rec.autos.simulators

   I have always used as soft as possible springs in GPL since most
setup sites I visit say it gives better grip and faster laptimes.In
real life softer springs give better grip because they allow the tires
to follow the road instead of bouncing over the surface.

Since GPL doesnt model high frequency bumps I always thought that
Papyrus made an unrealistic attempt at the spring setting in that
softer springs gave more grip and the harder one makes the springs the
less grip the sim allows.

  So for a kick I took all of Allison's Brabham setups and raised the
spring rates so that they  were 290F and 400R.Thats a total spring
rate of.......1380lbs.I figured that the car would have no grip at all
but to my suprise I was just as fast and had a much easier time racing
the car.Same exact amount of grip as before but now the chassis was
super stiff and it felt real solid.The car doesnt wander all over the
place under braking and takeoff from the start line is ridiculusly
easy.I can start about 4 rows behind and just gun it and make it past
the other cars before the first turn.Im guessing that papyrus didnt
use an unrealistic way to give less grip as the spring rates go up.So
since theres no high frequency bumps modeled Im gonna use as stiff as
possible setups from now on.

 One thing though is that with these setups the jumps at the Ring are
impossible because when you land you just bounce back up again and
ususally in an unstable direction.

    Skeeter, guess what, you just found the biggest physics bug in all
Papyrus sims! The have modelled springs incorrectly from Day 1!
Look for it in N4 as well!

    Pete

  Stiff springs at all four corners should give less grip?  I don't believe
this is true.  Only if you're comparing the stiffness of one end of the car to
the other, or one wheel compared to the others.  When a car turns and reaches a
steady state cornering balance, you should observe the same weight transfer
from one side to the other regardless of spring rates.  It's mostly in the
transitional state, right when you first turn the wheel or change
throttle/braking inputs (or the vehicle isn't really "set" into a turn or nose
down/up attitude yet) that you'll notice grip and handling changes.
 Of course, if you stiffen one spring more than the others, you'll effectively
get more weight transfer at that particular wheel (if the car rolls 2 degrees,
and the spring compresses 1 inch, the spring rate is what downforce will be
added at that wheel), but we're talking balance here.  Taking ALL springs and
doubling their rates should result in a more twitchy car to drive (with
hi-frequency bumps as you mentioned, this  would reduce grip as you said), but
the steady state weight transfer and grip should be the same (once the car has
"set" into the turn).  Weight would just transfer more quickly and with less
body roll.  Remember to adjust camber after a body roll change like this.  I
wouldn't, however, say Papyrus modelled the weight transfer or spring activity
inaccurately from your findings.  
  Anybody agree/disagree?
Todd
http://PerformanceSimulations.com    

  I understand that stiffer springs will not alter the amount of
weight that is transfered during cornering and I agree completely that
since these bumps arent modeled there should be no loss in grip.

I have read that in real life stiffer springs will give less grip(on
the same surface)due to the fact that the tires will bounce across the
surface rather then follow it.

  I feel papyrus has modeled the springs correctly because of the fact
that running super stiff springs(1380 lbs) causes no loss in grip.What
I mean is that if Papyrus went and unrealistically deducted grip as
spring rates went up(to simulate the less grip at higher spring
settings)I would of slid off at each and every turn,but I didnt since
loss of grip from stiffer springs has to do with the high frequency
bumps.Now if Papyrus had implemented high frequency bumps and I raised
my springs to the super high settings that I did,at high speeds the
car would just skip across the surface and Id have no grip at all!

 I think its great that people with lots of knowledge such as yourself
and Doug Miliken frequent this newsgruop and talk about vehicle
dynamics as this goes to show me that GPL is very close to simulating
real life vehicle dynamics.Im pretty sure you guys wouldnt be here if
we were posting about about a racing sim with unrealistic physics.Goes
to show how good Papy sims are getting:)
Later