GPL Programming Question

To any of you who can affect changes in GPL: Would it be possible to move the tire screeching sound to just before the wheels lock under braking instead of just after? -- Mark Jeangerard [email hidden] Administrator GPVL F2 Division http://home.att.net/~m.jeangerard/GPVLF2

How can anyone tell the wheels gone lock , before you brake hard enogh ? Stefan Zscharnack ************* Q -- > Would it be possible to move the tire screeching sound to just before the wheels lock under braking instead of just after?

On Fri, 8 Jun 2001 01:17:38 -0600, "mark jeangerard" <[email hidden]> wrote: >To any of you who can affect changes in GPL: > >Would it be possible to move the tire screeching sound to just before the wheels lock >under braking instead of just after? Mark, 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.

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> 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

Thanks Maxx 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 [email hidden] Administrator GPVL F2 Division http://home.att.net/~m.jeangerard/GPVLF2 "Maxx" <[email hidden]> wrote in message news:[email hidden]... > On Fri, 8 Jun 2001 01:17:38 -0600, "mark jeangerard" > <[email hidden]> wrote: > > >To any of you who can affect changes in GPL: > > > >Would it be possible to move the tire screeching sound to just before the wheels lock > >under braking instead of just after? > > Mark, > > 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. > >

Wouldn't say that Mark, and I haven't really tested this, but in my experience it stops better with slight tyre squeal as well. 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 wrote...

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> Thanks Maxx > > 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 > [email hidden] > Administrator > GPVL F2 Division > http://home.att.net/~m.jeangerard/GPVLF2

Hmm... need more testing... will be back... -- Mark Jeangerard [email hidden] Administrator GPVL F2 Division http://home.att.net/~m.jeangerard/GPVLF2 "Jan Verschueren" <[email hidden]> wrote in message news:[email hidden]... > Wouldn't say that Mark, and I haven't really tested this, but in my > experience it stops better with slight tyre squeal as well. <snip>

On Mon, 11 Jun 2001 15:14:55 -0600, "mark jeangerard" <[email hidden]> wrote:

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>Thanks Maxx > >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?

I was just going by what the situation is in real-life, I've never tested it in GPL. I look forward to reading the results of your tests, Maxx

It can be shown that indeed the sound occurs before the maximum force is achieved in GPL. The reason is, it's possible to maintain the squeal and not lock the wheels when braking there. 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 mark jeangerard wrote:

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> > Thanks Maxx > > 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 > [email hidden] > Administrator > GPVL F2 Division > http://home.att.net/~m.jeangerard/GPVLF2 >

Well... there's one question answered, and I hope you find this story as amusing as I do: 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 crap 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 crap 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 [email hidden] Administrator GPVL F2 Division http://home.att.net/~m.jeangerard/GPVLF2 "Jan Verschueren" <[email hidden]> wrote in message news:[email hidden]... > Wouldn't say that Mark, and I haven't really tested this, but in my > experience it stops better with slight tyre squeal as well. > > 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.

But you were right any way. :-) -- Mark Jeangerard "Maxx" <[email hidden]> wrote in message news:[email hidden]... > I was just going by what the situation is in real-life, I've never > tested it in GPL. I look forward to reading the results of your > tests, > > Maxx >

I think I know what Mark is saying. It seems max braking force is generated just before audible tire squeal. So if you rely on that sound for brake control, as I tend to do too, I think you're give up some grip. 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. :-� Marty mark jeangerard wrote:

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> To any of you who can affect changes in GPL: > > Would it be possible to move the tire screeching sound to just before the wheels lock > under braking instead of just after? > > -- > > Mark Jeangerard > [email hidden] > Administrator > GPVL F2 Division > http://home.att.net/~m.jeangerard/GPVLF2

Is it possible that your swerving problem was caused by a controller problem? 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.

Check out my webpage. The so called 'pressure sensitive brake pedal' gives you the following scenario: You step onto the brake until it reaches the physical limit, then you control the fine line between no screetch and tire lockup easily by the applied pedal pressure. It's just like a real car (of course w/o brake servo). Use it since ages and love it. JensSchumi On Mon, 11 Jun 2001 15:14:55 -0600, "mark jeangerard" <[email hidden]> wrote: >Thanks Maxx > >I'm having a completely different experience than you are. Bearing in mind thatI am well >versed in all the principals you state in your message, my interpretation ofthe braking >sound in GPL is that once it's heard, braking is no longer efficient. I havedone >extensive testing with the engine sound removed and the car definitely slowsfaster just >before the tire sound starts, in my game. I use fairly standard setups with abrake bias >of 53 to 56 typically. The only problem is that it is so hard to memorize thepedal >position then when in the heat of battle it's always over or under but neveron. As a >result I have taken to the habit of locking then releasing which is just asinefficient, >but more consistent than the other way. I'm just not "feeling" it. > >Anyone else see it my way, or am I completely mistaken? -- LWFF Ball Bearing conversion at: http://members.nbci.com/JensSchu/ GPLRank: -12 Monsters of GPL: sub 200