A few questions about the LFS version of the Formula BMW FB02.

1) Pushrod Monodamper Front Suspension
Is the car in LFS a monodamper front suspension? If so, what are the differences between a pushrod monodamper configuration and the more common twin damper layout.
Am I correct in understanding that in a monodamper configuration the anti-roll bar has a much larger effect on body roll? If so how differently does spring stiffness correlate to wheel rate and body roll? Along with the spring, does the damper also affect pitch more so than roll in a monodamper front end?

2) Tires
Which tires in LFS are closest to the FBM's real-life counterparts?

For short races;(R1s are obviously best for a hotlap)Should the car be setup softer to take advantage of R1 grip, or setup in a more overall optimum way using R2s?

3) Setup parameters
Now for the part that most on here will probably disagree with. Why do we have a realistic car model, with unrealistic tire options and setup parameters?

Why have a real car that, after we all get to it, doesn't actually handle like a F BMW? How are we supposed to diagnose problems with LFS's physics if we are first changing setups to unrealistic measures AND THEN complaining about tire wear,handling issues and other problems that arise. Why not make the real cars have realistic setup parameters, while the rest could remain the way they are.

In my opinion realistic setup parmeters have a few extremely large advantages.

#1: Its a real car, with unreal setups...enough said...hardcore simmers or motorsports fans will be turned away when they see the setup options for the car, I know I would be if I wasn't already addicted to LFS's feeling of driver/car connection.
#2: Better racing. Less setup options make it easier to make a setup; more time is spent driving.
(for me it would result in maybe 40% more driving and 40% less time starring at the setup screen and then changing spring stiffness by .5 and 6th gear by .001.)
#3: More fun to drive; realistic tires and setups will venture away from this...."slide once and be warned, slide twice and suffer the consequences" type deal going on. If you've ever seen a F.BMW race in real life they are sliding quite a bit every once and a while, without suffering from near burnt up tires because of a few bad corners. Yes I know, R2s or even R3s are closer to real life, but come on, we all know we will use R1s because the fast guys are...and who wants to give up an advantage!
Also, the setup options, more importantly the differential. IRL they are limited to ramp angles of 60/80 (60 power and 80 coast) This results in a diff. setting of 40% power and 20% coast. The preload is limited to 30Nm. All of this makes the driving and setup more realistic.
#4: More realistic setups will help us help the devs. It will also limit complaining about unrealistic driving styles and setups. We need to have a realistic car AND setup to diagnose unrealistic problems that we will find.

Sorry for the long, 2 part post!

Great post, definitely agree about the restrictions on setups. As you probably know already, I don't have any answers, but a big +1 from me about your comments! When we were racing the other night, I much preferred the feel of my more realistic setup to the quick setup I tried afterwards. I really enjoyed driving with my setup, but we are all sacrificing that in order to get the times that everyone else with the less realistic sets are getting.

Quote from KartRacer :

Also, the setup options, more importantly the differential. IRL they are limited to ramp angles of 60/80 (60 power and 80 coast) This results in a diff. setting of 40% power and 20% coast.

I thought the relationship between ramp angles and locking factors was a simple cosine, so that:

60° = 50% (rather than 40%)
80° = 17.5% (rather than 20%)

???

Yes, the lower the ramp angles, the higher the locking factor. In LFS we set the locking factor directly, NOT the ramp angles.

Also the default setup that comes with the FBM is supposed to be equal to a real FBM setup. I reckon R3-similar tyres are most commonly used in the real thing, considering how it's an entry level formula car that goes through a lot of abuse.

I agree though that the setup is far too adjustable (like for most LFS cars). Seeing how the front antiroll bar works I seriously doubt you'd be able to set it up like we can in LFS.

Yup Bob, I'm not sure on the exact locking percentage, I worded that incorrectly. I meant 40%power in LFS is a 60 ramp angle so on and so forth. The gear ratios in the default setup are more or less what they can actually run. Heres some info that me and [DSR]Delusion figured out using the Formula BMW rulebook;

lb/in.......N/mm

500 87.5
600 105
700 122.5
800 140


800 140
900 157.5
1000 175
1100 192.5

thats actual spring rate, but LFS uses the wheel rate, so;

Front
500 58.5 N/mm
600 70.5 N/mm
700 82 N/mm
800 94 N/mm

Rear
800 66 N/mm
900 74 N/mm
1000 82.5 N/mm
1100 90.5 N/mm

Available Gear Ratios:
1st:
3.167

2nd:
2.2
2.667

3rd-6th:
1.765
1.667
1.529
1.438
1.389
1.334
1.278
1.238
1.211
1.190
1.144
1.105
1.056

Final Ratio:
3.889

Plently of setup options, dampers are not adjustable and it would take a bit more research in order to figure out the ARBs, but I think we would still have plenty of options. Plus, as I've mentioned before we need bump stops and packers, both of which are used in Formula BMW. They also allow two different anti-sqaut options(back rear upper A arm mounting point). Me and Delusion are experimenting with a possible DSR Formula BMW series that uses the actual rule book, we still have a few things to figure out, but the times are only a few tenths off the regular fast LFS sets but they are much more forgiving tire wise and a blast to toss around!

Quote from Bob Smith :

I thought the relationship between ramp angles and locking factors was a simple cosine, so that:

60° = 50% (rather than 40%)
80° = 17.5% (rather than 20%)

???

I think it'd be tangent, for using a ramp to scale force in one direction to another:

(locking %) = A * 1/tan(ramp angle) = A * cot(ramp angle)

where A is a constant determined by ramp placement and friction coefficients of the clutch pack.

Friction having an impact might make more sense, although a tan function will let you go past 100% lock with low ramp angles. I don't totally believe the formula I found either, though. It was just mentioned in some document I found while googling just the other week, and doesn't tie up with the values posted by KartRacer either.

Quote from Bob Smith :

Friction having an impact might make more sense, although a tan function will let you go past 100% lock with low ramp angles. I don't totally believe the formula I found either, though. It was just mentioned in some document I found while googling just the other week, and doesn't tie up with the values posted by KartRacer either.

You acutally can get higher than 100% force scaling out of a ramp, like how you can get higher than 100% of input torque out of a gear ratio. Ever see people splitting big rocks? Just insert a wedge into a crack and hammer that wedge (like a ramp anyway), and the hammering force gets amplified beyond 100%, proportional to cot(wedge angle), too.

So the outside wheel could get 130% of the engine torque while the inside wheel is given -30%?

Quote from Bob Smith :

So the outside wheel could get 130% of the engine torque while the inside wheel is given -30%?

First, the outside is likely spinning faster than the inside, so the torque to the outside should be lower than the torque to the inside. LSD's, whichever kind, always takes torque from the faster side to feed the slower side.

Second, I'd say "the torque at the outside wheel is reduced by the amount (30% of engine torque + preload), while the torque at the inside wheel is increased by the same amount." This is on top of the 50:50 split of engine torque by the (open) diff.

Well, yes, if you are cornering and then apply throttle, the outside wheel will be turning faster to turn a larger radius, but once the grip of the inner tyre is reached, it will begin to spin, so the outer wheel will then get the majority of the torque until the inner wheel stops spinning. So, depending on the situation, either wheel could get the majority of the torque, and that's before bumps are taken into account.

I thought the pre-load only acted as a minimum torque difference, so shouldn't have any effect most of the time (assuming low pre-load anyway).

Gah, another thread been has taken over trying to understand diffs.

Open diffs don't split the torque 50:50

Quote from Bob Smith :

Well, yes, if you are cornering and then apply throttle, the outside wheel will be turning faster to turn a larger radius, but once the grip of the inner tyre is reached, it will begin to spin, so the outer wheel will then get the majority of the torque until the inner wheel stops spinning. So, depending on the situation, either wheel could get the majority of the torque, and that's before bumps are taken into account.

I thought the pre-load only acted as a minimum torque difference, so shouldn't have any effect most of the time (assuming low pre-load anyway).

Gah, another thread been has taken over trying to understand diffs.

I guess you're right about inside wheel spinning!

Isn't the preload the force "pre-loaded" onto the clutch pack before engine torque gets loaded through the ramp? So preload makes sure there's still some locking when you're at neutral throttle or when you clutch. Low preload gets drowned by the ramp, perhaps, but still the force on the clutch pack should resemble (locking*torque+preload).

Sorry for the hijack... Is it possible to pull this into a new thread?

To tristancliffe:
Yes they do.
http://auto.howstuffworks.com/differential3.htm

Quote from tristancliffe :

Open diffs don't split the torque 50:50

Unless you're referring to a technicality, I thought they do?
50:50 distribution, as in both wheels always get the same torque (besides the differences due to friction in the differential).

Well, yes, put like that I suppose they do. But the real world effect is that one wheel spins (zero torque) so the other gets zero...

I'm getting out of diff talk now, whilst I can still see!!!

Found some info on the shock absorbers in case you didn't find it already

http://www.sachsracing.com/owx_medien/media360/36043.pdf

From page 3 it seems the RD45-2 are used in the FB02

Pages 14-15 show the settings (Nr.6 front, Nr.4 rear from the regulations). don't know how that translates into lfs setups though...especially with the monodamper up front

ARB stuff is hard to find but I checked out how it works in front-->

http://www.f1technical.net/forum/viewtopic.php?t=2911

Definately should create some sort of "realistic setups" FBM server where setup limitations would be applicable (based on trust for the moment i guess)

edit : additional info on monodamper
http://forums.autosport.com/sh ... php?s=&threadid=15596

i like the idea of a real setup server, i would really like it if the setup options in lfs would have different setup ranges for different car that correspond to real life setup ranges.

hey guys, any of you have a good set for FBM in Blackwood Rev? Mi normal BLackwood is not working fine.
thanks !

I'm beginning to doubt that the mono-damper is correctly simulated in LFS, if this is true, the the info we've found on springs/shocks...means ...a lot less than I thought.
Reasons:
1)Two shock/damper damage bars in F10 screen
(unless its simulating push-rod damage, or damage to the rod-ends on the lower wishbone and its mounting point, or the rod-ends mounted to the bell crank, which I doubt all of those)
2)Pull up on a curb, a ramp or banking with only one front tire...the front behaves very independently.
3)A zero setting for front ARB? Which ever unit they are using...you shouldn't ever be able to have a setting of "0" on a mono-damper configuration unless one wheel is completely disconnected. (which again, it doesn't behave like that, both corners still are dampened when you drive with 0 front ARB)

If this is all true and we have a car without a mono-damper front end...I'm not sure what kinda of car we have.
-unrealistic setups and settings
-tire selection, not to mention possible unrealistic characteristics/behavior for even the closest compound corresponding to its r/l compound
Its a Formula BMW graphically only then...

-slightly unrelated question....
Why wouldn't spring stiffness spring height/height and ride height effect weight distribution? AT All? Or is the % in the info setup screen only calculated from the default setup?

Small rant/question post, sorry about that!

Quote from JasonL220 :

i like the idea of a real setup server, i would really like it if the setup options in lfs would have different setup ranges for different car that correspond to real life setup ranges.

Quote from PhilS13 :

Definately should create some sort of "realistic setups" FBM server where setup limitations would be applicable (based on trust for the moment i guess)

Look for the [DSR]DarkSideRacing S2 server, we are on quite frequently using setups from our "Spec-FBM" series. The series uses realistic options(as close as me and Delusion could get, from the series rulebook and the best we could guess on stuff that wasn't in the rulebook, in a couple days)
Check out our forum for more info!
http://www.darksideracing.net/forum/viewforum.php?f=22

-Hopefully the dev's will realize enough people are interested in realistic options for setups and will soon offer a "button" in the options menu to turn on/off realistic parameters and that could also be made a server-side option. Its the only way to keep everybody happy here. Every time I've posted about realistic setup options I get nailed with excuses, about how they like it,its what LFS is all about, its what makes it unique or that it is realistic...so on and so forth...so I stopped arguing for that! Anyways, the setups for the series are great fun to drive, make for even closer racing and are a bit more exciting and forgiving on the track! See you online!

not trying to get into the discussion on diffs... i think my head would explode.
:ouch:


however, i would like to comment on the idea of realistic setups.

i think its a great idea to have realistic setups built into lfs.
but instead of having the devs limit the options, i would like to see done somewhat like this:
instead of having [hard track] and [rallycross] be the default sets and non-changable, we should have them implement a few realistic setups as the default and un changable setups.
this would mean, for the non-gtr and formula cars, there would be setups imitating a completely stock street driven car
then there would be the upgraded, "level one track-day" car, with stiffer shocks, shorter springs and sticky-er tires.
then there would be the
"level two track-day" car with thicker arb's, racing spec springs and dampers, better brakes, ect...
level three would be completely adjustable, as it is now, and we wouldnt have to be limited in any way.

for the gtr and formula cars, (including the RAC imo) the setups default setups would acurately reflect the rules regarding suspension setups.

this is just my opinion.

i really enjoy maxing out a cars suspension for the specific track, but i would also like to see realistic options in place