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Tatra 603-2 B5 Marathon

Cars Tatra 603-2 B5 Marathon 1.2

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Fuzo submitted a new resource:

Tatra 603-2 B5 Marathon - The endurance legend



Trained Monkey Modding team presents Tatra 603-2 B5 Marathon

So this is another Czechoslovak legend from our workshop - Tatra 603-2 in B5 Marathon edition. It is powered by V8 engine producing 170BHP cooled by air with help of those 2 big barrels on the rear of the car (ejector cooling). This car was used mostly for...

Read more about this resource...


Basic Tatra 603 3D model is scratch made model bought from commercial 3D modeling portal, but we had to model the whole interior, tires and some additional assets typical for B5 version by ourselves (Fuzo’s skills are slightly improving). Physics was made with help of the historic documentation available from various sources. Luckily for this mod we didn’t need to use Kunos sounds because we contacted one of the best sound modders on the scene -ACFan and he made the sound for us.
Sounds legit. Doubt this car was available in one of the typical "sources"
Amazing mod. The car is just awesome. Despite the fact that I changed the settings of some shaders and replaced some textures, it’s awesome!

Physics is also on top. But it’s a little wierd that car is very nimble for such a dinosaur.
oh yeah Tatras!
(Note TATRA not TATA, this is Czechoslovakian car manufacturer named after mountain range Tatry).

Any plans for Zikmund & Hanzelka's Tatras (t87, t805)? They were more of touring trips sure but definitively stand on pedistol above 603 in my personal ranking.

Regardless thank you so much for making this gorgeous car.


Here is some info about the "Marathon de la Route" race, very interesting reading...


Fuzo updated Tatra 603-2 B5 Marathon with a new update entry:

Hotfix 1.01

Updates and fixes in version 1.01:
  • hotfix for rear suspension (should be a little more predictable)
  • added extended CSP file (thx x4fab)
  • added real license plate to “Marathon de la Route” skin (thx @TheSosunser )
We found small issue in rear suspension geometry which could affect the behaviour of the car, especially under lower grip conditions, now it should be a little better even on 100% grip and you will survive a little longer on the track in...

Read the rest of this update entry...
Wow what can I say about this grand old lady of racing. What an amazing discovery, I love it when a mod comes along and teaches me something about racing that I didn't know. I've learn't about a car I didn't know about and had an amazing time caressing this old lady around an old circuit! Absolutely fantastic mod, drives well, looks beautiful. I took the time to make a video about it, it's was well worth doing! Excellent work from Trained Monkey Modding! :)
Okay, but the oversteering are not fixed in 1.01. Feels like 1.0.
Maybe a rear little more deeper or a little softer dampers or in fron harder stabilizer.
Stabilizer front from 13223 to 23223 don't helps.
30% lower Damping at the rear axle are helping nothing. I think its completly unimportnat for AC, how high the values of damper are. The car will drive also with 0 0 0 0. I will test it later.
Now i reduced, the rear high to 0.025 (from ROD_LENGTH=0.025) but nothing. The car oversteers at the first corner at magione with all theese changes.

I will try this:
Oh, surprice, this feels like the car has no damper. Fine! I changed damper at a another car 1 year ago and it has the same feeling with another values.

I think, you have to rise the grip at the rear and thats it.
Its with all the changes this driving like in this video:

The tires rear has the same size, but different values. I think, thats wrong. The friction limit angle are lower but it don't make sense because the tire are the same and look at the rear DX_REF=1.0, the fron has 1.2 and that value are for traction and braking.

With DX and DY at the rear at 1.25 it fixed that problem, but its not the gracefuls way.
With 1.3 DX and DY its nice to drive and you can't make many mistakes.

But, i hope you find a better way to make the car nicer(or that car was not easy< to drive. You feel, that it was very very heavy and not realy a race car. May be it have to feel like that.)
Try a little less of friction limit angle. 4.0 or something like that. It makes the car more lively.


Tumultageddon thank you for awesome video review, we are happy that you enjoyed the car. That's the main reason we keep doing some stuff for AC, to make people smile while driving :) . I must confess I didn't know about this car either, I was more into Skodas but when I saw this car for the first time, I knew we have to do it :). But what's more impressive than the car itself is its history. I never heard about Marathon de la Route or something similar, but when I read something about it I was astonished.

Jeremy Chaim there might be some "issues" with the sound when AC tries to apply the reverb effect, but we set the levels as we thought it should be right, that car's noise was in fact compared to Spitfire airplanes, but I understand that someone can see it a little loud or off, so for this case you can either play with your volume settings in AC or open ext_config.ini in extension directory and there is a section for audio and you can set the audio levels there and you don't need to mess with your AC settings. But you have to have CSP for this to work.

Manuel Staedel thank you for your effort but the car behaves as we intended and we won't make any tweaks to make it less oversteery. People just need to realize that this is not a cup car or a pure race car, it is slightly tuned civilian car and to master it people need to adjust their driving style to it. I struggled with it a little by myself, but when I realized how it should be driven, I was able to do Norschleife Endu layout constantly under 12:30.00 without single spin :)

Guys try this car on Nordschleife Endurance and tell me your times, I am curious :) My best time is something around 12:24.00 but I know a guy who did 12:14.000 with it and he is a casual driver, not a "UFO" :)
Tumultageddon thank you for awesome video review, we are happy that you enjoyed the car. That's the main reason we keep doing some stuff for AC, to make people smile while driving :) . I must confess I didn't know about this car either, I was more into Skodas but when I saw this car for the first time, I knew we have to do it :). But what's more impressive than the car itself is its history. I never heard about Marathon de la Route or something similar, but when I read something about it I was astonished.

Thanks very much, I'll have to get the kettle on for a nice cup of tea and get the biscuits out for a good read. I do like learning about Motorsport heritage. Thanks again for the mod, I'll have to take a better look at your other cars, as I haven't tried them yet.


The rear suspension is wrongly made. That's just it. The car isn't right and I don't understand why this mod team's physics guy(s) is so incompetent and doesn't just analyze my trailing arms like I said. The people giving the feedback are not talking out of their ass.

The 2D roll center in the KS viewer is negative 102mm, or -102mm. There's camber LOSS on compression. Due to the extreme upwards angling of the upper arms.

That's not right at all. What the hell are you guys doing? Stop trying to justify this dumb ****. There should be significant camber gain due to the trailing arm geometry, and perhaps around a 100 - 150mm *positive* roll center depending on the angle of the chassis links.

My suggestion is to build the trailing arm component with the *upper* arm, then make the lower arms long and move the assembly down and adjust their angle for curves and roll center.
Determine the instant center via Z placement of the lower arms, and look how I made the toe arm placement, then determine the exact curve with the relative height of the chassis link.
That way you get acceptable anti, very good curves, very good roll center static height and the roll center migration in jounce and roll are *a little* off but the % is so low, it is basically unnoticeable. A few mm too much over 100mm of total travel or so usually.

However the method is easy and doesn't require hours of software analysis.

Please just like rip the rear out of my Singer 911 because it's the most recent, up to date one which is made most correctly. If there are some questions I will try to answer.

EDIT: Also the tires are a complete disaster. Stiffer than slick tire relax length, asymmetric values F/R in an unlikely manner, big grip difference F/R etc etc.

Also has very unlikely, extremely high inertia. You didn't just put in the car dimensions did you?

EDIT 2: Oh christ I just noticed the SAI line is going along where the damper probably is. Goddamnit ****ing hell. The SAI line in a MacPherson strut is a *virtual* axis which travels from the top of the mounting point of the strut on the car, down into the lower balljoint, because the knuckle, strut, wheel and balljoint are essentially one piece. It doesn't actually steer along the strut tube; which can even be angled backwards and at any angle you want, almost. For example the Porsche 964 and 993 have a backwards angled strut, yet the caster is positive.
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Our modding team doesn't and never will guarantee the accuracy of the car physics or car handling to the real counterpart by any means. Our mods are available for free, are built in our free time with the best intentions to capture the "spirit" of the particular vehicle and with limited engineering knowledge available to us. If you don't mind this fact, feel free to try it, if you do, feel free to make your own version. If you feel somehow offended or misled by driving our innacurate mods, we are deeply sorry.