Physic discussion thread

How have other sims gone about addressing this problem or situation?

 

Yes, I tested also with zero preload and modifying clutches and ramps.
The Ginetta responds quite well.

 

Preload zero is my new fave thing to do on some cars where I'm bombing it.

Well then because diff attaches to wheels via Axel's ect I guess now with a new tire model they'll do something about this.

New cars are great to drive then there's always p1s and roco don't exhibit this behaviour, mc2000. But some definitely egregious diff issues. No longer Ultima I would say, never ginetta, f3s seem great and open wheels usually.

What do people think the biggest problem cars to have a play with

 

I tried 0 preload with 85 coast and 50 power ramp. McLaren F1 GT1 at Interlagos. This is T4 (or whatever that left turn number is after the long straight). Just a massive snap, rear turns into a shopping cart and I have a code brown. Big correction follows. Just impossible to race like this, cause I have 0 condidence in the rear. The default setup is better in that it doesn't slip that much once it decides to open at all.

This is just before the diff opens. I'm turning left and trail braking. As you can see the rear tire speeds are practically identical at this point. But that's not the biggest problem. It's how much difference there is just a few tenths later. Peak difference there at the bottom is 9 rad/s.



Another thing I will say about the driving experience now vs previous versions: it was somewhat easier when you knew the rear was stiff and did not loosen up in a blink. You had to throttle oversteer your way through tight corners. This was of course unorthodox driving technique, but car control nevertheless. Now on some cars you have limited ability to throttle oversteer, because there's so much inside tire slip on acceleration (it stabilises the car somewhat). And then you have this sudden code brown in slower corners. Or worse mid corner when you've applied a lot of steering input to hit the apex with the stiff rear in mind.

 

So the vague rear problem is still there but reduced in prevalence but issue remains all the same?

The diff has a lot to answer for. Most cars improved out of sight for vagueness. Not Camaro road but many others.

Now upon pushing cars and isolating issue as much as able they have a hole.

To get around this one must drive slow I know the turn well. That defeats the purpose of racing or to accept slide or chopping the corner.

If the rear is more tight and present surely the feel will improve.

Can they not impose hard limits on a per car basis

 

Nope, 2nd gear there for a while. I think it hits a bump or something and that triggers the differential to open.

 

But no diff ever operates in a vacuum. Gears slip, diffs clunk and jut now and then.

There needs to be an invisible downward counter weight on cars thrusting them forward. Edit: Or..ok... A wider look at components.

If tires slip in a limited fashion then they need to be alleviated or otherwise buffed. They just don't do everything exactly at the right moment for the contact patch to affect things maybe

 

Cool! What about gear ratios and the like in the diff

 

Maybe some problems that I thought were in the tire model were actually in the differential.

Specifically, a general lack of on-power oversteer exiting all but hairpins, but the hairpins having too much oversteer.

Is this the cause of the problem wherein even very high horsepower cars won't spin around in medium and high speed corners when the throttle is heavily abused?

This thread should definitely be kept alive.

 

@SlowPoke80 its a physics thread in a racing sim. Have no fear, it will live forever.

very glad its here though, am learning things already.

 

I thought the Super V8s are nice to drive as well. I mean the concept is tricky, but it's like that 24/7 so you can rely on the rear.

I think many LSD cars used to behave like spools before thanks to some drivetrain bug which locked the diff completely. It would never open. And while the car control required relative to their real counterparts was incorrect, they were easy to control after a while and felt correct for spools. Well as easy as spools are ever. If you could drive the Super V8, you could drive a lot of the other cars.

This is important to me, because consistency is key within a sim. It doesn't matter if the car matches the real counterpart on paper if a lot of feeling is missing and it behaves randomly.

Now with the clutch LSD doing whatever it wants it's hard to push some cars in my opinion. It'll just wait for the perfect moment to ruin your day with a violent snap.

I believe the tire model never contributed to these issues as much as the unreliable differential. And who knows if the current tire situation is a temporary measure to make the cars drive correctly. With the known issues of course. It's actually a bit surprising how well the Group A cars turn seeing as their diff is also very much locked 98% of the time.

Yep. The inside tire likes to spin which stabilises the car rather than making it oversteer. And when you lift, rather than turning more (what people are used to with GT3 for example), it'll just want to go straight. I would set up the differential like this if I wanted to maximise confidence for whatever reason.

 

Crimson, did you have a look at Project Cars 1, and compared it to Project Cars 2 / AMS 2? I came across a video a few days ago from someone that seems to prefer the way that cars in pc1 drive (compared to pc2). Maybe this could be diff related, who knows?

 

Tested the Porsche GT1 at Ortona track...
It's more agile than a fVee

I think this kind of tracks tell you a lot about vehicle dynamics and their implementation in game...