Cars Tatra 603-2 B5 Marathon 1.2

Kyuubeey · May 15, 2020

ACFAN said:
I originally had the external sound a lot quieter. But increased the volume at the request of the modding team

The interior is great, good job

but originally I just thought the exterior and reverb is perhaps an audio mix issue. On second though, the exhausts act more like megaphones than anything else.

Nicecuppatea · May 15, 2020

Gelly916 said:
Alright, I thought I had it fixed by updating CSP to 0.1.52 but I still get a crash when I try the car. Any ideas?

Try deleting 'main_geometry.vao-patch' in the car folder. I was having a similar problem and that solved it for me, not sure why but I haven't really delved into the Shader Patch settings so I'm guessing something there isn't set right in my copy.

Great mod though, really good fun to drive.

Gelly916 · May 16, 2020

Fuzo said:
this is strange indeed, you have 1.1 version of Tatra? Did it work with previous versions for you or you weren't able to load it at all? Try to delete ext_config.ini from extensions directory of the mod and try it, this way we can leave out the possibility that there is something broken in car data. If you dont' mind please delete the whole mod. install it again, run it and if it crashes, go to Documents/Assetto Corsa/logs, pack the whole logs dir to some archive and send it to me via PM and I will look on it.

So I deleted the ext_config and that seemed to do the trick. I can now drive the car in single player. Will this have any lasting effects? Such as checksum errors in multiplayer? Or anything else? Sorry, I'm a noob and don't even know what the file did that I deleted! haha, I appreciate the help though!

AccAkut · May 16, 2020

Gelly916 said:
So I deleted the ext_config and that seemed to do the trick. I can now drive the car in single player. Will this have any lasting effects? Such as checksum errors in multiplayer? Or anything else? Sorry, I'm a noob and don't even know what the file did that I deleted! haha, I appreciate the help though!

the ext_config should have no issues with online use, as its a file only CSP uses. It's not a file that is used by vanilla AC

Fuzo · May 16, 2020

guys as I mentioned on our facebook page our mods were introduced to the CUP - content manager auto update system, but this system is quite new and we found small bug in it which prevents our Tatra to auto update. If some mods have version number with more than one decimal, the system won't offer update, so if you are still on version 1.01 just delete the "1" on the end, save it and CM will imidiately offer you update to 1.1. Sorry for the inconvenienece, it was already reported to the author.

Kyuubeey · May 17, 2020

@thegreger

It is a bit weird people expect a luxury car turned into an endurance car to be hard to drive for some reason, even if there's no real reason it should be. You'd be surprised to hear that even if the suspension layouts are dated, older cars weren't designed by incompetent engineers and can be easier than modern ones.

thegreger · May 19, 2020

@Kyuubeey
I used to work as an automotive engineer before switching fields, and one of my hobbies is converting classic cars (currently an MGA, before that an MB 220SE) for race and rally use. Trust me, I'm well aware that you can build an old car to handle well.

That said, we're talking about a huge luxury barge with a rear-mounted V8. It took Porsche close to 40 years to figure out how to make a similar configuration not want to murder you, and that was in a purpose built sports car. If the Tatra 603 handles as well in real life as it does in v1.1 then it's a miracle. A more likely explanation is that many people in the sim world don't really want cars to be difficult to drive.

Edit: After taking a peek in suspensions.ini, like I suspected the car is configured to use double wishbone suspension in the rear, rather than a swing axle. This could be one clue as to why it really doesn't handle like a race prepped classic car, and particularly not one as notorious for poor handling as the 603. I would really like the feedback from anyone on the mod team on whether or not anyone involved in the team has driven a replica of the real thing IRL. If not, I will assume that it's just a bit dialed back to be easier to digest than it should have been.

Second edit: I should add that this is not meant as a particulary harsh critique. I still rate this mod five stars, because I think that it is incredibly well made. I'm just not convinced that it's 100% realistic the way it's currently set up.

Fuzo · May 19, 2020

thegreger said:
@Kyuubeey
I used to work as an automotive engineer before switching fields, and one of my hobbies is converting classic cars (currently an MGA, before that an MB 220SE) for race and rally use. Trust me, I'm well aware that you can build an old car to handle well.

That said, we're talking about a huge luxury barge with a rear-mounted V8. It took Porsche close to 40 years to figure out how to make a similar configuration not want to murder you, and that was in a purpose built sports car. If the Tatra 603 handles as well in real life as it does in v1.1 then it's a miracle. A more likely explanation is that many people in the sim world don't really want cars to be difficult to drive.

Edit: After taking a peek in suspensions.ini, like I suspected the car is configured to use double wishbone suspension in the rear, rather than a swing axle. This could be one clue as to why it really doesn't handle like a race prepped classic car, and particularly not one as notorious for poor handling as the 603. I would really like the feedback from anyone on the mod team on whether or not anyone involved in the team has driven a replica of the real thing IRL. If not, I will assume that it's just a bit dialed back to be easier to digest than it should have been.

Second edit: I should add that this is not meant as a particulary harsh critique. I still rate this mod five stars, because I think that it is incredibly well made. I'm just not convinced that it's 100% realistic the way it's currently set up.

miracles can happen

thegreger · May 19, 2020

Fuzo said:
miracles can happen

Seriously though, amazing work on this mod, but I actually think that v1.0 handled much more like the car in the video appeared to be doing, even if it might have been "for all the wrong reasons".

jlnprssnr · May 19, 2020

@thegreger Kyuubeey is not the guy to dial back physics for drivability. He uses double wishbone to simulate the real suspension, as it's the most flexible to approximate camber curves etc with.

thegreger · May 19, 2020

@jlnprssnr Yes, I realize that you can do this, but doing it accurately without having driven the car? I'm very sceptical.

Let me put it this way: No classic car that I have ever driven in anger irl has behaved as well when pushed towards its limit as this car does in v1.1. And we're talking about a model that is absolutely infamous for its unpredictable handling. I don't think it's unfair to assume that it's set up to be overly forgiving.

But I won't waste energy arguing about it, I will just revert to v1.0 since I don't believe that the v1.1 is really a step forward. Well, the steering lock certainly is an improvement!

Kyuubeey · May 19, 2020

thegreger said:
@Kyuubeey
I used to work as an automotive engineer before switching fields, and one of my hobbies is converting classic cars (currently an MGA, before that an MB 220SE) for race and rally use. Trust me, I'm well aware that you can build an old car to handle well.

That said, we're talking about a huge luxury barge with a rear-mounted V8. It took Porsche close to 40 years to figure out how to make a similar configuration not want to murder you, and that was in a purpose built sports car. If the Tatra 603 handles as well in real life as it does in v1.1 then it's a miracle. A more likely explanation is that many people in the sim world don't really want cars to be difficult to drive.

A more likely explanation is that I matched the suspension, CoG, aero and inertia as close as I could and this is what came out because automobiles rarely if ever completely match user expectation.

It's almost 50/50 longitudinal split; it's not as much of a rear engine car as you think it is. The whole thing is so massive that the inertia and longitudinal balance gets spread out a bit more evenly and the balance isn't under 40% front like you would assume, from a smaller, lighter 911 for example. The configuration isn't really the same even if the engine is quite rearward.

The suspension is dated yes, but it's well matched and the racecar even has a front stabilizer. The steering is also slow as to not cause the driver to induce sudden yaw acceleration which could break traction. Front has very bad suspension curves which will avoid excessive front grip, and in stock form it even has a quite high roll center. Remember also the racing version has harder springs and dampers, and the (Large diameter which I assume to be solid) front stabilizer which the roadcar doesn't even have at all!

I'll remind you that everyone always says the same thing about nearly all my well-made cars. People said I dumbed down the FD3S when I made the suspension work correctly and the inertia and CoG more favorable based on manufacturer data.
Hell, people said I dumbed down the 964 because it understeers; even though owners/prior drivers of the 964 told me that it's correct and 964's are notorious for excessive understeer due to Porsche freaking out about the 930's reception.

In short, the only thing which doesn't really agree with the behavior is your own expectation. There's surely bigger error in the period-correct tires than the suspension at this point.

I'm not gonna make complete physics for the roadcar and release it just to prove wrong one guy, but you can be sure I have compared to the roadcar as well, as well as to modern onboards of reproductions; which have harder springs and dampers nonetheless, but they're similar. I made most of the physics first before comparing to any video or written description to make sure my biases don't come into play, because some things didn't have data and had to be guessed.

The only thing even close to bad behavior which I see here is the rear letting go on throttle in lower gears, which is a given for swing axles. I think it lets go a tad faster than our car because the tire is more modern and a bit more peaky with more grip I bet, and the springs are stiffer in the modern ones, I have been told. Of course, the very dusty and probably bumpy road doesn't help.

If you look at the sections of more steady-state cornering at higher speed, it looks as composed as any modern car to me.

You also don't need to ever drive, or even lay eyes on a swing axle suspension to properly dial in the curves with DWB, I don't know why you think so. It has literally nothing, at all, to do with that. Either the numbers are correct or they're not. I'm not going to be able to decide how the links move or how high the roll center is just because I drove the car.

PS: Could I have a source for the Tatra 603's notoriously unpredictable handling? I've only ever read the opposite, but okay.