisty) road, I can keep the throttle open much longer than with the M3, or at least without sliding too much. And I always braked very late with the M3 (often getting the back to step outwards), to get enough weight to the front to get it in and have always accelerated as early as possible.
With my Evo, I do the same thing but I can accelerate a lot earlier and have traction.
Am I drawing the wrong conclusions from this fact?
And first of all do you agree with it?
I dont think you are trying to fool me, so there must be something I'm missing.
All the best
Simon
#57
Scooby Regular
Join Date: Oct 2001
Location: Europe
Posts: 3,414
Likes: 0
Received 0 Likes
on
0 Posts
![Post](images/icons/icon1.gif)
How can you be sure you were accelerating as early as possible?
Remember the evo deals with much of the driving for you with the AYC.
I now have a TME but need to junk that AYC which glues the back to the road and gives me understeer unless I am being *very* brutal on it.
#59
![Post](images/icons/icon1.gif)
What I mean Claudius is that you are surely not saying that nobody could get on the gas any earlier than you and make it not understeer?
It is possible that your driving style means that this will happen.
Cheers
Simon
It is possible that your driving style means that this will happen.
Cheers
Simon
#60
![Post](images/icons/icon1.gif)
FWIW, friction between tyre and road will apply an opposing force in one direction, which is exactly the opposite direction to the sum of the forces on the tyre. So if you're putting a force laterally on the tyre, friction will act laterally in exactly the opposite direction, however, if you add a longtitudinal force to that friction will now be applying a force somewhere between the two forces (dependant on the relative sizes of the two forces), it will also have to be applying a larger force, so if you add too great a longtitudinal force friction will be overcome and the tyre will slide. A diagram would probably help, but I can't be arsed ![Wink](images/smilies/wink.gif)
NB: This is just pure mechanics!
![Wink](images/smilies/wink.gif)
NB: This is just pure mechanics!