rec.autos.simulators

Would it be possible to move the tire screeching sound to just before the wheels lock
under braking instead of just after?

--

Mark Jeangerard

Administrator
GPVL F2 Division
http://www.racesimcentral.net/~m.jeangerard/GPVLF2

*************
Q -- > Would it be possible to move the tire screeching sound to just before
the wheels lock                 under braking instead of just after?

You actually do get the tire screeching sound before the tires lock,
it starts as soon as the tires start to skid. In a braking situation
this means your car is travelling at say 120mph, whereas the tires
are travelling at say 90mph.

This is actually beneficial as a tire that is sliding has more grip
than a tire that is not UP TO A CERTAIN DEGREE.

It's the same principle as cornering, a tire which is exhibiting
a moderate amount of squeal is actually gripping better than
a silent tire.

As far as braking is concerned then the trick is to tread
this very fine line between ZERO screech and LOCKUP.

Often times you may think you have locked up, because
you hear the screech, but in fact you have been braking
perfectly. Unless you run 50% or less Brake Balance you
will rarely if ever lock the rears before the fronts, so if
the front wheels are still moving adn you are getting
screech, it's GOOD screech.

Maxx

PS. There are som Higher Volume screech sounds out
there (skid.wav) which might help you pick this up earlier.

You might get some good headphones (Sennheiser HD600's are amazing). I
probably look ridiculous, but I hear a lot more with the headphones than
with desktop speakers.

--Jeff

I'm having a completely different experience than you are. Bearing in mind that I am well
versed in all the principals you state in your message, my interpretation of the braking
sound in GPL is that once it's heard, braking is no longer efficient. I have done
extensive testing with the engine sound removed and the car definitely slows faster just
before the tire sound starts, in my game. I use fairly standard setups with a brake bias
of 53 to 56 typically. The only problem is that it is so hard to memorize the pedal
position then when in the heat of battle it's always over or under but never on. As a
result I have taken to the habit of locking then releasing which is just as inefficient,
but more consistent than the other way. I'm just not "feeling" it.

Anyone else see it my way, or am I completely mistaken?

--

Mark Jeangerard

Administrator
GPVL F2 Division
http://home.att.net/~m.jeangerard/GPVLF2

Last night in a race at Kyalami I nailed T1 a couple of times... when this
happens there is slight, intermittent squealing under the straight line
braking. Then, as I begin to turn in and trail off the brakes the pitch
rises as the inside front starts being unloaded and the wheel
locks-rolls-locks.. etc. in quick succession. I haven't checked all players,
but of the laps I compared to mine (to see where they were quicker still...
gotta keep learning ;-)) I was the quicker in the 1st sector (which ends
just after T1). Now if could trail into the Esses effectively (i.e. without
the car swapping ends on me) I'd be looking at a 1m21s.<g>

Jan./set a new PB, didn't make any big mistakes and still lost 50 seconds
over an int long distance... damn.
=---

--

Mark Jeangerard

Administrator
GPVL F2 Division
http://home.att.net/~m.jeangerard/GPVLF2

<snip>

Maxx

If you look at the longitudinal force vs slip ratio curve when braking,
it starts linearly at close to 0, reaches a maximum at a certain slip
ratio, and then slowly drops off to a slightly lower value after the
maximum is reached until the wheel is locked.

When you are braking optimally, you are keeping your wheels spinning at
just this maximum of the longitudinal force curve. The moment you apply
more brakes than the wheels can take, they start rotating slightly
slower, thus reducing the longitudinal force as the area past the
maximum is entered. This reduction in force means that the wheel will
start to slow down even faster if the brake pedal is kept constant, and
the wheel will soon lock unless the brake pressure is modulated.

The result of the above discussion is, with a constant application of
brake, it's impossible to apply too much braking force to go past the
optimum without actually locking the wheels in a short while after. If
you apply a constant brake pressure and still see the wheels rotating
after a while (e.g. during a long braking), you can be sure you haven't
gone over the limit. Since the screeching sound is still present in this
case in GPL, this shows that indeed it sets in just before the limit is
reached.

-Gregor

Watching replays of top drivers there is a noticeable lack of squeal in straight line
braking and low to moderate in the turn.

Just one of the things that separates the best from the rest of us. :-T

Marty

The reason I asked the question is because, for the past three years, I've been under the
strong impression that braking in GPL was nothing more than a ***shoot and I was
concerned that Asgeir and Natas would soon develop an unfair advantage in the leagues by
being the only ones to positively know the braking limit on a corner by corner basis. My
firm belief was fostered by a string of unfortunate circumstances and incorrect
observations. As a result, I had not utilized the braking capabilities in GPL until last
night for the first time.

Imagine that. This whole time I've never braked at the limit. It started with a really bad
swerving problem. Whenever I braked at the limit the car would lurch to one side or the
other. (No! It was not brake bias! It was not sliding at the rear! I'm tired of hearing
that. Like I'm too stupid to figure that out over three years.) The front of the car would
dive off the track and no amount of steering input or brake releasing would bring it back.
Sort of like a broken rotor. As you may imagine, going off every three laps was
discouraging at best, and I was needy of a fix. I tested without an engine sound and found
that the car was most effective without going off the track just before the skid sound
came in. So, before maximum braking power. Made sense considering my problem. I was under
the impression that everyone else had the same swerving problem from the posts I'd read
and attributed their shorter braking distances online to latency. I thought you only
appeared to be braking 4 cars lengths later at the hairpin because of the 400 ms delay.

About a year ago the swerving problem went away. I still have no idea what it was and the
list of things I tried is longer than this post and part of it is as obscure as my
appendix. I continued on, believing that I was braking as efficiently as GPL would allow.
My tests had shown that. Last night I repeated the test and came to the same conclusion
but with different results in my driving style. Yes, GPL does seem to brake as well just
before the skid sound, but I mean *just* before. So, if one is trying to avoid the skid
sound, the window of success is terribly small. Thus, it's a ***shoot. I was right. In
the manner I was braking, and thought everyone else was as well, it was pretty much a
matter of chance that the car ever slowed down and I had to leave a lot of room that was
totally unnecessary. Now I am comfortably in the skidding sound and the whole game has
changed for me. Knowing that I am braking at the limit has made the problems of latency,
sense of speed, and perspective much less critical and I think I found the #1 reason I
kept getting my attention shifted to the foreground. I was constantly trying to gauge my
braking progress by deceleration of the road and verges. Now I am looking properly ahead
and I did my first 28 at Monza in the Ferrari during my no sound tests last night.

Not only is the experience of driving GPL no longer dreadful. It's kinda fun.

--

Mark Jeangerard

Administrator
GPVL F2 Division
http://www.racesimcentral.net/~m.jeangerard/GPVLF2

--

Mark Jeangerard

I know that with my TSW when I switched to a certain set of pots with
particular resistances (I forget what), fully depressing the accelerator
would cause a small amount of brake to come on.

If you got interference between the brake and the steering, that would
certainly cause you to lose control - you need to be braking in a straight
line while you have the brakes full on.

JensSchumi

On Mon, 11 Jun 2001 15:14:55 -0600, "mark jeangerard"

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Monsters of GPL: sub 200