I'm starting to notice some odd things with the diff physicsPS4 

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I've posted some other oddities in the bug thread where with some diff changes cars can bounce down the track or even pull wheelies.

Can someone explain what's happening here? It seems/feels like some inconsistent diff physics to me.

Basically this is every single last corner footage I recorded from a race today. 3 times some odd "super turn" happens. The rest is fine. Obviously my corner entry varies a bit but my use of the throttle, steering and revs are the same.



Pay attention to what happens at 1:00 and 2:50.

At the time I thought I might have over-revved the engine and locked the rears but each time I got this problem I have about 1000rpm to spare. So it's not that and besides it *should* do it as I engage the gear not a second or so afterwards.

It's like it suddenly turns too much. Not rear "oversteer" but too much "turn" for the whole car. I get no tyre slip feedback from the FFB - as far my wheel is concerned it's cruising round the corner. It's like the rears dig in and get too much grip and turn the car more than they should. And it's extra weird the way it happens AFTER that car is balanced for the corner. Particularly at 1:00. You can see the car is settled for the corner THEN it over-turns. The only reason I caught it on lap 13 was because I was expecting it to happen by now and caught it visually (and as such almost too late).

edit: I've also noticed there's a slight bounce from the suspension the moment it happens especially at 1:00, but there is no bump on the track here. It's almost as if it happens when the preload kicks in, in between braking and throttle blips. I have it set to 0. I wonder if it's getting a divide-by-zero error?

Diff settings were Preload 0, Power 75, Coast 35, so it's not like the coast diff was too aggressive.

Feel free to say it's a driving error, but please explain it. I suspect it could be a setup error and I won't be setting the preload to 0 anymore. I prefer controlling the attitude in the corner with my right foot but will settle for workarounds because getting this in a race really buggers up your championships.
 
I dunno it kind of looks like the phantom bumps I sometimes feel sometimes I'm quick enough to catch it other times not?. I was starting to think maybe it was some sort of spring/rebound thing so I stopped lowering my tunes as much.
 
Diffs working like always here, PC.

When I use very locked diffs for drifting and powersliding never before have I come across that oddity.

Anyway why are you using locked diffs on an openwheel?, open it widely bro. 75% at the very least. Actually use open acceleration diffs on any racing car with slicks prefereably, and you won't run into that weiird stuff anymore you'll see.

Locked accel. diffs are for rallY; rallycross; drifiting; not hugely powerful road cars, etc. Open wheels and GT?, go open.
 
I find the car isn't great with rear traction especially out if slow corners. I usually run lie a power diff but Dubai is mostly slow corners.

None of my settings are at extreme ends, only the preload. Plenty of damping to use and even ride height is fairly high as it looks like the rear bottoms out on replays although not on the hud.

Just seems random.
 
Open diff is precisely to make you regain traction as fast as posible as you take the corner. Locked is for drifting through understeering.

I'd seriously recommend you open diff for openwheel and learn fighting the problem you describing through better overall setup and taking lines better
 
Open diff is precisely to make you regain traction as fast as posible as you take the corner. Locked is for drifting through understeering.

I'd seriously recommend you open diff for openwheel and learn fighting the problem you describing through better overall setup and taking lines better
But he was a race car driver. Till his mom threw out his trophies.
 
@mattikake I have a honest question for you? have you ever had a good day playing project cars 2? Cause going by all your threads and post it doesn't seem like it.

Yes. As the patches come out I'm having more good days than bad especially by controling the issues - minimal live track, turning off TL's etc. It's about 6 good days in 10. If I can understand around issues it helps improve that ratio.

But what are the options? GTS which isn't realistic enough for me or nor do I like how the online racing works - too arcadey. Or AC which hardly anyone plays.

I'm waiting for AC ultimate edition in the hope it draws more players in.
 
Open diff is precisely to make you regain traction as fast as posible as you take the corner. Locked is for drifting through understeering.

I'd seriously recommend you open diff for openwheel and learn fighting the problem you describing through better overall setup and taking lines better
You have your diff settings mixed up. An open diff is just going to be a one wheel smoke show and you won’t be going anywhere fast. I don’t know of any race cars that use open diffs unless they are forced to by regulations.

I've posted some other oddities in the bug thread where with some diff changes cars can bounce down the track or even pull wheelies.

Can someone explain what's happening here? It seems/feels like some inconsistent diff physics to me.

Basically this is every single last corner footage I recorded from a race today. 3 times some odd "super turn" happens. The rest is fine. Obviously my corner entry varies a bit but my use of the throttle, steering and revs are the same.



Pay attention to what happens at 1:00 and 2:50.

At the time I thought I might have over-revved the engine and locked the rears but each time I got this problem I have about 1000rpm to spare. So it's not that and besides it *should* do it as I engage the gear not a second or so afterwards.

It's like it suddenly turns too much. Not rear "oversteer" but too much "turn" for the whole car. I get no tyre slip feedback from the FFB - as far my wheel is concerned it's cruising round the corner. It's like the rears dig in and get too much grip and turn the car more than they should. And it's extra weird the way it happens AFTER that car is balanced for the corner. Particularly at 1:00. You can see the car is settled for the corner THEN it over-turns. The only reason I caught it on lap 13 was because I was expecting it to happen by now and caught it visually (and as such almost too late).

edit: I've also noticed there's a slight bounce from the suspension the moment it happens especially at 1:00, but there is no bump on the track here. It's almost as if it happens when the preload kicks in, in between braking and throttle blips. I have it set to 0. I wonder if it's getting a divide-by-zero error?

Diff settings were Preload 0, Power 75, Coast 35, so it's not like the coast diff was too aggressive.

Feel free to say it's a driving error, but please explain it. I suspect it could be a setup error and I won't be setting the preload to 0 anymore. I prefer controlling the attitude in the corner with my right foot but will settle for workarounds because getting this in a race really buggers up your championships.

I notice the same things as you described. Specifically when you are pushing hard on entry and brake hard. When you let off the brakes the rear end steps out aggressively. Some of this is definitely expected as you add lateral slip to the car on entry combined with the weight distribution when you are in a hard braking zone. If you decrease the coast ramp or increase the clutches it will help a lot in that situation. In my opinion this is one area where SMS could improve upon.

Corner exit bouncing happens to me as well. Some car are worse than others, the Huracan GT3 is easily the worst offender I’ve driven. I don’t think it’s a diff problem and simple testing could help here. I’ve felt inconsistent feedback from my steering wheel in real life when a wheel is losing and gaining traction quickly, but the car doesn’t bounce.
 
You have your diff settings mixed up. An open diff is just going to be a one wheel smoke show and you won’t be going anywhere fast. I don’t know of any race cars that use open diffs unless they are forced to by regulations.

I've done a lot of test laps and the Lotus 72 (and other cars) seem to benefit from a tight diff that seems to add to exit traction, allowing you to get harder and more stable-ly on the power at the cost of some understeer [car and suspension dependent].

I notice the same things as you described. Specifically when you are pushing hard on entry and brake hard. When you let off the brakes the rear end steps out aggressively. Some of this is definitely expected as you add lateral slip to the car on entry combined with the weight distribution when you are in a hard braking zone. If you decrease the coast ramp or increase the clutches it will help a lot in that situation. In my opinion this is one area where SMS could improve upon.

Yep. I tend to go to max clutches and/or increase front slow bump to compensate. While it seems to behave right and consistently, 1 lap in ... well... 13.. it seems to get it a bit wrong. It's very unexpected (you can hear my surprise in that vid). I rely on that extra bit of turn and it doesn't require any opposite lock, just throttle control, so it's not even close to spinning. But every now and then it seems to go a bit odd and suddenly you need massive opposite lock even just to catch it. What I find strange is way the rear seems to dig in *below* the surface of the track, rather that bounce off the surface of the track.

What I don't get is why it is inconsistent?

I don’t think it’s a diff problem and simple testing could help here. I’ve felt inconsistent feedback from my steering wheel in real life when a wheel is losing and gaining traction quickly, but the car doesn’t bounce.

I'm playing with all settings a hell of a lot, going to extremes on setups and everything that many wouldn't even touch like dampers to toe, but it's only the diff settings that seem to generate odd results, which is naturally why I think something is up with the diff calculations. As said, I have a few vids uploaded where ONLY changing diff settings can get cars to bounce on invisible bumps or even pull full wheelies.

Like this:-

and this:-
 
You have your diff settings mixed up. An open diff is just going to be a one wheel smoke show and you won’t be going anywhere fast. I don’t know of any race cars that use open diffs unless they are forced to by regulations.
So you use a closed diff setting (a tighter angle in pc2, in other words setting the slider more to the left, like 25º, 30-35º etc) for lets say a racing car like a GT3?, well not sure as to who really has the diff setting mixed up. I mean I guess you prefer traction over drifting when you go on a race car with slicks. If you lock accel diff on these cars then oversteer won't certainly make you very fast.
 
So you use a closed diff setting (a tighter angle in pc2, in other words setting the slider more to the left, like 25º, 30-35º etc) for lets say a racing car like a GT3?, well not sure as to who really has the diff setting mixed up. I mean I guess you prefer traction over drifting when you go on a race car with slicks. If you lock accel diff on these cars then oversteer won't certainly make you very fast.
There are many, many settings on the diffs in between locked and open.
 
I tried this car with a fully locked diff at 90deg and it has immense traction and doesn't understeer at all really execept on light throttle.
 
I tried this car with a fully locked diff at 90deg and it has immense traction and doesn't understeer at all really execept on light throttle.
Lower ramp angles are more locking. At 90 you have very little locking. Likewise more clutches is more locking on power and coast.
 
I tried this car with a fully locked diff at 90deg and it has immense traction and doesn't understeer at all really execept on light throttle.

A 90° angle means zero locking...
As ozwheels said, the lower the angle, the higher the diff lock.
 
I tried this car with a fully locked diff at 90deg and it has immense traction and doesn't understeer at all really execept on light throttle.
See?, open diff for openwheels. Same for GT cars, trying to find a balance at around values of 65-70º.
 
Actually I just checked and it's 85deg not 90.

I will openly admit I'm confused and a total noob with diff locking! It's a pretty new thing to me (Karts don't have diffs and road cars I've driven with LSD are fixed by the manufacturer). Mostly I fiddle until the car does what I want.

I go by the description in the game which says "Lower ramp angles ... can improve acceleration out of corners by preventing the inside tyre from spinning, and sending power to the tyre with the most grip instead. Too much locking effect [high value?] can give power understeer in light throttle situations... 90 degrees effectively disables the diff."

Cars appear to behave as described. For e.g. in the 72D here, if I set a lower power diff setting of <45 it loses a lot of rear traction and can be very power oversteery if too much throttle is used, as the outside tyre gets overloaded. Undoubtedly faster if you can balance the power better, but this is of course always harder to do. If I set a high diff power setting of 70 - 85 it has a lot more traction and very little power oversteer, so I can use a lot more throttle, indeed even use 100% throttle. Feathering the throttle mid-corner gives noticeable understeer. If I set it to 90, which to me means effectively a live rear axle, the traction is still good but I can hear and feel the inside wheel spinning up but with no power oversteer effect and tyre temperature is affected accordingly and light throttle mid-corner is considerably understeery.

So my experience seems to be as described by the in-game help. From what you lot are saying it should be the reverse? i.e. a lower power setting is more locked whereas the in-game help and my experience seems to create a less locked diff - the opposite?

Or does "locking the diff" (90deg) NOT mean creating a live rear axle effect?
 
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This is the way i read it, The higher the number the less locking I:E The inside and outside wheel can rotate at higher revolution difference before the locking affect kicks in forcing both wheels to rotate at the same speed. So setting it at 90 deg will disable the locking altogether. setting it 0 deg will be like a locked rear axel forcing both wheels to rotate at the same speed at all times. This will cause rotation problems or wheel spin on the inside wheel


Actually I just checked and it's 85deg not 90.

If I set a high diff power setting of 70 - 85 it has a lot more traction and very little power oversteer, so I can use a lot more throttle, indeed even use 100% throttle. Feathering the throttle mid-corner gives noticeable understeer.

Edit :after re reading the above this could be related to the coast dif setting. Locking the rear axel limiting turn in if it's set to low compared to power diff. (low as in 0-35) try 80 on on-power diff and about 55+ on coast see if that helps

Also the bounce in the rear end? Are you running really low ride hights without bump stops if so could it be you back end hitting the deck?
 
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I go by the description in the game which says "Lower ramp angles ... can improve acceleration out of corners by preventing the inside tyre from spinning, and sending power to the tyre with the most grip instead. Too much locking effect [high value?] can give power understeer in light throttle situations... 90 degrees effectively disables the diff."?

Lower ramp angle means more diff locking, which results in understeering when you're accelerating lightly and in power oversteering when you're accelerating hard.
When you're having no lock, the wheel torque is always the same on both wheels. When the inside wheel gets unloaded through weight shift it can't handle much torque anymore and since the torque distribution is 50:50 the outside wheel can't get more torque than the inside wheel can handle. Therefore you can't put much power down and accelerate slower, but your rear is more stable.

With a high amount of locking (part of) the torque that the inside wheel is losing is transferred to the outside wheel.
This can be a good thing because you can put more power down but the downside is, that the outside wheel can be overloaded quickly by the high amount of torque which will result in snap oversteer.

Cars appear to behave as described. For e.g. in the 72D here, if I set a lower power diff setting of <45 it loses a lot of rear traction and can be very power oversteery if too much throttle is used, as the outside tyre gets overloaded. Undoubtedly faster if you can balance the power better, but this is of course always harder to do...

This is exactly the behavior you'd expect from a highly locked diff. That's also what the ingame tooltip is saying BTW.
 
I see so I do have it backwards. I thought the power would be limited by the outside tyre not the inside tyre - that the inside tyre would spin freely and match the rpm of the outside tyre. But in fact it's the inside tyre's grip level that limits what the outside wheel can do?

So when the game help says "too much locking" it's referring to a low power value not a high value. I often sit there rereading that text trying to visualise what the settings do, give up, then just pick a setting and go for a drive to see what happens!

I guess sms assume everyone has experince of changing diff settings in the real world/other sims and haven't worded it for the average Joe.
 
Also the bounce in the rear end? Are you running really low ride hights without bump stops if so could it be you back end hitting the deck?

Anyway, back OT. The ride heights are plentiful as confirmed by the HUD and replays. Always run with a bit of bump stop. But the thing is, this is a smooth section of track with no bumps and all I changed in the last vid I posted, was the diff settings. I can't see why the car would suddenly encounter bumps that are not present on a different diff setting.
 
haha my bad i did not watch the complete video as i was/am at work using a windows xp antique with no sound. It so **** the video it stutters and will only play in resolutions sub 360p in the web browser sized window. I also dont understand what the on screen hud tells us apart from tyre temp and pressures regards to suspension lol. But unless it happens (the bounce) at the same corner consistently i would call it glitch within the game. because like you i dont think changing the diff would make that happen. To me with no sound and a stuttering video it looked like the back end bottoming out. Lol its p cars maybe its some kind of land landmine glitch like what we had in p cars. I sometimes get a random wheel tugs, its strange its like there is ghost in my house and just decides to do a quick yank on the wheel to one side. It feels like aquaplaning for 1 second and you have to correct it. Again off toppic ill check out the videos properly later and speak in the lobby.
 
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Wow that’s kind of ****ed up. Does it do that on all tracks with that setup or was it pasiffic brno. Becuase it happenes the whole round Brno but at Dubai it was just the last corner? Also noticed that at Dubai it was off throttle when it slid without the aggressive bounce like at Brno. And the bounce at Brno was always on throttle near the top end. Maybe try the same setup at zic or hock as they are nice and flat.
 
I'm convinced it is a glitch related to high locked diff values. I have even seen it jump when accelerating from 0mph from the pit box. It's not extreme but i can tell instantly within 1 second of moving that the setup will have to change.
 
I don’t think it’s a diff problem. It happens for me most often when I accelerate out of slow corners. My theory is the car is sliding a little on exit and the tire sidewall sort of digs into the ground and causes the car to hop across the track like you’re driving through a rut off road. It could be a simple tire model flaw. The high diff locking could just be causing the initial sliding due to power oversteer rather than the diff itself being bugged.
 
I don’t think it’s a diff problem. It happens for me most often when I accelerate out of slow corners. My theory is the car is sliding a little on exit and the tire sidewall sort of digs into the ground and causes the car to hop across the track like you’re driving through a rut off road. It could be a simple tire model flaw. The high diff locking could just be causing the initial sliding due to power oversteer rather than the diff itself being bugged.
It's not necessary a tire model flaw, that kind of grip and tear effect does occur on slick tyres when they are up to temperature, it can also be compounded by damper 'sticktion' which is when dampers don't travel smoothly due to lateral loads being placed on them.

It's an effect that's certainly visible in reality and also occurs in AC.

However extreme levels of diff locking can cause tyres to skip as well, after all a diffs job is to ensure that wheels on a given axle can travel at different speeds, seriously reduce the ability to do that and you will get the two sides working directly against each other.
 
It's not necessary a tire model flaw, that kind of grip and tear effect does occur on slick tyres when they are up to temperature, it can also be compounded by damper 'sticktion' which is when dampers don't travel smoothly due to lateral loads being placed on them.

It's an effect that's certainly visible in reality and also occurs in AC.

However extreme levels of diff locking can cause tyres to skip as well, after all a diffs job is to ensure that wheels on a given axle can travel at different speeds, seriously reduce the ability to do that and you will get the two sides working directly against each other.
What happens in game is far more dramatic and cartoonish than what I would ever call reasonable. At least from what I’ve seen.

To add to what I described, there are some cars that will damn near roll over when you get sideways. As if the highly loaded side of the car is digging in the ground, R8 LMS for example.
 
What happens in game is far more dramatic and cartoonish than what I would ever call reasonable. At least from what I’ve seen.

To add to what I described, there are some cars that will damn near roll over when you get sideways. As if the highly loaded side of the car is digging in the ground, R8 LMS for example.
I've not come across that myself, will have to give the R8 a go again.
 
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