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11-04-2004, 15:50 | View Warnings #1
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
Posts: 882
vCash: 7500
Universal pacejka...

Well, not completely universal, but I have some pacejkas that I have been working on that seem to be quite close to the real thing.
The thing is that almost every car that have been released for Racer that claimes to have a real pacejka seem to behave strange in some way or another. The reason for this I guess is because when you don't have all the data, using some real data together with estimated values does not work. You will then get a tire that behavies realisticly in some situations and unrealistcly in other. All in all a bad pacejka.
So what I did is to put all my driving knowledge to use. I've been racing cars for a long time, and driven all types of cars with all types of tires. So when I first started to make a pacejka for drifting, I figured I should make it from scratch and just keep trying and testing until every strange behavior was gone. I still feel that there is improvements to be made, but I think it's time to release data for a couple of wheels that I have been working on.
The thing is, I have not really paid attention to how different tire profiles behave. I honestly don't think you can feel wether a tire is 40 or 50 profile or if it has 20 or 25psi of pressure in the game anyway. The point must be to make the cars feel like a real car within the limitations of the game. And to be honest, I feel like I'm on the right track.
Now, here are the pacejkas that I'm most happy with. The first one is the front wheels from Imamuras D1 car, the A'PEXi RX-7. It's about 225/35-18. This is also the pacejka that I've used on the New Beetle RSI. It's good for any low profile street tire really. I mean, there is no point in making a new pacejka for every dimension, as the changes would be so small anyway. The point here is to make a pacejka that is representative for a universal street tire. Then the grip levels and stuff can be adjusted slighly for different tires.
Universal low profile, high-performance street tire (around 205/45-17 to 255/30-18):
This tire is sharp, but still forgiving. Quite slippery, but that can be adjusted to suit the car.
pacejka
{
; Lateral force
a0=1.350
a1=-46.000
a2=1345.000
a3=1675.000
a4=11.000
a5=0.013
a6=-0.140
a7=0.140
a8=0.019
a9=-0.019
a10=-0.180
a111=-11.000
a112=-0.021
a12=0.480
a13=10.200
a13=-2.400
; Longitudinal force
b0=1.350
b1=-90.000
b2=1425.000
b3=23.300
b4=400.000
b5=0.000
b6=0.007
b7=0.055
b8=-0.024
b9=0.014
b10=0.260
b11=-86.000
b12=350.000
; Aligning moment
c0=2.10
c1=-3.900
c2=-3.900
c3=-1.260
c4=-8.200
c5=0.025
c6=0.000
c7=0.044
c8=-0.580
c9=0.180
c10=0.043
c11=0.048
c12=-0.003
c13=-0.180
c14=0.140
c15=-1.029
c16=0.270
c17=-1.100
optimal_slipratio=0.14
optimal_slipangle=0.16
}
Standard size street tire (from 195/55-15 to 225/45-16 or so):
This tire is not as sharp as the low profile tire, but the grip levels are about the same. Quite similar really...
pacejka
{
; Lateral force
a0=1.1
a1=-46
a2=1345
a3=1495
a4=11
a5=0.013
a6=-0.14
a7=0.14
a8=0.019
a9=-0.019
a10=-0.18
a111=-11
a112=-0.021
a12=0.48
a13=10.2
a13=-2.4
; Longitudinal force
b0=1.35326
b1=-90.00000
b2=1345.00000
b3=23.30000
b4=400.00000
b5=0.00000
b6=0.00680
b7=0.05500
b8=-0.02400
b9=0.01400
b10=0.26000
b11=-86
b12=350
; Aligning moment
c0=2.10000
c1=-3.90000
c2=-3.90000
c3=-1.26000
c4=-8.20000
c5=0.02500
c6=0.00000
c7=0.04400
c8=-0.58000
c9=0.18000
c10=0.04300
c11=0.04800
c12=-0.00350
c13=-0.18000
c14=0.14000
c15=-1.02900
c16=0.27000
c17=-1.10000
optimal_slipratio=0.14
optimal_slipangle=0.16
}
Avon semi slick tire (somewhere between 185/65-13 and 205/50-15):
This tire is more grippy than a normal street tire, but still not a full racing slick tire. Perfect for Caterhams and light track racers.
pacejka
{
; Lateral force
a0=1.4
a1=-46
a2=1625
a3=1875
a4=11
a5=0.013
a6=-0.14
a7=0.14
a8=0.019
a9=-0.019
a10=-0.18
a111=-11
a112=-0.021
a12=0.48
a13=10.2
a13=-2.4
; Longitudinal force
b0=1.35
b1=-90.00000
b2=1545.00000
b3=23.30000
b4=400.00000
b5=0.00000
b6=0.00680
b7=0.05500
b8=-0.02400
b9=0.01400
b10=0.26000
b11=-86
b12=350
; Aligning moment
c0=2.10000
c1=-3.90000
c2=-3.90000
c3=-1.26000
c4=-8.20000
c5=0.02500
c6=0.00000
c7=0.04400
c8=-0.58000
c9=0.18000
c10=0.04300
c11=0.04800
c12=-0.00350
c13=-0.18000
c14=0.14000
c15=-1.02900
c16=0.27000
c17=-1.10000
optimal_slipratio=0.14
optimal_slipangle=0.16
}
I hope someone tries these out and let me know what they think. I don't think Racer needs hundreds of different pacejkas that are semi-realistic. Maybe we should find a few that works, and then adjust them to fit whatever car we need it for, rather than having a lot of strange ones. After all, it's hard to make one that feels real, and still use real values. there's just som much information missing...
Fredrik

11-04-2004, 18:00 | View Warnings #2
Rebelrocker Registered Join Date: Nov 2002 Location: Finland Age: 21
Posts: 1,282
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I was about to bring this up myself, its very annoying to see good modeled cars going bad because they lack good tire data. If we only would get people to use these and/or alpine's pacejka for the cars, it would be good. We may not have pacejka for F1 or other special race cars but those pacejkas you posted should IMO be enough for making various road cars. Thanks alot for those pacejka's i'm going to try them ASAP This thread should be made sticky!

Last edited by Rebelrocker : 11-04-2004 at 18:08.

12-04-2004, 01:50 | View Warnings #3
Bumper3D Registered Join Date: Mar 2004 Location: Finland Age: 29
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I will use your pacejka in my future releases...
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12-04-2004, 03:58 | View Warnings #4
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
Posts: 882
vCash: 7500
Feel free to modify it though. This is not something I own or feel is mine. Most of the values are the same. As you can see, the only values that I've played with that really makes a lot of difference is a0, a2, a3, b0 and b2. Changing the other values simply doesn't make much difference, or improvement...
Having said that, I'm no pacejka master. Hell, I hardly know what most of the values do. I don't even understand some of them. But I've driven them a lot, and know what to look for in a cars handling. Guess that makes up for it.
The suspension also playes a big part. In fact, I use very similar settings on a lot of cars. Simply because I want them to feel like a real car. Now, I think that must be the goal. And I hardly doubt that you can feel the difference between a Nissan Silvia and a Mazda RX-8 in a game anyway, Minor caracteristics if they're exaggerated maybe. However, there should definately be a difference between an Audi A3 and a Porsche 911. But still, it's just no way you can simulate real life without a lot of research and one of those hydraulic things to sit on

Last edited by FSR : 12-04-2004 at 04:03.

25-04-2004, 13:22 | View Warnings #5
El_Tate Registered Join Date: Oct 2003 Location: Argentina Age: 18
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FSR: do you have a pacejka for a 185/45 R13???, or somebody.
Thanks
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25-04-2004, 13:27 | View Warnings #6
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
Posts: 882
vCash: 7500
Quote:

Originally Posted by El_Tate FSR: do you have a pacejka for a 185/45 R13???, or somebody. Thanks

Not really, but don't worry too much about the dimensions. A 185/45-13 is a strange dimesion by the way. Anyway, the important thing is what kind of tire it is. I'd say you'd be fine with the 195/50-15 style pacejka if it is for a street tire. With only a force feedback wheel, you'd never be able to tell if it's a 45 or 50 profile tire anyway...

25-04-2004, 14:02 | View Warnings #7
El_Tate Registered Join Date: Oct 2003 Location: Argentina Age: 18
Posts: 834
vCash: 2300
So, in this case where I can find a Pacejka for a 195/50 R15 (or R13), for a street car (the Dacia 1300 (Renault 12))
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25-04-2004, 14:10 | View Warnings #8
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
Posts: 882
vCash: 7500
Start out with the standard street tire and just play with it. I'm guessing a little less grip, but that would depend on the brand and tire model really. It should work fine as it is too... As you can see, most of the values are the same for all the tires anyway. Just use one that gives you the balance and grip you are looking for.

26-04-2004, 02:12 | View Warnings #9
Mr Whippy Awaiting Activation Join Date: Sep 2002 Location: United Kingdom Age: 24
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vCash: 7500
Hmmm, I'm no expert, but your A0 and B0 values seem quite low, ie, forgiving.
We even have a real data for a fairly wide low-profile tyre, and the lateral fall off coeff is 1.5 or even 1.6, and the longitudinal is similar at 1.6 ish.
I was thinking of doing something similar, but with ALL my Pacejka coeffs, they are tuned from the real data, and are quite made up now, to do and feel how they should/how they need to!
I think it was Cubits that once pointed out that it isn't really the size at all that makes the biggest difference, it's the compound!!!
Two exact same tyres can be worlds apart in feel and response, forgivness and grip.
Start with a good base (ie the real data, your data, or even better, a car that handles how you like, and then to copy that and work on it more), and then work from there. Thats all we can do
Main thing though, is for it to react realistically. It doesn't matter if the grip or feel is 100% right, as long as it's predictable relative to real life. Thats the main thing!!!
Dave

26-04-2004, 02:40 | View Warnings #10
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
Posts: 882
vCash: 7500
Yup, they are quite forgiving. But after hundreds of laps of testing, the only way to make it possible to push the car as much as in real life is to lower these values. It doesn't really affect the handling, just smoothens out the difference between grip and no grip. I'd say that 1.3 - 1.4 is what feels the most realistic without being to hard to drive. Still, I usually choose to lower it even more to make the car even more playable. Basically, it's a matter of taste I guess. It's no problem to make it 100% realistic, but it sort of takes away the fun as the car becomes way too snappy to be drivable on a computer.
That's my view anyway

26-04-2004, 03:44 | View Warnings #11
Mr Whippy Awaiting Activation Join Date: Sep 2002 Location: United Kingdom Age: 24
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vCash: 7500
Yeah, I've lowered these values on most of my Pacejka coefficients, simply because the "sharpness" is blunted, which takes away that snappy behaviour.
I think a good deal of the problem is, for me anyway, FF damping. I set the FF multiplier to ~2 in the latest beta, and use a linearity of ~0.25.
I still get centre-line sharking, left to right, and it can make some cars jolt left to right. Making the a0 and b0 lower means this goes away some what, and makes the limit more "wide", so you can drive on the limit, not bounce around too far past it, and then too far under it.
It's totally ok to tune the pacejka coeffs' to what you want. I gave up a long time ago trying to get it anywhere near "real", since there was no benefit except irritation from it not "feeling" real.
Gran Turismo dumbed GT3 and I expect GT4 down alot, simply because you can't be expected to drive a car and have it feel realistic when your sat at a desk with a plastic wheel and stuff. Still, the cars still did what they should, lift-off oversteer, power-oversteer etc.
As I said above, as long as the car reacts the same kind of ways as it does in real life, and has the same kind of limits. Just making the limit somewhat accessible is what is the key to tweaking the pacejka numbers!
Seya
Dave

26-04-2004, 04:44 | View Warnings #12
Raiden Registered Join Date: Mar 2003 Location: Norway Age: 19
Posts: 208
vCash: 7500
Quote:

Originally Posted by Mr Whippy Hmmm, I'm no expert, but your A0 and B0 values seem quite low, ie, forgiving. We even have a real data for a fairly wide low-profile tyre, and the lateral fall off coeff is 1.5 or even 1.6, and the longitudinal is similar at 1.6 ish.
I was thinking of doing something similar, but with ALL my Pacejka coeffs, they are tuned from the real data, and are quite made up now, to do and feel how they should/how they need to!

Would you mind posting your pacejka here so I can try it out? I'm converting a tuned car (trying to keep it non-rice), so I need to have realistic pacejka for a set of low profile, high performance tires.. I'll release the car if I can do it without any copyright issues..
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26-04-2004, 06:08 | View Warnings #13
mh Registered Join Date: Feb 2001 Location: Sweden Age: 28
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Cool stuff guys!
I will use these as a base for tires...
Thanks for all the work you did with those datas.
Cheers!
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26-04-2004, 09:23 | View Warnings #14
f50 Moderator Join Date: Nov 2002 Location: United States Age: 20
Posts: 3,147
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Quote:

Originally Posted by Raiden Would you mind posting your pacejka here so I can try it out? I'm converting a tuned car (trying to keep it non-rice), so I need to have realistic pacejka for a set of low profile, high performance tires.. I'll release the car if I can do it without any copyright issues..

why don't you just use the first set of data that FSR posted? thast for high performance street tires.
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26-04-2004, 13:33 | View Warnings #15
Raiden Registered Join Date: Mar 2003 Location: Norway Age: 19
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Quote:

Originally Posted by f50 why don't you just use the first set of data that FSR posted? thast for high performance street tires.

I know, but I want something to compare with..
Not that FSR's is bad, because they aren't
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27-04-2004, 14:00 | View Warnings #16
Outlaw Registered Join Date: Feb 2003 Location: St.-Petersburg, Russia Age: 21
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That is nice and very usefull work! Hope now we will have less "arcade"cars...
Fredrik, i sent pm to you, did you see it?
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03-05-2004, 13:43 | View Warnings #17
Raiden Registered Join Date: Mar 2003 Location: Norway Age: 19
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The low profile tire is non-controllable if you got much power..
Trying to have about 420hp in a rwd car and it just makes it spin out if you got just a small amount of applied throttle in a bend..
The semi-slick has lots of grip, but when it lets go, there isn't any way to control it. Butt first in the dunes at carlswood..
These are my experiences, and it may even be that this is the way ther are supposed to handle. Is it?
How can I make a tire that will make the car controllable in a drift, and at the same time is possible to do hotlaps?
The best overall car for this is in my opinion the Georg's Silvia, but I want a car like that one with more power.
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03-05-2004, 19:04 | View Warnings #18
f50 Moderator Join Date: Nov 2002 Location: United States Age: 20
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Quote:

Originally Posted by Raiden The low profile tire is non-controllable if you got much power.. Trying to have about 420hp in a rwd car and it just makes it spin out if you got just a small amount of applied throttle in a bend.. The semi-slick has lots of grip, but when it lets go, there isn't any way to control it. Butt first in the dunes at carlswood..
These are my experiences, and it may even be that this is the way ther are supposed to handle. Is it?
How can I make a tire that will make the car controllable in a drift, and at the same time is possible to do hotlaps?
The best overall car for this is in my opinion the Georg's Silvia, but I want a car like that one with more power.

You can give yourself more longitudinal grip on those road tires by raising the value of B2.
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12-05-2004, 03:48 | View Warnings #19
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
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Raiden: I actually find the tires very controllable and driftable. In fact, even more so than in real life. Have you ever driven a 400+ bhp car on a curcuit? Trust me, if you apply just a little to much power in a turn, you will have a handfull of steering wheel work to do! As for the semi-slicks, it's kind of simple. The more grip you have, the more you will notice it when it's gone. So yes, a slick tire is very snappy. The "snappyness" can be adjusted with the a0 and b0 values though. The lower the number, the more forgiving the tire. IRL this value is usuallye somewhere in the area of 1.5 - 1.6. I tend to lower it to 1.2 - 1.3 to compensate for the lack of feel with the car.That will buy you some time when you start to slide.
And as I said, it's very driftable indeed. Just like a real road tire. I can drift the A'PEXi RX7 all around the ring if I want to

15-05-2004, 14:33 | View Warnings #20
Raiden Registered Join Date: Mar 2003 Location: Norway Age: 19
Posts: 208
vCash: 7500
when using the low profile tire pacejka the QLOG comes up with this:
Quote:

Sat May 15 23:19:19 (WARN) : [racer/2156] Wheel 0 pacejka leads to longitudinal force (379.63N) at no input. Wheel will rotate by itself! Sat May 15 23:19:19 (WARN) : [racer/2156] Skipping unknown geode chunk '' of length 1179599941 (rwheel.dof)
Sat May 15 23:19:19 (WARN) : [racer/2156] Skipping unknown geode chunk '' of length 1179599941 (brake_fr.dof)
Sat May 15 23:19:19 (WARN) : [racer/2156] Wheel 1 pacejka leads to longitudinal force (379.63N) at no input. Wheel will rotate by itself!
Sat May 15 23:19:19 (WARN) : [racer/2156] Skipping unknown geode chunk '' of length 1179599941 (lwheel.dof)
Sat May 15 23:19:19 (WARN) : [racer/2156] Skipping unknown geode chunk '' of length 1179599941 (brake_bl.dof)
Sat May 15 23:19:19 (WARN) : [racer/2156] Wheel 2 pacejka leads to longitudinal force (379.63N) at no input. Wheel will rotate by itself!
Sat May 15 23:19:19 (WARN) : [racer/2156] Skipping unknown geode chunk '' of length 1179599941 (rwheel.dof)
Sat May 15 23:19:19 (WARN) : [racer/2156] Skipping unknown geode chunk '' of length 1179599941 (brake_br.dof)
Sat May 15 23:19:19 (WARN) : [racer/2156] Wheel 3 pacejka leads to longitudinal force (379.63N) at no input. Wheel will rotate by itself!

how can I repair this?
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15-05-2004, 15:17 | View Warnings #21
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
Posts: 882
vCash: 7500
Quote:

Originally Posted by Raiden when using the low profile tire pacejka the QLOG comes up with this: how can I repair this?

Strange. I've never experienced this...

28-06-2004, 18:24 | View Warnings #22
SuziAerio02 Registered Join Date: Nov 2002 Posts: 20 vCash: 7500
Thanks for all the hard work!
They are all great Pacejkas that are great for all multi tiered model.
The HiPerformance tire lowered my lateral G's from 1.5 to 1.05 which is a bit more realistic for a Street Modified SoloII car.
Excellent work and KUDOS!

12-08-2004, 23:45 | View Warnings #23
Boomer541 Registered Join Date: Apr 2003 Location: Oregon Age: 67
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vCash: 7500
Wheel 2 pacejka leads to longitudinal force (379.63N) at no input. Wheel will rotate by itself!
These Qlog errors caused by b9, b10, b11 and b12 not = 0.
This was on another thread, I'm not sure where in this forum.
Note to FSR:
Take a look at what I did to your Swift FF over on the "Cars - New Releases" thread.

Last edited by Boomer541 : 12-08-2004 at 23:55.

23-08-2004, 15:30 | View Warnings #24
f50 Moderator Join Date: Nov 2002 Location: United States Age: 20
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just noticed this the other day, but why is a13 listed twice in each set of pacejka? is the 2nd one supposed to be a113?
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22-01-2005, 17:19 | View Warnings #25
FSR Registered Join Date: Apr 2003 Location: Oslo Age: 27
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Well, these pacejkas are really outdated now. And frankly, they never where that good. They where ok in 050f where one didn't have that many suspension settings to play with. In the newer versions however, I'd use way more realistic pacejkas and rather play with suspension settings for drivability. Whippy's M3 is a good example of a very good pacejka...

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