rFactor simulation oddity?

[NJH]

Guys, sorry if this has been asked before but is there a bit of an oddity in rFactor where the corner exit traction seems too low?

The reason why I ask is that I have been using the Kodi A-type rwd car to try and emulate my real race car. Even though its heavier and has less torque than my real car it seems to have nowhere near the traction, even though I reckon the grip with sports tyres, braking and corner speeds are fairly close to reality (perhaps a tiny bit lower but I haven't modified the car yet to be as close as possible to my real car).

Otherwise after a week on it I am now banned by the wife as my right foot hurts like hell from pushing on the brake pedal, and I have a nice sim racers limp as a result .

[DAVID PATERSON]

Are you spinning both drive wheels or just the one? Have you tried adjusting the diff lock?

[ptclaus98]

Originally Posted by DAVID PATERSON

Are you spinning both drive wheels or just the one? Have you tried adjusting the diff lock?

Can you go in depth on that? I've never figured out exactly what the diff settings do.

[NJH]

Not got enough points yet to mod the car like that, it shows up as 10% both ways on the diff which I guess is pretty much like an open diff which is what my real world 944 S2 has anyway. Its basically the Kodi A type bog standard spec but with sports tyres added.

Its not necessarily a bad thing as you have to be smooth and progressive on the throttle which is a good thing to learn, its just that something I learned very quickly with my real car is you can be very aggressive with the throttle, perhaps only a tiny fraction of a second between balanced throttle and full throttle. Maybe its a trait of my car as they are well known to grip better when the back end squats down on power than in any other situation.

The tight right hander before the grid (luffield 2?) at Silverstone is where I really notice the difference. On the game the car manages about 52 to 55 mph or so as you try to get round, feels very much like real life, once you go over the patch of tarmac to the apex and can see the corner open up you get on the throttle, again very much like reality. The difference is in my real car I can get to full throttle very very quickly and keep it planted, the car will drift out but only just up to the kerbing on the outside of the corner. In the game there you have to feed the throttle in slowly and even then the car will drift out right over the kerb.

Anyways I am going 4 seconds faster than I managed in reality in a car which on paper should be much slower than my real car so I really do hope rFactor is as real as possible and what I see is just my imagination .

[NJH]

Sorry I should have elaborated right at the start, its not so much traction as just grip on the corner exits as the car seems to slide far to easily compared to braking, corner entry and what look like very realistic apex speeds.

[NJH]

Embarrasing this . I tried driving a bit more within the envelope to try and replicate exactly my real world effort on the same track. Hey presto hardly any sliding on exits and much lower speeds everywhere, which is good in some respects. The conundrum now though is the game says these tyres give 1.2g but the car has nothing like the grip of my real car on Dunlop DZO3's, or for that matter the straight line grunt which is surprising. Clearly some work required on my part to get the sim car more like my real one.

Noob stuff no doubt part of the learning process.

As you were and all that .

[Alex Hodgkinson]

Two words - Weight Transfer.

If the suspension files are way out you'll have little weight transfer and therefore trouble getting into and out of the turns.

Easy to diagnose, hard to rectify.

Good luck!

[Spudgun]

I haven't got involved in any modding, but I have read some articles in the past that talk about the way tyre contact patches are modelled in sims. In the real world the contact patch would be pushed backwards during accleration and forwards under braking but this isn't in a lot of sims. This has the effect of making cars more unforgiving than their real world counterparts, particularly under hard acceleration.

That's only what I have come across in research and perhaps there is someone better qualified than me to clarify!

[Alex Hodgkinson]

If the person who's working on the physics knows what they're doing, the phenomena you mention can be simulated in rFactor.

Open up an rFactor tyre file (.tbc extension) and look for a line with the text PneumaticTrail=.

That line denotes in decimals of a metre the longitudinal measurement between the contact patch of the tyre and the tyre's centreline. Reference data for this value is pretty much non-existant unless you have a source of tyre manufacturer data, so it can only really be programmed on 'feel.'

However on a real tyre, the contact patch moves in the opposite way you say, seeing as contact patch movement is an opposite reaction to acceleration and deceleration. ie. under acceleration it will move forwards and under braking it will move backwards.

I would also add that as the value is a fixed number I would presume that it's not used in a dynamic way in-game.

[NJH]

Interesting comments guys, and something I have definitely noted is how long it takes for the tyres to bite back. I wouldn't say my real car is more forgiving as it reacts very quickly, but equally a quick bit of throttle modulation is often all that is required and to me it feels like full grip comes back almost immediately. The result of this difference is that on rFactor that Kodi ZR A spec thing takes up more track to recover from a slide and throttle modulation doesn't seem to recover a twitch from the back end quite as easily or immediately as in real life.

However when I get the car on track this year if everything I have tried and learned in rFactor makes me that much faster then its paid for itself many times over.

[Spudgun]

Originally Posted by Alex Hodgkinson

If the person who's working on the physics knows what they're doing, the phenomena you mention can be simulated in rFactor.

Open up an rFactor tyre file (.tbc extension) and look for a line with the text PneumaticTrail=.

That line denotes in decimals of a metre the longitudinal measurement between the contact patch of the tyre and the tyre's centreline. Reference data for this value is pretty much non-existant unless you have a source of tyre manufacturer data, so it can only really be programmed on 'feel.'

However on a real tyre, the contact patch moves in the opposite way you say, seeing as contact patch movement is an opposite reaction to acceleration and deceleration. ie. under acceleration it will move forwards and under braking it will move backwards.

I would also add that as the value is a fixed number I would presume that it's not used in a dynamic way in-game.

Thanks for the insight, that's good stuff. IIRC this subject was raised about one of the F1 mods where the car was more nervous than it would otherwise be because of it.

As for getting it the wrong way round, my excuse is it's been a long day!