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Sezona 1 [2011]


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Ma pozabite že na te avtke. Če se že organizira prvenstvo, naj to bo Prvenstvo. To pomeni spodobni dirkalniki. Sem že pred časom rekel, da se bo folk naveličal teh nezanimivih avtekov, no vsaj jaz sem

Ne vem, dirkanje je dirkanje in tudi ce si krog zaostal... jaz se nikjer v življenju nisem videl pravila da zaostankar ne sme dirkat z voznikom pred seboj če je hitrejši... Po tej logiki v Le Mansu 24

Če ti ne predstavljajo nobenega izziva, kako to, da nisi zmagal nobene dirke? . Sicer pa bolj kot je osnovno, bolj smo si dirkači blizu in bolj zanimivo je vozit. Meni je lepo, če dirkam z avtom, ki g

Ker sem zadnje čase kar preiskal kar nekaj vodičev kako začeti nastavljati avto in ne samo kaj kakšna nastavitev pomeni sem naletel na tale vodič, ki ga je napisal David S Peterson. Sicer opisuje nastavitve Corvette samo pride prav tudi za ostale avte.

The fixed sets available for the Corvette are, for the most part, quite good. Many top drivers use them as is. They generally make a good starting point for producing a custom set rather than starting from scratch.

The fixed sets all share certain characteristics. Most particularly, they are all stable and feature understeer. They make the Corvette relatively easy to drive, which gives the driver more freedom to toss the car around on the track. And, in general, it's necessary to toss the car around like that to go fast when using the fixed sets.

Custom sets usually adjust for less understeer and make the car more naturally lively and willing to turn... potentially too willing. Careful throttle control in particular is generally a must with fast custom sets.

There are a myriad of settings that can be changed. And they can all seem rather bewildering at first. Which setting gives me more oversteer, please? Well, there's not quite an easy answer to that. Many of the settings affect the car's balance. But the trick is that they each affect the balance under different circumstances. So in order to adjust the car properly, you need to feel out exactly where and when you want more or less oversteer, and know what settings affect that specifically.

FUEL

Fuel is always the first setting to work with. The fuel tank in the Corvette is located toward the rear of the car. So the amount of fuel being carried changes the balance of the car.

Determine the amount of fuel you'll need, and set that first before you change anything else. Then take the car for a spin to see what it feels like.

The fixed set starts with maximum fuel, and since you're probably going to run less fuel than that, the rear of the car is going to become lighter. This will lift the rear of the car, change the rake, and alter the wheel cambers... all of which would tend to make the car oversteer more. However, the great loss of weight rearward generally causes the car to understeer more overall.

BRAKE BIAS

Front brake bias: Brake bias is the first real setting to work with on the car. It has significant impact on the driving style that will be used, and thusly how the remainder of settings will come into play.

Front brake bias is the percentage of brake force that applies to the front wheels when you brake. A value of 58% is approximately neutral. 59% and higher will tend to lock up the fronts first. 57% and lower will tend to lock up the rears first.

Beginning drivers tend to favor higher values here because the car is much more stable under braking with more forward bias. As they become more experienced, they'll tend to want to move the bias rearward.

Brake bias below 58% tends to be used with gas on brake techniques to allow the driver greater dynamic range in their brake bias from moment to moment. That is, a bit of throttle is applied to cancel some of the rear brake at will. The driver can intentionally lock the rears at any point by simply letting off the on the throttle while braking. Gas on brake techniques require either left foot braking or heel and toe.

I don't think low bias values are generally used with straight braking. Low brake bias settings are one of the chief reasons why alien setups are slow and dangerously unstable in the hands of less advanced drivers.

Fixed setups tend to have rather high brake bias settings of 60% or more. Dropping it down to 58% or even 57% will reduce the braking distances, but also make the car much less stable under braking. Keep in mind that if you're struggling to keep the car under control while braking, the potentially shorter stopping distances aren't worth it. Don't try for a lower brake bias than feels comfortable, or you'll be slower, not faster.

DIFFERENTIAL

The Corvette as a car is defined by its massive power. The differential has a dramatic effect on what's going on with those meaty rears, and its affect on the balance and overall driving experience of the Corvette is more dramatic than many drivers might expect.

The differential tends to lock the rear wheels together the tighter you set it. The main purpose of this is to prevent the car from wasting its power spinning the inside wheel at the exit of a turn while the outside wheel remains unpowered, as would happen with an open differential.

The downside of locking the wheels together is that the car won't want to turn properly. Imagine lifting the front of the car off the ground and then trying to rotate the car on its rear wheels while they are locked together. They wouldn't roll. You'd have to force them to slide to turn the car. When your differential is tight, your own tires resist against your car turning.

This seems like it should promote understeer and stability, but it actually doesn't. The forces that are preventing your car from turning properly are actually subtracting from the available traction in your rear tires. Your rear tires are resisting _each other_! (No, Gir. That's bad!)

So loosening the differential promotes more understeer because then the rear tires aren't wasting their traction on infighting. This is a good thing to do as much as possible because there are more efficient ways of tuning that oversteer back in with other settings. Loosening the differential improves the overall traction of the car.

The down side of loosening the differential is that you can start spinning that inside tire on turn exit. That will lose speed. So the general idea is to have the differential just tight enough to prevent that from happening.

The fixed sets all feature tight differentials which exhibit their locking force all the time. There's speed to be gained by loosening them.

Clutch Plates: You can have between one and three clutch plates. More clutch plates makes the differential much tighter with the same settings. It's already plenty tight with a single clutch plate, so I don't see a reason to ever use two or three.

Preload: The tightness of the differential is variable depending on how much engine power is being applied. This setting determines how tight the differential is when no engine power is applied at all.

I generally set this to 0. I see no point in having my rears resist each other from letting the car turn when I'm neither accelerating nor decelerating. You may want to run with a preload if you find the balance transition of locking the rears together when you do get on the gas too jarring, but that's the only reason I can think of. If you're trying to alter the overall balance of the car in general, you're better off using other settings that don't make your wheels fight each other.

Drive ramp angle: The lower you set this value, the more tightly the rears will lock together when you get on the gas. The car will rotate more when you punch it.

Generally, my goal is to tune the car so that stomping the gas will kick out the rear end a bit but then stop rotating on its own so that I don't have to counter it.

Coast ramp angle: When you're completely off the gas, the engine drags, effectively applying a braking force to the rear wheels through the drive line. This setting determines how tightly the rears lock together when this happens. It's just like the Drive ramp angle, but the opposite direction.

I tend to favor high values (minimal locking) for this setting. The effects aren't generally as pronounced as the drive ramp angle since there is less power involved on the coast side. You could set lower values here if you want the car to kick out the rear on coast.

CHASSIS

Spring rate:

I subscribe to the notion that the purpose of springs is to keep the car's chassis from sitting on the ground. They are not a primary method of balancing the car. As such, we will fiddle with them early.

The things to consider with spring rates are ride height and compliance with the road. The more bumpy a track is, or the more three dimensional it is with steep bankings, crowns, crests, and other non-flat features, the softer your springs need to be in order to keep the wheels in contact with the road at all times.

The softer your springs are, the more ride height you'll need to keep the car from bottoming out. Stiffer springs allow you to lower the car more, but they only work well on tracks which are rather flat. And remember that curbing counts, too. The lower and stiffer you make the car, the more it will freak out over the curbs.

Contrary to common belief, stiff springs _do not_ reduce weight transfer. The same amount of weight transfers from the inside to the outside in a turn whether the car leans on soft springs or not. However, reducing the ride height does reduce weight transfer. And stiffer springs allow lower ride height. So this may be the origin of the misconception. But understand that it's not the springs themselves.

The fixed sets generally have pretty good spring rates and generally need little or no adjustment at all. Good spring rates on most tracks tend to be around the bottom of the adjustment range.

Note that if you're making a qualifying set with low fuel, you're removing quite a lot of weight. And consequently the springs will lift the rear of the car up. It can be a good idea to take some spring out of the car to compensate, dropping the car back down a bit. The car is lighter, so less spring force is needed to hold it at the same level.

Spring perch offset: This is the other end of the spring rate and ride height equation. This is how to directly adjust the ride height of the car. Higher numbers drop the car down.

Keep in mind that you're not just lowering the car, you're also compressing the suspension which changes all of the geometry. In particular, your cambers will change when you adjust the ride height. Take note of what your cambers were prior to the change and then set the cambers back to what they were afterward.

In general, I haven't had much luck lowering cars below the fixed sets except for very flat tracks like Suzuka.

Camber: Negative camber tilts the tires inward so that when the car leans into a turn, the outside tire will be flat against the track. Ideal cambers on the Corvette are typically in the range of 1.1 to 1.5 or so.

The more camber you run, the harder the car will turn (up to a point). But the trade off is you lose straight line braking because the tires are not flat against the track surface when moving in a straight line.

Camber is generally set by checking the outside, middle, and inside tire temperatures after running a few laps. Ideally, you want to see slightly higher temperatures on the insides than the outsides. The insides should be a little hotter because the car is running on the insides when its going straight.

The front wheels should generally have a good bit more camber than the rear wheels. You can tell whether a change in camber increased or decreased the car's traction if a change on one end of the car changes the balance of the car in that direction. For instance, if you add negative camber to the front of the car and the car starts oversteering more, then it worked! This is increasing the overall traction of the car, not just shunting the balance around like swaybar adjustments do, so it's definitely worth pursuing.

Note that positive camber is never used in road course sets.

Anti-roll bars: The sway bars are your primary overall balance tuning devices for the car. They pretty much adjust the balance evenly across the board.

Soften the front and/or stiffen the rear to produce more oversteer.

Stiffen the front and/or softer the rear to produce more understeer.

The more stiff the sway bars are overall, the less compliance the wheels will have with bumpy and unflat roads, just like using heavier springs.

Bump stiffness and Rebound stiffness: These are damper (shock absorber) settings. They affect the balance of the car just like swaybars do except that they only affect the stiffness of the suspension when it's in motion.

So that means the stiffness of the suspension is momentarily increased when the car leans into a turn. Or when it levels back out again after a turn.

You can tune these settings to make the car more lively so that it has a more oversteery edge when you first start to turn. Or you can set it opposite to ease into a turn more smoothly.

One effect to watch out for in particular is when you turn the car, and the front end initially turns in very rapidly as if too spin, and then immediately washes out again and settles into the turn all on its own. This is what happens when your dampers are set for a lot of nervous oversteer while the springs/swaybars are set for much less. The balance difference is too extreme.

I haven't actually found much need to change the damper settings from the fixed sets.

Bumpstop gap: The bumpstops limit the suspension movement in an effort to prevent the car from ever bottoming out. Essentially, they're like very stiff springs which are reached only when the suspension compresses beyond a certain point.

They would be important to work with on a real car, but in iRacing, there doesn't seem to be much downside to just letting the Corvette bottom out on the track if it's going to. So I just leave these alone.

Caster: I have yet to see a reason to change the caster on the Corvette. Theoretically, you can use caster to alter your camber settings for high speed versus low speed corners. But the fixed sets feature near maximum caster anyway, and less caster probably isn't desirable.

Toe-in: Theoretically, you can use positive toe-in to make the car more stable. And negative (toe-out) to make it less stable. In practice, I haven't found a reason to change these settings on the Corvette. I don't believe in toe settings very much because it's another example of making wheels fight each other.

Wing setting: Unless you're visiting the salt flats, leave this on the highest downforce setting for the Corvette. Always.

TIRES

The tires pane shows you the condition of the last set of tires that came off the car. That is... their condition at the moment that you left the track after slowing the car to a halt. Keep in mind what effects that will have. Tires heat up and cool down rather quickly. So if the last turn you did was a hard left sweeper, your right front tire is going to show more temperature. And if you just locked up all four tires while you came to a halt, your readings will pretty much all be garbage.

The main two things that you're adjusting when looking at tire temperatures are cold pressure and camber.

Ideally, what you'd like to see if an even heat spread from a little hotter on the inside of each tire to a little cooler on the outside.

If the middle temperature is lower than the outside and inside temperatures, then the tire is underinflated. If it's higher than the outside and inside, then it is overinflated.

Increase camber (more negative) to get more temperature on the inside of the tire. Decrease camber (less negative) to get more temperature on the outside of the tire.

If you are destroying a particular tire, the most common cause isn't setup. It's driving technique. The usual culprit is turning the steering wheel even further when the car won't turn any harder. Even if the tire doesn't emit smoke, you're hurting it unnecessarily when you do this. This will show up as very high overall temperatures for that tire immediately after the turn in question.

Setup can be used to try to make life easier on particular tires. You could try lowering that end of the car to reduce weight transfer to the outside tire. You could also concentrate on making that end of the car more planted so that it's sliding less.

CONCLUSION

Setting up the car is an iterative process. Make changes slowly and try them out for a while before giving them the yay or nay. Often times a good setup change will feel bad at first because you have to change the way you're driving to accomodate it.

Conversely, it is good to practice with the straight fixed setups and learn how to make them go as fast as they can. If you can't make the base setup go fast, then you have no basis for making changes to it, really. Indeed, you're likely to use setup changes to cover for weaknesses in your driving technique in that case. Don't do this! That approach will prevent you from ever learning to drive correctly. Setup should not be used as an attempted cure for bad driving.

Ring everything you can out of the fixed setup, and then turn to modifying it when there's just nothing more to ring out of it otherwise.

Let me know if you found this guide helpful. I write up these materials to aid the Corvette community in general and promote participation for this awesome car. The more drivers it helps, the more motivated I am to write more of this stuff. :)

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