Itt van a GT2(kettõ) néhány(!) tulajdonsága. Autókhoz és fizikához értõ emberek írják le a tapasztalataikat. Még a hátrányokat is megemlítik, pl. "GT2 doesn't accurately model the effects of ride height", szóval elég fair... Csak tudnám, minek foglalkoznak ennyit egy arcade játékkal... (Feljebb folytatódik.. :))
To fully understand cornering, acceleration, braking and race physics you have to look at the cars weight distribution and the effects it has under various situations on the car and its handling characteristics and performance. At stand-still, a car will have its weight distributed equally over the wheels. When the car is put under acceleration all of the weight is shifted from the front to the rear thus giving the rear tyres more grip. In an FR car this is perfect for starts and of course powering out of corners. When turning a corner the wheels will lack grip and thus understeer unless the weight is shifted to them for a brief moment allowing them traction and grip to cope with the corner. Therefore to get the weight back to the front you have to slow the car down by braking thus throwing the weight to the front of the car and giving the steering wheels that bit more grip allowing the car to get around the corner fast without understeering.
You can get a car up a hill a lot quicker by selecting a lower gear and using all the rpms that the engine can dish out. You can use a higher gear to gain a little extra traction and control when accelerating. Corners can be taken at a higher speed due to selecting gears. You can sometimes brake a second or so later by engine braking. (Shifting down a few gears and then braking allowing the engine to help in slow the car down by reducing the power).
Using higher gears for traction at the corkscrew at Laguna Seca and learning to downshift quickly for the last turn will help immensely and supply you with the necessary practice needed for a huge range of possibilities. When approaching this turn line the car on the far right of the track and brake when necessary. (different cars require various braking points). Shift to a gear where in a normal situation the car would bog down. Manouvre the car so that you can almost take the entire turn in one direct line. Trial and error is the order of the day here as each car handles differently. By using a higher gear the driving wheels will be gaining traction through the mid point of the turn. As you pass this point shift down a gear so that you can get out of the turn quickly and use the cars acceleration. By using this shifting technique you are stabilising the car, maintaining control through the corner and of course gaining that necessary acceleration and speed for the exit.
When you kick the rear of the car out via dabbing the brakes, sharply turning and then jamming on the accelerator, the car will go into a power slide into the corner. To continue the slide through the corner you must use tact agility on the brakes and accelerator to keep the speed as constant and as high as is possible while using varying degrees of counter-steering to keep the car heading in the direction you want it to go in, i.e. the exit of the corners. A perfect power slide would be where the car loses as little speed as possible and obtains good grip upon the exit of the corner with no loss of speed. Ideally a slide should be performed on the edge of what is known as the Friction Circle. It's easy to initiate a slide, what's difficult is maintaining it through a corner.
Simulation/Control/Real-Life Tyres
Now here is where we delve into the mysteries of real life and where GT2 shows us how good its physics engine really is. Can you really take a corner at 70 mph? Try it with these babies strapped to the legs of your car then. I can guarantee you will fly off the course and hit the barrier. As with sports tyres the grip of the car is significantly reduced. Gears are quite useful when using these tyres. Some cars have different peak power and this can help in steering the car around the corners. When you are approaching a turn and you have slowed started turning in but the nose of the car is sweeping to the outside of the turn, you are almost certain to lose speed if you brake. The solution would be to shift up a gear and pump the gas every second or so. Chances are that the lower revs will allow the car to gain more grip on the surface and bring the nose around back onto the racing line and allow you to get the power down for the subsequent section.
Freaky Physics/Ground Effects
These effects are different styles of racing from the norm. They were stumbled across by many people over the last year and have been researched thoroughly by Grampa1951 (or gramps as he is now known). Gramps argues that what we term freaky physics is actually an effect in racing known as the ground effect.
GROUND EFFECT - This describes the nature of airflow near the ground. In airplanes, this refers to a cushion of air that builds up as a plane nears the ground. In racecars, this refers to artificially-generated low-pressure areas underneath the car which help it adhere to the ground. This is done by use of three-sided ground-effect 'tunnels' on each side of the bottom of the car, which start off small near the front and gradually get bigger towards the rear, creating a vacuum as the car moves forward using the ground as the fourth side of the tunnel. This is carefully managed by teams, using rules which specify the dimensions of the tunnels and how high the outside edge of each tunnel must be from the ground. The greater the gap between the tunnel side and the ground, the more vacuum escapes and the less down force is generated.
Grampa1951:
Now I have a question for the engineers. Is it possible that this effect is closer to r/l than everyone thinks? I am thinking of the air hockey table and the way the puck is held down by the air blowing from underneath it. Something that seems to defy logic.
In my playing with these cars/settings it seems to be the cars set up for ground effects that benefit the most and it is like a sucktion that is established and then can be broken if the car bounces too high.I noticed with the R30 at Midfield if I establish the sucktion before the first corner it can be maintained all the way to the overpass. If I loose that suction(by driving on the curb or anything that causes the car to bounce) even though I am at the same speed the ground effect does not hold.
It would seem to me if this were a "bug" the exact same settings would work on all cars of sufficient hp/downforce and of the same drivetrain. In my experience that is not the case. It looks to me like it is a matter of getting the suspension set up to establish some sort of harmonics in the tuning that allows the car to maintain this optimum ground effects condition.The springs setting being key in maintaining the suction.
GasMan:
I'm guessing and always had a suspicion that this effect was a result of ride height and that's what this kind of hints at (rather than the suspected suspension value although it helps in the overall effect). I can understand exactly what it indicates with the air flow and all that but I'm thinking that it is maybe an emphasised or enhanced type of Ground Effect in GT2.
Grampa1951:
Gas I think the lowered springs makes the suspension softer so the car can be sucked down tighter into that ground effect condition. In my playing w/the cars each one is different in how it responds to settings, again it seems pretty well modeled after the properties of each car.
Again it does not mean the things these cars can do is realistic but it does obey the laws of physics. It would seem perfectly reasonable to regulate settings to limit ground effects as is done in R/L.
GasMan:
Correct. The springs are an added force which complements the whole setup. The soft setting allows the car to stay level over the undulations of the track which means the airflow can stay relatively constant.
I think the reason the R30 is one of the better Ground Effect cars is due to it's minimum ride height. If my memory serves me correctly its minimum value was 55. That's pretty damn low for a car, which in turn substantiates and provides further evidence that a tunnel is created at the base of the car causing the Ground Effect.
I have noticed though that with stiff settings on the springs, dampers and stabilisers the car does tend to get faster but I think that is more a value of the tyres being 'planted' on the track which gives better grip. I think Deep Forest exploits the Ground Effect which is surprising considering it is a bumpier track. I'd have chosen SSR5 (or similar course) as a candidate with the smooth surface available there.
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Spring Rate : The springs are there to allow the car to return the wheel to the original position whilst allowing some sort of travel between the wheels and chassis of the car itself. Having soft springs allows the car to travel over bumps and uneven surfaces and make the journey that bit smoother. With stiff settings the car will be more noticeably unstable over uneven terrain and bumpy surfaces but the advantages are that the car will become more responsive, due to the unsprung mass (the body) being less able to move around relative to the sprung mass (the wheel, and suspension) and will upon acceleration gain speed more quickly due to the maximum weight transfer occurring more rapidly due to the reduced travel per unit of weight. Generally the stiffer the faster. (that is the best way to remember it). Settings wise, to induce oversteer you want the rear springs to be stiffer than the front. Likewise, understeer is induced by having stiffer front springs, because when a wheel is connected via a stiff spring, less weight can be transferred to it, so it has less grip, but changes in direction can be more rapidly transferred to the body of the vehicle.
Ride Height : This is the value(s) used to determine the distance the actual body of the car is off of the ground. Generally a low value means the car will be stable and responsive. The downside is that on bumpy tracks the car can start bouncing too much on the track. To remedy this, increase the value. A larger value at the rear of the car produces oversteer and increased acceleration at the initial point of accelerating. A point to note about the ride height settings is that with the minimum front value and the maximum rear value, the car will have a slight advantage over a normally level ride height value. The car will accelerate faster and gain speed better. The downside is that the car can become very unstable depending on the accumulation of the other settings. GT2 doesn't accurately model the effects of ride height so it is sometimes of benefit to lower the ride height all the way and you might actually get away with it.
Dampers/Damping : Damping occurs within a shock absorber so that the energy transferred to the unsprung mass (the tyre/wheel/brakes/suspension assembly) by a bump is not just passed on to the sprung mass (the rest of the car). Without damping you would have a spring, not a shock absorber. A variety of means are used for damping, but all use friction. Elastomeric shocks use the inherent properties of elastomer, air shocks restrict the flow of air out (compression/bound) and in (rebound) of the shock body, coilover shocks usually resrict the flow of oil out (compression/bound) and in (rebound) of the shock body. I'll use coilover shock for illustration. When you drive over a bump, the spring is compressed. This forces oil out of the shock body, through the damping mechanism, usually through some form of valve or shim (good for speed sensitive damping). Having passed over the bump the spring will rebound. Oil will then be drawn back through the damping mechanism, usually through a different circuit. In both directions, the forcing of the oil through the damping mechanism converts some of the kinetic energy into heat, reducing the kinetic energy transferred from the unsprung mass to the sprung mass. Increasing the compression damping reduces body roll, and subsequently weight transfer effects. It makes the car feel like it is more stiffly sprung. Rebound damping stops the spring kicking back, and makes the car feel less wallowy. However too much rebound damping can cause the car to pack down, reducing the available travel.
Bound Dampers : The bound and rebound settings on a car are there to help control the pitch and roll approaching and during cornering. The bound setting controls the rate at which the damper compresses when you touch the brakes so by giving the bound setting a higher value you slow down the rate of travel or if you decrease the bound value the faster it will compress. The smoothest way to approach and execute a corner is by keeping the whole car as level as possible throughout the whole turn. When travelling at high speed there is a greater force acting on the car when you touch the brake pedal, therefore by increasing the bound figure you will prevent the nose of the car from diving. If the nose dives too much you will end up with the rear of the car excessively high. This moves the weight off the rear tyres which means you now have reduced grip to travel through the turn which will be dangerous in a rear wheel drive car as the driven wheels now have little grip and the chance of spinning will be increased.
Rebound Dampers : To the same degree the rebound settings are just as important as the bound settings and need to be matched together to work properly. The rebound setting will control the rate at which the damper decompresses. The pitch of the car is equally affected by controlling the front diving as well as how fast the front comes back up when you take your foot off the brakes. The higher the rebound setting the stiffer the damper is when returning to it's normal position. The purpose of this is too make sure that the car doesn't swing back and fourth when on and off the brakes keeping the maximum amount of grip on the track and not in the air. If you set either the bound or rebound too high then it will affect the braking distance of your car. The most effective braking is done by transferring as much weight as you can to the front wheels whilst keeping the rear of the car as close to the ground as possible. Setting the bound/rebound too high will mean that you will restrict the amount of damper travel and thus affect the amount of weight you can transfer so you will need longer to stop or a lower cornering speed to eliminate understeer or oversteer depending on FWD or RWD.
Camber : With no camber on a flat surface the wheels will make contact 100%. With a slight bit of camber the angle of the wheel is changed and as a result the coverage of the wheel on the ground is reduced. i.e. less grip. Initially this seems bad but when turning the car the camber value allows the wheel to align with the ground and its camber will mean the wheel and ground make full contact. Thus more grip is produced and a faster time through the corner. Increased camber means better grip through corners. A higher front value induces oversteer. One thing to take into account with camber is the fact that it can increase grip. If you have a car that likes to slip its rear out every so often (oo-er missus), it is sometimes useful to increase the rear camber to counter that effect and stabilise the car again. I have in the past came across settings which look almost radical yet the car handles superbly. A Mazda RX-7 handles a little better under power with engine mods attached if it's camber values are around 0.8/1.2, trust me, it works.
Toe : This is similar to camber but on a different level. Toe means the wheels can be already angled towards the turn thus causing resistance during straight sections but allowing the car to turn in and out of a corner initially at greater speed and more responsively. The sketchy diagram below shows what position the wheels are in when viewed from above in various values of toe.
//==\\ - Toe-out - negative number (Positive toe)
| |==| | - Zero Toe
\\==// - Toe-out - positive number (Negative toe)
Positive toe will allow the car to have a quicker reaction when entering a corner at the initial point. Negative toe will slow the response down a little. There has been much discussion on the values of toe and the exact effects that a value inducts on the car. It has been decided that toe out (negative number) in GT2 will give the car more bite out of the corner and thus more grip. The diagram above is a reflection of the theory of the way GT2 treats toe. Real life values of toe are slightly different and are in fact almost reverse of what I have stated here. To be sure, test it and see what your own conclusions are. We're still not 100% sure what is going on here except to say that negative numbers help steer the car better. Read up on some of the links related to toe and determine the correct values for yourself.
Stabilisers : These settings are handy for altering the balance of the car without making too much of a fuss around the more technical aspects of the car and its suspension. Generally the higher the front stabiliser the more oversteer that is induced. (or more properly, the less understeer is found).
Brakes : Settings to the brakes only come into effect obviously when the car is under braking. By setting the front value higher than the rear the car will have a tendency to turn in when you brake. This can be helpful if you find the car wanting to head straight ahead when you need to turn the car. It is sometimes useful to use a softer setting on higher powered cars to stop the brakes locking. With a lower value the brakes will not be applied as powerfuly and thus the chance of locking the wheels is reduced and of course there will be less sliding through the corners... which is 'a very bad thing'.
Downforce : Low downforce means more speed but less grip. High downforce is 'grippier' but slower. In GT2 it doesn't make too much of a difference. Normally the best values to use are right at the maximum that these values can go to. No real advantage can be gained from low downforce under regular GT2 racing conditions. If however you are racing under a course such as the Test Course it may be wise to remove some of that downforce. With less drag the car does in fact have a higher top speed. This is simply because of the length of the straights on the test course. Again, under a regular GT2 race and its conditions downforce should be set near maximum.
Traction Controller : Simply put this device controls the traction. (sorry I couldn't resist). There have been discussions in the past questioning if the setting here actually helps at all. The mere existence of the controller is normally enough to reduce any wheel-spin and gain more grip. No real value has been found from fiddling with this setting. Traction control is only really needed in the high output cars, especially the Speed 12. It will help most cars off the start line by reducing the amount of wheel-spin. Sensors located on the hubs will send a signal back 100 times a second monitoring the speed of each wheel. If it detects a sudden increase in speed then it will decrease the amount of power to that wheel and transfer it to those that have grip. This does help the Speed 12 when exiting corners by limiting the wheel-spin when you hit the power-band and get a sudden burst of acceleration.
Stability Controller : Another one of those devices with a question mark over it. The existence of it helps but not the values used. Generally the higher the setting the less roll the car has. Really this is very closely linked to the bound and re bound settings. The stability controller measures excessive body roll during cornering and electronically stiffens each individual damper to keep the car as level as possible through the bend. This reduces any sudden weight shift in the car which would upset the balance and grip and potentially cause you to spin.