Gran Turismo Scientist symposium

[SportWagon]

It seems like power-induced oversteer occurs when the game models rear tire slippage.

The game presumably models tire slippage due to the action of the differential when cornering, and reduces that slippage according to the LSD parameters. Since, according to some sources, the game apparently doesn't do independent wheel modeling, what would be the effects of those wheels must be modeled as direct parameter to the forces calculated as acting to rotate the car model.

 

[AERO_HDT]

That's very interesting, I have not played a great deal with LSD settings in GT...

I wonder if a strong enough LSD setting will cure my elderly 1980s MR2 1600 of wild oversteer.... I'm having a tough time driving it around ANY track at the moment....

Oh, and the game must do independant wheel modelling of at least 2 wheels because otherwise there would be no such thing as coming out of a corner in an old car and lighting up the inside tyre for miles on end (240Z anyone?). The LSD appears t cure this, so does this not say that the physics is indeed independant with reference to each wheel?

 

[LeGeNd-1]

I don't recall GT1 having an LSD setting, but in GT2 a high setting generally increases understeer/stability while a low setting allows more maneuverability at the risk of spinning out. Then again, I don't play that much with LSD settings so don't take my words that seriously. Matter of fact, the only car I remember fiddling with the LSD is the TVR Speed 12 in GT2. For other cars suspension tuning is generally sufficient to dial out any handling issues.

 

[SportWagon]

I don't recall GT1 having an LSD setting,

Good point. Oops.

 

[Dazzla]

First time I've ever seen this...a self-proclaimed GT Scientist. Sounds like Gran Turismo is a disease in need of a cure

 

[gtmaster08]

First time I've ever seen this...a self-proclaimed GT Scientist. Sounds like Gran Turismo is a disease in need of a cure

Please! I'm not REALLY a GT Scientist, I use the term in a rather prosaic manner. Then to your second sentence, well I don't know about that. I mean, sure the first game is flawed in some parts like some of the other scientists on this thread say, but I wouldn't EXACTLY call it a "disease". After all, doesn't some games start out with need of some improvements? Oh, and one more thing;

to the others: It MAY seem like I'm asking for help on these matters, but I already know these things after 7-8 years of playing the game. I'm just giving you guys... a refresher, if you will.

 

[Parnelli Bone]

That's very interesting, I have not played a great deal with LSD settings in GT...

I wonder if a strong enough LSD setting will cure my elderly 1980s MR2 1600 of wild oversteer.... I'm having a tough time driving it around ANY track at the moment....

OH yes....which game are you talking about? GT2? GT4? or real-life? In either game, a limited-slip of some sort will work wonders for those swivelly MR2s. The 1.5 or 2-way fixed diffs may solve most of your problems; and if not, you can (of course) try a full-custom differential.

Leonidae came up with some good MR2 settings called "Mr. Black", but it was a mid-90s MR2, not an '80s car. Still, i think those settings might help anyways. (see the Mad Finn tuning thread in the GT4 section)

 

[AERO_HDT]

GT1 no LSD's?

Gee, I must play that game more, LOL, I was of the impression that an LSD was a staple upgrade in all the games. Are you guys certain that the original game does not feature LSDs?

 

[SportWagon]

Yes I'm certain it did not feature LSDs.

 

[gtmaster08]

I'm back! And this time the new topic is about tire wear! I know that it may not be an EXCITING topic I picked but believe it or not, I theorize that the endurance races makes up the bulk of the racing experience in the game! What you you all think?

 

[Parnelli Bone]

Well yes of course. The Enduros feature lots more laps to complete than all the sprint races combined. At least I think so.

One thing I learned recently (in GT4) is that more camber=more tire wear. Lots of camber in an endurance in this game will wear tires out faster. Not sure if this is true of the first game or not.

 

[nk4e]

Wouldn't weight be also a factor?

 

[SportWagon]

I'm back! And this time the new topic is about tire wear! I know that it may not be an EXCITING topic I picked but believe it or not, I theorize that the endurance races makes up the bulk of the racing experience in the game! What you you all think?

There are 120 laps of Endurance Races in the game.

XXvsXX is 3*5*3 = 45 laps, and Normal and Tuned are 5*5 = 25 each, for 95.
The category races are 4*3*2 = 24 laps. Mega Speed is another 9, totalling now 128laps. So we've exceeded the number of laps even before beginning to enumerate GT League. (3*2 + 3*2 + 4*3 + 6*3 = 42 laps more). The enduro tracks are some of the longer ones, but they are used extensively in some of the other races. (3*3 + 2 + 3 = 14 laps at SSR11, IIRC), so I doubt distance in Enduros will exceed distance in other events. (But such a detailed calculation is left as an exercise for the reader).

So it sort of comes down to what you mean by "bulk"?

Certainly my first GV300 felt like an almost genuine real-life race experience, being almost identical in length and time to a modern Formula One race. And it was a good three months after starting the game that I first prepared to undertake such a time-consuming venture.

But, on the other hand, the long series, like Hard-Tuned, Normal and GT World Cup, require you to drive on a variety of courses.

That said, I never put a lot of scientific investigation into tire wear. It seemed to me you could gain seconds a lap by going softer on the tires, and you really didn't need much more than a fraction of a second to make up for extra pitstops. When I get time, I'll try to give some formulas which can be used to determine tire choice and pitstop spacing.

 

[SportWagon]

Calculating effective average lap time.

Given:
S = number of laps in a tire shift or stint (whole number)
L = average non-pitstop lap time, in standard time units (usually seconds)
P = overall pitstop cost in same units
R = number of laps in the race

Number of pitstops in the race is
N = ceiling(R/S - 1), which gives zero if S >= R
(The -1 occurs because you do not take a pitstop if your tires are worn-out at the end of a race).

Distributing the time for those pitstops over all laps gives
N*P/R
as the average cost per lap of pitstops.

That is, average lap time will be
A = L + N*P/R

As R becomes very large that tends towards
A = L + P/S
which is an intuitive figure, and a good mental approximation. That is, the time penalty for a pitstop is distributed over the laps in the shift.

It is very important, however, to remember that the number of pitstops taken must be a whole number--you either take a whole pitstop or you don't; you cannot take a fractional pitstop. (In games with fuel consumption this changes, as pitstop length can actually change).



I created charts corresponding to the SSR11 races and the GV300 which show the average penalty per lap of various stint lengths, assuming a range of pitstop times from 20 to 40 seconds (by 5).

R=30,P=20 to 40, N=# of pitstops
S  N  N*20 N*P/R N*25 N*P/R N*30 N*P/R N*35 N*P/R N*40 N*P/R
 1 29  580  19.3  725  24.2  870  29.0 1015  33.8 1160  38.7
 2 14  280  9.33  350  11.7  420  14.0  490  16.3  560  18.7
 3  9  180  6.00  225  7.50  270  9.00  315  10.5  360  12.0
 4  7  140  4.67  175  5.83  210  7.00  245  8.17  280  9.33
 5  5  100  3.33  125  4.17  150  5.00  175  5.83  200  6.67
 6  4   80  2.67  100  3.33  120  4.00  140  4.67  160  5.33
 7  4   80  2.67  100  3.33  120  4.00  140  4.67  160  5.33
 8  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
 9  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
10  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
11  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
12  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
13  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
14  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
15  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
16  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
17  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
18  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
19  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
20  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
21  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
22  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
23  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
24  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
25  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
26  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
27  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
28  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
29  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
30  0    0  0.00    0  0.00    0  0.00    0  0.00    0  0.00

R=60,P=20 to 40, N=# of pitstops
S  N  N*20 N*P/R N*25 N*P/R N*30 N*P/R N*35 N*P/R N*40 N*P/R
 1 59 1180  39.3 1475  49.2 1770  59.0 2065  68.8 2360  78.7
 2 29  580  19.3  725  24.2  870  29.0 1015  33.8 1160  38.7
 3 19  380  12.7  475  15.8  570  19.0  665  22.2  760  25.3
 4 14  280  9.33  350  11.7  420  14.0  490  16.3  560  18.7
 5 11  220  7.33  275  9.17  330  11.0  385  12.8  440  14.7
 6  9  180  6.00  225  7.50  270  9.00  315  10.5  360  12.0
 7  8  160  5.33  200  6.67  240  8.00  280  9.33  320  10.7
 8  7  140  4.67  175  5.83  210  7.00  245  8.17  280  9.33
 9  6  120  4.00  150  5.00  180  6.00  210  7.00  240  8.00
10  5  100  3.33  125  4.17  150  5.00  175  5.83  200  6.67
11  5  100  3.33  125  4.17  150  5.00  175  5.83  200  6.67
12  4   80  2.67  100  3.33  120  4.00  140  4.67  160  5.33
13  4   80  2.67  100  3.33  120  4.00  140  4.67  160  5.33
14  4   80  2.67  100  3.33  120  4.00  140  4.67  160  5.33
15  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
16  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
17  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
18  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
19  3   60  2.00   75  2.50   90  3.00  105  3.50  120  4.00
20  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
21  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
22  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
23  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
24  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
25  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
26  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
27  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
28  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
29  2   40  1.33   50  1.67   60  2.00   70  2.33   80  2.67
30  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
...
59  1   20  0.67   25  0.83   30  1.00   35  1.17   40  1.33
60  0    0  0.00    0  0.00    0  0.00    0  0.00    0  0.00

The important thing is the change in penalty as you go down a particular "N*P/R" column.

To clarify a bit, consider just the P=25 columns, since I think 25 seconds is a good approximation of the time taken by pitstops in [size=+1]GT1[/size].

R=30,P=25 to 40
S  N  N*25 N*25/R
 1 29 725  24.2
 2 14 350  11.7
 3  9 225  7.50
 4  7 175  5.83
 5  5 125  4.17
 6  4 100  3.33
 7  4 100  3.33
 8  3  75  2.50
 9  3  75  2.50
10  2  50  1.67
11  2  50  1.67
12  2  50  1.67
13  2  50  1.67
14  2  50  1.67
15  1  25  0.83
16  1  25  0.83
17  1  25  0.83
18  1  25  0.83
19  1  25  0.83
20  1  25  0.83
21  1  25  0.83
22  1  25  0.83
23  1  25  0.83
24  1  25  0.83
25  1  25  0.83
26  1  25  0.83
27  1  25  0.83
28  1  25  0.83
29  1  25  0.83
30  0   0  0.00

R=60,P=20 to 40
S  N  N*25 N*25/R
 1 59 1475  49.2
 2 29  725  24.2
 3 19  475  15.8
 4 14  350  11.7
 5 11  275  9.17
 6  9  225  7.50
 7  8  200  6.67
 8  7  175  5.83
 9  6  150  5.00
10  5  125  4.17
11  5  125  4.17
12  4  100  3.33
13  4  100  3.33
14  4  100  3.33
15  3   75  2.50
16  3   75  2.50
17  3   75  2.50
18  3   75  2.50
19  3   75  2.50
20  2   50  1.67
21  2   50  1.67
22  2   50  1.67
23  2   50  1.67
24  2   50  1.67
25  2   50  1.67
26  2   50  1.67
27  2   50  1.67
28  2   50  1.67
29  2   50  1.67
30  1   25  0.83
...
59  1   25  0.83
60  0    0  0.00

Notice how once you get to the "realistic" range of stint lengths (6 laps or more), the change in per-lap penalty for taking one less pitstop is less than 1 second. If you can gain more than 1 second per lap with softer tires, but need only 1 more pitstop, you will have a better average lap time.

 

[nk4e]

X_x

 

[Parnelli Bone]

Jesus, SPortwagon. That's alot of info.

 

[SportWagon]

It's a lot of data, but really only a part of the info.

In practice, you want to take the above charts, and try and "ease" towards schedules which are the earliest to allow a particular number of pitstops. That's only because the effects of tire wear follow a regular pattern of decreasing your lap times for the first two or three laps, and then increasing them; you know that, after getting tires green, the longer you stay out, the slower your (good) laps will get.

Suppose for the GV300 you get 13 laps on the tires in testing; you might as well come in every 12, because the 13th lap will just be slower, and you won't save any pitstops. However, if your tests suggest 14 laps, well then it just might pay to stretch to 15 to save an entire pitstop. (Depends just how bad that extra lap is; if it actually ends up 8 seconds slower or worse, dropping back to 12 laps might pay off; in fact, since the 13th and 14th laps will in turn be slower than previous laps, a margin even less than that might indicate you should drop to 12 laps; e.g. 2sec+3sec+4sec would probably exceed the approximately 25 seconds pitstop time).

 

[LeGeNd-1]

Jeez, SW, sometimes you remind me of my math textbook . Great stuff though, just give me a few mroe hours to take it all in 👍.

Anyway, back to topic. I don't think endurance races in GT1 make up the bulk of the game. They're long, but there's only 3 of them compared to the numerous tournament series. The "bulk" I think, is either the GT League or the Country vs Country races.

On tire wear, I learned the hard way that maintaining your tyre in enduros is much more important than going as fast as your car allows. My first GV300 race was in a GTO TT, cranked up all the way to 930 horses. I drove as I normally would back then, which includes drifting all over the place plus the occasional visit to the sand trap. Needless to say, I was also a poor strategist, preferring to stay out rather than pitting in, even if my tires were burning red. So I lost my lead on lap 57 and finished second.

Next race though, I detuned the GTO to 600-ish horsepower, and applied some serious pitstop strategy. I followed the 1st place car all the way until his first pitstop, driving very very conservatively to save my tires. When he pitted, I quickly banged in some fast laps until my tires got orange, then I pitted. I came out a few seconds in front of him, and drove at 80% speed for the rest of the race, and everytime pitting a lap after he pitted. I won, and learned a huge part of racing that up until then had been trivial to me. I still think it's one of my best races ever...

 

[Parnelli Bone]

It's a lot of data, but really only a part of the info.

In practice, you want to take the above charts, and try and "ease" towards schedules which are the earliest to allow a particular number of pitstops. That's only because the effects of tire wear follow a regular pattern of decreasing your lap times for the first two or three laps, and then decreasing them; you know that, after getting tires green, the longer you stay out, the slower your (good) laps will get.

Suppose for the GV300 you get 13 laps on the tires in testing; you might as well come in every 12, because the 13th lap will just be slower, and you won't save any pitstops. However, if your tests suggest 14 laps, well then it just might pay to stretch to 15 to save an entire pitstop. (Depends just how bad that extra lap is; if it actually ends up 8 seconds slower or worse, dropping back to 12 laps might pay off; in fact, since the 13th and 14th laps will in turn be slower than previous laps, a margin even less than that might indicate you should drop to 12 laps; e.g. 2sec+3sec+4sec would probably exceed the approximately 25 seconds pitstop time).

Yes. Such are the dilemmas of racing. Should we come in early in hopes towards maintaining overall premium lap times? Or do we wait, risking a bad lap time(s) in exchange for one less pit stop overall? GT4, with fuel management, takes all of this one step further, and in GT5 I just learned random weather will also definately factor in.

And just think: in GT, we are only forced to employ perhaps less than 10% of the possible issues which come up regularly during real-life racing. I've recently started playing ToCA 3 with what little free time I have, in which blown engines, overheating coolant systems, and such are also strong possiblilties. Whew!

 

[gtmaster08]

I'm back again! I've been away for a while making some youtube videos which took up a lot of my time. Anyway, the new topic this time is speed. I know, it sounds a little open ended but I'm talking about increasing top speed or acceleration at the expense of another. Is there ways to do either on GT1?

 

[SportWagon]

I'm back again! I've been away for a while making some youtube videos which took up a lot of my time. Anyway, the new topic this time is speed. I know, it sounds a little open ended but I'm talking about increasing top speed or acceleration at the expense of another. Is there ways to do either on GT1?

https://www.gtplanet.net/forum/showpost.php?p=3337290&postcount=26

 

[daan]

I'm back again! I've been away for a while making some youtube videos which took up a lot of my time. Anyway, the new topic this time is speed. I know, it sounds a little open ended but I'm talking about increasing top speed or acceleration at the expense of another. Is there ways to do either on GT1?

So are you just going to pop in every now and then and give a random subject without commenting on anything that's been said while you were away?

 

[gtmaster08]

So are you just going to pop in every now and then and give a random subject without commenting on anything that's been said while you were away?

Well actually no. It's just that I needed one more topic in before I really discuss the topics. That way we can cover more ground, if you will.

 

[gtmaster08]

Um guys, I'm sorry to break this to you but due to me now being a Youtube artiste I won't be able to carry this thread any further. So I am naming LeGeNd-1 as my successor. And if you're wondering "what youtube videos?" then my username is musicboy311 on there. That's all I had to say except for one more thing...

to daan: "You are part of the Rebel Alliance, and a traitor!"
to everyone else on this thread: "TAKE HIM AWAY!"

 

[LeGeNd-1]

lol wut?

*clears throat* ahem *clears throat*

Uhh....since gtmaster has appointed me as the successor of this thread, I request this thread to be locked, because personally I don't see any more purpose in it. Unless anyone here still intends to carry on our few-months-old scientific discussions?

 

[Parnelli Bone]

Um guys, I'm sorry to break this to you but due to me now being a Youtube artiste I won't be able to carry this thread any further. So I am naming LeGeNd-1 as my successor. And if you're wondering "what youtube videos?" then my username is musicboy311 on there. That's all I had to say except for one more thing...

to daan: "You are part of the Rebel Alliance, and a traitor!"
to everyone else on this thread: "TAKE HIM AWAY!"

Dude, this is the most enticing thing you've added in this entire thread! And you're leaving???

lol wut?

*clears throat* ahem *clears throat*

Uhh....since gtmaster has appointed me as the successor of this thread, I request this thread to be locked, because personally I don't see any more purpose in it. Unless anyone here still intends to carry on our few-months-old scientific discussions?

*snick*

 

[LeGeNd-1]

*snick*

Pardon my ignorance, but what does that mean? Is it a good thing or a bad thing?

 

[Parnelli Bone]

Pardon my ignorance, but what does that mean? Is it a good thing or a bad thing?

That's the sound of a brand-new padlock snicking into place. *Snick*

 

[gtmaster08]

Hey whoa now! I didn't say I was leaving. I just said that I can't carry this thread any longer. So don't lock it just yet. And plus one thing I forgot to add is that LeGeNd-1 is only a temporary successor until I get my videos done. And so far, I've only got 9 more weeks to go in the game! Then I will return to continue this thread, is that ok?

to parnelli bone: Did you really like my lines? And it's true that LeGeNd-1, SportWagon, Viperin, Famine, even you are all part of the Rebel Alliance!

to others: No offense...

 

[Famine]

I find your lack of faith... disturbing.