Hi guys, hoping for some responses from experienced people who're good with setups and technical know-how here
So, I'm working on an fxo setup, and basically what i'm doing is doing a lap, then watching the replay, observing the forces on the car and tyre heat/how much is actually on the surface of the road etc.
What I notice is.. around the sharper corners, the front inside tyre (closest tyre to the corner) is spinning and leaving a nice skid line behind it.
Observing the forces I think it's safe to conclude that this tyre has no-weight on it around the corner and infact it might even be being slightly lifted at points which would be an obvious cause of the skidding.
My question is.. Is there a way to prevent it from skidding? I tried adding lots of anti-roll to the front and stiffening it up in the hopes this would help keep it firmly on the ground so that the car wouldn't 'tip' but this didn't make much of a difference I still see skidmarks and the weight still very much goes to the outside of the car..
The FXO eats up the front tyres a lot lol, maybe change the spring stiffness - softer/harder. Otherwise I can't really help you out with that, maybe get a race setup and have a look at if it has the same problem? If not then compare the settings?
Maybe try and take the corner with less acceleration or steering?
I have no experience with FWD setups, but you can try to add more locking to the diff, and even try a fully locked diff. But it might cause power-understeer if you are too hard on the throttle.
With a FWD car you're not going to get away from that entirely. Weight transfer is happening on two axes away from that tire - towards the outside of the corner, and since you're trying to accelerate, you're also transferring weight to the rear... so that tire has everything against it and you can't do much about that.
As has been said, the only real solution is to play with the differential settings but all you can do is find a balance between power understeer and inside wheelspin. the way LFS tires are working right now (well, have been for the last number of years but that's not the point I suppose) is that you're better off with a high locking or locked diff, and messing with the rest of the suspension to make that work since unlike real life it will help to "pull" the car around the corner.
Agreed with the posts above about increasing "on power" differential locking, but also increasing front ARB will increase the load on the outside tyre and decrease the load on the inner one, worsening the problem. A lower front ARB / stiffer rear ARB should help.
@rocklan, I wouldn't say it's "wheelspin" you are experiencing since most people attribute that to on throttle conditions only. But off throttle oversteer can be fixed in many ways in the F1, including increasing the engine braking reduction, increasing differential preload and coast locking. Obviously moving brake bias forward can help too. :P
What I think is: A stiffer differential should help but it would affect driving properties. Its all about compromises.
BTW: If your inner wheel is under very low force there wont be so much energy transfered into heat. Depends on situations but in some occasions the very low slip of inner tire may be still transferring less heat to tire than no slip at outer tire.
Hello fellow racer! Do a search for VHPA (the main host site is linked from lfs forum). This great tool will help take away the guesswork of staring at the forces screen in LFS.
Try these steps, install VHPA (in preferences make sure to find and select LFS cars as default) and open your FXO set. In the "live settings" screen (live settings is in a drop down with vehicle data and vehicle settings) adjust the vehicle speed, throttle and steer angle to imitate the situation you are talking about. start with maybe 60 km/h, 70% throttle and 0.1 rad left steering. in the bottom half of the app, select springs view and play with the live settings until you see the force on the left front tire is around zero.
now change from "live settings" to "vehicle settings" and go to the suspension tab. If you add front ARB you will see the data in the bottom shows even more force on the front right. if you lower the front ARB you should see some weight come onto the front left. (inside)
note as other more experienced ppl have said here, setting up is all about compromise. as a noob I would suggest you have a look at the ratios of pitch and roll stiffness which you can also find in the springs screen and try to change where the suspension resists roll so there is less at the front without changing the overall roll stiffness.
lastly, to really do the job right, look into exporting RAF data and loading that into VHPA. once you know the cornering force needed for the application you're designing the set for, you can get a good spring rate from the moment arm calculation. (VHPA also provides accurate center of gravity data)
would be the maximum vertical load of outside tires and the g forces at that moment. the live settings ability of VHPA is great, but it must be using an ideal flat corner representation for its calculation, so I would go with the raw data from lfs to account for the dynamic environment. road bumps, valleys, curbs and whatnot might factor in?
Interesting point. I'll make note to allow forced extra body roll and lateral acceleration from transients for the next update. Sounds like it could well be useful.
Well, it depends much from kind of track which you go.
Arbs are one of main things which can fix your problem of slipping front inside tyre.
They got two functions:
1. overall car ballance setting (oversteer/understeer)
2. force transfering from outside wheel to the inside when cornering
For example: westhill tracks (and overally tracks where you have most of fast corners) car likes bigger arbs (wr fxo we1 have 60/120 arb) but on medium or slow cornering speeds tracks likes them less ( f.ex.fe2 15/25 arb).
Now what my point is: bigger speeds in corners, then bigger the arbs should be because if faster you go then force transfer on outside tyre is bigger.
If you take my example arbs from fe2 you may think they are small but you should think about them in the way - small but highest needed for current corners. Because too much arb is a bad thing too so you have to make them good for overall track corners. Slow corners dont make that much mass/force transfer so they no need to be soo high.
Also you can see something kinda like they have 3rd function:
Less arb you have then car is more "nervous" and it turns quicker into a turn on entry (its more responsive).
another part its cambers and pressuress and it also depends from track you are currently hotlapping.
about a tyres:
high pressures: car is more slippery but you get little more top speed on it and your tyres overheats slower
low pressures: car have more grip and is slower on straights a little and your tyres overheats faster
for a hotlapping: they have to be warm all the time but i can give you a tip: after a hotlap they should be overheated or almost overheated after last turn or after your hotlap (not sure but for fxo highest temp should be around 75-78 degrees after end of lap)
Cambers:
for fxo i see ppl like to set them highest as possible for getting some speed and around medium possible by lfs degree in fronts for a compromise between speed and grip (ofc. lower camber = more grip but as it was with arbs, not too low) and overally for very fast tracks on hotlaps for tbo class cars people setting cambers for highest as possible.
Typical for all cars it to set all four wheels in negative for tracks where you have f.ex 5 left and 5 right turns
There is a way of setting them for better grip like positive cambers on left wheels and negative for right wheels
This works well for tracks which have only turns in left side, like ovals or South city 2 or you can set them opposite (negative left positive right) for FE1
and finally final drive and gears setting:
Its all about best acceleration without wheelspin.
its a turbo car so it gets full horsepower when turbo is fully loaded and there is a tip for slow corners like you can set the gears and do the corners without turbo or with half loaded turbo (then you have less bhp and you can use your turbo kinda like a differential and its quite popular way of make it in tbo and gtr turbo cars) and because of that you can set your wheels differential fully locked.
And here you have to gain your own experience about which rpm's are correct for slow corner, which for medium speed, and which for very fast corners (160-180km/h).
For example: turns around 80km/h you can set your gears longer to make apex at half turbo power and getting full turbo power when you exit from that turn.
thats some things from me which i hope help you with that, have fun with trying
You can make it just by making a little bit longer gears (mainly that which was used for slow turns) and when you make them longer then your turbo works slower. Cars from lfs dont have something like a compressor which works as fast as engine when hitting a throttle.
this is used mainly at 2nd (sometimes 3rd) gear turns, higher gears have to work normally. Ofc. its a compromise between turbo power and how fast/short your gears should be.
A differential lets two wheels spin at different speeds while being driven. How does having longer gear ratios accomplish that? Also, the way I have the gearing set up in the FXO I seemed to have been hitting higher speeds than someone in an LX6 and everyone else in TBOs at blackwood (sans chicane) on some Cargame.nl server I think. And I believe i was hitting the rev limiter. So, i really don't think having really long gear ratios will accomplish much good, but if it works for you then keep doing what works for you,
Nah, you take it wrong and also i've written it with a mistake by saying its little like diff - thanks to Morgan for correcting me, its more like traction control where you are controling your bhp in current moment.
You dont have to make ultra long gear ratios, thats also a stupidity.
I it works in this way: you can see your Turbo after hitting accelerate pedal is not fully loaded to that 0.8bar its in 0.4 or little more for some time on the beggining,
and when your turbo its not fully loaded you dont have full fxo power (234hp)
on this time you have hm... for example 160-180hp which not overloads your drive wheels as much as 234hp. How much power you put on your wheel gives you advantage in slow turns like turn 1 of BL1 when you're going around 80-90km/h (if slower you go and more power and nm you put then its easier for making drive wheels spin which you dont want because your car bahaves bad and you loosing a time on it) but rest of BL1 track is faster than that turn 1 so you no need to reducing your horsepower that much as it was on slow T1 and your gears can work normally. Making things like that also needs some experience which rpm's are correct for exact turn with current car.
And probably you may not know it but most of sets you get from setupgrid or some other players online already uses this technique in better or worse way
