GT4 Driving Physics

DiabolicalMask

There is a thread posted some time ago talking about this in the GT4 Prologue forum.
It's here.

It's the first time this happens in a Gran Turismo game and apparently it only works with the DFP on 900º mode.
I play GTP with a Wingman FF and it doesn't happen unfortunately.

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This week I finished my race cockpit and finally tried my red Momo Force wheel on GT3 and GTC02.

I was very surprised to find out that the "EVER present and hated" steering aid was NOT present in GTC02 on the tarmac of the rally track Tahiti Maze. And only there! (and off course in both games off-road, even with the DS). There is steering aid in GT3, even with the wheel in "simulator mode", and there is steering aid on the regular asphalt tracks in GT3 and GTC.

But on Tahiti Maze in GTC, the wheels turn exactly as far as you turn the steering wheel, and if you turn so far that you go in understeer, the tyres start smoking, exactly as described for the DFP wheel in GT4P

I like it!

Did nobody notice this

You're right. I found that myself as well.
At the beginning it all feels very strange because you don't know what's happening, but then it turns out to be very nice.

And it also happens on the Grand Canyon rally course in GT4P.

Can't wait to try a DFP on tarmac.

DiabolicalMask

And it also happens on the Grand Canyon rally course in GT4P.

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Is that on the tarmac part of the hidden Grand Canyon rally?
and with an "old" GT Force (or how was it called) Wheel, as the Momo Force doesn't work with GT4P?

Theres two versions of the same Grand Canyon layout, one has a tarmac section as sen in the Toyota MTRC disc, it's the same layout as in GT4 though.

Buggy Boy

Is that on the tarmac part of the hidden Grand Canyon rally?
and with an "old" GT Force (or how was it called) Wheel, as the Momo Force doesn't work with GT4P?

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It happens throughout the whole course.
I use a Wingman FF (red wheel), which is the same as the GT Force.

The technical definition of a "tank slapper" has to do with the fuel inside the fuel tank moving about.

Fuel is a liquid mass, when the fuel tank isn't full or empty, there is room for fuel to go splashing about in there. When you steer the fuel will be delayed in following the rest of the car. If you have enough fuel back there, you will feel a slight pull on the rear when the fuel hits the outer wall. Chuck in a quick left/right combo and you get a bigger "slap" which can pull the back end out.

Springs are also evil. If you turn a car left, you load up the right springs. If you then turn right, you transfer the energy from the springs, and add more energy to the roll left (extra energy comes from steering effort). This is why tall cars will fall over in an "elk test" that won't fall over from a single swerve.

Fish-tailing results from both components, usually aided by over-correction. You can fish-tail a fwd car.

You're preaching to the choir man!!

if the gt4 platform enables for tank slapping, then it is a true indication of how advanced the engine is, though i imagine the actual fluid motion within a tank is unlikely to be guaged and inserted into the game engine (we might have to wait for gt5 for that).

The steering wheel's delayed turn when using the DS controllers would be part of the steering assist engine, the wheel is only turned as the weight is sufficiently transferred through the shockers to enable it. I, for one, am genuinely excited by the prospect of a steering wheel that enables understeer, as i am with the prospect of brakes you cannot simply slam on.

This game is meant to be a driving simulator, and in a car we are unable to simply put a joystick left or right in order to turn, any machine that regulated such a device would likely be less than perfect, and result in negative performance. Current mechanics also obviously disallow for perfect braking to be achieved through braking assist, and steering assist should (in my eyes) also have it's limits within the game.

Anyone who is good enough to record their scores on the internet is not exactly someone who just picked up a controller last week, and some minute time disadvanted experienced via steering assist and braking would not be really tangible in their enjoyment of the game. However minute advantages for using the steering wheel would enable those who wanted to to take the game to another level, not just in their ability to goof around with understeer and drift. Besides you can always register DS controller records on a different page.

I think a miniscule advantage for using the steering wheel absolutely perfectly should be incorporated into the game (it may already be in the prologue, but noone is good enough to use it, if the claim that the highest scores is a mix of both is accurate).

Anyone who whinges about any lack of driving assist is overlooking the objective of the game, though if the makers truly wnat it to be 'more accessible' then i don't see why any amount of driving assist couldn't be enabled easily within the options. However, in the strict sense of things, addicts should be 'punished' for using any kind of assist.

But i live in Australia, the steering wheel isn't likely to come out here for ages, will be exhorbitant, and im probably rambling: i haven't slept in a while and this is my first post ever. Hope i didn't bore you

PS did anyone else find GT2 better than GT3? or am i just too obsessed with drifting old school beasts? Im sure the brakes were too good in GT3...

Hi Lachy B,

That's an impressive first post. Are you sure about "the prospect of brakes you cannot simply slam on"?

Regarding GT2 vs GT3 : yes, I sometimes have the nostalgic impression that GT2 provided more satisfactory race sensations, with imo better AI. From the other side, I never raced standard cars in GT2, as it lacked the sense of speed (at low speed), again, imo.

Gt2 had a few things Gt3 lacked, such as the subaru 360 () but in general i do still think gt3 was better as a whole, not just because better graphics, sound etc, but also because there was more to it. Gt2 could be finished (barring the impossible Gt300 series) within a short time.

Tank slap can be fudged with a fairly simple spring and damper routine. It's been done in PC racing sims for a few years now.

The GT4 wheel has been out in australia for 8 months or so (i think... cant remember when i got mine). I think it was 200 bucks (or was it 300...). At any rate, not too bad for what you get.

What's wrong with "the prospect of brakes you cannot simply slam on"? In reality, if you instantly hit the brakes, the front wheels would lock without hesistation. Of course, hitting a pedal in a real car takes a lot longer than a button, which allows the weight to shift forward sufficiently.

I want GT4 to finally fulfill the promise of dropping that damned braking aid (and no, its not ABS), giving us ABS on cars that have it, 4 channel ABS on cars that have that, and no ABS on cars that have neither. If the aural/visual feedback is good enough, you can brake with utmost consistency, and have the warm fuzzy feeling that you are indeed a driving god.

hmmm yeh. I think from what i''ve see Gt4 is to have more body roll than GT3. I hope so, because in real life a car travelling at high speed when you turn the wheel doesn't just skid and not turn... you get some major body roll, don't you?

Polyphony001

hmmm yeh. I think from what i''ve see Gt4 is to have more body roll than GT3. I hope so, because in real life a car travelling at high speed when you turn the wheel doesn't just skid and not turn... you get some major body roll, don't you?

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After playing the BMW Demo I'd have to agree, the suspension seems to be alot more 'dynamic' and act more realisticly.

sinbad

I actually prefer GT3 handling. I play with a DS2 so can't comment on how GT4 feels with a wheel, but I don't like the ultra slow steering, and the bizarre difficulty to have the tail swing around no matter how rough you are with the "analogue" thumbstick - feels to me like they are trying to even things up by penalising controller users. Whatever they've done, and for whatever reason, I'm not a fan, from an enjoyment (not realism) point of view. And yes, I've turned the assists off.

If I get round to getting a wheel I'll possibly change my mind. GT3 isn't more realistic I'm sure, it's just more fun to me.

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interesting but a heavy car feels like a heavy car in prologue and you "feel" like your going faster i mean that the speed seems more relistic and stock road cars and much more of a challenge . gt3's braking points were a bit on the un real side i mean braking at the 100m into turn 2 on ss11 in a stock 34 gt-r maybe in a formula one car. play gt4p with a dfpro its the ultimate race sim experience

I'd love to but where is the money coming from? I've already placed my 'funds' (since i don't work yet) in higher places, but yeah that would be cool and i'm sure it improves the experience. 👍 👍
but... 👎 👎
Maybe one day, let's face it, Gt5 won't be out for ages so i'm sure ill get one eventually...

Body roll is dependant on the car, and limited by grip. The more grip, the more body roll you can have. This doesn't mean cars have more body roll in higher speed corners.

Some cars have a lot of body roll (umm, taurus), and some have no noticeable body roll (f1 cars). Although F1 cars do still have some roll from the crushing of the outside tyres.

BMW's typically have very little body roll, and great composure over bumps. I love the way the body stays still over bumpy surfaces in a modern bimmer.

Yeah i know, but the point is, find me some body roll in Gt3, go on...

when i say i would turn like an absense of braking assist, im not saying i wouldn't initially use it. what im saying is i want the game to be a driving simulator. A capacity to simply lock the front brakes, and be forced to time my weight transfer in order to get oversteer instead of understeer would definately increase the reality of the gaming. THen we could all feel like driving gods, though alas clutchless.

GT2 didn't have much to offer? The 'feeling of speed' is all well and good, but i rather a driving simulator and the novelty of having a ridiculous amount of cars to choose from, sick up a new silvia or skyline to your taste for the hell of it to see how it handles. Tell me you dont get over the graphics within the first 2 days of playing, and tell me you listen to the audio at all anyway...

No but i get a bit tired of driving all these fancy cars when they look (now) so naff. I can't believe that Gt2 had 'good' graphics. it shocks and appalls me.

The AE86 has some considerable body roll in GT3...

Does it? Hmm i must have just not noticed, i'll have another look...

Mr P510

After playing the BMW Demo I'd have to agree, the suspension seems to be alot more 'dynamic' and act more realisticly.

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Yes, a very clear example is the Nissan R390GT1, which can be unlocked with a cheatcode in GT4P.

When you've driven over a curbstone with only 2 wheels, you can see in the replay the reaction by the stabilisator on the wheel at the other side. I compared this with the same car in GT3, and the action of the suspension did noticeably change. I was impressed by the realism!

Yeah the Gt series has always done that and hopefully always will...

The physics are new in gt4 were as gt3 used the same physics(tweaked) as gt1 and 2.

Importantly, suspension dive following hard breaking is realistically modelled in the BMW demo. (It feels as if your front bumper will scrape the track when braking from high speeds.) Hence breaking must now be more decisive to ensure controlled entry into the corner.

Yeah, i'll agree with that. I don't have the bmw demo but i do have prologue....

Polyphony001

Yeah, i'll agree with that. I don't have the bmw demo but i do have prologue....

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Suspension dive is considerably more pronounced in the BMW demo. However the slight feeling of break lockup in prologue is not as discernible in the demo. Virtual ABS for potential customers?

Hmm, possibly!!

I've tested my new Logitec Driving Force Pro wheel yesterday all PM long.

Turning ratio :

To who it might interest : there is a wrong idea about this wheel!

Unlike said before and unlike written by IGN, the steering ratio (in 900° and in 200° mode) is the same for all cars. To test this, drive with several cars around the first 180° corner of Tsukuba at low speed (30 km/hr, so there's no tyre drift). You will discover that you have to turn the wheel to 2 o'clock for all cars. I tried a.o. Kei-cars, the Viper, the Honda Odyssey, the HSC (all on street tyres), rally-cars and race cars (on slicks).

The reason why it may seem that race cars have another steering ratio, lies in the fact that in GT4-P, these cars are on slicks by default. The steering ratio at speed depends of the drift angle of the tyres, and slicks corner with a smaller drift angle.

Lock-to-lock is 900° for all cars. You can check that easily by turning the wheel while you can see the front tyres, e.g. during the start count-down, or in 3th person view.

The turning circle is different for all cars however! It depends not only from the Max turning ratio, but also from the wheelbase. An easy way to check this, is on New York : line up against the right wall after the start, turn the wheels completely to the left, perform a low speed 180° turn and look where you end up. You can refer the position of your car to the white lines. Short cars (e.g. Kei cars) need little street width, long wheelbase cars (e.g. Ford Focus) need a lot of space.

Force Feedback :

The FF acts quite unreal imo. Untill a certain angle it remains inactive, then it starts to "grip". At low speeds it grips with small hesitations, at high speeds it grips "firm". With some imagination this is comparable to the feeling you get with slicks in real life. But the transition between no FF, and "firm" grip at high speeds is to hard imo on road tyres.

It almost looked to me that something was wrong with my wheel, hence my question in the Driving Force Pro Thread.
Then I compared GT3, GT3C, GT4P and GT4BMWdemo.
In GT4P and GT4BMWdemo, the FF is exactly the same.
In GT3C it is a lot smoother. No shocks here, unless you drive over a cerbstone. I drove GT3C with my Momo Force, and the FF was the same. This makes me conclude that the smoother FF is software-related to GT3C. PD said GT3C physics were more "arcade", so I guess they wanted it to feel like this.
In GT3, FF is comparable to GT4P, however the transition is smoother and the shocks less violent.

Adjusting the FF (by software or on the wheel itself) does not change the way the FF feels, besides making these effects more pronounced : the transition from "no FF" to "grip" is only harder if the FF is set harder.

GT3 and GT3C are very hard to play in 900° mode, as you have to turn too much for even a small turn. They work quite well in 180° mode.

Overall feel :

The DFP is by far not as ruggedized as the Momo Force 👎

Although this might not sound to positive, driving GT4P with a steering wheel, without driving assistance is definitely a great improvement. It allows you to steer more precise, and to play with understeer 👍 .

The glazy feeling, as it was called by Werner Winkels in the first post of this thread, is gone with this wheel.

I had the impression that - without steering assistance - it was possible to corner harder. To test it as good as possible, I compared the g-meter in the BMW-demo, by driving the same turns at Max speed with the DFP and the DS2. However, there seemed not be any difference in Max cornering force.

Conclusion :

Despite the strange behaviour of the FF, the use of a steering wheel with GT4P adds very much to the realism. Great part of the advantage comes from the absence of the steering assistence, which is too little appreciated or even known by the average user.
The more robust Momo Force wheel, with its 270° radius, would be a preferable alternative, if it only was compatible with GT4.

Good sumation there Buggy.
The fact is the game isnt real life, and theyve done a pretty good job, much better than has been seen before.
Youll quickly get over the issues you have with the wheel.

Thing is, not to over analyse everything, else youll always have that niggling feeling that its a fault.
Just settle into the mind set that, the wheel is doing its best to give you the feel required to help you to push on in the game, use it and embrace it and enjoy, its vastly better than the DS2 experience and that of the old Wheel.