Uhm, you know that you are actually describing another phenomen?
I havent worked with following formulas for a while, but basically you are describing this:
m = mass of the vehicle
a = acceleration at a given speed
v = velocity
D = this is a basic variable I use to describe friction/drag/etc
r = tyre radius
F = Force between tyre and road
i = gear ratio
n1 = rpm at the wheel
n2 = rpm at the crank
P = engine power
m * a = F - D = (Torque at the Wheel)/r - D
= (torque at the crank * i)/r - D
= n2/n1 * (torque at the crank)/r - D
= P* 2 *pi / v - D
(I know this formula is pretty basic, but the physics are (atleast I hope so!) more or less correct)
so we have a = (P* 2 *pi / v - D) / m
This means that increasing mass leads to a decreasing acceleration.
Yes, the friction between tyre/road increases, I know, but above has a much bigger influence.
Edit: Maybe I was just confused by what Scaff pointed out, weight/load. I thought you were only talking about the weight?
No, I am not talking about the weight of the car itself being all round "good" for performance. A heavier car ALWAYS car means more inertia and more weight to have to displace from one location to another.
This phenomenon alone and only if you consider it alone is pretty straightforward and it should be the same as imaging a car on a frictionless surface, or something close to it like ice, but remove the tyres from the equation and the heaver car will FUNDAMENTALLY be harder to move around and will require more force, even if its just a bunch of guys pushing it around on an ice field they will always have an easier time passing a elise around than a veyron. So in this sense it is pretty easy to say weight is a bad thing, but even this simple concept is NOT 100% straightforward as if the car weights a few pounds it will just get blown away by the wind, so there are always dynamics involved.
I think where people seem to be getting confused is how this is how this extra weight on a car usually translates into more grip that I am referring to, being applied to the tyre. Well basically it presses it down putting more load on it and this giving more grip, in the same way downforce does. This is a very simple concept IMO
It is in fact exactly the same as effect as downforce except with downforce the trade off is increased drag instead of increased weight.
Just ask yourself, if a cars grip was so depending on mass (and you don`t really reduce the "mass" by playing around with the suspension), why were the race cars from the 30s-66s (low downforce) so light?
In the end its very difficult to overcome the benefits of lightness vs the weight = more grip effect I am pointing out. Lightness will win in most scenarios because it has more points on the pros list than cons and the cars are heavy enough to stay on track under their circumstances. I am just saying the gap between heavy car and light car should be closer, and there is a range in the GT5 physics engine where I am not feeling these benefits of a heavier car.
For example in your race car example. What I am saying is if you got those cars in the GT5 physics engine, and then made a copy of them doubling their weight, but made sure to keep things like acceleration and braking capacity were relatively scaled to match the performance so we only isolate weight as the variable, then did the same thing with the same cars in real life, the GT5 version of the cars with double the weight will perform a lot worse than the real life cars.
IN Gt5 the heavier cars will just push like crazy and the added benefit of the extra load on the tyres will not be as apparent as in real life.
The Bently Continental GT Sport and Veyron pull over 1g on the skid pad easy which is more than an Lotus elise. I think the Continetal GT super sport pulls almost 1.3G
And its not just a simple matter of having fatter tyres. If you got those same fat tyres on an elise however they will NOT provide the the same grip as the Continental Gt super Sport because it does not have the weight to do so.
But the Lotus has a LOT less weight, Actually one Continental GT weighs as much as 3 Lotus elises.
So obviously even with the HUGE weight disadvantage where the Bently weighs almost 2.5 tons, it still manages to go around a corner faster than a 800kg lotus elise. Clearly there is more at work here than just fatter tyres.
It looks like in GT5 the reason it doesn't seem so glaringly obvious that something could be off is heavier cars usually have bigger contact patch/base grip value/fudge factor whatever you want to call and so to most people maybe it is not that obvious, but what I am saying is I don't feel that "bite" of the heavier car pushing the tyre into the ground proplery like in real life as weight increases in GT5. I feel the other effects of momentum and increased weight just fine though.
However, I am not saying GT5 does not have load based grip whatsoever, where the more weight is shifted on the tyre the more grip, it has. Ofcourse it does, that is one of the most fundamental parts of a racing sim, otherwise it would feel like Ridge Racer.
I am just saying it does not seem done right based on what I feel, and it is just a theory of mine that this is the reason the ride height setting feel backward.
I think the extent to which weight makes a tyre dig into the ground in GT5 is not present as it should be.
Snake -
I am curious to what your credentials are. Why should I take some random forums poster opinion as some sort of scientific fact when PDI has known experience with Nissan and Red Bull (for example). Plus, I doubt you have access to PDI's engine.
You would figure if there was a discrepancy in PDI's physics engine, someone with knowledge in this field would surely inform PDI over this. If PDI is aware of this, I have to wonder if this alleged "problem" was allowed to remain in due to the fact that GT5 is after all, a game.
Even if what you have concluded is true, it will not matter much to me. In fact, I believe this issue only bothers a select group of gamers including those who wish to prove game "x" is superior to game "y".
I have no credentials. I am just telling you what I feel about the game, real life and thinking about it logically.
You don't have to take anything as scientific fact. It is a discussion If you need credentials then perhaps trying to have a logical discussion on its merits alone is not your strong point
I also have no interested Forza 4 or fanboiing one game over another which Is what I assume you were on about. In fact I think the physics engine in FM4 are a joke, but the rest of the i.e the non Driving parts I enjoy.
If you take that aggressive close minded approach and theres probably little point in bothering explaining anything to you but I have no problem giving it a shot for a while.
It is just a theory as Ive said. I did I give a great practical example of the concept earlier.
Its is by pushing an eraser along a table lightly and then pressing down, i.e putting more load on the eraser and then pushing it along the same table again.
The eraser will dig into the table the more you push it and it will have much much more resistance to sliding, which is what grip is in car terms. Of course if you can push so much the rubber will begin to give way shred, fall apart etc and grip will reduce so it is never that linear or simple, but What I am saying is PD have not modeled this properly
