Well, who's telling you that this is the case in real life. If the tires of F1's were "flat" through a corner, the outside would never get warm.
When comparing the static camber of the roadgoing cars you also have to keep in mind the camber curves of the specific suspension layout. A car with a twist beam/trailing arms setup like the XFG will always need lots of static camber. Same goes for MacPherson struts on the XRG.
Yes. Just think of the driveshaft as a big torsion spring to make it easier to visualize. Let's say you're in 1st gear and getting 1000lb-ft from the output shaft of the tranny. The tires still have grip and the torque "winds up" our driveshaft torsion spring (say 1 revolution). Now you give it more throttle, the tire breaks loose and because of the higher slip it can only transmit 800lb-ft onto the road (let's ignore the final drive). The result is that the driveshaft unwinds partially and makes the tire slip even more.
When the driveshaft is unwound to like 750lb-ft, the tire regains grip. Since the gearbox is putting out over 1000lb-ft and the tire does not slip anymore, it'll spend the first tenths of a second winding up the driveshaft again and due to that torque at the wheels increases relatively slow, until the driveshaft is wound up and the tire breaks loose again...
In the real world it's not so much the driveshaft that acts as a spring, but rather the engine/transmission mounts, the suspension bushings etc., but the effect is the same.
It's pretty much the same problem as trying to balance an object. You have to find THE perfect angle at which all forces cancel out each other.
It's the same with wheel-spin in LFS, unless you use JUST the right amount of throttle (which is also a moving target), you will quickly be on one side of the friction peak or the other.
Ever seen someone on a unicycle trying to stay on one spot? They don't just stand still and try to correct every little movement to one side. Going back and forth the whole time makes it a lot easier for them to keep their balance, and the alternating slip ratios are also what makes it easier to control wheel slip in real cars, since you don't have to hit that one magical throttle position.
It's the same with wheel-spin in LFS, unless you use JUST the right amount of throttle (which is also a moving target), you will quickly be on one side of the friction peak or the other.
Ever seen someone on a unicycle trying to stay on one spot? They don't just stand still and try to correct every little movement to one side. Going back and forth the whole time makes it a lot easier for them to keep their balance, and the alternating slip ratios are also what makes it easier to control wheel slip in real cars, since you don't have to hit that one magical throttle position.
I'm starting to think that the rest of the car may be real the problem.
Let's take a look at this first;
http://www.ismirdochlad.de/decel-slip.gif
(For the non-Germans, the graph shows slip ratio vs. friction coefficient of a tire)
The peak we see in the graph is also in LFS, you can verify this by looking at the longitudinal acceleration readout(F9) while launching with lots of wheel-spin. There's a spike in acceleration right when the tires regain grip.
If we were able to hold the tire at 20% slip (or wherever the peak is in LFS' model), we would see better acceleration. Problem is, you can't get near the peak without going over it. You can have wild wheel spin or virtually no slip at all, but nothing in between.
So either the edges of said peak are simply to steep, or the problem lies elsewhere. I suspect if it really was as simple as tweaking the slip vs. friction curve of the tire, this would have been fixed long ago.
My guess is that real cars behave differently because they have lots of slack and flex in the drivetrain. When you see a real car slightly chirping its tires, it's not a constant slip ratio like in LFS, but it changes as the engine rocks back and forth in its soft mounts, the suspension flexes and the driveshafts twist.
When you launch a car in LFS with spinning wheels and the tire goes from slip to grip, it STAYS that way unless you apply a lot more throttle to break it loose again.
When you launch a real car with spinning wheels and it goes from slip to grip, suddenly there's a lot more torque being applied to the engine because of the additional tire grip. That means the engine will move inside the flexible mounts. Since the engine moves relatively quickly, the maximum travel inside the mounts doesn't just depend on the torque being applied to the engine, but also on the engines momentum. That means it'll move quite a lot and then be pulled back towards its center location as soon as it runs out of kinetic energy. Moving back towards the center location will now in turn apply additional torque to the wheels and break them loose again.
Long story short, a real tire doesn't just go smoothly from 24% slip to 20% to 16%. The slack and flex of the drivetrain will make it grip and knock it loose over and over again several times per second (the frequency depends on how tight the drivetrain is), so it's basically cycling between 16% and 24% slip the whole time, which can have a significant impact on the transient phase between slip and grip.
My 0.02 €...
Let's take a look at this first;
http://www.ismirdochlad.de/decel-slip.gif
(For the non-Germans, the graph shows slip ratio vs. friction coefficient of a tire)
The peak we see in the graph is also in LFS, you can verify this by looking at the longitudinal acceleration readout(F9) while launching with lots of wheel-spin. There's a spike in acceleration right when the tires regain grip.
If we were able to hold the tire at 20% slip (or wherever the peak is in LFS' model), we would see better acceleration. Problem is, you can't get near the peak without going over it. You can have wild wheel spin or virtually no slip at all, but nothing in between.
So either the edges of said peak are simply to steep, or the problem lies elsewhere. I suspect if it really was as simple as tweaking the slip vs. friction curve of the tire, this would have been fixed long ago.
My guess is that real cars behave differently because they have lots of slack and flex in the drivetrain. When you see a real car slightly chirping its tires, it's not a constant slip ratio like in LFS, but it changes as the engine rocks back and forth in its soft mounts, the suspension flexes and the driveshafts twist.
When you launch a car in LFS with spinning wheels and the tire goes from slip to grip, it STAYS that way unless you apply a lot more throttle to break it loose again.
When you launch a real car with spinning wheels and it goes from slip to grip, suddenly there's a lot more torque being applied to the engine because of the additional tire grip. That means the engine will move inside the flexible mounts. Since the engine moves relatively quickly, the maximum travel inside the mounts doesn't just depend on the torque being applied to the engine, but also on the engines momentum. That means it'll move quite a lot and then be pulled back towards its center location as soon as it runs out of kinetic energy. Moving back towards the center location will now in turn apply additional torque to the wheels and break them loose again.
Long story short, a real tire doesn't just go smoothly from 24% slip to 20% to 16%. The slack and flex of the drivetrain will make it grip and knock it loose over and over again several times per second (the frequency depends on how tight the drivetrain is), so it's basically cycling between 16% and 24% slip the whole time, which can have a significant impact on the transient phase between slip and grip.
My 0.02 €...
Last edited by bal00, .
You mean CO2, don't you? Because NO2 = NOx.
In general you don't want to get it sideways at entry because it costs speed and it's easy to run wide, because you have to open the steering a little to catch the slide. The default set which I'm forced to use for the training is very nervous when turning in without being on the throttle, so I couldn't really avoid sliding a bit.
What's important though is your exit speed. Since the car doesn't have a lot of power, you need to exit the corner before long straights with as much speed as you can, cause a 3 mph disadvantage will cost you several car lengths on a long straight.
As for powering through the turns, I usually make small throttle adjustments mid-corner and don't go wide open throttle until I know I'll make the corner without getting onto the grass or having to slow down at the exit. Wheel spin is usually not much of a problem with a setup that doesn't use an open diff.
IMHO the best way to learn is the slow in/fast out approach. Braking earlier or entering slower doesn't really cost much time, but a messed up exit will cost your dearly because of the straights that follow. Of course I don't know your driving style, but in my experience the most common mistake of new drivers is trying to brake too late or corner too fast. They gain 0.1 sec by braking at the last possible moment and then lose 1.0 sec cause they barely make the corner and thus exit 5-10mph too slow.
Don't worry though, this will become easier as you get a better feel for the car. You'll anticipate slides and you'll be able to tell where the car is gonna be 2 secs down the road.
What's important though is your exit speed. Since the car doesn't have a lot of power, you need to exit the corner before long straights with as much speed as you can, cause a 3 mph disadvantage will cost you several car lengths on a long straight.
As for powering through the turns, I usually make small throttle adjustments mid-corner and don't go wide open throttle until I know I'll make the corner without getting onto the grass or having to slow down at the exit. Wheel spin is usually not much of a problem with a setup that doesn't use an open diff.
IMHO the best way to learn is the slow in/fast out approach. Braking earlier or entering slower doesn't really cost much time, but a messed up exit will cost your dearly because of the straights that follow. Of course I don't know your driving style, but in my experience the most common mistake of new drivers is trying to brake too late or corner too fast. They gain 0.1 sec by braking at the last possible moment and then lose 1.0 sec cause they barely make the corner and thus exit 5-10mph too slow.
Don't worry though, this will become easier as you get a better feel for the car. You'll anticipate slides and you'll be able to tell where the car is gonna be 2 secs down the road.
Yes, that's it. The worst thing about your pingplot is the latency of the first few hops. Hop #2 is right in your area, and the pings to that one are less than great already. There may be a problem with your line (adsl?) or BT's service in your area is simply oversubscribed.
Hops 2-9 are within BT's network and apparently you can't even access these properly. I'd recommend doing a pingplot to the same IP (216.239.59.104) at different times of the day (or night) with the same number of samples. If it looks significantly better at off-peak times, then your ISP's network is to blame. If it doesn't, it would indicate a problem with your line.
Hops 2-9 are within BT's network and apparently you can't even access these properly. I'd recommend doing a pingplot to the same IP (216.239.59.104) at different times of the day (or night) with the same number of samples. If it looks significantly better at off-peak times, then your ISP's network is to blame. If it doesn't, it would indicate a problem with your line.
Not sure about the details, but as far as I know the tires have more longitudinal grip and the transition between slip and grip has changed. The brakes are still the same, but the default setups might have changed.
If the pull away from you on the straights, it's probably down to exit speed out of the corner. Shifting when the light tells you to is correct. However you may want to turn off "throttle cut on upshift" in the driver options (assuming you're not using automatic gears). Sounds a bit weird when the engine revs up between the gear changes, but it's a tad faster.
You should be aiming for a decent setup.
Race_S isn't too bad, but the default one is completely useless.
I'd recommend getting the WR setup (and placing it in your data/settings folder):
http://setupfield.teaminferno. ... php?p_setup_usage_id=1630
I had a go myself. Not a perfect lap since the steering lock, brake force etc. of the default set is all wrong for me, but you get the idea.
http://www.blinkerfluid.net/AI_race.spr
Well, the AI's are fairly dumb at this stage. I wouldn't worry about it, since it's usually not a problem online. Newbies usually have a hard time keeping the car on the road, so they aren't really able to stick to the racing line and experienced players will leave room for you.
Depends on the gauge. An electronic gauge run off the cars MAP sensor will read absolute, since that's all that matters for the ECU. So it would read lower at high altitude.
Most mechanical gauges read relative to ambient, so they'd be accurate.
Yep. Most turbos still have some headroom at stock boost levels, though, so the ECU usually allows a slightly higher pressure ratio. As a rule of thumb you need 1% more rpm from the turbo for each 500ft of altitude.
Exactly. Btw, if you want something to ponder, what kind of absolute pressure does the air have which a scuba diver breathes at 40m?
Yep, they do, but not as much as naturally aspirated engines. It's easier to understand when you consider the absolute air pressure, not just relative.
Say the atmospheric air pressure at sea level is 14.7 psi absloute. So a naturally aspirated engine has an intake air pressure of...well...14.7 psi absolute. A turbocharged engine at sea level running 1 bar of boost would have a manifold air pressure of 29.4 psi absolute.
At high altitude with an atmospheric pressure of say 12 psi absolute, the naturally aspirated engine would lose ~18.4% of its power cause the air is ~18.4% less dense.
A turbocharged engine would still try to achieve 14.7 psi over atmosphere (remember the wastegate is spring-loaded, and you still need the same amount of boost pressure acting on the spring to compress it), making it 26.7 psi absolute in total, so the turbocharged engine only loses ~9.2% of its power.
Now, what's relevant for the efficiency for the turbo is the pressure ratio across the compressor (boost (abs.)/ambient air pressure (abs.)). While it's 2:1 at sea level, it goes up to 2.225:1 at high altitude. That means depending on the turbos efficiency range, the drop in power may be slightly smaller or slightly bigger than 9.2%. To determine that you'd need the compressor map of the turbo, though.
By the way, modern engines with electronic boost control often have an altitude sensor. At high altitude they pull a small amount of boost in order not to overspin the turbo, despite the higher pressure ratio.
Well, depends on how you measure it. If said bottle has 14 psi over ambient at 12 psi ambient pressure, it would only have 11.3 psi over ambient at sea level, simply because the reference point changed.
If it has 14 psi absolute at 12 psi ambient, it'll have 14 psi absolute anywhere.
Here's an article with throttle and brake input comparisons for Barichello and Schumacher:
http://www.blinkerfluid.net/f1racing.pdf
Perhaps an interesting read if you want to learn about left foot braking in F1.
http://www.blinkerfluid.net/f1racing.pdf
Perhaps an interesting read if you want to learn about left foot braking in F1.
If it was my car, I'd know for sure what kind of turbo is on there.
It's supposed to run 1 bar. The spike is due to the manifold being held completely shut for as long as possible. When it actually hits target boost, it takes a bit of time to fully open and bleed off the excess exhaust. This is also why the spike is less pronounced in the upper gears.
Small correction to my post above, which was worded a bit poorly. The actual boost pressure tapering off is more commonly found on modded cars having a stock turbo spinning at the top of its lungs. Completely stock cars usually just see a decrease in efficiency in the upper rev range (hotter air, less density).
Efficiency is also why 1 bar of boost can be either 230hp or 330hp on the same engine, depending on what kind of turbo is used.
It's supposed to run 1 bar. The spike is due to the manifold being held completely shut for as long as possible. When it actually hits target boost, it takes a bit of time to fully open and bleed off the excess exhaust. This is also why the spike is less pronounced in the upper gears.
Small correction to my post above, which was worded a bit poorly. The actual boost pressure tapering off is more commonly found on modded cars having a stock turbo spinning at the top of its lungs. Completely stock cars usually just see a decrease in efficiency in the upper rev range (hotter air, less density).
Efficiency is also why 1 bar of boost can be either 230hp or 330hp on the same engine, depending on what kind of turbo is used.
1. How the car responds to trailbraking depends on how it's set up, because you're not only affecting the weight transfer but also the traction budget of each tire. If a tire has to do lots of braking, it'll have less traction available for cornering and vice versa. If you want to learn more about this, read up on the Kamm circle or in German "Kammscher Kreis" (http://de.wikipedia.org/wiki/Kammscher_Kreis).
Lots of front brake bias will induce understeer when trailbraking, lots of rear brake bias will induce oversteer.
If you have a car that understeers a lot by nature (XFG or UF1 for example), you usually change the setup (suspension, tire pressures, ...) to combat that. However it'll also be more difficult to turn in with this new more oversteery setup. In this case you would add more front brake bias and use trailbraking to induce a bit of understeer when entering a corner. Once the suspension has settled and you're near the apex, you would release the brake and the car would be neutral.
If you have a car that oversteers a lot by nature (LX for example), you do the exact opposite. You make the setup more understeery and use a bit more rear brake bias to assist turn in.
2. Do you mean left-foot braking or heel-toeing(right foot on both pedals)?
Heel-toeing is used to blip the throttle on downshifts to avoid locking up the drive wheels.
Left-foot-braking is usually used for turbo cars to maintain boost while slowing down, as Vain said. F1 drivers also use left-foot braking to adjust the balance of the car while braking. More throttle = less brake force on the rear wheels = more front brake bias. Not even all F1 drivers do this, so I don't think it's necessary for F1.
Lots of front brake bias will induce understeer when trailbraking, lots of rear brake bias will induce oversteer.
If you have a car that understeers a lot by nature (XFG or UF1 for example), you usually change the setup (suspension, tire pressures, ...) to combat that. However it'll also be more difficult to turn in with this new more oversteery setup. In this case you would add more front brake bias and use trailbraking to induce a bit of understeer when entering a corner. Once the suspension has settled and you're near the apex, you would release the brake and the car would be neutral.
If you have a car that oversteers a lot by nature (LX for example), you do the exact opposite. You make the setup more understeery and use a bit more rear brake bias to assist turn in.
2. Do you mean left-foot braking or heel-toeing(right foot on both pedals)?
Heel-toeing is used to blip the throttle on downshifts to avoid locking up the drive wheels.
Left-foot-braking is usually used for turbo cars to maintain boost while slowing down, as Vain said. F1 drivers also use left-foot braking to adjust the balance of the car while braking. More throttle = less brake force on the rear wheels = more front brake bias. Not even all F1 drivers do this, so I don't think it's necessary for F1.
Interesting thread. We should get the terminology right, though. Boost LAG and the engine speed by which the turbo is producing full boost are two different things.
Boost lag depends on the inertia of the spinning parts...how much is the boost pressure lagging behind compared to a 100% load/constant engine speed scenario. Take the RA up to 220km/h, let off, then floor it at 200km/h. You'll notice it'll take some time to get back up to full boost. That's lag. It's also the reason engines with big turbos often don't reach full boost in the lower gears, even though the engine speed/load would be sufficient.
Boost response on the other hand depends on the geometry of the turbo (turbo vs. engine size, A/R ratio, etc.) and the boost control mechanism and refers to the boost vs. rpm curve you get in a 100% load/costant engine speed scenario barring any lag.
As far as I can tell there are 2 problems with the boost modelling in LFS.
1. Too much lag - After letting off, it simply takes too long to get back full boost.
2. Unrealistic boost response curves - The RA for instance starts making boost at 1000rpm but doesn't reach full boost until 5000 rpm. It should climb steeper and peak sooner. Additionally the boost usually tapers off slightly towards the redline. Manufacturers tend to pick small turbos to improve boost response and low-end torque, and these usually start to choke at high revs.
For reference, here's a small video:
http://www.blinkerfluid.net/0auf290mittel.wmv
The engine is a 2.0L with about 330hp. The turbo is either a KKK K26 or K29, so a good bit bigger than what you would find on the 250hp-ish 2.0L engines in LFS.
A dyno graph along with the boost curve can be found here:
http://www.eds-motorsport.de/D ... /Calibra_C20LET_PH-35.jpg
(not the same engine, but an identical one)
The video does a good job of showcasing turbo lag (or lack thereof), boost spike ("overshooting" the target boost level) and the slight drop in boost at higher revs.
Boost lag depends on the inertia of the spinning parts...how much is the boost pressure lagging behind compared to a 100% load/constant engine speed scenario. Take the RA up to 220km/h, let off, then floor it at 200km/h. You'll notice it'll take some time to get back up to full boost. That's lag. It's also the reason engines with big turbos often don't reach full boost in the lower gears, even though the engine speed/load would be sufficient.
Boost response on the other hand depends on the geometry of the turbo (turbo vs. engine size, A/R ratio, etc.) and the boost control mechanism and refers to the boost vs. rpm curve you get in a 100% load/costant engine speed scenario barring any lag.
As far as I can tell there are 2 problems with the boost modelling in LFS.
1. Too much lag - After letting off, it simply takes too long to get back full boost.
2. Unrealistic boost response curves - The RA for instance starts making boost at 1000rpm but doesn't reach full boost until 5000 rpm. It should climb steeper and peak sooner. Additionally the boost usually tapers off slightly towards the redline. Manufacturers tend to pick small turbos to improve boost response and low-end torque, and these usually start to choke at high revs.
For reference, here's a small video:
http://www.blinkerfluid.net/0auf290mittel.wmv
The engine is a 2.0L with about 330hp. The turbo is either a KKK K26 or K29, so a good bit bigger than what you would find on the 250hp-ish 2.0L engines in LFS.
A dyno graph along with the boost curve can be found here:
http://www.eds-motorsport.de/D ... /Calibra_C20LET_PH-35.jpg
(not the same engine, but an identical one)
The video does a good job of showcasing turbo lag (or lack thereof), boost spike ("overshooting" the target boost level) and the slight drop in boost at higher revs.
That means you're running an S2 server, which a demo player can't join.
To open a demo server, you can either select demo-mode on the first multiplayer screen or use a dedicated server.
To open a demo server, you can either select demo-mode on the first multiplayer screen or use a dedicated server.
I'd disagree. The RB4 can be set up to be perfectly neutral on the throttle while the FXO requires more throttle control. If the lap times were down to how easy the cars are to drive, the RB4 would come out on top. Not only is the FXO 5km/h faster on the straights, it also has more grip, giving it the upper hand in (fast) corners.
At 155km/h about 25% of the engine power goes towards rolling resistance and about 75% towards aerodynamic drag. I wouldn't be surprised if the difference between roof and no roof was around 5mph. Thing is though, nobody would be using the open roof car if it was heavier (or just as heavy) and less aerodynamic.
Doesn't seem to. Tried both versions on BL1 and they both top out at 155km/h with some gear to spare.
No, just shift normal and stay on the throttle.
Try turning off "throttle cut on upshift" in the player options. It's hurting your 1st split a lot.
Would be easier to answer with a replay.
People vote to restart the races, usually 1-2 min after a race has finished.
As for the server list, check the filters you're using. Select "ALL" on the right and filter only empty servers (buttons at the bottom). The ping times depend on your location and connection, obviously. For me there are 39 non-empty demo server currently. 18 of them <50ms, 26 of them <100ms.
As for the server list, check the filters you're using. Select "ALL" on the right and filter only empty servers (buttons at the bottom). The ping times depend on your location and connection, obviously. For me there are 39 non-empty demo server currently. 18 of them <50ms, 26 of them <100ms.
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