This guide will help you tune and be faster. Beware this is a lot of reading so try not to soak it all in at once. lol. Sorry if there is no color its easier to follow with color but i do not know how to use it.
Thank you - CerebralColton for the Differential guide! And KTLR for the Damping guide
Guide written in German and a little more. Tuning Guide
You can't transmit your car's power and handling potential to the roadwithout the right tire setup, because tire pressure affects a tire'speak grip, responsiveness and wear. Adjust the front tire pressure whenthe tires are cold so they reach peak grip after they heat up to racetemperatures.
Note from Time: Peak Grip Temperature is between 180 and 210 degrees
This is a Master's Class Tuning and you need to use the telemetry for this.
Startby picking any track and test run 3 laps in test drive mode, now bringup the heat and tires misc. telemetry and observe the temperature &pressure.
Tires reach peak friction at 32 psi; however as longas you're running a race psi of 30-34 degrees, you're still in goodgrip range. Race psi and race temperature is measured after a few lapswhen your tires have heated up and reached their performance levels.
Tire Temp - Cause - Recommended Adjustment
Center hotter than edges - Tire pressure too high - Reduce 1 psi for each 5 deg F difference
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Edges hotter than center - Tire pressure too low - Add 1 psi for each 5 deg F difference
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Inner edge hotter than outer edge - Too much negative camber - Decrease negative camber
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Outer edge hotter than inner edge - Not enough negative camber or too much toe-in - Increase negative camber or decrease toe-in
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Tire below peak temperature range - Tire pressure too high, tire too wide or springs/sway bars too soft at that axle - Decrease tire pressure. reduce tire width or stiffen up springs and sway bars on that axle
Tires above peak temperature range - Tire pressure too low, tire too narrow, or springs/sway bars too stiff at that axle - Increase tire pressure, increase tire width or soften up springs and sway bars on that axle
Front tires hotter than rear - Caris understeering. Too much front spring/sway bar, not enough rearspring/sway bar, front pressure too high, front tires too narrow, reartires too wide - Soften up front spring and sway bar, stiffen up rear spring and sway bar, increase front pressure or decrease rear pressure
Rear tires hotten than front - Caris oversteering. Too much rear spring/sway bar, not enough frontspring/sway bar, front pressure too high, rear pressure too low, reartires too narrow, front tires too wide - Soften up rear spring and sway bar, stiffen up front spring and sway bar, increase rear pressure or decrease front pressure
Ihope you use the telemetry to adjust this setting based on yourdriving. This is the correct way to set it, so the next time some dudetell you 28/28 or 29/28 ask him how he came to that conclusion ...justmake that you did the 3 laps to see if the pressure reached its peakwhich is 32...
Handling characteristics are usually defined by oversteering and understeering.
Oversteering is fish tailing, when the *** comes out. good for drift bad for race pace.
Understeering is when the car experiences little or no steering when your trying to to turn left or right.
Camber, Toe and Caster
Thethree major alignment parameters on a car are toe, camber, and caster.Most enthusiasts have a good understanding of what these settings areand what they involve, but many may not know why a particular settingis called for, or how it affects performance. Let's take a quick lookat this basic aspect of suspension tuning.
Once you understand the terminology you can move into the adjustment stage.
What is Toe?
Mysimplest analogy is made to pigeons and ducks. Most people's feet pointstraight ahead. Compared that to a pigeon or duck there is asignificant difference. In some people, however, the feet point inward.This is called intoeing (say "in-toe-ing"), or "pigeon feet." If yourCharlie Chaplin then I'm sure you've seen his duck walk with his toespointing outward.
The amount of toe can be expressed in degrees as the angle to which the wheels are out of parallel
Toe settings affect three major areas of performance:
Forminimum tire wear and power loss, the wheels on a given axle of a carshould point directly ahead when the car is running in a straight line.Excessive toe-in or toe-out causes the tires to scrub, since they arealways rotating relative to the direction of travel.
Too much toe-in causes accelerated wear at the outboard edges of the tires
Too much toe-out causes wear at the inboard edges.
So if minimum tire wear and power loss are achieved with zero toe, why have any toe angles at all?
Theanswer is that toe settings have a major impact on directionalstability. With the steering wheel centered, toe-in causes the wheelsto tend to roll along paths that intersect each other. Under thiscondition, the wheels are at odds with each other, and no turn results.Even with slight steering input the rolling paths of the wheels stilldon't make a turn. In this way, toe-in enhances straight-line stability.
Corner Entry Only
Ifthe car is set up with toe-out on the front tires any minute steeringangle beyond the perfectly centered position will cause the inner wheelto steer in a tighter turn radius than the outer wheel. Thus, the carwill always be trying to enter a turn, rather than maintaining astraight line of travel. So it's clear that toe-out encourages theinitiation of a turn, while toe-in discourages it
What is Camber?
Haveyou seen the stance of a skier, usually their knees are closer than thefeet. This stance is said to be a camber effect. Imagine running on a200m oval track. When on the corner, you feel to get better tracktraction you need to make your outer feet is touch the inner side ofyour feet. Camber is the inward or outward tilt of the wheel whenviewing from the front or rear of the car. Camber is probably the mostuseful and popular alignment adjustment that can be made to a streetcar.
Maximum cornering force is achieved when the camber of theoutside wheels relative to the ground is about -0.5 degrees. A slightnegative camber in a turn maximizes the tire contact patch due to theway the tire deforms under lateral load. Hence, it is good to have somenegative camber to increase cornering force.
Thebest way to determine the proper camber for competition is to measurethe temperature profile across the tire tread immediately aftercompleting some hot laps. In general, it's desirable to have theinboard edge of the tire slightly hotter than the outboard edge.
What is Caster?
Thisis probably the hardest to explain. The technical description is theangle to which the steering pivot axis is tilted forward or rearwardfrom vertical, as viewed from the side. Lost? Don't worry I bring itback with some diagrams. Picture a harley with a long nose or fork.This a positive caster setting that is very high. Makes it good to gostraight mostly, but the mini will beat it at turning radius.lol
Ina car you have ball joints connected to your wheels. These keep thewheels attached to the car. Also you have a steering column attached tothe ball joint. The angle between the joint and the steering is thecaster angle.
Say you driving down the straight on the hwy andyou need to get your hands of the wheel. Notice how easily the carcontinues to go straight when you let your hands off. This is becauseof caster in the wheel. Anything attached to a wheel has caster. Withcaster you have a positve and negative setting. In Forza itsrepresented by low and high. Forza doesnt have a negative casterbecause cars are not designed the same way the casters are in shoppingcarts.
Positive Caster which provides good directional control but harder top speed cornering.
Negative Caster does not provide good directional control stability but easier low speed cornering.
Questions? What are you experiencing when you drive the car through turns. Oversteer or Understeer?
Patience is the key because alignment tuning is the hardest in Forza.
Againyou will need a telemetry for this. Stop the car completely on a flattrack with no elevation. Launch Telemetry and goto Tires. Note thecamber angle the car makes with the road. If it matches the setting youhave tuned then you are on flat surface.
Restart tuning andrace for a couple of hot laps. Usually 3 is good enough. Dont worryabout red penality. Stop after 3 and watch the replay. During thereplay launch the telemetry and jump to the "Tires Misc".
you need to watch the replay at least 2 times to get this down.
Start by looking at the camber angle on the front wheels.
Note how many times you see a positive number.
Repeat for the rear tires on the 2nd replay.
Now go back to tuning and change the following if applicable
Positive camber on straights - Decrease camber by .1
Positive camber on turns - Decrease camber by .1
No Positive camber on straights - Increase camber by .1
No Positive camber on turns - Increase camber by .1
Whats the point? Positive camber is the enemy and reduces traction and stability.
Tuning for Cornering.
For Left Turn
The Left Tire must be less than or equal to 0.0 degrees.
For Right Turn
The Right Tire must be less than or equal to 0.0 degrees.
Closer to 0 better the handling. Anything above 0 means that the tire is not helping you.
General Rule of Thumb Is to Improve the car for corner entry.
Front Toe + Rear Toe 0 <- Better Corner Entry Any Car
Front Toe - Rear Toe 0 <- Reduce Steer Sensitivity Bad Corner Entry
Front Toe 0 Rear Toe + <- Understeer tendencies but Better Corner Exit in any Car and stability under braking.
Front Toe 0 Rear Toe - <- Slow Corner Exit
Front Toe + Rear Toe + <- Provides stability under braking and creates oversteer tendencies in cornering.
Front Toe + Rear Toe - <- Amazing Handling on any car but can cause undertsteer
Front Toe - Rear Toe + <- Amazing Handling on any car but can cause oversteer
Front Toe - Rear Toe - <- Oval track
Any Car for Better Turn In Response
Front Toe Out : .1 (duck feet ready for turning left or right)
Brakebias is the balance of braking power between the front and rear brakes.It is usually represented as a percentage. For example, a brake bias of65/35 means that the front brakes get 65% of the braking power, and therear brakes get 35% of the braking power.
Why do I need to know?
Brakebias controls the way that the car handles when the brakes are applied.Therefore, it is useful in changing the corner entry handlingcharacteristics of a car if braking is necessary going into a corner.
What happens on adjustment?
Movingthe brake bias toward the front brakes makes the car tighter and morestable while braking and entering a turn. Moving the brake bias towardthe rear makes the car looser while braking and entering a turn.Excessive front braking power can lock up the front tires and decreasethe overall effectiveness of your brakes since you are not using therear tires to slow down the car.
Rule of Thumb
Thefront brakes should always have more braking power than the rearbecause the weight transfer during braking loads the front tires andunloads the rear tires. If you have too much rear brake, the rear tireswill lock as weight transfers forward and makes the rear of the carlighter. However, make sure you do not have too much front brake either.
How To Tune Brakes?
Asa starting point "TURN ABS OFF", try setting your brake bias between70/30 and 80/20. Fine-tune the car from there. I found that the OptimalSetting is 47% Front. I will get into the pressure later.
As Usual Replay Your Runs and Bring Up Telemetry and go to Friction.
Reading the Telemetry for Friction is as follows.
Red Circlesis a visual of the grip available at each tire, and the blue linesinside them are the amount of grip you are actually asking the tire toproduce. This displays a more detailed brakedown of the "FrictionCircle" type telemetry from the "Body Acceleration" telemetry screen.If you watch the red circles off the start line, the front ones willget slightly smaller and the back ones will grow. That is because atire's grip is related to the amount of weight on that tire... moreweight = more grip, to an extent. So as you jump on the gas, weightshifts backward, and the rear circles grow because your rear tires havemore grip. When you go into a corner, you will also see the circleschange size as weight shifts side-to-side. jump over a curb, and thecircles disappear if the tire leaves the ground! The blue lineshows how much you are asking of the tire - if it is outside the redcircle, it means you are pushing that tire too hard and it has lostgrip, so it is sliding. If you look at the telemetry during a spin, theblue lines will be well outside the red circles. If the blue line isinside the circle, it means that there is more grip available, sincethe circle is the limit. You are using your tires most effectively whenthe blue line is touching the red circle.
Notice while Brakingwhich circles are getting bigger, usually the front will get biggerthan the rear with the bias > that 50% Front. Keep moving 1% Fronttill you have lost grip completely skidded out as a result ofundersteer when braking. Move back 1% to be in the safe zone.
Tuning Brake Pressure
Alsolook at the brake indicator (vertical red line on the left of thetelemetry) notice if you are completely at 100% or just 70%. This willimply your braking input sensitivity on the controller. Once you havefound the optimal setting for your brake bias. Brake pressure willimprove your stopping.
Based On Braking Style You Maybe Doing 1 of the following:
1. On Demand (Pull the trigger all the way back)
2. On Power (Pull the trigger all the way back with acceleration)
3. Off Throttle Down Shift Half Brake (Pull the trigger half way)
With ABS OFF (ABS ON counters your braking, meaning more the light is on the more your travelling forward)
1.On Demand: Try going for a less brake pressure, you want all the tiresto skid only when the trigger is completely back. Try tunning so thatyou have a little play to create a skid and a good brake. Start at100% and keep going down 5% till you have that perfect brake. Using theTelemetry make sure you have 4 big red circles when skidding toindicate good brake bias.
2. On Power: Same as above but makesure you dont get into a race-brake situation where your locking thefront and burning the rears tires..looks cool but can be costly.
3.Off Throttle: Brake sensitivity is the key. You use only 10~40% onsensitivity (i.e depressing the brake 1/2 to 1/4, you never completelyhold the entire brake down during a race (unless you want to show offyour ABS skills lol). You know how to lock brakes to your advantage.You use the gear down to your advantage ONLY AFTER you started braking.Typically you keep going up in pressure settings because feel you canstop at a dime.
I'm personally at 130~160% in most carswithout ABS. Since the game came out I've been doing without ABS so nowit comes a bit natural. Bottom line is if you can drive with TCS offyou can do the same with ABS off. If you can gently squeezing thethrottle coming out of a corner, you can gently squeeze the brakes.
Tuning Gear Ratios
Gearing is the key to better acceleration, braking, cornering and top speed.
There are endless debates on torque and horsepowerand we wont get into that here.You know this because mostAmerican/German cars make torque and Japanese make horsepower. But itsimportant to understand the terminology.
Torque X RPM
Horsepower = -----------------------
Case for Torque
Anygiven car, in any given gear, will accelerate at a rate that *exactly*matches its torque curve (allowing for increased air and rollingresistance as speeds climb). Another way of saying this is that a carwill accelerate hardest at its torque peak in any given gear, and willnot accelerate as hard below that peak, or above it. Torque is the onlything that a driver feels, and horsepower is just sort of an esotericmeasurement in that context. 300 foot pounds of torque will accelerateyou just as hard at 2000 rpm as it would if you were making that sametorque at 4000 rpm in the same gear, yet, per the formula, thehorsepower would be *double* at 4000 rpm. Therefore, horsepower isn'tparticularly meaningful from a driver's perspective, and the twonumbers only get friendly at 5252 rpm, where horsepower and torquealways come out the same.
Case for Horsepower
OK.If torque is so all-fired important, why do we care about horsepower?Because, "It is better to make torque at high rpm than at low rpm,because you can take advantage of *gearing*.
Note you cars Peak Torque RPM and Peak Horsepower RPM.
Go to Test Drive in the Oval
Acceleration(accel)- The higher the percentage thequicker the differential locks, having your differential too quickly can cause your backend to slide out which it causes under steer and the frontwheels causing over steer. But if the diff doesn't lock quicklyenough, the inside wheel is likely to slip, causing you to losetraction, and can cause under steer and overseer in RWD cars. (understeer in fwd and AWD cars)
Deceleration(deccel)- Thehigher the percentage the more stable your car will be, but if its toohigh your car will under steer, if its too low then it won't really helpyou all. On AWD cars the the deccel on the front wheels shouldn't be anyhigher the 40%.
Controls the suspension's stiffness and compression between wheel and the wheel-well. Both Rebound and Bump work in "reverse-way", for example having the Front Rebound higher than rear increases grip on the rear, because more weight is concentrated in the front tires under spring compression, so rear wheels can work more freely.
Increasing Front Rebound - More grip in the rear (weight shift blah blah etc.)
Decreasing Front Rebound - Reduces transitional understeer
Increasing Rear Rebound - More grip in the front
Decreasing Rear Rebound - Reduces transitional oversteer
Front biased Rebound - Increases understeer & increases grip in RWD cars, sacrificing turn-in slightly
Rear biased Rebound - Increases oversteer & highly recommended for FWD & AWD cars.
(The bigger the balance difference, the bigger the effect - bigger than 3.0 differences not encouraged)
You cant really have excessively high Rebound setups, it all depends what the Bump stiffnesses are set to. If you are using high Rebound (9.0+) with low Bump (<4.0) your car may become upset by curbs and such, this is also modified by ride height and suspension stiffnesses. Higher Rebound than Bump is a must. The Bump stiffness should be 75% of the Rebound's stiffness at maximum.Although the in-game Damping description says ~50% of the Rebound's stiffness should be minimum, it really doesnt have to be. Low bump stiffness works great.
Increasing Front Bump - Increases understeer and slightly increases rear grip + modifies the effectiveness of Damping and Spring setups
Increasing Rear Bump - Increases oversteer and slightly increases front grip + modifies the effectiveness of Damping and Spring setups
Decreasing Front Bump - Improves bump absorption + modifies the effectiveness of Damping & Springs
Decreasing Rear Bump - Improves bump absorption + modifies the effectiveness of Damping & Springs
Front biased Bump - Increases understeer + slightly increases grip in RWD cars
Rear biased Bump - Increases oversteer & highly recommended for FWD & AWD cars.
(The bigger the balance difference, the bigger the effect - bigger than 2.0 differences not encouraged)
You will know when your Bump stiffness is excessively high. The chassis feels like it floats on the tires and you feel unconnected to the road. A good, practical way to test out your bump stiffness if you dont want understand all the mumbogumbo, is to take a mild curb aggressively and then seeing if the car rolls. (Dont try Sebring or Maple curbs, they'll roll you no matter what). If it rolls, your setup is too stiff, if you already had your bump at <3.5 then the problem is in your ride height or rebound. Bump stiffness can always be kept relatively low. (I personally never use 5.0+ bump stiffness). Bump stiffness in general fine-tunes the Damping & Suspension.
Tune the springs & ride height before going over to damping.
Also; Rear-biased Damping works for RWD cars well too, front-biased is just one of the several ways to increase grip on some RWD cars, not necessarily on all of them.