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N4 SS no plates observations, questions

10 posts by 6 people · 21 Jan 2002 15:25 UTC - 31 Jan 2002 17:14 UTC

Gerald Moore 21 Jan 2002 15:25 UTC#140680
I was messing around at Talladega over the weekend, and decided to remove the restrictor plates. One thing I noticed immediately is that the tires started melting after only about 3 laps, and that for this speed, were seriously over inflated. By decreasing pressures signifigantly I got the temps to where they looked much better. The overall temperature of the right side tires would still go red after about 4 or 5 laps. I went back in the track.ini and noticed a setting for tire heat. For Talladega, this was 1.3. I looked at Atlanta and Michigan and it was more like 0.90. After experimenting some at Tally, I settled on .75 (IIRC) where by driving carefully and coaxing the car through the corners, the temps can be held just below the point where they start getting too hot to provide optimum grip. Another thing I noticed in the track.ini is tire wear. For Talladega, it is set to 3, which indicates that tires wear 3x as fast here as at a track set to 1. I didn't check the wear rates for other tracks. All this got me to thinking about how N4 determines things like tire heat and wear. Why are these factors different for different tracks? I know Goodyear delivers a custom tire for each race, are these variables supposed to reflect that? In terms of "realism", what, if any, is the correlation between tire temperatures and wear rate and available traction or grip? I don't know much about tires, and zero about racing tires. Do stickier tires wear out faster? What factors determine how hot a tire will get and the temperatures it will endure before durability starts to become a concern? How do other games model things like heat and wear? I have read that NR2002 has revamped this part of the physics engine. Anyone with the demo looked further into this? What stuff have they changed? Gerald
Well, my .02 which isn't worth much :) Don't take the tire models to seriously; they're not done to great. Tracks that are in actual racing notorious for tire wear have relatively normal tire wear(Rockingham, i.e.,), and others that are easy on tires have excessive tire wear, etc. In general, a hotter tire will wear faster, as will a "grippier" tire. Lots of things affect how a tire heats up; chassis setup, driving line, track temp, air pressure, etc. WC cars get one compound per track(the same one at some tracks), unlike open wheel series that can have several compounds. -John Gerald Moore <[email hidden]> wrote in message news:[email hidden]...
Quoted text (38 lines)> I was messing around at Talladega over the weekend, and decided to > remove the restrictor plates. One thing I noticed immediately is that > the tires started melting after only about 3 laps, and that for this > speed, were seriously over inflated. By decreasing pressures > signifigantly I got the temps to where they looked much better. The > overall temperature of the right side tires would still go red after > about 4 or 5 laps. > > I went back in the track.ini and noticed a setting for tire heat. For > Talladega, this was 1.3. I looked at Atlanta and Michigan and it was > more like 0.90. After experimenting some at Tally, I settled on .75 > (IIRC) where by driving carefully and coaxing the car through the > corners, the temps can be held just below the point where they start > getting too hot to provide optimum grip. > > Another thing I noticed in the track.ini is tire wear. For Talladega, > it is set to 3, which indicates that tires wear 3x as fast here as at > a track set to 1. I didn't check the wear rates for other tracks. > > All this got me to thinking about how N4 determines things like tire > heat and wear. Why are these factors different for different tracks? > I know Goodyear delivers a custom tire for each race, are these > variables supposed to reflect that? > > In terms of "realism", what, if any, is the correlation between tire > temperatures and wear rate and available traction or grip? I don't > know much about tires, and zero about racing tires. Do stickier tires > wear out faster? What factors determine how hot a tire will get and > the temperatures it will endure before durability starts to become a > concern? > > How do other games model things like heat and wear? > > I have read that NR2002 has revamped this part of the physics engine. > Anyone with the demo looked further into this? What stuff have they > changed? > > Gerald
I think you will find that many of these settings are just trial and error. They have a target time and targets for tirewear, fuel consumption etc. Once they know how many laps they need to run, they start adjusting all the parameters til they have a fairly close approximation of those factors. I'm sure a slide-rule math guy and get them pretty close but , and this is just my own guess... they just use trial and error. Keep in mind that just because two tracks have asphalt for a surface, the grip factors vary greatly. It's fairly common in race broadcasts to hear the announcers talk about some tracks that eat up tires or some tracks that are slicker than others. Even the time of year affects this...a spring race vs a hot summer race. Or listen during the Charlotte 600 how a car running good during the day turns to junk as the Sun goes down. dave henrie "Gerald Moore" <[email hidden]> wrote in message news:[email hidden]...
Quoted text (38 lines)> I was messing around at Talladega over the weekend, and decided to > remove the restrictor plates. One thing I noticed immediately is that > the tires started melting after only about 3 laps, and that for this > speed, were seriously over inflated. By decreasing pressures > signifigantly I got the temps to where they looked much better. The > overall temperature of the right side tires would still go red after > about 4 or 5 laps. > > I went back in the track.ini and noticed a setting for tire heat. For > Talladega, this was 1.3. I looked at Atlanta and Michigan and it was > more like 0.90. After experimenting some at Tally, I settled on .75 > (IIRC) where by driving carefully and coaxing the car through the > corners, the temps can be held just below the point where they start > getting too hot to provide optimum grip. > > Another thing I noticed in the track.ini is tire wear. For Talladega, > it is set to 3, which indicates that tires wear 3x as fast here as at > a track set to 1. I didn't check the wear rates for other tracks. > > All this got me to thinking about how N4 determines things like tire > heat and wear. Why are these factors different for different tracks? > I know Goodyear delivers a custom tire for each race, are these > variables supposed to reflect that? > > In terms of "realism", what, if any, is the correlation between tire > temperatures and wear rate and available traction or grip? I don't > know much about tires, and zero about racing tires. Do stickier tires > wear out faster? What factors determine how hot a tire will get and > the temperatures it will endure before durability starts to become a > concern? > > How do other games model things like heat and wear? > > I have read that NR2002 has revamped this part of the physics engine. > Anyone with the demo looked further into this? What stuff have they > changed? > > Gerald
>"Gerald Moore" <[email hidden]> wrote > All this got me to thinking about how N4 determines things like tire > heat and wear. Why are these factors different for different tracks? > I know Goodyear delivers a custom tire for each race, are these > variables supposed to reflect that? I'm not Papyrus, but I speculate it's a very good way as trial&error to find an optimum realistic effect to the different tracks and the tyres Goodyear bring. I know it's probably the "next big thing" in simracing to have realistic tyre effects, and Papyrus is on the good road to someday achieve that. Ask anybody here, and they will all agree that tyre simulation is incredibly difficult even for today's modern PC's. If you check out the track.ini in NR2002, you will see the difference from the same file in N4. -- -- Fran�ois M�nard <ymenard> -- http://www.ymenard.8m.com/ -- This announcement is brought to you by the Shimato Dominguez Corporation - helping America into the New World...
I think the tire model is fine (as a whole), the problem is with getting the heat/wear settings correct. The thing is, it's not just a matter of factoring in the track surface, you have to simulate the tyre compounds Goodyear uses at that track. Since Goodyear is constantly changing tire compounds, I'd be surprised if a sim were ever able to get the heat/wear variables 100% spot on realistic. This year everyone killed their right fronts at New Hampshire, by next year tire wear there may be minimal. It's no wonder some big name teams (particularly Rousch) had problems last year with overextended tires when there's really no consistency between the tires the teams are given week-in and week-out. By the same token, the values the original poster gave sound about right. If Tona/Dega were being run without restrictor plates, Goodyear would likely try to supply tires that were more up to the speeds/cornering loads. Jason "John Pancoast" <[email hidden]> wrote in message news:<[email hidden]>...
Quoted text (54 lines)> Well, my .02 which isn't worth much :) Don't take the tire models to > seriously; they're not done to great. Tracks that are in actual racing > notorious for tire wear have relatively normal tire wear(Rockingham, i.e.,), > and others that are easy on tires have excessive tire wear, etc. > > In general, a hotter tire will wear faster, as will a "grippier" tire. > Lots of things affect how a tire heats up; chassis setup, driving line, > track temp, air pressure, etc. WC cars get one compound per track(the same > one at some tracks), unlike open wheel series that can have several > compounds. > > -John > > > Gerald Moore <[email hidden]> wrote in message > news:[email hidden]... > > I was messing around at Talladega over the weekend, and decided to > > remove the restrictor plates. One thing I noticed immediately is that > > the tires started melting after only about 3 laps, and that for this > > speed, were seriously over inflated. By decreasing pressures > > signifigantly I got the temps to where they looked much better. The > > overall temperature of the right side tires would still go red after > > about 4 or 5 laps. > > > > I went back in the track.ini and noticed a setting for tire heat. For > > Talladega, this was 1.3. I looked at Atlanta and Michigan and it was > > more like 0.90. After experimenting some at Tally, I settled on .75 > > (IIRC) where by driving carefully and coaxing the car through the > > corners, the temps can be held just below the point where they start > > getting too hot to provide optimum grip. > > > > Another thing I noticed in the track.ini is tire wear. For Talladega, > > it is set to 3, which indicates that tires wear 3x as fast here as at > > a track set to 1. I didn't check the wear rates for other tracks. > > > > All this got me to thinking about how N4 determines things like tire > > heat and wear. Why are these factors different for different tracks? > > I know Goodyear delivers a custom tire for each race, are these > > variables supposed to reflect that? > > > > In terms of "realism", what, if any, is the correlation between tire > > temperatures and wear rate and available traction or grip? I don't > > know much about tires, and zero about racing tires. Do stickier tires > > wear out faster? What factors determine how hot a tire will get and > > the temperatures it will endure before durability starts to become a > > concern? > > > > How do other games model things like heat and wear? > > > > I have read that NR2002 has revamped this part of the physics engine. > > Anyone with the demo looked further into this? What stuff have they > > changed? > > > > Gerald
Is part of the problem that it is difficult to gather real world data to validate the simulation? Or is it just that it eats lots of processor cycles? Gerald "ymenard" <[email hidden]> wrote in message news:<HV438.2241$[email hidden]>...
Quoted text (9 lines)> I'm not Papyrus, but I speculate it's a very good way as trial&error to find > an optimum realistic effect to the different tracks and the tyres Goodyear > bring. I know it's probably the "next big thing" in simracing to have > realistic tyre effects, and Papyrus is on the good road to someday achieve > that. > > Ask anybody here, and they will all agree that tyre simulation is incredibly > difficult even for today's modern PC's. >
I played around some more. I raised the tire pressures back to where I usually run them. This resulted in much cooler tires and not as severe overinflation as when I first started mucking around. So I raised the tire_heat setting up to 0.90 (same as Atlanta, IIRC) and this again gets them to around borderline overheating. Now I wonder, what kind of wear rate would be realistic for a tire that could stand up to these speeds, and how would that affect traction? I looked around for some baseline data, without luck. Would a good goal be something like tires getting yellow (or even almost/slightly red) at the end of a fuel run? Gerald [email hidden] (jason moyer) wrote in message news:<[email hidden]>...
Quoted text (75 lines)> I think the tire model is fine (as a whole), the problem is with > getting the heat/wear settings correct. The thing is, it's not just a > matter of factoring in the track surface, you have to simulate the > tyre compounds Goodyear uses at that track. Since Goodyear is > constantly changing tire compounds, I'd be surprised if a sim were > ever able to get the heat/wear variables 100% spot on realistic. This > year everyone killed their right fronts at New Hampshire, by next year > tire wear there may be minimal. It's no wonder some big name teams > (particularly Rousch) had problems last year with overextended tires > when there's really no consistency between the tires the teams are > given week-in and week-out. > > By the same token, the values the original poster gave sound about > right. If Tona/Dega were being run without restrictor plates, > Goodyear would likely try to supply tires that were more up to the > speeds/cornering loads. > > Jason > > > "John Pancoast" <[email hidden]> wrote in message news:<[email hidden]>... > > Well, my .02 which isn't worth much :) Don't take the tire models to > > seriously; they're not done to great. Tracks that are in actual racing > > notorious for tire wear have relatively normal tire wear(Rockingham, i.e.,), > > and others that are easy on tires have excessive tire wear, etc. > > > > In general, a hotter tire will wear faster, as will a "grippier" tire. > > Lots of things affect how a tire heats up; chassis setup, driving line, > > track temp, air pressure, etc. WC cars get one compound per track(the same > > one at some tracks), unlike open wheel series that can have several > > compounds. > > > > -John > > > > > > Gerald Moore <[email hidden]> wrote in message > > news:[email hidden]... > > > I was messing around at Talladega over the weekend, and decided to > > > remove the restrictor plates. One thing I noticed immediately is that > > > the tires started melting after only about 3 laps, and that for this > > > speed, were seriously over inflated. By decreasing pressures > > > signifigantly I got the temps to where they looked much better. The > > > overall temperature of the right side tires would still go red after > > > about 4 or 5 laps. > > > > > > I went back in the track.ini and noticed a setting for tire heat. For > > > Talladega, this was 1.3. I looked at Atlanta and Michigan and it was > > > more like 0.90. After experimenting some at Tally, I settled on .75 > > > (IIRC) where by driving carefully and coaxing the car through the > > > corners, the temps can be held just below the point where they start > > > getting too hot to provide optimum grip. > > > > > > Another thing I noticed in the track.ini is tire wear. For Talladega, > > > it is set to 3, which indicates that tires wear 3x as fast here as at > > > a track set to 1. I didn't check the wear rates for other tracks. > > > > > > All this got me to thinking about how N4 determines things like tire > > > heat and wear. Why are these factors different for different tracks? > > > I know Goodyear delivers a custom tire for each race, are these > > > variables supposed to reflect that? > > > > > > In terms of "realism", what, if any, is the correlation between tire > > > temperatures and wear rate and available traction or grip? I don't > > > know much about tires, and zero about racing tires. Do stickier tires > > > wear out faster? What factors determine how hot a tire will get and > > > the temperatures it will endure before durability starts to become a > > > concern? > > > > > > How do other games model things like heat and wear? > > > > > > I have read that NR2002 has revamped this part of the physics engine. > > > Anyone with the demo looked further into this? What stuff have they > > > changed? > > > > > > Gerald
>"Gerald Moore" <[email hidden]> wrote... > Is part of the problem that it is difficult to gather real world data > to validate the simulation? Or is it just that it eats lots of > processor cycles? I can't say much, but I speculate that tyre dynamics is presently a too chaotic process to really be correctly simulated. Perhaps with Quantum computers someday... ;) -- -- Fran�ois M�nard <ymenard> -- http://www.ymenard.8m.com/ -- This announcement is brought to you by the Shimato Dominguez Corporation - helping America into the New World...
Quoted text (7 lines)> >Is part of the problem that it is difficult to gather real world data >to validate the simulation? Or is it just that it eats lots of >processor cycles? > >Gerald >
The biggest (by far) problem is getting real world data. This costs mega $$ to do on a stationary machine, although it's probably a little cheaper on something like this: http://www.ocp.tudelft.nl/tt/vehicle/testing/trailer.htm The process is to (basically) start the tire rolling at a 0 slip ratio (free rolling), then sweep it from a +20 to -20 degree (or whatever) slip angle and save the force data. (In other words, with 0 slip ratio and 2.5 degrees of slip angle, how much forward/rearward and sideways force is generated, and what's the aligining torque?) This might first be tested with 200 lbs of force (weight) on the wheel. Then, you'd do the entire sweep again and again at different slip ratios (or vice versa, not sure how it's really done). Then, you've got to do ALL of it again at maybe 400 lbs or force, then again at 600 lbs, etc.. This takes a long time ($) and can eat several sets of tires from what I've heard. The tire temperature can't really be controlled yet from what I've read, and the tires are continuosly wearing throughout the testing process, so you'd need to probably "lock" a tire in at a certain slip ratio, load, and vertical force (weight) to measure how the force changed as it was wearing down at each test point you wanted. Oh yes, then if you want all this data at different camber angles, multiply the entire number of tests done so far by the number of camber angles you want data for. The number of tests quickly multiplies many times for every new thing you want data for. Want it at 10 different tire pressures? Multiply it by 10 again.. Big, big $$. Just for kicks, let's imagine getting data for the ultimate simulator: If we wanted data for +/- 30 degrees of slip angle, at -.15 to .15 slip ratio, taken in .02 slip ratio increments (just pulling these numbers out of thin air). That's 15 test sweeps (say goodbye to the tire, probably). If we wanted this done at 6 different tire loads, that's 90 test sweeps. If we wanted all of this at camber angles from +/- 3 degrees, at every .5 degree, we're now at 1080 tests. Want 5 different tire pressures too? 5400 tests... And we haven't even begun trying to compensate for tire temperature and wear yet.. I heard it can cost something like $10-20,000 just to run a basic test without camber or tire pressure changes, so multiply that a few times to get the whole thing. If a tire could stand 15 tests before wearing to the point where the data is changing significantly, that'd be 360 sets of tires... Youch! lol How much is a racing slick for Winston Cup? $3000? I dunno, but if it was, that'd be a cool million $ just in tires, let alone testing time... Once you DO have the data you want, it's not too difficult to include it in a simulator, the CPU isn't really an issue anymore. The good news is, there are methods that can do a good job of prediction without making nearly all these tests. The MRA Radt non-dimensional approach springs to mind, although I'm certainly no expert on it. http://www.millikenresearch.com/mrandim.html Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com My little car sim screenshots: http://performancesimulations.com/scnshot4.htm
Cool info! GM [email hidden] (J. Todd Wasson) wrote in message news:<[email hidden]>...
Quoted text (76 lines)> > > >Is part of the problem that it is difficult to gather real world data > >to validate the simulation? Or is it just that it eats lots of > >processor cycles? > > > >Gerald > > > > The biggest (by far) problem is getting real world data. This costs mega $$ > to do on a stationary machine, although it's probably a little cheaper on > something like this: > > http://www.ocp.tudelft.nl/tt/vehicle/testing/trailer.htm > > The process is to (basically) start the tire rolling at a 0 slip ratio (free > rolling), then sweep it from a +20 to -20 degree (or whatever) slip angle and > save the force data. (In other words, with 0 slip ratio and 2.5 degrees of > slip angle, how much forward/rearward and sideways force is generated, and > what's the aligining torque?) This might first be tested with 200 lbs of force > (weight) on the wheel. > > Then, you'd do the entire sweep again and again at different slip ratios (or > vice versa, not sure how it's really done). Then, you've got to do ALL of it > again at maybe 400 lbs or force, then again at 600 lbs, etc.. This takes a > long time ($) and can eat several sets of tires from what I've heard. The tire > temperature can't really be controlled yet from what I've read, and the tires > are continuosly wearing throughout the testing process, so you'd need to > probably "lock" a tire in at a certain slip ratio, load, and vertical force > (weight) to measure how the force changed as it was wearing down at each test > point you wanted. > > Oh yes, then if you want all this data at different camber angles, multiply > the entire number of tests done so far by the number of camber angles you want > data for. The number of tests quickly multiplies many times for every new > thing you want data for. Want it at 10 different tire pressures? Multiply it > by 10 again.. Big, big $$. > > Just for kicks, let's imagine getting data for the ultimate simulator: > > If we wanted data for +/- 30 degrees of slip angle, at -.15 to .15 slip > ratio, taken in .02 slip ratio increments (just pulling these numbers out of > thin air). That's 15 test sweeps (say goodbye to the tire, probably). If we > wanted this done at 6 different tire loads, that's 90 test sweeps. If we > wanted all of this at camber angles from +/- 3 degrees, at every .5 degree, > we're now at 1080 tests. > > Want 5 different tire pressures too? 5400 tests... And we haven't even begun > trying to compensate for tire temperature and wear yet.. > > I heard it can cost something like $10-20,000 just to run a basic test without > camber or tire pressure changes, so multiply that a few times to get the whole > thing. If a tire could stand 15 tests before wearing to the point where the > data is changing significantly, that'd be 360 sets of tires... Youch! lol > How much is a racing slick for Winston Cup? $3000? I dunno, but if it was, > that'd be a cool million $ just in tires, let alone testing time... > > Once you DO have the data you want, it's not too difficult to include it in a > simulator, the CPU isn't really an issue anymore. > > The good news is, there are methods that can do a good job of prediction > without making nearly all these tests. The MRA Radt non-dimensional approach > springs to mind, although I'm certainly no expert on it. > > http://www.millikenresearch.com/mrandim.html > > > > Todd Wasson > --- > Performance Simulations > Drag Racing and Top Speed Prediction > Software > http://PerformanceSimulations.Com > > My little car sim screenshots: > http://performancesimulations.com/scnshot4.htm

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