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PostSubject: DRIVING / RACING / TUNING HELP GUIDE   Sat Sep 24, 2011 12:49 am

I heard them mention this website during the ALMS broadcast of the 12 hours of Sebring.

Racers Check this out...much of it does apply here.

Click the links below  

SAFE IS FAST

HOW TO PASS

LEARNING A NEW TRACK


Overall some good information.

To improve the  driver experience of all racers:

be curtious of others.

when starting a race.
-IF YOU ARE THE CLEAR MAN. DON'T LAY BACK RUN FORWARD TO ANTICIPATE THE GO GO GO SIGNAL

when a car/cars is on your side.
-HOLD YOUR LINE UNTIL YOU ARE CLEAR TO MOVE OVER.

when following a car.
-LEARN WHERE THEY BRAKE BEFORE YOU TRY TO OUT BRAKE THEM.

when pitting.
-STAY ON THE SIDE OF THE TRACK WHERE PIT LANE IS AND DO NOT CUT OFF TRAFFIC AS YOU EXIT!

when you go off track:
Wait for any near by cars to pass before you return back to the track. You dont want to go off track and when coming back on track, ruin another drivers race (potentially more), along with ruining your own


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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Mon Oct 17, 2011 12:16 pm

Tuning Help

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

-----------------------------------------------------------------------------------------------------------------------------------------------

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:

Tire Wear
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.

Straight-line Stability
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.

Corner Entry Only
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)


/ \ **** ****
| **** ****
| **** ****
| **** ****
| **** ****


/ **** ****
/ **** ****
/ **** ****
/ **** ****
/ **** ****

-----------------------------------------------------------------------------------------------------------------------------------------------

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. ( I disagree with this. When you brake most of the weight is transferred to the front of your car so you need to have a little more to the front. I would say start at 51% front. However you can use brake bias to tune your turn in. If you have more rear brake bias your car will tend to oversteer under braking into corners and less brake bias will give you a more stable braking but you could get a bit of push. Play with it and see what works for you)

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.

-----------------------------------------------------------------------------------------------------------------------------------------------

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

-----------------------------------------------------------------------------------------------------------------------------------------------

Thanks to KTLR

Springs/Rebound/Bump Damping

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.



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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Tue Apr 17, 2012 12:19 am

New Videos and Information Added. This is helpful race info. SAFE IS FAST WEBSITE

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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Tue Jul 24, 2012 6:11 pm

COMPLETE TUNING GUIDE

Tire Pressure

Having good tires is important to get the best out of your engine. Tire pressure affects a tire’s grip, responsiveness and wear so adjusting front and rear tire pressures under different circumstances is important to keep that grip. You need to adjust the front tire pressure when the tires are cold so that they can reach their grip potential after they heat up to race temperatures.

Maximum grip potential of a tire ranges from 180 to 200 degrees. You can use the telemetry to get an idea about the grip potential of your tires and what setup you would need in race.

Peak friction of the tires is generally 32 psi but, you are doing even if you are somewhere between 30-34 degrees. You will still have necessary grip. You will know the tire temperatures and PSI once you have raced through few laps and tires have heated up.

When your tires heat up, you may need to do some adjustments to keep them in good grip range. The general rule is if the tire center is hotter than edges, tire pressure is too high and you need to reduce 1 psi for each 5 degree temperature difference.

If tire edge are hotter than center, tire pressure is too and you need to add 1 psi for each 5 degrees of temperature difference. If inner edge of the tire is hotter than outer edge, your tires have too much camber so you need to decrease negative camber.

If outer edge is hotter than inner edge, there is too much toe or not enough negative camber so you need to increase negative camber or decrease toe-in. If the tire is below peak temperature range, tire pressure is too high or tire is too wide or springs are too soft at the axle. In this case, you need to decrease tire pressure or reduce the tire width or stiffen up the springs and sway bars on the axle.

If the tires are above peak temperature range, tire pressure is too low or tire is too narrow or springs and sway bars are too stiff at the axle. In this case, you need to increase tire pressure, increase tire width or soften up springs and sway bars on the axle.

If front tires are hotter than rear tires, your car will under steer. This is because, too much front spring/sway bar, not enough rear spring/sway bar, or front pressure is too high or front tires are too narrow or rear tires are too wide. In this case, soften up front spring and sway bar, stiffen up rear spring and sway bar, decrease front pressure or increase rear pressure.

If rear tires are hotter than front tires, your car will over steer. This is because, too much rear spring/sway bar, not enough front spring/sway bar, rear pressure is too high, front pressure is too low, rear tires are too narrow or front tires are too wide. In this case, soften up rear springs and sway bar, stiffen up front spring and sway bar, decrease rear pressure or increase front pressure.

Your best shot to help you adjust these settings appropriately is Telemetry. Instead of following your guts when adjusting the tire pressure, do a quick 3 lap session in quick race and find out your tire pressures and other variables that will help you adjust your tires’ pressure for that track.

Alignment

Camber, Toe, and Caster are the three major alignment parameters. Let’s first see why these alignment parameters are important to adjust.

Camber is the inward or outward tilt of the wheel, which makes it the most important alignment adjustment for a street car. If you want maximum cornering force, set camber of the outside wheels on the ground to about -0.5 degrees.

It is good to have some negative camber as it increase cornering force but the important question is, how you would know how much negative camber you need for a particular track ?

You will find this out in a quick session before the race by measuring the temperature profile across the tire immediately after completing few laps. You want the inboard edge of the tire slightly hotter than the outboard edge.

Toe affects three major aspects of car performance. Tire Wear – excessive toe-in or toe-out can cause the tires to scrub, since they are always rotating relative to the direction of the travel.

If you set too much toe-in, it will cause accelerated wear a the outboard edges of the tires and if you set too much toe-out, it causes wear at the inboard edges of the tires.

Straight-line Speed – When the steering wheel is centered, toe-in causes the wheels to tend to roll along the paths that intersect each other. Under this condition, even with slight steering input, the rolling paths of the wheels don’t make any turn so toe enhances the straight-line stability and helps you keep the speed.

Corners Entry – If the car is set up with toe-out on the front tires, any small steering angle will cause the inner wheel to steer in a tighter turn radius than the outer wheel. Under this condition, the car will always be trying to enter a turn, rather than maintaining a straight line speed.

Now we are left with Caster. It’s tricky, and difficult to grasp but let’s try. Caster is your angle to which the steering pivot axis is tilted forward or backward from vertical, as viewed from the side. In a car, ball joints connect your wheels and steering column. The angle between the joint and the steering is called the caster angle.

You have positive and negative settings for the caster. It’s your low and high settings in Forza Motorsport 4. High caster setting is good for straights but makes it harder to turn, low caster is good for turns but makes it harder to keep the straights.

Tuning these settings depends on your style of driving. Do you understeer or oversteer through turns ? This will decide how you should go about tuning the alignment in Forza Motorsport 4. Remember, it will need great deal of trial and testing before you will finally fine tune the alignment of your car.

Tuning Camber
To adjust Camber, stop the car on a straight road with no elevation and go to telemetry to note the camber angle the car makes with the road. If it matches the setting you have tuned then you are on a flat surface.

Do a quick race and after three laps, watch the replay. Launch Telemetry and go to ‘Tires Misc’ to get what you need. You need to note the several times you see a positive camber for your front and rear tires by looking at the camber angle.

Once you have noted down these values, go back to tuning adjust these settings as follows:

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
We can conclude that positive camber reduces traction and stability. Now, let’s tune 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.
We can conclude that close to 0 better the handling and anything that’s above 0 means that the tire is not helping you. You must have negative camber and if you are tuning for drag racing, set camber and toe at 0.

Toe
Toe improves the handling of 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 +

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 -

Brakes

Brake Bias maintains the balance between the front and rear brakes. It is represented by a percentage such as, a brake bias of 65/35 means that the front brakes get 65% of the braking power, and the rear brakes get 35% of the braking power. It’s an important setting that you would need to adjust subjected to how you go into the corner and get out of it.

Now to the tuning part – When you move brake bias toward the front brakes, the car is tight and more stable while braking and entering a turn. When you move the brake bias toward the rear, the car is loose while braking and entering a turn.

Be careful though, excessive front braking can lock up the tires and decrease overall effectiveness of your brakes since you are not slowing down the car by using the rear brakes.

It is recommended that your car always have more front braking power than the rear because the weight transfer during braking loads the front tires only. If you set brake bias toward rear, the rear tires will lock as weight transfers forward and makes the rear of the car lighter.

Set the brake bias between 70/30 and move from there to fine tune your car. Don’t forget to ‘Turn ABS OFF’. How would you fine tune the brake bias ? Replay and Telemetry combo… read the telemetry for friction.

How Should You Read Telemetry For Friction ?
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
Once you have found the ideal setting for brake bias, the brake pressure will increase your stopping power. To fine tune brake pressure, look at the brake indicator and notice if you are at 100% or 70%.

Subjected to your braking style, you may do one of these:

On Demand (Pull the trigger all the way back)
On Power (Pull the trigger all the way back with acceleration)
Off Throttle Down Shift Half Brake (Pull the trigger half way)
On Demand
Go for less brake pressure as you want the tires to skid only when the trigger is pulled all the way back. Start at 100% and keep going down 5% till you have the perfect brake. Using the Telemetry, make sure you have 4 big red circles when skidding to show good brake bias.

On Power
Similar to On Demand but make sure you get into a race-brake situation you are locking the front tires and burning the rear tires.

Off Throttle
Squeezing the brakes coming out of the corner is similar to squeezing the throttle, you will learn it over time and it comes natural afterwards.

Differential

Differential controls how your car transfers its power and torque to the road. Differential sends the power to the wheels with least grip and because of the way your car transfers power to the wheels, it is prone to wasting it and losing traction.

Similarly, when the differential sends the uneven amount of torque to the wheels, the limited slip kicks in, and locks the wheel together. Though, it evenly locks both wheels still one wheel is receiving more torque.

Differential has two settings, Acceleration and Deceleration. Acceleration controls at what point the differential locks while on gas. Having a higher percentage of acceleration will prevent each wheel from slipping, which will allow you to harness more power when exiting a corner but if you are driving an RWD car, it is easier to spin out a drift.

Having a lower percentage will make it easier for each wheel to slip, resulting in power loss when exiting a corner but if you are driving a RWD car, it is hard to spin out and drift.

Use the high-slip rate, even in front wheels because it usually creates a less sloppy feeling when you exit a corner and it allows you to leave the corner with higher speeds but if back-end of your car slides out more than you should stick to lower rate.

Deceleration controls at what point the differential locks when you let off the gas, usually when entering the corner. The high the rate, the more stable your car will be.

It will make your car less agile, and can cause under steer. Having the higher rate while accelerating, makes it harder to stop the skid, so be careful with whatever setting you choose. Use the low-slip rate here, because it will make your car more agile. If your car tends to over steer, increase the slip-rate a bit.

The central differential of AWD cars control how the torque is divided between the front and back wheels. It sends more power to wherever there is least amount of grip, just like any other differential. Rear biased central differential gets the most performance out of AWD, so give it a try.

Damping

It controls the suspension’s stiffness and compression between wheel and wheel-well. Rebound and Bump work in ‘reverse-way’ like having the Front Rebound higher than rear increases grip on rear, because more weight is concentrated in the front tires under spring compression, so rear wheel con work more freely.

Rebound Stiffness

Increasing Front Rebound

More grip in the rear.
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.
How high rebound setups you can have depends on the Bump stiffness that you have set. If you are using high Rebound with low Bump, your car may get upset by curbs etc. This is modified by ride height and suspension stiffness.

Higher Rebound than Bump is must but the Bump Stiffness should be 75% of the Rebound’s stiffness at maximum. Low Bump Stiffness goes great so don’t limit yourself with officially given tip that 50% of the Rebound’s stiffness should be a minimum.

Bump Stiffness
It fine tunes damping and suspension.

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.
To test the excessive Bump Stiffness, let your car take a mild curb aggressively and then see if your car rolls. If it rolls, your setup is too stiff. If you already had your bump

Anti-Roll Bars
Anti-Roll Bars support the balance of the car at cornering or stop it from rolling over at corners. There are two types of Anti-Roll Bars – Front Anti-Roll Bars and Rear Anti-Roll Bars.

Upgrading Anti-Front Roll Bar will decrease front chassis roll while giving your more rear grip, while upgrading Anti-Rear Roll bar will decrease rear chassis roll and give your more front grip.

You can choose between Soft and Stiffer Bars and benefits are:
Softer Front Anti-Roll Bar

Increases front chassis roll.
Increases front grip or traction, while decreasing rear grip or traction.
Slower steering response.
Increases off-power steering at corner entry.
Stiffer Front Anti-Roll Bar

Decreases front chassis roll.
Decreases front grip or traction, while increasing rear grip or traction.
Faster steering response.
Decreases off-power steering at corner entry.
Softer Rear Anti-Roll Bar

Increases rear chassis roll
Increases rear grip or traction, while decreasing front grip or traction.
Less on-power steering.
Stiffer Rear Anti-Roll Bar

Decreases rear chassis roll.
Decreases rear traction, while increasing front grip or traction.
Faster steering response in high-speed corners and chicane.
Increases on-power steering.

Hope this helps.

Admin

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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Wed Aug 14, 2013 1:03 pm

Talks about the tires and what the differential does for the car.

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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Wed Aug 14, 2013 1:03 pm

DRIVERS THERE IS A LOT OF GOOD AND HELPFUL INFORMATION HERE. THIS CAN BE THE EDGE YOU NEED TO GET BETTER FASTER!

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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Wed Aug 14, 2013 5:03 pm

Great vid pred. Some great info in there. If you have trouble setting up a car to corner, there's some great info on how your diff should be set.
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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Fri Jan 03, 2014 2:12 pm

I base a great deal of my tuning on real world principles from this book:
http://www.carrollsmith.com/books/index.html

Tune to win
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PostSubject: Re: DRIVING / RACING / TUNING HELP GUIDE   Fri Jan 03, 2014 9:36 pm

MTBVator wrote:
I base a great deal of my tuning on real world principles from this book:
http://www.carrollsmith.com/books/index.html

Tune to win

Looks great. Ordered a copy.
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