Assetto Corsa Car Setup Guide
By: ChockrickBear | Feb. 7, 2020 | Views: 8 | Keywords: technical guide
An explanation of all of the settings to get the most out of the cars.
Back in my youth, I played a lot of Need for Speed: Porsche Unleashed, and it had made me a bit of a Porsche fan, an effective marketing ploy I admit. I did not really understand how cars settings worked, so I just followed Kasey Chang's guide, which was my first exposure to a more objective explanation of vehicle physics. The cars worked well enough with the extreme settings it recommended because the game's physics were not that complicated, even though the physics were touted as "realistic" by game reviewers back then.
Assetto Corsa interested me because I wanted a realistic simulator that also features lots of Porsches. However, there are a lot of settings of obscure purpose and the game does not do a good job of explaining how everything works. While the game provides tool tip explanations and there are plenty of online resources to learn more about how cars work, they are rather vague at explaining how the settings translate in practice, using broad definitions of oversteer and understeer without describing the exact context. You are expected to figure everything out by trial and error and make uneducated guesses about the how and why. Thus, I have decided to write this guide to explain everything.
Compared to other racing games, you cannot upgrade cars in Assetto Corsa. All cars can only be driven with default parts, which may or may not be tunable. The street cars have limited tuning options while race cars have access to a wide range of settings. It is important to understand that bad driving cannot be fixed with tuning. If you take a corner too fast, you will drive off the track no matter what your settings are. This makes tuning especially tricky because it can be difficult to tell whether you could have done better with tuning, slowing down more, or taking a shallower angle through a turn. Also, different cars handle differently, so they require different settings, but all cars operate on the same principles. I will suggest my settings as a reference point since figuring out what settings to use can be quite intimidating at first. However, they are not absolute and can be adjusted depending on the car.
If you are like me and drive with a gamepad, getting your gamepad settings right is important to the overall feel of handling. Driving games are a genre that cannot be optimized for keyboard and mouse due to the need for at least three separate analog controls for steering, throttle, and brake. Assetto Corsa supports mouse steering, but it cannot snap back to centre like an analog stick for straight driving, and you would still be without granular control for throttle and brake, which are very important for precise management of cornering speed.
Gamepad control is not perfect because some cars give you the ability to change certain settings on the fly and there are not enough buttons on a typical gamepad for everything. You will need separate mappings for different cars. Another problem with the gamepad is that you are working with a very limited range of motion with the analog stick. Cramming the full range of a steering wheel into a tiny analog stick makes the steering extremely sensitive and difficult to be precise with. To mitigate this, the game gives you a number of options.
Steering speed affects how quickly your character will steer in response to input. However, I find that anything higher than the minimum is too fast. Even then, your character's hands will move unnaturally fast, which is why this has to be combined with the filter setting to get slower steering.
Filter dampens steering so that it turns in a gradual, smooth motion even if you abruptly push the analog stick. However, this has the side effect of slowing down steering. The reason why steering speed is so fast is to counter this slowdown effect, but raising steering speed only becomes necessary with very high levels of filter. Setting steering speed to minimum and raising filter to slow it down works quite well. I suggest a setting of 0.42.
Gamma modifies how analog stick input is translated across the range of steering. Zero means linear translation of input, so if you move the stick by 10%, the game will steer by 10% of the full steering range. However, this makes it very difficult to make fine steering adjustments. Higher settings means you get an accelerating translation of input so that the game steers less for small inputs, but steers more the farther you tilt the analog stick. This setting is absolutely vital for stable handling. However, do not set this too high or else steering will get more abrupt for sharper turns because the steering range gets compressed near the edge of the stick. I suggest a setting of 2.4.
At high speed, small amounts of steering will result in a large amount of turning because the car's turning sensitivity is tied to how fast the wheels spin to move the car in the direction you steer. Speed sensitivity dynamically lowers steering speed the faster you go with the goal of making you less prone to accidentally steering too much at high speed. Higher settings mean more slow down, while zero means you get the same steering at low speed as high speed. I recommend setting this to zero to ensure consistent input. With a good gamma and skillful control of the stick, you do not really need this as it makes input inconsistent.
Virtual steering wheel rotation limit
Virtual steering wheel rotation limit is oddly placed in the video settings under "View". This affects the maximum range your character will steer, which affects the input because the game maps the full range of the analog stick to the full range of steering regardless of what the steering range is. The larger the range, the faster you will steer to fit into that range. Another problem is that different cars have different built-in steering ranges. Street cars give you a bit more than 360 degrees of steering, while race cars only give you 180 degrees. In order to keep the steering input consistent between cars, you would have to set the rotation limit to the shortest range, that is, 180 degrees. It is good enough for most cornering, but if you spin out, you will have a harder time turning the car around.
If you want to use a wider range of steering to be able to turn more sharply on street cars, you will need separate input settings, and the game lets you save multiple configurations. Higher steering ranges will require more gamma and filter to compensate. Avoid having a wider range than you need so you do not accidentally oversteer.
When you connect a large gear and small gear together, rotating the large gear will cause the small gear to spin faster than the large gear without any additional energy added to the system. In exchange for this faster rotation speed, a small gear cannot deliver as much torque, which is rotational force to accelerate something that spins, such as a wheel. A large gear uses its mass to provide more torque to make a wheel spin from rest, but it cannot spin as fast as a small gear, so a transmission system takes advantage of this behaviour to allow a vehicle to reach higher speeds.
If you have ever rode a bicycle with multiple "speed" settings, you have first-hand experience of how vehicle transmissions work. When you ride a bike, think of your legs as the engine and the speed of your pedaling as the engine rotations per minute (RPM). When you ride on the lowest gear, which is the physically largest gear, you will find it very easy to pedal because you are leveraging the larger gear to apply more torque to the wheels to turn them, allowing you to easily accelerate from rest and get rolling. However, your legs will soon be pedaling quickly, but the bike will stop accelerating and not go very fast. Your legs have hit maximum RPM, so what you should do is shift up the gear. This adds some resistance, but then the bike will start moving faster and then it becomes easier to pedal again. Then you shift up again. When you reach top gear doing this, you will hit dangerous levels of speed.
Gear ratios affect what speed each gear will reach before you need to shift and what RPM each gear will start with. Lowering the setting for an individual gear makes the gear physically larger, which reduces its top speed, but increases its acceleration as well as make it start at a higher RPM. However, this causes the next gear to start at a lower RPM since it starts at a lower speed, so it has to work harder to accelerate up to its own top speed.
You want to set up your ratios so that each gear starts as close as possible to the engine's optimal RPM according to the peak torque indicated in the car's power graph, which you can check in the car's description. Modern race cars have a bright, colourful meter that will start lighting up when you are in the optimal RPM range, and you want the meter to start close to empty for each gear. Setting up the gears this way makes the most efficient use of each gear by working them across a wide RPM range before needing to shift up.
The final ratio refers to the gear connecting the transmission to the wheels (i.e. the differential). This allows you to simultaneously adjust all of the gears at once to change the top speed without affecting the gear proportions, and it provides more granularity than adjusting the individual gears. Since this affects all gears, start off as low as possible and only raise if you need to extend the top gear because you do not want it to interfere with the acceleration of lower gears. Most likely, you will not need to raise this at all because lengthening the top gear will usually get you the top speed you need.
For the gears themselves, start off by setting the first gear as low as possible, then raise each following gear so that they all start as close as possible to the optimal RPM. Your settings should have a downward sloping appearance where you have lower settings for lower gears and higher settings for higher gears. Having lower settings for your lower gears allow you to accelerate faster out of corners, while making the top gear longer allows you to reach the top speed you need on straights. If you cannot reach the top speed you need while maintaining optimal RPM, raise everything simultaneously until you can, or raise the final ratio if it has less impact on the lower gears. It is a good idea to use the drag race track to test gear progression without worrying about turns.
The nominal top speed displayed on the top gear should generally be higher than what you can actually reach for the given track so that you avoid running on max RPM. You do not want to run on max RPM on your top gear because acceleration drops off dramatically as you try to squeeze out the last bit of top speed. You can actually lose acceleration by shortening the top gear to just barely reach the top speed, but do not set it too high or else you will impact its overall acceleration.
There is no need to religiously target the optimal RPM for the higher gears because even if your engine is producing maximum torque, the gear itself might not actually be transferring that torque to the wheels. Gears still accelerate faster using a shorter setting even if it starts above optimal RPM because the engine is still producing plenty of useful torque that a shorter setting can transfer more effectively. The optimal RPM is more like the minimum RPM a gear should start so that you are not introducing inefficiency from the engine.
You should tune your gears so that there are no sudden acceleration drops when you shift. Look at the speedometer and watch how fast the speed is increasing as you progress. If a gear suddenly accelerates slower than the previous gear, you should shorten it or lengthen the previous gear to keep the acceleration smooth. Make use of replays with slow motion to watch your speed as you progress.
Gear ratios can also be used to target RPMs to avoid awkward gear shifts during slow turns. Downshifting mid-turn can potentially destabilize the car if it makes the gear start with a high RPM, so modifying gear ratios can help you avoid it. Ideally, you want to set up the ratios so that the speed at which you take a turn puts you at the beginning of a gear. This allows you to leverage the full length of the gear to accelerate out. Look at the speed and gear at which you take a turn and target the top speed of the previous gear to that speed. If you take a turn at 80 km/h, you can set your first gear to end at that speed while adjusting the second gear proportionally, so that you will be at the beginning of the second gear when you start accelerating out of the turn. However, modifying your ratios for this can make overall acceleration worse as some gears might end up shorter or longer than optimal.
Keeping the lower gears low gives you more acceleration while making the top gear higher gives you the top speed you need, but they need to be balanced so that each gear starts at a consistent RPM.
Assetto Corsa models tire heat and wear. Tires have an optimal temperature range for maximum grip and you can enable an in-game HUD app that lets you see your tire temperatures and pressures in real time. The wheels will start blue, turn green when you are in the optimal temperature range, and turn red when you overheat them. Tires heat up when cornering, but cool down when driving straight. The more you stress the tires with sharper turning and higher speed, the more heat you will generate. Getting the tire temperature and pressure green is vital to being able to take corners at high speed.
You are given a choice of tire compounds to manage heat and wear. Street cars give you the option between street tires and semi-slicks, with street tires producing more heat and wear as well as having less grip since the grooves in the tire are just air spaces that produce no friction and exist mainly to displace water. Race cars give you options of different slick hardnesses, with softer slicks generating more heat and wearing out faster. If your tires refuse to turn or stay green, try using a softer compound. If you are overheating a tire, use a harder compound. An overheated tire has very little grip, so you are better off with a harder compound even if it prevents some wheels from becoming green.
Tires are filled with air to give them a balance of rigidity and flexibility, and tire pressure is about managing that balance. Higher tire pressures make the tires more solid so that they roll smoothly and react to steering quickly. Lower pressures give you softer tires so that more of the rubber contacts the ground for more grip. However, this makes the tire flex more, which makes handling less responsive and can even add resistance to the wheel.
Regardless, do not bother setting tire pressures according to your subjective feeling. The tire app will tell you when your car hits optimal pressure when the pressure readings turn green. Tire pressures are always set below optimal pressure to account for pressure increase due to heat. To find the optimal pressure, you can deliberately increase your tire pressure and then look at the tire app to see what pressure gives you bright green. That will be your target pressure. Then, lower the pressure and see if you can hit and stay at the target pressure as you drive. Some cars, particularly open-wheel cars, require extreme settings since they have atypical tires. The Ferrari SF70H with soft slicks benefits from a cold pressure as low as 8 psi because the optimal pressure is 20 psi and the tires will heat up enough to reach that.
The tire app displays the temperatures and pressures for each tire, showing green when you are at optimal levels. Tires that are stressed more heat up more, resulting in unbalanced tire grip, but this is often due to the track itself making you turn in one direction more than the other.
Wheels are not fixed in place and may tilt and turn as you drive, which can affect grip due to reduced tire contact with the ground or reduce stability due to the wheels not pointing where you want them to go. Alignment settings are for compensating for this to maximize grip and stability.
When adjusting alignment, the real-time numbers on the right panel show the true numbers of your car while the numbers on the sliders is the added adjustment applied to the car. While the real-time numbers may show differences between the wheels, it may be due to uneven terrain where your car is sitting. I recommend using the drag race track to check the actual values because it is perfectly flat. Also, wheel alignment changes when you adjust the ride height of the car, so you will need to readjust these settings as needed.
Camber refers to the vertical tilt of the wheel. Negative values (lower settings) mean the wheels are tilted outward from the bottom. When you turn, the car will push against the wheels on the outside of the turn and cause them to tilt. By having more negative camber, the wheels will be straighter when turning, increasing tire contact with the road to maximize grip and make the car roll more smoothly and sharply through turns. However, when the car is driving straight, the wheels will be tilted and have less contact with the road, which reduces acceleration and braking performance.
The ideal camber depends on the car and the turn. A suspension with more travel allows the wheels to tilt more, thus require more camber to compensate. Too little camber will make the car run wide. Too much camber will make it harder to reach full tire contact, lowering overall grip in addition to reducing acceleration and braking. I suggest settings between -2.00 and -3.00 for both front and back. If the car turns too much to the point of spinning out, try adjusting the differential, suspension, and rear wing first because you do not want to limit your turn radius and grip.
You can tell whether you are at the optimal camber by listening to the screeching of your tires as you turn. Basically, you want to minimize screeching while being able to turn in at speed. If the tires are screeching loudly while resisting turn-in, you need more camber. If you can roll through a corner at speed with low screeching, you have good camber. If the screeching gets louder as you increase camber without an increase in turning, you have too much. You can use the volume app to lower the engine and wind volume so you can hear the tires more clearly. You will not be able to eliminate all screeching, just work to minimize it.
Toe refers to the horizontal tilt of the wheel. Toe-in means the front of the wheels point into the car when looking from above while toe-out means they point away from the car. Toe-in helps make the car more stable on straights since the wheels are driving into each other and countering each other's tendency to drift away. Toe-out makes the car react faster to steering, but makes handling less stable overall, so it is not recommended. Having the wheels not point straight forward also makes the car a bit slower, so keep the toe as close to zero as possible and only adjust when there is nothing else to adjust for straight-line stability.
Toe can change while driving depending on the car. Some cars naturally toe out their front wheels when accelerating due to a loose steering mechanism, so toe-in is used to compensate for this to keep the wheels straight. Releasing the throttle will reduce the toe-out effect. The Lamborghini Aventador SV exhibits this behaviour, so it needs a resting front toe-in as high as 0.30. There is no HUD app that lets you see wheel alignment in real time, but you can catch a glimpse when you immediately exit back to the pit and look at the numbers before they change back to rest.
Negative camber is when the wheels are tilted so that when the car pushes against that wheel when cornering, it will straighten out.
The real-time values on the right show the actual values for the car. Even though the real values show different numbers for each wheel, they are actually balanced because the car is not sitting on flat terrain.
Because road surfaces are not perfectly flat, a car needs a suspension system of springs and dampers to allow each wheel to dynamically extend and retract to keep the wheels on the road. The problem is that you need the suspension to be rigid enough to prevent the car from bobbling around, while soft enough to handle bumps and to lean in for sharp turns. When a car turns, it leans on the outside wheels of a turn. This transfers the car's weight to that side of the car, which helps the car turn.
As a general rule, start off with settings as soft as possible and raise as needed. A stiff suspension allows the car to have a faster initial turn in, but it can make the car break loose easier and widen the turn radius of the car. Too soft, and the suspension will have a harder time recovering after a turn, as well as more easily bottom out in a turn. A bottomed out suspension results in a mid-turn interruption that suddenly limits turning. However, bottoming out is not necessarily a bad thing because it prevents the suspension from travelling too much and slowing down handling.
Dampers are hydraulic pistons that resist and smooth out the springs' bounce and oscillation. Without dampers, a car will uncontrollably bounce around on its four springs. This makes the car difficult to handle because the car will keep bobbling its weight around between each of the four wheels.
Damper settings allow you to control how stiff the dampers are during compression (bump) or extension (rebound) to have smoother and more responsive handling. A stiffer bump slows compression and makes the car turn in faster because of more direct weight transfer on the leaned-in wheels. It also slows damper compression so that the car does not lean in as much, allowing it to straighten out sooner. Too stiff, and the car will have a wider turn radius despite the faster initial turn-in. A stiffer rebound slows extension to have more stable and sharper turning on slow corners, but too stiff and the damper will not recover quick enough to straighten the car as you exit, making the car more willing to oversteer and be less responsive for s-curves.
As a good starting point, I suggest 4,4 (bump,rebound) for the front, and 2,4 for the back. Being able to turn in faster is important for reducing cornering time, but this depends on the overall grip and response of the car. If the car has less stable handling, use softer bump settings, especially for the rear. If the car has a lot of rear-end grip, raise the rear bump for faster turning. Bump settings that are stiffer than the car can handle will make the car prone to breaking loose. You can set stiffer bumps for the LMP1 and open-wheel cars since they have enough grip to handle it. However, it becomes a trade-off between turn-in response and turn radius, so you should not go too stiff. Rebound is not as useful to stiffen or soften because you want the car to recover quickly after a turn, but you do not want to impair turning and stability.
Fast bump and rebound
The fast bump and rebound settings affect how the dampers compress and extend due to sudden jolts. They are important because they affect the dampers' ability to take bumps without becoming unstable. The tracks are a lot bumpier than they look, and entering a corner over a bump can make the wheel will deflect off the ground.
A stiffer fast bump makes the car shakier to drive, worsening wheel contact with the ground if it is too stiff. However, if the damper compresses too easily from bumps, it will make handling less consistent as the car shifts its weight more easily and the dampers bottom out. Fast rebound is needed to prevent the dampers from bouncing back too quickly after a bump, which can cause the wheels to hit the ground with the force of the springs and bounce the tires. Too stiff, and the dampers will not rebound fast enough before the next bump, which will compress the dampers more and more with each successive bump and bottom out the dampers. I suggest settings of 2,5 for the front and back.
Springs and dampers compress and extend as the car runs over bumps and turns corners. Good damper settings make the car feel more intuitive to handle.
Heave dampers are extra dampers for the front and back that only come into play when braking and accelerating, that is, when the car "heaves" forward or backward. These are often found in the most powerful race cars because they have very high acceleration and brake power. When the car throws its weight forward during braking, the front gets more grip while the rear gets less, which results in oversteer. Conversely, when the car accelerates, it throws its weight back and reduces front grip, which results in understeer. This is why it is possible to regain control of your car from a drift by gently accelerating, whereas braking can make it worse.
Without heave dampers, weight transfer from braking and accelerating would be exerted on the normal dampers, which can bottom out the dampers when you need to turn. Heave dampers resist and smooth out the forward/backward weight transfers, allowing you to reserve the normal dampers for side to side handling. This allows you to be more aggressive with braking and accelerating during cornering without interrupting your steering. However, they do not completely eliminate weight transfer, so turning too sharply while braking hard can still cause the rear end to break loose.
For the front, a stiffer bump slows down the transition to oversteer from braking, allowing you to brake later and turn into a corner without destabilizing the car, but too stiff and it will make turning more difficult. A stiffer rebound keeps the weight on the front so you can keep turning after releasing the brakes, but you do want to recover quickly enough to stabilize the car. For the rear, a stiffer bump allows the car to turn more as you accelerate out, so you can start accelerating out of a turn earlier without understeering. A stiffer rebound makes the car more resistant to turning after releasing the throttle, which can improve stability when entering shallow turns that do not require braking. I suggest 5,3 for the front, and 8,4 for the rear.
The fast bump and rebound are similar to that of the normal dampers. Any bumps that hit both wheels will affect the heave dampers. I suggest setting them the same as on the normal dampers for consistent road bump handling.
Springs and anti-roll bars
Without springs, dampers will just compress from the weight of the car. Both damper and spring settings affect the speed of compression and extension and thus, the responsiveness of handling, but there is a subtle difference. Stiffer springs are harder to compress and stretch, which helps the car recover faster and makes it harder to bottom out the dampers. However, they can increase turn radius and cannot handle bumps as well. I suggest using middle to middle-high settings for both front and back, less if the car does not have differential settings to help you turn.
Heave dampers also come with heave springs, and you can adjust their stiffness as well. Stiffening them will reduce the effects of forward-backward weight transfers. These need to be fairly stiff compared to the normal springs to adequately do their job because the force of braking and accelerating needs enough spring resistance to offset the weight transfer. Making the front softer allows faster turn-in when braking, while a stiffer rear allows more turning when you accelerate. Middle to middle-high settings are adequate, setting the front a bit softer than the rear (e.g. 5 for the front, 6 for the rear).
Anti-roll bars are bars that connect the suspensions of the right and left sides of the car to the body with the goal of reducing the amount of body roll to make the car react and recover faster. In practice, they are redundant to other suspension settings and lack the level of nuance that the other settings provide. My advice is to set them as low as possible and just use springs, dampers, and ride height to get the balance of stiffness and travel you want. It is only when you do not have access to the aforementioned settings while having access to anti-roll bars, such as on the Porsche 911 R, that you might use them to have stiffer handling.
Ride height affects how high the car body is off the ground. A low ride height reduces the car's centre of gravity, which reduces the inertia of the car and makes for more responsive handling. However, a lower ride height is accomplished by shortening the damper rods, which limits the dampers' range of movement and makes it easy to bottom out the dampers. You want enough damper travel to allow the car to lean in for a sharper turn, but you also want a low enough ride height so the car does not shift too much of its weight to make handling slow and wobbly. You should set up ride height so you bottom out near the end of the sharpest turn.
When setting ride height, keep the rear height higher than the front to create a positive rake angle that improves downforce. However, you have to account for the fact that under acceleration, the rear end will sink down, so the resting rear ride height has to be much higher than the front to maintain positive rake while driving. Positive rake gives you tighter handling, but too much rake makes handling less responsive, and gives you the inertia of a high rear or the bottomed-out steering of a low front. Good resting rake angles can be between 10 to 25 mm of height difference depending on the car. Then, you can raise or lower both front and back at the same time to get more or less damper travel.
You can check rake angle by watching replays, press F5 to go into free camera mode, and look at the car bottom. Under full throttle, the car should be almost parallel to the ground. When coasting or feathering the throttle, which is when you are turning, there should be a noticeable angle. When at full throttle, it can be hard to spot, but small amounts are effective, so it is better to start off with more rake and then lower it until the handling becomes noticeably looser, then raise it back to tighten.
A good positive rake angle is barely perceptible when the car is at full throttle, but aerodynamics work within a tolerance of millimetres, so you only need a slight angle to create an effect on handling.
Travel and packers
Travel affects the maximum range of movement of the dampers. Restricting the travel can help the dampers recover faster by ensuring the dampers do not compress more than is necessary to make it through a turn, especially when you have stiff rebound. Since ride height already shortens the dampers, you can set travel to maximum and lower the ride height to eliminate excess travel.
Your rear will have a higher height than the front because of rake, so setting the rear travel lower than the front by the difference in heights will balance out the dampers. However, you should add some extra travel to the rear, since the rear needs to lean in a bit more to stay stable and complete the turn. I suggest adding about 3 mm of extra travel, which still allows the rear to hit the packers.
Packers are rubber stops on the end of the dampers to cushion them when they bottom out. They come into play during very sharp turns when the car is leaning hard on its dampers and need just a little extra help to overcome understeer and complete the turn. Softer front packers help the car turn in more, but they can make you oversteer during a hard turn. Softer rear packers makes the rear more stable, but harder to turn. However, you should only adjust packers after you have adjusted the differential since the differential comes into play first.
You do not want to limit the car's turning, so I recommend starting with the front soft and the back stiff. Stiffen the front to avoid excessive turn in, and soften the rear enough to keep it from swinging out too fast. If the dampers take too long to engage the packers in a sharp turn, you can reduce ride height to hit them sooner. Lowering the rear travel just enough allows you to hit the rear packers at almost the same time as the front, allowing faster turning if the rear is stiff. However, packers have limited travel, so you should adjust your ride height so that you will only hit them near the end of a sharp turn. I suggest 15 to 30 points away from the extremes.
When a car takes a turn, the wheels on the outside of the curve have to spin faster than the wheels on the inside so that the car properly rotates. A differential is a complex system of gears that connects the powered wheels (i.e. front or rear wheel drive) on the left and right side of the car so that both wheels can be driven by one engine while still able to rotate independently of each other and independently of the engine. However, it is a mechanical system that takes the path of least resistance. If one of the wheels slip, it will spin with less resistance and draw power away from the wheel that still has grip.
A differential lock locks the two wheels when the difference is too much, forcing the wheels to spin at the same speed, which transfers power from the slipped wheel back to the non-slipped wheel. It acts as a poor man's traction control, although using traction control with it does not override its effects. Traction control comes into play when a wheel is slipping, but differential locks can activate even when you have grip, which can be useful because too much relative rotation can cause your car to turn too quickly and spin out. Differential locks have different behaviours when accelerating or coasting.
The differential power setting affects when the lock will engage while turning and pressing the throttle. If a wheel slips, it will waste engine power and worsen acceleration, so it is important to engage the lock before this happens. Higher settings mean it will lock the wheels at lower rotation differences. However, this makes the car more resistant to turning because the wheels need to have some relative rotation for the car to turn properly. Too high of a setting can cause slipping of the opposite wheel, which results in oversteer.
You should balance this setting with the differential coast to ensure that when you start feathering the throttle after entering a corner, you do not get a sudden change in turning. In general, you should set this lower rather than higher to avoid limiting your turning, but it should be high enough to prevent loss of acceleration due to a wheel slipping. Different cars let you adjust to different levels of precision, giving you 25%, 10%, or 5% increments. I suggest settings of 20% to 35%.
The differential coast setting is a lock for when the car is coasting or braking, that is, when turning into a corner. Most noticeably, it affects how fast you can turn into a corner. Being able to turn quickly is important for cornering time, so you want this to be as low as possible. However, if the car turns in too quickly, especially on very sharp turns, it can make you spin out, so raising this setting helps prevent that.
The problem with higher settings is that even though you can prevent a spinout, you will still be slower for all other turns. Rather than raise this, it is better to use stiffer springs and/or damper bump as well as careful steering to compensate for the oversteer. One thing to note about differential spinouts is that braking controls it, whereas sliding due to insufficient downforce can be mitigated by accelerating.
The differential preload setting keeps the differential locked until the torque difference between the wheels is enough. While the power and coast locks determine the maximum difference, the preload determines the minimum difference. This affects the very start of the turn, when the wheels start trying to diverge in relative rotation speed. Keeping the differential locked at first is useful to prevent abrupt turn in that can destabilize the car.
Lower values allow the car to turn in faster, but too low and the car will feel twitchy until the power or coast locks engage. Higher values resist turn-in to make it more stable, but too high and you get slower cornering, override the power and coast locks to have permanently locked wheels, or get a jerky transition to the power or coast locks when there is a slight moment of unlocked wheels before the lock re-engages. Like differential coast, you should avoid limiting the car's turning by keeping this value low, but it is not important to set this to minimum, so setting this one or two clicks from the minimum works.
Race cars have a wing on the back and either a wing or a splitter on the front that are designed to catch the air and push down on the car as it drives. Raising the angle of these creates more drag that lowers top speed and acceleration at high speed, but gives you more downforce to increase grip. Front splitters have a lower impact on drag, but open-wheel cars have a front wing that creates more drag to provide more front downforce that allows them to take corners at higher speed. The idea behind these wings is that the extra speed you can take corners at should more than offset the loss of speed on straights, considering that turns are the slowest part of the track.
You want to be able to take turns as fast as possible, so start off with a high front angle and stress the car's turning to get an idea of how fast you can take each corner. You will also need to raise the rear wing so that the rear does not slide out from the sharp turning. You should also consider more camber, lower differential, and softer, longer suspension settings because stiff settings can limit turning no matter how much downforce you have. You can usually get away with front splitters being as high as possible, but front wings on the open-wheel cars need to be balanced so you do not turn more than you need.
Cars have a built-in computer called an engine control unit (ECU) to automate and optimize various aspects of the car's components that would otherwise be difficult to manually control without sacrificing performance. However, the ECU does not always know what you want, so you can adjust settings as needed.
Traction Control (TC)
TC detects whether a wheel is spinning much faster than the other wheels, indicating a loss of traction, and slows down that wheel with the goal of helping it regain traction. Without TC, if a wheel is stressing the limit of its grip in a corner and you accelerate hard, that wheel will suddenly spin too fast and break grip, so you spin out. Street cars only let you turn this feature on or off, but others have multiple settings that affect the amount of intervention, with higher settings giving you less intervention so you can have looser handling while still having enough intervention to prevent oversteer. Set it to 1 for maximum stability.
Some race cars do not have TC because they make driving easier and reduce the competitive skill ceiling. You would have to feather the throttle to stay just under the slipping point, and wait until you are straight before flooring it, but you will likely be slower since you cannot optimize power to each wheel with computer precision, and any hesitation will slow you down.
Anti-lock brake system (ABS)
ABS prevents you from braking so hard that the wheels stop spinning before the car has stopped. Without it, the wheels will slide and prevent steering because wheels need to spin to actually let you go where you want. ABS makes the wheels gradually slow down so that they do not slip, which lets you steer the car while braking, as well as make braking more efficient by precisely optimizing brake pressure on each wheel.
Similar to traction control, cars with multiple settings let you control how much intervention you get. Less ABS or higher settings means the wheels are allowed to slow more and slip, giving you understeer while braking as well as worse braking distance unless you are precise with gradually easing the brakes as you slow down. Set it to 1 for maximum brake performance.
Motor-Generator Unit (MGU) settings
Hybrid cars have an electric MGU that adds additional power to the combustion engine as well as regenerate energy from coasting and braking. This gives the ability to boost for much higher acceleration and top speed, but the amount of energy is limited, so you have to balance consumption and regeneration, but there is a limited amount of energy allowed per lap. The MGU delivers and recovers energy either through kinetic energy or heat, hence the -K and the -H.
This setting selects from a number of power delivery profiles that automatically controls how much energy the MGU uses at what points during acceleration. Higher settings provide more aggressive boosting, but uses more energy.
You can change profiles while driving by pressing the appropriate hotkey, so you can switch to a low power mode to recover energy until you need it later. If you are recovering energy faster than you can use it, you can use a higher profile to make more efficient use of the MGU. In general, it is better to just use the most power-saving profile that is not "Charging" and boost when you need to with the KERS Activation button, which gives you maximum power when you hold it down. However, you have to manually conserve energy by knowing when and how much to boost. You do not want to boost just before you have to brake.
Most hybrid cars do not have settings beyond MGU-K delivery, but the Ferrari SF70H gives you additional settings. MGU-K recovery affects how much energy is regenerated through coasting and braking. Higher settings give you more energy for you to boost with, but it makes the car lose speed faster when coasting (referred to as "retardation") as well as reduce brake performance.
While you can regenerate energy, you are only allowed a limited amount of energy per lap, so recovering energy you cannot use will affect your braking performance for nothing. However, you still need to recover energy for the next lap, so you will need to alternate between power and recovery laps. You can adjust this setting on the fly with the appropriate buttons so when you go for a power lap, you can lower this setting for maximum brake performance. If you do not want to fiddle around with controls while driving, setting this higher while using a lower delivery profile will allow you to run a surplus as long as you do not manually boost.
MGU-H mode affects whether to direct exhaust to add power or to increase energy recovery. Unless you are struggling to recover energy despite a higher MGU-K recovery, you should just set this to "Motor" to supplement engine power. You can also assign a button to change this while driving depending on what you want to focus on.
The brake engine setting affects how much fuel the combustion engine uses when coasting to reduce retardation and blow more exhaust towards the diffuser, which is the fins on the bottom-back of the car for generating downforce through aerodynamics. Lower settings use more fuel, but give you more downforce and reduce retardation when coasting, which offsets the retardation added by higher MGU-K recovery. In short, start at the lowest setting and raise it if you need to conserve fuel, or if you want more retardation to avoid having to brake for certain turns.
Hybrid cars have a fancy screen that displays how much MGU energy you have, portrayed as the meter on the bottom. The gears app (the HUD element in the middle) displays how much boost the car is using with the blue meter on the left, the amount of energy with the green bar, and the amount of energy allowed per lap with the yellow bar.
The Lotus 98T has a turbocharger that lets you adjust how much compressed air it will blow into the engine to increase combustion efficiency and thus, engine power. Higher settings make you faster, but it makes the car less stable, especially because the car does not have traction control. Settings higher than 70% will also add damage to the engine, but you can adjust the turbo while driving with the appropriate buttons. You can judiciously overdrive your engine on long straights and take the damage as long as you get a good lap time. You could also turn off damage and just go 100% all the way.
Brake balance and power
Brake balance affects how much brake force is applied to the front instead of the rear. The problem with braking is that the car throws its weight forward and reduces rear grip. If you applied the same brake pressure on both front and rear wheels, the rear will slow with less resistance. The rear will either lock up sooner than the front, or the wheels will slow too much relative to the car's momentum, causing them to slide. ABS will already correct for this, but if your car does not have it, brake balance is important for stability.
Increasing forward brake balance compensates for this, which not only improves stability, but also braking performance. Also, if the rear end is at the limit of its grip, bumps on the road can push it over, so you will need some extra. Too much forward balance, and the front wheels will slow down too much, which makes it harder to turn in addition to reducing brake performance. Therefore, only use as little as needed to prevent the rear from suddenly sliding out. I suggest 63% for most cars. You can get away with less if you have ABS or heave dampers.
Brake power allows you to reduce the brake force if you find braking too sensitive. You might find it too easy to slow down more than you need or lock up the wheels when driving without ABS. Of course, this reduces braking performance and forces you to brake earlier, making you slower overall. Generally, you should keep this setting at maximum to get the most out of the car and just learn to ease on the brakes.
Some cars have an adjustable engine limiter, which helps protect the engine from damage due to blind downshifting that would result in engine RPM exceeding safe levels. Many cars that have this setting also have downshift protection that prevents a downshift if it will damage the engine. However, there is a very small margin that downshift protection does not cover that will result in over-revving and damage.
Lower settings reduce the chance of damage, but it is still possible. Too low of a setting prevents the engine from reaching redline, which impacts acceleration as you would have to shift early. In general, you do not really need to lower it as the risk of damage is quite small. Some of the older open-wheel cars let you increase the limiter to let you hit higher RPMs to squeeze out the last bit of torque if it provides more acceleration than just upshifting, but too high and you will damage the engine, especially from aggressive downshifts.
If you have only played video games for all of your life, you might not realize that cars need fuel to run. However, the more fuel in the tank, the heavier the car will be, thus slowing you down. As the car burns fuel, it gets lighter. Just make sure you have enough fuel to make it through the race. You will have to run two laps to get an estimate of fuel consumption per lap.
A big part of getting good lap times is your ability to precisely clip corners at speed because if you turn too late, you have to massively slow down to stay on track. Too early, and you have to massively slow down to drive around the corner or have your lap invalidated for cutting the track. I am not the best driver as I have a hard time consistently judging exact brake distance and turning points, but the suggestions I have come up with here have certainly helped my lap times by making the cars feel more intuitive and able to turn more sharply.
I do much of my testing on Silverstone GP because of its awkward turn angles. The Porsche 911 RSR is more tunable than the Pagani Zonda R, and I was able to get a lap time of 2:07 with the 911 compared to 2:06 with the Zonda, even though the 911 has 510 hp and weighing 1245 kg compared to the Zonda's 750 hp and 1070 kg. While the Zonda is more powerful on straights, it is slower to handle because you cannot adjust the differential and ride height, so it loses more time on corners. It is not a scientific comparison, but it does provide a perspective of the "intelligent performance" tuning can give you.