Professor Zabbey's Guide to B Class Tuning

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Professor Zabbey's Guide to B Class Tuning

Post by Zabbey21 on Wed Oct 10, 2012 10:16 pm

Zabbey's Guide to B Class

Introduction

This guide is intended to provide my insight towards tuning for B Class public lobbies and sometimes race serieses here on OZFM. Please note that this guide contains my own personal preferences towards upgrades and tuning. Depending on your driving style, you may find that the tunes posted in this guide may or may not work for your driving style (too oversteery, too understeery, not fast enough in a straight line etc) I will go through the steps I take to tune my cars for B class and hopefully at the end of the guide you have gained a greater understanding of tuning and you have also found yourself to have been quicker Wink

Why B Class?

B Class is a fairly good class to start out in as the cars are medium speed, medium handling cars, and most cars can be tuned to be competitive in this class, giving a wide variety of available choices of vehicle.

Step One: Picking the Car

Picking a car is usually a simple process. Just by gauging the cars stats, you can immediately tell the cars weaknesses and strengths. For example:

1977 Dodge Coronet Super Bee (C377)

An American Muscle Car, due to its massive 7.0L V8 it produces 317kw and 664Nm of torque. This car will have good launch off the start line and will accelerate hard. Due to its large weight and size and old chassis, the car itself will not handle the best straight out and will be outmanoeuvred in the corners by smaller, newer cars. Suited to higher speed tracks with faster corners.

2009 Volkswagen Scirocco GT (C382)

A European Hot Hatch with the chassis of a Golf, known for its sexy styling and great handling figures, it can outhandle most cars in its class. Compared to the Coronet, it has a modest 2.0L turbo engine producing 147kw, which means while it may outhandle the Dodge, it certainly won't outdrag or outmuscle it. Suited to smaller and twistier tracks.

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So, first piece of advice is to pick a car suited towards the track. I'm going to be tuning all of these cars on Catalunya National, one of my personal favourites and also a good track for the specs of B class. My first car that I'll go through the tuning process will be:

1994 Nissan Fairlady Z Version S Twin Turbo (C379)
Speed: 5.8
Handling: 4.9
Acceleration: 6.1
Launch: 6.5
Braking: 4.7

This is a good allround car with a good base to work from. Being C379 it leaves lots of room for potential upgrades.

Step Two: Upgrade Choices

Choosing which upgrades to use is as important as the tuning itself. Adding power when you should be adding tire width makes a key difference to your lap times and depending on what track, it may cost you a fair amount of time. We'll work our way from right to left in terms of upgrades (Aero and Appearance, Tires and Rims, Drivetrain, Platform and Handling, Power). Sometimes after the final build is done, you can make adjustments to suit either power or handling. (Note: Conversion Modifications are rarely used in my builds, I will specify if there is a conversion done)

Aero and Appearance

You'll usually find a lot of bodykits and wings that aren't adjustable, meaning that they are purely cosmetic. For the sake of these builds, I will either use Forza Adjustable Aero or running the stock bodykits. The exception to this is bonnet/hood upgrades, which reduce the weight at the front end.

Front Bumper

An Adjustable Aero Front Bumper will increase the downforce on the front end of the car, enabling greater handling at speed, but sacrificing top speed.

This upgrade changes the stats:

Speed: (-0.3)
Handling: (+0.0)
Acceleration: (-0.0)
Launch: (-0.0)
Braking: (+0.1)

Rear Wing

An Adjustable Aero Rear Wing will increase the downforce on the rear end of the car, enabling greater handling at speed, but sacrificing top speed.

This upgrade changes the stats:

Speed: (-0.6)
Handling: (+0.1)
Acceleration: (-0.1)
Launch: (-0.0)
Braking: (+0.1)

Aftermarket Hood

An aftermarket hood will reduce the weight on the front end of the car, slightly reducing understeer and decreasing overall weight.

This upgrade changes the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.0)

So far, the stats for the Nissan Fairlady Z are:

Speed: 4.9
Handling: 5.0
Acceleration: 6.0
Launch: 6.5
Braking: 4.9

Tires and Rims

This can be the make or break point in the handling of your car. Race tires offer better grip than Sport tires, but sometimes this can come at a cost of heavier weight and/or less power. Choosing the right tires for the build can sometimes be quite difficult.

Tire Compound

In terms of stats, I usually compare the sport and race tires and see how much difference they make.

On this Nissan, when the sport tires are put on, the stats change:

Handling: (+0.4)
Braking: (+0.4)
Launch: (+0.0)

Personally, when I put sport tires on, the handling should be low to middle 5.0s. This means that the sport tires are well suited to this build.

Tire Width

The wider the tire width, the easier it is to put the power down coming out of a corner and the grippier your car will be during the corner. The rear tire width is usually larger than the front on most cars, mainly in RWD due to the rear wheels handling all the power.

With nearly all of my builds for most classes, I increase the tire width to maximum, as it boosts the handling up and enables greater power delivery.

For the Nissan, I used maximum tire width upgrades on the front and the rear wheels.

Front Tire Width upgrades changed the stats:

Handling: (+0.1)
Braking: (+0.1)
Acceleration: (-0.0)
Launch: (-0.0)

Rear Tire Width upgrades changed the stats:

Handling: 5.6 (+0.1)
Braking: 5.5 (+0.1)
Acceleration: (-0.0)
Launch: (-0.0)

Rim Style

Lightweight wheels can reduce the unsprung mass of the vehicle, meaning that the centre of gravity is closer to the centre of the car, enabling greater handling.

For the Nissan, I picked a set of Konig After Burners, which is the equal lightest rim available in Forza Motorsport.

These Rim Upgrades increased the stats:

Handling: (+0.0)
Acceleration: (+0.1)
Launch: (+0.0)
Braking: (+0.0)

Rim Size

I tend to steer away from rim sizing due to it being almost fully cosmetic. Sometimes increasing the wheel size by a small amount will increase tyre response time, but it won't be that noticeable.

For the sake of the build, I left the rim size as standard.

So far, the stats for the Nissan Fairlady Z are:

Speed: 4.9
Handling: 5.6
Acceleration: 6.1
Launch: 6.5
Braking: 5.5

Drivetrain

Drivetrain includes clutch, tranmission, driveline and differential upgrades. These upgrades increase how the power is put down to the road. The differential controls the wheel rotation speeds of each wheel, the transmission controls the duration of power throughout the gears, the clutch reduces the amount of time between shift changes. and the driveline increases throttle response and reduces throttle lag between gearchanges. These modifications can sometimes make or break your car, a good drivetrain setup will be the good basis for suspension and handling tuning.

Clutch

For the Nissan, we'll upgrade to the Race Clutch. This will reduce the amount of time between gearchanges.

This upgrade changed the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.0)

Transmission

For the Nissan, we'll upgrade to a Sport Transmission. This will reduce the amount of time between gearchanges and allows for an adjustable final drive ratio, which can change the length of the gearing to accomodate for the track. (Note: Race Gearbox features fully adjustable ratios, where each gear can be manipulated. Sport Gearbox only affects final drive, which changes the length of each gear as one, not individually).

This upgrade changed the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.1)
Braking: (+0.0)

Driveline

For the Nissan, we will upgrade to a race driveline, which will decrease driveline inertia and will also improve throttle response and decrease the overall weight of the car.

This upgrade changes the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.0)

Differential

For the Nissan, we will upgrade to a race differential. This will allow us to control the acceleration and deceleration settings of the driveline, which can improve responsiveness and allow for more controllable acceleration and deceleration.

This upgrade changed the stats:

Handling: (-0.0)
Acceleration: (-0.0)
Launch: (-0.0)
Braking: (-0.0)

So far, the stats for the Nissan Fairlady Z are:

Speed: 4.9
Handling: 5.6
Acceleration: 6.1
Launch: 6.6
Braking: 5.5

Platform and Handling

These upgrades include brakes, suspension, anti-roll bars, chassis reinforcement and weight reduction. These upgrades are designed to increase the handling and stability of the car, aswell as decreasing the weight. This enables better launch and acceleration, as well as better handling and less tire wear.

Brakes

Brakes are important for pulling the car up to a corner. Without decent brakes, the car will overshoot certain corners and may not be able to slow down in time for certain corners. Decent brakes reduce the weight, increase braking power (which decreases the amount of braking needed to slow for a corner) and adjustable brake bias.

For the Nissan, we will upgrade to Racing Brakes.

This upgrade changed the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.4)

Springs and Dampers

Springs and Dampers are important in keeping your cars tires in contact with the road. A good spring and damper kit will cause better overall stability in cornering and under braking and acceleration, as well as being adjustable to suit different road textures and elevations.

For the Nissan, we will upgrade to Race Springs and Dampers.

This upgrade changed the stats:

Handling: (+0.1)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.0)

This upgrade also lowers the ride height -3.5cm from stock.

Front Anti-Roll Bars

Front Anti-Roll Bars provide extra stability in the front of the car when cornering and braking. Anti-Roll Bars help the car ride more level and reduce body roll and movement.

For the Nissan, we will use Race Front Anti-Roll Bars.

This upgrade changed the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.0)

Rear Anti-Roll Bars

Rear Anti-Roll Bars provide extra stability in the rear of the car when cornering and braking. Anti-Roll Bars help the car ride more level and reduce body roll and movement.

For the Nissan, we will use Race Rear Anti-Roll Bars.

This upgrade changed the stats:

Handling: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)
Braking: (+0.0)

Chassis Reinforcement and Roll Cage

Chassis reinforcement, such as racing strut bars, subframe braces and roll cages increase the rigidity of the car, reducing chassis flex and body roll which allows the suspension to work better.

For the Nissan, we will use Sport Chassis Reinforcement and Roll Cage.

This upgrade changed the stats:

Handling: (+0.0)
Acceleration: (-0.1)
Launch: (-0.1)
Braking: (+0.1)

Weight Reduction

Weight Reduction involves the removal of nonessential materials and replacing stock parts with lighter variations. This decreases the overall weight and can improve performance in straight line and corner speeds. This can include the removal of the entertainment system, rear seats, power windows, A/C system, carpets etc.

For the Nissan, we will use the Sport Weight Reduction.

This upgrade changed the stats:

Handling: (+0.2)
Acceleration: (+0.3)
Launch: (+0.4)
Braking: (+0.1)

So far, the stats for the Nissan Fairlady Z are:

Speed: 4.9
Handling: 5.9
Acceleration: 6.3
Launch: 6.9
Braking: 6.1

Engine and Power

Engine and Power upgrades increase the power and torque of your engine. This can increase straight line speeds, and by using lighter constructed parts can also reduce the overall weight of the car. Combining engine modifications is the best way to get the most out of the engine.

Exhaust

Exhaust upgrades such as headers and mufflers allow the engine to exhale more freely, by reducing backpressure and extracting exhaust gases more efficiently. This increases the power and will also decrease the weight.

For the Nissan, we will install a Race Exhaust.

This upgrade changed the stats:

Speed: (+0.2)
Handling: (+0.0)
Acceleration: (+0.3)
Launch: (+0.4)
Braking: (+0.0)

Valves

Upgraded valves improve the intake of air and exhaust gas flow, which allows the engine to breathe freely and produce more power in the higher RPM range of an engine.

For the Nissan, we will use Sport Valves.

This upgrade changed the stats:

Speed: (+0.1)
Handling: (+0.0)
Acceleration: (+0.1)
Launch: (+0.0)
Braking: (+0.0)

Fuel System

Fuel System upgrades provide better fuel flow and timing, as well as extracting more power from the fuel that is used. The upgrades can range from installing a reprogrammed ECU chip to changing the fuel pump and tank, injectors and hoses.

For the Nissan, we will use the Street Fuel System.

This upgrade changed the stats:

Speed: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)

Displacement

Displacement upgrades make the engine more durable. The also reduce friction and inertia and make the engine more powerful and responsive.

For the Nissan, we will use the Street Displacement upgrade.

This upgrade changed the stats:

Speed: (+0.0)
Acceleration: (+0.0)
Launch: (+0.0)

The Final Specs and Stats for the Nissan Fairlady Z are:

Speed: 5.3
Handling: 5.9
Acceleration: 6.8
Launch: 7.4
Braking: 6.1

Power: 252 KW
Torque: 433.1 NM
Weight: 1,350 KG
Weight (Front %): 53%
Displacement (Engine): 3.0L

Step Three: Tuning the Car

For me, the tuning process is relatively simple, but I'll explain it the best I can. First off, pick a track (Catalunya National) and go for a few laps around the track. You can immediately tell what needs some fixing and what doesn't, but I'll explain how to tune what.

Note: Turn limited or simulation damage on so you can calculate tire wear.

Tire Pressure

Tire pressure involves how inflated your tires will be, which effects how quickly they will heat up to race temperatures. Having the tire pressure set lower causes the tires to heat faster, but they will have an overall lower temperature, which means they won't be at optimum grip. Setting the tire pressure higher causes the tires to heat slower, but they gradually reach a higher peak temperature.

If you want to run fairly quick laps straight away, set the pressure lower. If you want to gradually increase your speed and then ultimately run quicker laps, then set the tire pressure higher.

For my cars, I usually set my tire pressures anywhere from 1.8 to 2.4 bar. Experiment in that range with the Nissan and see what feels comfortable for you.

Gear Ratios

The gear ratios can be important in the launch and acceleration figures of your car. With the sports transmission, a lower final drive ratio will increase the top speed and length of each gear, but the car will get to that speed fairly slow, and may not even make it to its theoretical top speed. Setting the final drive ratio higher means the top speed of the car is reduced, and the speeds in each gear are shorter. This is better for acceleration and the car will reach its top speed on most tracks.

I like having shorter gear ratios in my car, so I set the final drive ratio higher so the gear changes come quicker. The Nissan is a 5 speed, so experiment between the 4.45 and 5.00 margin and see what feels comfortable for you.

Camber

Camber effects the way the wheels come into contact with the road. Negative camber is when the top of the tires are closer together than the bottom, and it creates better corning grip, but reduces straight line grip. Positive camber is when the tops of the tires are further away from each other than the bottom, which increases straight line grip but can cause the car to become unstable.

Negative Camber: / \ (what the tires look like from the front)

Positive Camber: \ / (what the tires look like from the front)

Adjust the camber so the car turns into the corner better, but not so much so that the car understeers or oversteers. As a general rule, I usually have my front camber either equal or a little more negative than the rear.

With the front, experiment between the -0.6 and -0.9 camber margin and see what feels comfortable for you.

With the rear, experiment between the -0.6 and -0.8 camber margin and see what feels comfortable for you.

Toe

Toe involves the inward or outward angle of the wheels. Positive Toe/Toe Out means the front of the wheels point slightly outward, causing better turn in but decreases stability. This applies to both wheels.

Negative Toe: / \ (what the tires look like from the top)

Positive Toe: \ / (what the tires look like from the top)

Adjust the toe so that the car turns in smoothly, but not too much so that it is unstable. A good rule to follow is always have your front toe more positive than the rear, so you reduce the amount of oversteer.

With the front, experiment between 0.1 and 0.4 degrees of toe, and see what feels comfortable for you.

With the rear, experiment between 0.0 and 0.3 degrees of toe, and see what feels comfortable. If the car is fairly oversteery with 0.0 degrees of toe, give it a little bit of toe in, which should help reduce the oversteer.

Caster

Adjusting the caster of the steering axis increases straight-line stability. With positive caster, the steering axis is inclined rearward. As the suspension compresses and the tires go through steering lock, negative camber increases. Therefore, increasing positive caster lets you run less negative camber, which means in a straight line you'll have more stability under acceleration and braking and will provide a good amount of negative camber for turning corners.

In my experience, I haven't fiddled around with the caster angle too much, going to too far extremes can cause the car to handle waywardly.

Try adjusting the caster from between 4.9 - 5.3 degrees and see what's comfortable for you.

Anti-Roll Bars

Anti-roll bars provide stability under cornering, decreasing body roll and increasing stiffness in the chassis. It also helps reduce understeer and oversteer in stead cornering (fast sweeping turns). Decreasing anti-roll stiffness in the front reduces understeer. Increasing the front anti-roll stiffness increases understeer, but too much anti-roll stiffness can cause the front tires to lift off the ground during hard cornering.

Decreasing anti-roll stiffness in the rear reduces oversteer. Increasing anti-roll stiffness in the rear increases oversteer, but excessive anti-roll stiffness can cause the inside tires to lift off the ground during hard cornering.

Adjusting the anti-roll bars can provide a balance between understeer and oversteer.

From personal experience, I usually set the front anti-roll bars stiffer than the rear to reduce oversteer, but not so much so that it becomes understeery.

Springs

Spring stiffness controls how the cars weight is transferred under acceleration, braking, and cornering. Stiffer front springs transfer more weight, but too much can cause the tires to lose traction under heavy load. Softening the front springs in relation to the rear increases front grip and reduces understeer. Softening the rear springs will increase rear grip and reduce oversteer.

Try adjusting the front springs harder than the rear springs so the front has more grip than the rear. Experiment with hard and soft springs and see what works for you.

Ride Height

Ride height involves how close the car sits to the ground. The lower the car is, the lower the centre of gravity and the better it will corner. Lowering the ride height too far can cause the car to bottom out and lose control suddenly.

I usually make the car as low as possible. If the car feels a little oversteery, increase the rear ride height to help control weight transfer.

Rebound Stiffness

Rebound stiffness controls how quickly the suspension rebounds away from the wheel well, and also controls how rigid and stiff the suspension will be when travelling over bumps.

Setting the front rebound stiffness higher than the rear causes more transitional understeer. Setting the rear rebound stiffness higher than the front causes more transitional oversteer.

Try setting the front rebound stiffness higher than the rear, so the car doesn't oversteer too much. Experiment with the damping settings and see what works (Note: try using less damping on tracks with more elevation changes and bumps)

Bump Stiffness

Bump stiffness controls the rate of compression as the suspension goes up into the wheel wells. Increasing front bump damping increases transitional understeer. Decreasing front bump damping stiffness increases transitional oversteer. Increasing front bump damping stiffness increases transitional understeer. Decreasing rear bump damping stiffness increases transitional understeer. Increasing rear bump damping stiffness increases transitional oversteer.

Try setting the bump damping at the front higher than the rear, so the car doesn't oversteer too much. Experiment with the front and rear and see what feels best for you (note: set the bump damping to 50-75% of the rebound damping, so the car squats before the rebound makes it stand up)

Downforce

Increasing the downforce causes the air running over the car to push down on the car more, which enables greater cornering speeds and quicker tire heating. Too much downforce can cause excessive drag, which will reduce top speed and increase tire wear.

Try setting the rear downforce higher than the front, so the back of the car is more stable. Experiment with different values of the downforce to see what feels best for you.

Brake Balance and Pressure

Brake balance adjusts how much brake bias towards the front or the rear happens under braking. Increasing the front brake bias causes the car to understeer under braking, becoming more stable, but can lead to excessive understeer under braking. Increasing the rearward brake bias causes the car to oversteer under braking at the expense of stability.

Experiment with the brake bias. If you like to brake quicker at the expense of turn-in, then increase frontward bias. If you like to brake slower but have more control over the turning ability under braking, increase rearward bias.

Braking pressure controls how much braking is needed to lock the tires. Increasing brake pressure means stronger braking force, but the more likely you will lock the brakes, losing control of the car. Decreasing brake pressure means less braking force, but the more pedal travel required to lock the brakes.

Experiment and see how aggressive you want to be with your braking. If you brake quite hard and slam them, reduce the braking pressure. If you're a little bit more controlled under braking and use less pedal travel, increase the braking pressure.

Differential

The differential allows the tires on each side of the car to turn at different rates, since the inside tire travels a shorter distance around a turn than the outside tire. An LSD locks at a preset point to limit the difference in rotational speed, providing maximum traction under acceleration and deceleartion.

Increasing the accel setting makes the diff lock quicker under acceleration. Increasing the Accel setting can increase oversteer in rear and all wheel drive cars.

Try experimenting at around 70% for the acceleration setting, and see how much the car wants to slide out when you accelerate during a corner. If it slides, try reducing the acceleration settings. Increase the acceleration settings until you have maximum possible grip out of a corner without sliding.

Increasing the Decel setting makes the diff lock quicker under deceleration, which can impair handling. Decreasing the Decel setting reduces lift off oversteer coming into a corner.

Try experimenting at around 25% for the decel setting. See how the car reacts when you shift down to 1st in a slow corner and when you lift off coming in to a corner. If the car wants to slide, or skids along the ground, reduce the decel setting.

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That is all for Zabbey's Guide to B Class Tuning, I hope you learnt something and I'll see you with your B Class monsters on the track Wink
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Zabbey21
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Re: Professor Zabbey's Guide to B Class Tuning

Post by crimson eagle73 on Fri Oct 12, 2012 4:59 pm

Best guide I have read on Forza... Thanks mate. Surprised no one else has commented. EDIT I'm a bonehead because this thread is locked Smile


Last edited by crimson eagle73 on Fri Oct 12, 2012 7:36 pm; edited 1 time in total

crimson eagle73
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Re: Professor Zabbey's Guide to B Class Tuning

Post by surferofthemind on Fri Oct 12, 2012 5:08 pm

You need that poll like I added to my additions to the Uni.
Was this helpful? YES!

Nice work Zabby. Looking forward to you next addition.






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Re: Professor Zabbey's Guide to B Class Tuning

Post by Zabbey21 on Fri Oct 12, 2012 8:33 pm

crimson eagle73 wrote:Best guide I have read on Forza... Thanks mate. Surprised no one else has commented. EDIT I'm a bonehead because this thread is locked Smile

It's not locked Razz

Cheers guys, thanks for the positive feedback
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