Whats the point of Front Wheel drive?

[Moppie]

Originally Posted by slideways...

huh? moppie, i didnt say one word against him. i said his car isnt the best at a lot of things. its simple fact. the iroc was old technology when it came out. im sorry if it may have come off as offensive, it wasnt meant that way. im a smartass but im not a jerk.

if you have some sort of problem with me, spell it out. all you ever do is jump down my throat at every opportunity whether i deserve it or not. which i mostly do not.

You are as arrogant as you are ignorant, its a dangerous combination.

When you have some real experiance, can provide some useful and real world advice, then you might be in a position to question others on their choice of car.
In the mean time, as far as you are concerned, the Camaro is a very good car.
It sold in very large numbers, and there are thousands of owners who are very passionate about it.
I bet you have never even driven one.

It puts you in about the same class as the 15 year old kids who make assumptions about cars based on the car magazines their daddy brings home.

[Nereth]

The point is it's economical, and also, understeer saves lives.

From a performance perspective, it's useless in almost all cases.

[Polygon]

Originally Posted by Nereth

The point is it's economical, and also, understeer saves lives.

From a performance perspective, it's useless in almost all cases.

I suggest you go back and read the entire thread because that's not even close to true.

[Nereth]

Originally Posted by Polygon

I suggest you go back and read the entire thread because that's not even close to true.

A quick scan reveals not much to the contrary.

Understeer is probably the biggest problem FWD has. It is not influenced 'far more by suspension geometry', unless the designer was an incompetent fool. The fact remains that the same suspension geometry (well, slightly tweaked) on a RWD would yield better results due to the better weight distribution. It can be fixed to some extent with anti roll bars, but at the expense of ride, comfort and bump handling. Also, with some horrible weight distributions, roll stiffness may not be enough - you may lift the rear inside tyre off the ground, and then you have even more problems.

And I would like to hear the logic behind using lift off oversteer, to solve these problems as well.

And you all know they have horrible drive traction (unless they are on a low friction surface). And while I'm at it, under braking, even more load gets chucked to the front which is already heavier, making the situation worse there aswell.

So in short, the G-G diagram is generally smaller in every direction. I think that is a pretty big problem in performance situations.

And yes, they do handle fine for everyday road use. Obviously we are talking about beyond that.

[Moppie]

I don't think anyone can deny that we will never see a FWD F1 car, but FWD has been proven to be very effective in a variety of very high performance applications.
British, European and Australian tour cars have shown that the FWD chassis can compete on equal terms with the RWD ones, and are often faster.
A variety of Japanese racing classes have shown the same things.
Honda and Mazda have successfully campaigned FWD production cars at Le Mans and other events.

In a road car the difference becomes meaningless. You reach the limits of road legal tyres and surface materials long before you reach the limits of a FWD or RWD chassis.

I suggest you go and drive a couple of performance FWD cars before you start making blanket judgements.

[Polygon]

Originally Posted by Nereth

A quick scan reveals not much to the contrary.

Understeer is probably the biggest problem FWD has. It is not influenced 'far more by suspension geometry', unless the designer was an incompetent fool. The fact remains that the same suspension geometry (well, slightly tweaked) on a RWD would yield better results due to the better weight distribution. It can be fixed to some extent with anti roll bars, but at the expense of ride, comfort and bump handling. Also, with some horrible weight distributions, roll stiffness may not be enough - you may lift the rear inside tyre off the ground, and then you have even more problems.

And I would like to hear the logic behind using lift off oversteer, to solve these problems as well.

And you all know they have horrible drive traction (unless they are on a low friction surface). And while I'm at it, under braking, even more load gets chucked to the front which is already heavier, making the situation worse there aswell.

So in short, the G-G diagram is generally smaller in every direction. I think that is a pretty big problem in performance situations.

And yes, they do handle fine for everyday road use. Obviously we are talking about beyond that.

1. It is all about suspension geometry. The engineers aren't stupid. Undedsteer is a lot safer than oversteer. You will find AWD and RWD cars that understeer. They do that on purpose because people are stupid, not the engineers.

2. Weight distribution isn't determined by what wheels drive the car. Most cars have a front engine, not just FWD.

3. Under breaking it would be no different between an FF or FR car or even a car with AWD and a front engine.

4. Like Moppie and I have already mentioned Lotus, Honda, Mazda, Alfa Romeo, and others have good FWD performance cars. As a matter of fact Alfa FWD cars have been beating up on a lot of RWD cars in European touring races, this includes the likes of BMW. So that reiterates, it's more about suspension geometry than which wheels drive the car.

[Nereth]

Originally Posted by Moppie

I suggest you go and drive a couple of performance FWD cars before you start making blanket judgements.

Sorry if it sounds like I'm making a blanket statement. I know there are FWD cars that handle well. The point I am making is that being FWD isn't helping any.

Originally Posted by Polygon

1. It is all about suspension geometry. The engineers aren't stupid. Undedsteer is a lot safer than oversteer. You will find AWD and RWD cars that understeer. They do that on purpose because people are stupid, not the engineers.

I know. Thats why I said 'understeer saves lives.' in my first post. The problem is when a FWD car understeers more than is nescessary. If the engineers could, then in a lot of cases they would most likely get a lot closer to neutral handling than they do with a FWD car. I am aware that most modern cars understeer. It's a question of magnitude.

Originally Posted by Polygon

2. Weight distribution isn't determined by what wheels drive the car. Most cars have a front engine, not just FWD.

And most rear wheel drives have a differential in the back and a transmission in the middle. They also are free to put more weight towards the back or move the tyres forward, because they don't lose drive traction by doing so. Ignoring aerodynamic downforce, a 50:50 FWD car would not have nearly enough load on the front wheels for decent acceleration.

Originally Posted by Polygon

3. Under breaking it would be no different between an FF or FR car or even a car with AWD and a front engine.

Look up tyre load sensitivity. With a 60:40 weight distribution to start with, a FWD will wind up braking at something more like 80:20. A RWD which is most likely closer to 50:50, will wind up closer to 70:30 (the numbers are just pulled out my ass to give you an idea).

Originally Posted by Polygon

4. Like Moppie and I have already mentioned Lotus, Honda, Mazda, Alfa Romeo, and others have good FWD performance cars. As a matter of fact Alfa FWD cars have been beating up on a lot of RWD cars in European touring races, this includes the likes of BMW. So that reiterates, it's more about suspension geometry than which wheels drive the car.

If I made an AWD car with solid front and rear axles, 20 degrees of toe in all around and 130 mm wide tyres, and then put it up against, I don't know, a corvette, the corvette would win in pretty much everything. Does that make RWD better than AWD? No. It makes that particular setup of RWD better than that particular setup of AWD. Like I said to Moppie, I am aware that some FWD cars handle better than some RWD cars. But it isn't because they are FWD that that happens.

[GreyGoose006]

oh and nothing personal, but if you think theres nothing better than an iroc for .... well, anything, then you need to get out and drive more cars. camaros are ok for what they are, but theres cars that do everything better.

ok...
I issue you a challenge.

find me a car for 500 dollars that has a 5 speed manual transmission,
performance suspension,
can run 12 second quarters (ive never tried, but i hear from the previous owner)
has EITHER a targa top or T-tops,
is fuel injected,
has 6month insurance premiums in the $275 range,
can 90% of the replacement parts for it at autozone, that day
and comes WITHOUT all the automated systems that are so "convieneint" to drivers today...
i hate automatic lights, seatbelt dingers, lane change warning systems, ect...


i anxiously await your reply







what it really comes down to is that for what I want, my iroc is perfect.
of course an s2k might be better around an autox track, or an evo xxx or whatever might out corner me
im not even worried that audis or astons will beat me in a straight line.
i like the fact that i have to remember to turn the headlights on, and that if i dont put my seatbelt on right away, it doesnt bing at me, and that there is no traction control to turn off and that it will take a bit of playing with to get it to run perfectly.

if i were you, id start by shutting your mouth

and finish with not ever opening it again...



either that or buy a good shovel, cause you seem to enjoy digging yourself holes.

[GreyGoose006]

back on track with the thread...

Originally Posted by moppie

In a road car the difference becomes meaningless. You reach the limits of road legal tyres and surface materials long before you reach the limits of a FWD or RWD chassis.

this about sums it up

[Moppie]

Originally Posted by Nereth

Like I said to Moppie, I am aware that some FWD cars handle better than some RWD cars. But it isn't because they are FWD that that happens.

Which just re-enforced my point, unless your talking about the absolute limit of performance, the drive lay out is not as important as people like to think it is.
Over all chassis design has more impact.


Your point about braking is very relevant, and shows there is more to drive lay out than just the ability to accelerate.
Weight distribution is very important here, and the front heavy tendency of many FWD cars can actually make them quite un-stable under heavy braking.
The result is most FWD cars have large amounts of front brake bias, with the corresponding increase in under steer under brakes.
Personally I like it a bit of oversteer under. Which is one reason I like Honda's. All the performance versions of the Civic and Intega are set up with more than the usual amount of rear brake bias.
The result is a car that turns in very easily and very precisely under brakes, much more so than a RWD car, as the Honda are able to rotate about a CG point that is shift a long way forward, almost over the front wheels.

[Nereth]

Originally Posted by Moppie

Which just re-enforced my point, unless your talking about the absolute limit of performance, the drive lay out is not as important as people like to think it is.
Over all chassis design has more impact.

I am talking about the limits - thats where you are supposed to be for high performance driving, and I thought that was what we were talking about (this whole discussion started from me saying 'From a performance perspective, it's useless in almost all cases.').

It would be nice if you could expand on the chassis design comment - I don't really know much about chassis design, all I know is it needs to be stiff, it needs to provide packaging room, and it needs to be at least somewhat aerodynamic (and offcourse it has to be acceptable from a NVH perspective). I am probably oversimplifying things as I have no experience in that area. Anyway, what are you after from the chassis other than this? What impact does it have?

[Moppie]

One mans performance is another mans afternoon nap.
Its such a subjective term that you simply can not make blanket statements about it, and the existence of very successful FWD performance cars proves that.
If we simply want to talk about the best, then we would be talking F1 cars with out the restrictions placed on them by the FIA.
But how many people can handle a car with 1000hp, that is able to generate enough G force under brakes to make you pass out.
The technology has already reached a point where engineers can build car that will out perform even the best human body.


With regard to Chassis design?
Well the chassis determines weight distribution, wheel position and suspension geometry.
3 things that have a far bigger impact over performance than which wheels are driven.

[Nereth]

Originally Posted by Moppie

One mans performance is another mans afternoon nap.
Its such a subjective term that you simply can not make blanket statements about it, and the existence of very successful FWD performance cars proves that.

By ignoring the way the car interfaces with the driver (because that is too complex and winds up just being subjective) and transient pheomena (again, too complex for most internet based discussions), you are basically left with the G-G diagram, which in my oppinion is a very good indication of how a car handles. What I have been saying is that the G-G diagram of a FWD car is generally going to be smaller in most directions, in most conditions.

Originally Posted by Moppie

With regard to Chassis design?
Well the chassis determines weight distribution, wheel position and suspension geometry.
3 things that have a far bigger impact over performance than which wheels are driven.

Oh right, I have always thought of the chassis as just the cage that holds all those things. Suspension geometry, wheels, etcetera, are seperate items to me.

The problem is, while 'chassis design' (using your definition) can change the amount of under/oversteer, it cannot 'decide' it. For a FWD car, a lot of the weight is going to be towards the front, since all of the drivetrain is towards the front. Furthermore, there isn't much you can, or even should, do about this, because you need it up the front if you want to be able to accelerate at all.

Given that you are stuck with a forwards weight bias to start with, you are left trying to remove understeer with suspension geometry, and unfortunately, there is only so much suspension geometry can do to increase front end grip (if you really want I can try to put some example numbers to this in an hour or two when I get some time). After that, the only way to deal with understeer is to degrade rear end grip, and to me, that is just a waste.

[KiwiBacon]

Originally Posted by Nereth

I know. Thats why I said 'understeer saves lives.' in my first post. The problem is when a FWD car understeers more than is nescessary. If the engineers could, then in a lot of cases they would most likely get a lot closer to neutral handling than they do with a FWD car. I am aware that most modern cars understeer. It's a question of magnitude.

Funnily enough I happen to own a bog standard fwd japanese car which drifts evenly when pushed hard through a corner.
There is still plenty of scope in the suspension tuning to give my car oversteer if I wished (it doesn't have a rear sway bar for example).
I have driven other bog standard honda accords which handled in a very similar manner.
A friend who races karts for fun ran a data logger in his fwd toyota windom (sold as a lexus in the US, basically a big fat camry). It pulled 1.1g sideways.
I'm curious as to how many fwd cars you've driven in anger as your blanket statements don't fit with the majority of fwd cars I've driven.

Your comments on braking are way off too. COG height is the biggest factor in weight shift, not COG longitudinal position.

[Nereth]

Originally Posted by KiwiBacon

Funnily enough I happen to own a bog standard fwd japanese car which drifts evenly when pushed hard through a corner.

There are ways to get the car to drift or oversteer even if it understeers stock - as you know, rear roll hardness, or more optimal suspension geometry, etc. But these things have compromises involved. For example, a sway bar links the wheels in question and throws off bump handling. Also, it's entirely possible to sacrifice drive traction for lateral traction by moving the COG backwards.

Originally Posted by KiwiBacon

I'm curious as to how many fwd cars you've driven in anger as your blanket statements don't fit with the majority of fwd cars I've driven.

None - this is based purely on engineering theory. That way you can cut the subjective stuff out, and you can cut the outliers out.

Originally Posted by KiwiBacon

Your comments on braking are way off too. COG height is the biggest factor in weight shift, not COG longitudinal position.

Maximum traction is achieved (assuming similar tyres/pressure/geometry all around) when front and rear loading is the same. During braking, the front loads up and the rear unloads. lets say at 1 G 20% of the load moves forward. If you start with 60:40, in a FF car, you will wind up with 80:20. If you have an RR car, starting at 40:60, you wind up with 60:40. The loadings are more even the more weight is towards the back.