A very little updated version of FM3's guide. You are welcome, in advanced. If you have any questions, please ask.
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Tires.
You can't transmit
your car's power and handling potential to the road without the right tire
setup, because tire pressure affects a tire's peak grip, responsiveness and
wear. Adjust the front tire pressure when the tires are cold so they reach peak
grip after they heat up to race temperatures.
Peak Grip Temperature is between 180 and 210 degrees.
You will need to use the telemetry for this.
Start by picking any track and test run 3 laps in test drive mode, now bring up
the heat and tires misc. telemetry and observe the temperature & pressure.
As long as you're running a race
psi of 30-34 degrees, you're still in good grip range. Race psi and race
temperature is measured after a few laps when 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
*****
* ** *
* ** *
* ** *
*****
Edges
hotter than center - Tire pressure too low
- Add 1 psi for each 5 deg F difference
*****
* ** *
* ** *
* ** *
*****
Inner
edge hotter than outer edge - Too much negative
camber - Decrease negative camber
*****
* ** *
* ** *
* ** *
*****
Outer
edge hotter than inner edge - Not enough negative
camber or too much toe-in - Increase negative camber or decrease toe-in
*****
* ** *
* ** *
* ** *
*****
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 -
Car is under steering. Too much front spring/sway bar, not enough rear
spring/sway bar, front pressure too high, front tires too narrow, rear tires
too wide - Soften up front spring and sway bar, stiffen up rear spring and sway
bar, decrease front pressure or increase rear pressure
Rear
tires hotter than front - Car is over steering.
Too much rear spring/sway bar, not enough front spring/sway bar, front pressure
too high, rear pressure too low, rear tires too narrow, front tires too wide -
Soften up rear spring and sway bar, stiffen up front spring and sway bar,
decrease rear pressure or increase front pressure
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Alignment.
Handling
characteristics are usually defined by over steering and under steering.
Over steering is fish tailing, when the back end comes out. good for drift bad
for race pace.
Under steering is when the car experiences little or no steering when you’re
trying to turn left or right.
Camber,
Toe and Caster
The three major alignment parameters on a car are toe, camber, and caster. Most
enthusiasts have a good understanding of what these settings are and what they
involve, but many may not know why a particular setting is called for, or how
it affects performance. Let's take a quick look at this basic aspect of
suspension tuning.
Once you understand the terminology you can move into the adjustment stage.
What
is Toe?
My simplest analogy is made to pigeons and ducks. Most people's feet point
straight ahead. Compared that to a pigeon or duck there is a significant
difference. In some people, however, the feet point inward. This is called in
toeing (say "in-toe-ing"), or "pigeon feet." If you’re
Charlie Chaplin then I'm sure you've seen his duck walk with his toes pointing
outward.
Top down view of a tire in pairs
Toe
- Straight (0 degrees)
/ \ **** ****
| **** ****
| **** ****
| **** ****
| **** ****
Toe
- In (Positive Degrees)
/ **** ****
/ **** ****
/ **** ****
/ **** ****
/ **** ****
Toe
- Out (Negative Degrees]
\ **** ****
\ **** ****
\ **** ****
\ **** ****
\ **** ****
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:
For minimum tire wear
and power loss, the wheels on a given axle of a car should 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 are always 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?
Is that toe settings
have a major impact on directional stability. With the steering wheel
centered, toe-in causes the wheels to tend to roll along paths that intersect
each other. Under this condition, the wheels are at odds with each other, and
no turn results. Even with slight steering input the rolling paths of the
wheels still don't make a turn. In this way, toe-in enhances straight-line
stability.
If the car is set up
with toe-out on the front tires any minute steering angle beyond the perfectly
centered position will cause the inner wheel to steer in a tighter turn radius
than the outer wheel. Thus, the car will always be trying to enter a turn,
rather than maintaining a straight line of travel. So it's clear that toe-out
encourages the initiation of a turn, while toe-in discourages it
what
is Camber?
Have you seen the stance of a skier, usually their knees are closer than the
feet. This stance is said to be a camber effect. Imagine running on a 200m oval
track. When on the corner, you feel to get better track traction you need to
make your outer feet is touch the inner side of your feet. Camber is the inward
or outward tilt of the wheel when viewing from the front or rear of the car.
Camber is probably the most useful and popular alignment adjustment that can be
made to a streetcar.
Maximum cornering force is achieved when the camber of the outside wheels
relative to the ground is about -0.5 degrees. A slight negative camber in a
turn maximizes the tire contact patch due to the way the tire deforms under
lateral load. Hence, it is good to have some negative camber to increase
cornering force.
View from the front of a car
Camber
- Straight (0 degrees)
**** ****
**** ****
**** ****
**** ****
**** ****
Camber
- (Negative Degrees)
/ **** ****
/ **** ****
/ **** ****
/ **** ****
/ **** ****
Camber
- Out (Positive Degrees]
\ **** ****
\ **** ****
\ **** ****
\ **** ****
\ **** ****
The best way to determine the proper camber for competition is to measure the
temperature profile across the tire tread immediately after completing some hot
laps. In general, it's desirable to have the inboard edge of the tire slightly
hotter than the outboard edge.
What
is Caster?
This is probably the hardest to explain. The technical description is the angle
to which the steering pivot axis is tilted forward or rearward from vertical,
as viewed from the side. Lost? Don't worry I bring it back with some diagrams.
Picture a Harley with a long nose or fork. A positive caster setting that is
very high. Makes it good to go straight mostly, but the mini will beat it at
turning radius.
I na car you have ball joints connected to your wheels. These keep the wheels
attached to the car. Also you have a steering column attached to the ball
joint. The angle between the joint and the steering is the caster angle.
Say you driving down the straight on the hwy and you need to get your hands of
the wheel. Notice how easily the car continues to go straight when you let your
hands off. This is because of caster in the wheel. Anything attached to a wheel
has caster. With caster you have a positive and negative setting. In Forza it’s
represented by low and high. Forza doesn't have a negative caster because cars
are not designed the same way the casters are in shopping carts.
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.
Top
Down View of a car
******
****** () <- Lower Ball Joint
******
****** () <- Upper Ball Joint
******
Side
View of a car
********
*******(*)* () <- Lower Ball Joint
***********
****(*)**** () <- Upper Ball Joint
********
Low
Caster (Positive) of a Car
********
*******(*)* () <- Lower Ball Joint
***********
******(*)* () <- Upper Ball Joint
*******
High
Caster (Positive) of a Car
********
*******(*)* () <- Lower Ball Joint
***********
*(*)******* () <- Upper Ball Joint
********
Low
Caster (Negative) of a shopping cart
********
**(*)****** () <- Upper Ball Joint
***********
*****(*)** () <- Upper Ball Joint
********
Notice the shopping cart. See how easy it becomes to turn at a low speed. Imagine
60 mph with that caster setup turning left of right would be dangerous.
So high caster is good but makes it hard to turn, low caster is bad make it
hard to keep straight.
Now the fun part.
Tuning
Questions? What are you experiencing when you drive the car through turns? Over
steer or under steer?
Camber
Patience is the key
because alignment tuning is the hardest in Forza.
Again you will need telemetry
for this. Stop the car completely on a flat track with no elevation. Launch
Telemetry and go to Tires. Note the camber angle of the car makes with the
road. If it matches the setting you have tuned then you are on flat surface.
Restart tuning and race for a couple of hot laps. Usually 3 is good enough.
Don't worry about red penalty. Stop after 3 and watch the replay. During your
video 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
What’s the point? Positive camber is the enemy and reduces traction and
stability.
Tuning for Cornering.
For Left Turn
The right Tire must be less than or equal to 0.0 degrees.
For Right Turn
The left 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.
(You must have negative
camber on your car. Don’t tune your car to have 0 on the straights only in the
corners. But if you are tuning for drag racing. Always put camber and toe at
0.0)
Toe
General Rule of Thumb is to improve the car for corner entry.
Combination's include
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 + <- Under steer 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 over
steer tendencies in cornering.
Front Toe + Rear Toe - <- Amazing Handling on any car but can cause under
steer
Front Toe - Rear Toe + <- Amazing Handling on any car but can cause over
steer
Front Toe - Rear Toe - <- Oval track
Examples
Any Car for Better Turn In Response
Front Toe Out : .1 (duck feet ready for turning left or right)
\ **** ****
\ **** ****
\ **** ****
\ **** ****
\ **** ****
/ \ **** ****
| **** ****
| **** ****
| **** ****
| **** ****
Cars with massive power and no handling.
Front: 0
Rear Toe In: -.1 (pigeon feet, ready to face the direction of turn on
acceleration)
/ \ **** ****
| **** ****
| **** ****
| **** ****
| **** ****
/ **** ****
/ **** ****
/ **** ****
/ **** ****
/ **** ****
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Brakes.
What is Brake Bias?
Brake bias 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 the rear brakes get 35%
of the braking power.
Why
do I need to know?
Brake bias controls the way that the car handles when the brakes are
applied.Therefore, it is useful in changing the corner entry handling
characteristics of a car if braking is necessary going into a corner.
What
happens on adjustment?
Moving the brake bias toward the front brakes makes the car tighter and more
stable while braking and entering a turn. Moving the brake bias toward the rear
makes the car looser while braking and entering a turn.Excessive front braking
power can lock up the front tires and decrease the overall effectiveness of
your brakes since you are not using the rear tires to slow down the car.
Rule
of Thumb
The front brakes should always have more braking power than the rear because
the weight transfer during braking loads the front tires an dun loads the rear
tires. If you have too much rear brake, the rear tires will lock as weight
transfers forward and makes the rear of the car lighter. However, make sure you
do not have too much front brake either.
How
To Tune Brakes?
As a 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 Optimal
Setting 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 Circles is a visual of the grip available at each tire, and the blue lines
inside them are the amount of grip you are actually asking the tire to produce.
This displays a more detailed brake down of the "Friction Circle"
type telemetry from the "Body Acceleration" telemetry screen. If you
watch the red circles off the start line, the front ones will get slightly
smaller and the back ones will grow. That is because a tire's grip is related
to the amount of weight on that tire... more weight = more grip, to an extent.
So as you jump on the gas, weight shifts backward, and the rear circles grow
because your rear tires have more grip. When you go into a corner, you will
also see the circles change size as weight shifts side-to-side. jump over a
curb, and the circles disappear if the tire leaves the ground! The blue line
shows how much you are asking of the tire - if it is outside the red circle, it
means you are pushing that tire too hard and it has lost grip, so it is
sliding. If you look at the telemetry during a spin, the blue lines will be
well outside the red circles. If the blue line is inside the circle, it means
that there is more grip available, since the circle is the limit. You are using
your tires most effectively when the blue line is touching the red circle.
Notice while Braking which circles are getting bigger, usually the front will
get bigger than the rear with the bias > that 50% Front. Keep moving 1%
Front till you have lost grip completely skidded out as a result of understeer
when braking. Move back 1% to be in the safe zone.
Tuning
Brake Pressure
Also look at the brake indicator (vertical red line on the left of the
telemetry) notice if you are completely at 100% or just 70%. This will simply
your braking input sensitivity on the controller. Once you have found the
optimal setting for your brake bias. Brake pressure will improve 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 tires to
skid only when the trigger is completely back. Try tuning so that you 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 the Telemetry make sure
you have 4 big red circles when skidding to indicate good brake bias.
2. On Power: Same as above but make sure you don't get into a race-brake
situation where your locking the front and burning the rears tires..looks cool
but can be costly.
3.Off Throttle: Brake sensitivity is the key. You use only 10~40% on
sensitivity (i.e depressing the brake 1/2 to 1/4, you never completely hold the
entire brake down during a race (unless you want to show off your 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 can stop at a dime.
I'm personally at 130~160% in most cars without ABS. Since the game came out
I've been doing without ABS so now it comes a bit natural. Bottom line is if
you can drive with TCS off you can do the same with ABS off. If you can gently
squeezing the throttle coming out of a corner, you can gently squeeze the
brakes.
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Thanks to CerebralColton
Differential.
Differential: Your differential controls how well your car is able to put down
its power and torque to the road. A differential will send the power the wheels
with the least amount grip, in normal, everyday driving condition the power is
sent to the wheels on the left aka outside wheels, when turning right, or
the wheel which are not crossed out
/ /
I I
However in aggressive, racing
condition, power is often sent to inside wheels, or the wheels on the right aka
the inside wheels, when turning right, or the wheels which are not crossed out.
It does this because due to weight transfer to the left side of the car, the
inside wheels have the least amount of grip
/ /
I I
This causes the car to
lose traction and waste power, which is why high performance cars usually have
limited slip diffs. If the differential sends to much of the torque to the
inside, or outside wheel or wheels, the limited slip kicks in, and locks the
wheels together, although keep in mind that a limited slip diff evenly lock
your wheels together, one wheel is still receiving more torque, but only
slightly.
Acceleration (accl)=The acceleration setting controls at what point the
differential locks while on the gas. Having a higher % will prevent
individual wheels from slipping, allowing you to use more of the power when
exiting a corner, but in a rwd car, will make the car easier to spin out and
drift. Having a lower % will make it easier for individual wheels to slip,
causing you to waste more of the power when exiting a corner, but in a rwd car
it will make the car hard to spin out and drift and if its too low then you
will see a black patch coming from the inside wheel. Lower power cars usually
can withstand a high rate.
I recommend using a
higher slip rate, even in the front wheels, it usually creates a
less sloppy feeling when you exist a corner and I find that
it allows you to leave the corner with higher speeds. But if your back end
slides out more then what you want it to, then it may be a good idea to lower
the rate.
Deceleration (decel)= The deceleration setting controls at what point the differential
locks when you let off the gas, usually when entering a corner. The high the
rate the more stable your car will be, reducing over steer and create a
"on rails" feeling, but it will make your car less agile and can
cause under steer. Also if you do over steer, while accelerating, having a
higher rating can make it harder to correct the skid.
I recommend using a
lower slip, which will make will make your car more agile, but if your car
tends to over steer, or feels unstable, it may be a good idea to increase the
slip rate.
Center (Only with AWD cars): The center differential controls the how the torque is divided
between the front and back wheels in an AWD car. Like any other differential it
sends more power to wherever there is the least amount of grip. By
setting a rear biased rate your making it easier for the power
to be sent to the rear wheels. But the rate still changes biased
where the most amount of grip is and will still try to send more power to
the front wheels if they have less grip.
I recommend a slightly
rear bias, of around 60-75%,to get the most performance out of your AWD
system
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Thanks to KTLR
-Damping:
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.
Rebound Stiffness:
Increasing Front Rebound - More grip in the rear (weight shift blah blah etc.)
Decreasing
Front Rebound - Reduces
transitional under steer
Increasing Rear Rebound - More grip in the front
Decreasing
Rear Rebound - Reduces
transitional over steer
Front biased Rebound - Increases under steer
& increases grip in RWD cars, sacrificing turn-in slightly
Rear
biased Rebound - Increases over steer & 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 stiffness 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 stiffness. 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 doesn’t have to
be. Low bump stiffness works great.
Bump Stiffness:
Increasing Front Bump - Increases under steer and slightly increases rear grip +
modifies the effectiveness of Damping and Spring setups
Increasing
Rear Bump - Increases over steer
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 under steer + slightly increases grip in RWD
cars
Rear
biased Bump - Increases over steer
& 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 don’t want understand all the mumbo gumbo, is to
take a mild curb aggressively and then seeing if the car rolls. (Don’t 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.