Turn 10 Studios have introduced quite a few changes in Forza Motorsport 4 physics especially how tires react to real world situations, how track bumpiness affects the driving, steering has been overhauled, and how suspension works in the game.
The goal of tuning your car is to make the right trade offs for right scenarios and this guide will help you do just that. It is really important that you only upgrade the right components of your car and you may end having to adjust all these components again just to make it drive-able.
Our goal is to walk you through each tuning option, give you the pros and cons, and give you insight how that specific part will hold under different conditions.
For this reason, we have taken the suggestions of the pro’s and have written them in a precise way to help you understand the basics of tuning and upgrading your engine parts in Forza Motorsport 4.
I have already explained why 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.
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.
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 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.