Right, transmission calcs... as mentioned in another topic...

Using the initial FD setting calculation and table and the default ratios it wouldn't get out of 4th. This is very much so a case of the FD not the ratios...

Weight = 2268lbs
HP = 168hp

Weight/HP = 13.5

Using the table that gives a FD of 2.9 which is nowhere near enough... I had to change it to around 4.0 to get it in to the top end of the overdrive gear.

---

My Forza Cars
My Real Car

Great Web Hosting/Design Deals

i got a better lap time just by adding the suspension upgrades in the silverstone international circuit with 28 psi on the tires

with ur mods=1.25.685
my setup=1.24.345

RichMR2:

Right, transmission calcs... as mentioned in another topic...

Using the initial FD setting calculation and table and the default ratios it wouldn't get out of 4th. This is very much so a case of the FD not the ratios...

Weight = 2268lbs
HP = 168hp

Weight/HP = 13.5

Using the table that gives a FD of 2.9 which is nowhere near enough... I had to change it to around 4.0 to get it in to the top end of the overdrive gear.

The 2.9 initial FD setting is just an initial setting,......you HAVE to adjust it to find top speed before you do any f the remaining calcs.

It's meant to be lower than it should be, you should have to adjsu almost every low class cars FD to a lower FD gear(higher number).

Some cars fit ok,...others do not, thats why you have to find the actual FD in the top speed test.

chevy33191:

i got a better lap time just by adding the suspension upgrades in the silverstone international circuit with 28 psi on the tires

with ur mods=1.25.685
my setup=1.24.345

Um,...cool?!

You are supposed to tune for better results.  Congrats.

 OK, guys here it is, sorry it took so long.  The good news is that it's here, the bad news is that I ran out of testing time,....so once again, i'm going to ask for as much feedback as I can get.  There are MANY changes to pick up on this time around so if you are going to update your calculators PLEASE, PLEASE, PLEASE! pay attention to the details, and ensure all of you numbers are correct before reposting. 

There are a few tweaks that still need to be made with the rear and mid-engine drive types but they will most likely be very minor.  I need to run some more tests there, other than that, I hope it all works out, cause this endless testing and comparsion work is kickin' my butt.  But as promised, here's V3, enjoy!

Forza Motorsports 2
Suspension Setup Calculator
Version 3
by Feuerdog

INTRO - The new physics modeling of FM2 has changed the realism and overall feel from FM1. In order to take advantages of the new physics, a new guide with new calculations needed to be written. Improvements have been made in the guide, just as in the sim. Hopefully these new suspension setup calculations will provide you with a car that handles better, is easier to drive, and faster too. Enjoy!

PURPOSE - Why use this calculator?
- What it might do you for you....
- help drivers and tuners by giving them a way to tune or retune their own cars without having to understand all the definitions and relationships within a suspension setup.
- To possibly improve the performance of a car that is troublesome to drive and/or tune.
- To provide an easy way to establish a baseline tune from which more advanced tuning can be done.

- What it won't do for you...
- It is not intended to explain why or how everything works, independently or as a whole, but it might provide some useful information.
- No two cars, drivers, tracks, or setups will act exactly the same. Your results will be subjective and will vary.
- These calculations will not achieve a perfect tune, but they may be an improvement, or at least an alternative.
- This is NOT an ultimate setup guide. You can improve these tunes further. I do.

MY DRIVING STYLE - Do we drive the same way?
The same tune that works for one driver doesn't always work well for other drivers. In order for you to understand why the tune from this guide will handle the way it does, it helps to understand the way that I drive and what characteristics I look for.

- I use a standard controller(sometimes the wheel and pedals), with trigger brake, trigger throttle, and stick for steering.
- No assists usually except for ABS. In car view. Auto transmission.
- I memorize physical objects like signs, walls, barriers, and curbs to mark where my braking and turn-in points are.
- I like my tunes to be stable, balanced, and easy to drive.
- I like moderate spring, stiff damper setups.
- I tend to brake hard and straight at first, and then transition into a trail-braking turn-in. I then transition into full acceleration from apex to exit.
- I prefer on-throttle, and throttle lift oversteer characteristics.
- I usually use the same tune for every track, but there are always exceptions.
- I am not the greatest driver, but I manage to have fun.

REALISM - Keeping it real.
I have tried to tune my cars based, for the most part, on reality. If the physics of Forza are realistic, then realistic values should work in the sim, and they do, which is a good thing. The Turn 10 team did very well. Tuning and testing in a realistic way adds to the enjoyment of the whole simulation for me. Therefore, I have gone to some lengths to keep my tuning based on "real world" values and ratios. I have actually spent a lot of time, and some money, to learn more about suspension dynamics and racing car tuning in general. In the end it's all about fun. If this calculator can provide you with a car that is more fun and easier to drive then my work here is done.

SUSPENSION SETUP CALCULATOR
1. Before you begin.
2. Tires
- Pressure
3. Alignments
- Camber
- Toe
- Caster
4. Springs, Dampers, and Antiroll Bars
- Springs
- Dampers
- Antiroll Bars
5. Brakes
- Force
- Bias
6. Differentials
- FWD
- RWD
- AWD
7. Aerodynamics
- Camber
- Springs
- Brake bias

1. BEFORE YOU BEGIN -
1.1 - You need to have....
a. A basic calculator, a pencil, and something to write on.
b. A car with a Race suspension, Race brakes, Race Springs and Dampers, and a Sport or Race Differential.

1.2 - You need to know....
a. The weight of the car, and what the weight distribution values are for front and rear. This vehicle information is found in the game itself.
b. Any changes to the weight of the vehicle will mean you have to recalculate the settings!
c. These settings assume the use of ABS, but with NO TCS, and NO STM! There is a good chance your car won't handle very well with these assists enabled when using these calculations.
d. A few abbreviations:
AWD = All wheel drive
FWD = Front wheel drive
RWD = Rear wheel drive

FF = Front engine, Front wheel drive
FR = Front engine, Rear wheel drive
FA = Front engine, All wheel drive
MR = Mid engine, Rear wheel drive
MA = Mid engine, All wheel drive
RR = Rear engine, Rear wheel drive
RA = Rear engine, All wheel drive

Understeer - the car doesn't turn easily
Oversteer - the car turns too easily

2. TIRES -
2.1. Set Tire pressures -
a. Set all tires to 29psi

b. Adjust tire pressure for best operating pressures -
1. Free Run five or more laps of Tsukuba.
2. Watch the telemetry screen for tire pressures.
3. Note the pressure increase of the left side tires from lap one to lap five.
4. Adjust the tire pressures so that the tire heats "up" into its best operating pressure and/or temperature.

Advanced Tire Size tuning -
a. For cars with larger rear tires than front tires, add -1% brake bias and add .1 to front toe.

Advanced Tire Temperature tuning -
a. If single tire temperature differences exceed 10 degrees, then increase antiroll bar settings and retest.

Note: There is a relationship between the vehicles weight, aerodynamic downforce, and the tires ability to warm and cool to optimal operating pressures. Lighter cars may benefit from lower pressures, and high downforce or heavyweight cars may require higher than normal pressures.

3. ALIGNMENTS -
3.1. Set Camber -
a. Set camber to -.8 Front/-.8 Rear

Advanced Tuning - Add or remove camber to prevent uneven heating.

3.2. Set Toe -

FF = .1 front/.1 rear
FR = .0 front/-.2 rear
FA = .1 front/.1 rear
MR = 0 front/-.1 rear
MA = .1 front/0 rear
RR = 0 front/-.2 rear
RA = 0 front/-.1 rear

Advanced Tuning - Increase front positive toe to improve turn-in response, decrease to improve stability. Increase rear negative toe to improve rear stability, decrease to reduce understeer.

3.3. Set Caster -
- Set caster to 5.5

Notes: I don't want to get into the details of caster tuning, but it is very closely related to front camber settings, and it shouldn't be adjusted out of the 5.6~6.0 range while used with the other settings. 5.5 caster adds approx. 3 degrees of dynamic camber to the front wheels at full steering lock.

4. SPRINGS, DAMPERS, and ANTIROLL BARS -
4.1. Find the weight multiplier -
a. Get the weight of the car from the garage screen.
b. Subtract 300 from vehicle weight and multiply by .34
c. This is your weight multiplier - write this number down.
Example FF car: (2600 lbs - 300) x .34 = 782

Advanced Tuning -
- For slightly stiffer suspension add 50 to this result.
- For very stiff suspension add 100 to this result.
- For slightly softer suspension subtract 50 from this result.
- For very soft suspension subtract 100 from this result.

4.2. Find the modified weight distribution -
a. Get the weight distribution values for the car.
Example FF car: 57% front/43% rear

b. Calculate the cars modified weight distribution values by altering the stock weight distribution using the following table:

FF = subtract 8% from the front, and add 8% to the rear.
FR = add 8% to the front, and subtract 8% from the rear.
FA = subtract 5% from the front, and add 5% to the rear.
MR = add 2% to the front, and subtract 2% from the rear.
MA = add 2% to the front, and subtract 2% from the rear.
RR = add 2% to the front, and subtract 2% from the rear.
RA = add 1% to the front, and subtract 1% from the rear.

Example FF car: 57% front (-8%)/43% rear (+8%) = 49% front/51% rear

c. These modified percentages are your modified weight distribution - write this number down.

4.3. Find the Spring value -
a. Weight multiplier x modified weight distribution = Spring value - enter these settings.
Example FF car:
- 782(weight modifier) x .49(49% modified front weight distribution) = 383 Front Springs
- 782(weight modifier) x .51(51% modified rear weight distribution) = 398 Rear Springs

Advanced Tuning - You may need to adjust your ride height. Lower is better, but too low may cause excessive bottoming out. Adjust as needed.

4.4. - Find the damper Bump Stiffness -
a. (Spring value + 200) x .011 = Bump Stiffness - enter these settings.
Example FF car:
- (383 front springs + 200) x .011 = 6.4 front Bump Stiffness
- (398 rear springs + 200) x .011 = 6.5 rear Bump Stiffness

Advanced Tuning - For stiffer dampers multiply by .012, for softer dampers multiply by .010

4.5 - Find the damper Rebound Stiffness -
a. Get the Bump Stiffness values for the car.
Example FF car:
- 6.4 front Bump Stiffness
- 6.5 rear Bump Stiffness

b. Calculate the cars Rebound Stiffness values with the following table:

FF - Front Bump stiffness x 1.4 = Front Rebound Stiffness
FF - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

FR - Front Bump stiffness x 1.1 = Front Rebound Stiffness
FR - Rear Bump stiffness x 1.4 = Rear Rebound Stiffness

FA - Front Bump stiffness x 1.3 = Front Rebound Stiffness
FA - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

MR - Front Bump stiffness x 1.3 = Front Rebound Stiffness
MR - Rear Bump stiffness x 1.3 = Rear Rebound Stiffness

MA - Front Bump stiffness x 1.4 = Front Rebound Stiffness
MA - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

RR - Front Bump stiffness x 1.1 = Front Rebound Stiffness
RR - Rear Bump stiffness x 1.3 = Rear Rebound Stiffness

RA - Front Bump stiffness x 1.3 = Front Rebound Stiffness
RA - Rear Bump stiffness x 1.2 = Rear Rebound Stiffness

Example FF car:
- 6.4(front bump stiffness) x 1.4 = 8.9 front Rebound Stiffness
- 6.5(rear bump stiffness) x 1.1 = 7.1 rear Rebound Stiffness

Advanced Tuning -
- Increase corner entry oversteer OR Decrease corner entry understeer = Subtract .1 from the rear Rebound Stiffness multiplier, and recalculate.
- Increase corner exit oversteer OR Decrease corner exit understeer = Add .1 to the front Rebound Stiffness multiplier, and recalculate.

- Increase corner entry understeer OR Decrease corner entry oversteer = Add .1 to the rear Rebound Stiffness multiplier, and recalculate.
- Increase corner exit understeer OR Decrease corner exit oversteer = Subtract .1 from the front Rebound Stiffness multiplier, and recalculate.

4.6. Find the Antiroll Bar settings -
a. Weight distribution x 24 = AntiRoll Bar settings - enter these settings.
Example FF car:
- .57(front weight distribution) x 24 = 13.6 front AntiRoll bar
- .43(rear weight distribution) x 24 = 10.3 rear Antiroll bar

Advanced Tuning -
- For slightly stiffer antiroll bars change multiplier to 33
- For very stiff antiroll bars change multiplier to 44, and decrease caster to 5.4
- For slightly softer antiroll bars change multiplier to 17
- For very soft antiroll bars change multiplier to 12, and increase caster to 5.6

5. BRAKES -
5.1. Set Brake Force -
- Set brake force to 110% with ABS, or 90% without ABS.

5.2. Set Brake Balance -
- Set brake balance to 47% front

Advanced Tuning -
- If rear tires are at least 30mm wider than front tires subtract 1% from brake balance.
- Adjust force in +/-5% increments for best feel, or benchmark performance.
- Adjust balance in +/-2% increments for best feel, or benchmark performance.
- Use friction telemetry screen to determine which wheels are losing traction first and adjust balance accordingly.

6. DIFFERENTIALS -
- FWD = 35% Accel./0% Decel.

- RWD = 60% Accel./50% Decel.

- AWD Front = 35% Accel./0% Decel.
- AWD Rear = 80% Accel./70% Decel.
- AWD Split = 25% Front/75% Rear

Note: Gearing, power, and torque won't directly how the diff. work but they will change the feel of it's effects. Keep this in mind while tuning.
Sport differentials are adjustable in accel. only.

Advanced Tuning -
Accelerating oversteer?
- Adjust rear diff. = -5% Accel.

Accelerating understeer?
- Adjust front diff. = -5% Accel.

Braking oversteer?
- Adjust diff. = +5% front Decel. OR -5% rear Decel.

Braking understeer?
- Adjust front diff. = -5% Decel. OR +5% rear Decel.

7. AERODYNAMICS(Optional adjustments)-
7.1. Adjust camber based on aerodynamic downforce -
- Add +.1 camber per 100lbs downforce
Example R4 car: 150lbs front/300lbs rear
(150lbs front = +.1) = (+1) + (-.8 camber) = -.7 front camber
(320lbs rear = +.3) = (+.3) + (-.8 camber) = -.5 rear camber

7.2 . Adjust spring value for aerodynamic downforce -
- (Downforce x .15) + Spring value = Adjusted Spring value
Example FF car: 110lbs front/25lbs rear
(110lbs front x .15) = 16 + 383 = 399 front springs
(25lbs rear x .15) = 3 + 398 = 401 rear springs
Note: Do NOT recalculate damper settings after this spring adjustment is made.

Advanced Tuning - For lower compensation multiply by .1, for higher compensation multiply by .2

7.3. Adjust brake bias based on aerodynamic downforce -
a. Subtract front downforce from rear downforce.
Example FR car: 80lbs front/190lbs rear
190lbs rear - 80lbs front = 110lbs positive(rear bias) DF difference

b. Adjust brake bias using the following:
- For every full 100lbs of negative(front bias) adjust brake bias by +1%
- For every full 100lbs of positive(rear bias) adjust brake bias by -1%
Example FR car with 110lbs positive(rear bias) DF difference:
110lbs(positive) = Brake bias 47% - 1% = 46% front brake bias

 

 

 

Corrections:

7-16-07 - Clarified DF brake bias calc examples
7-17-07 - Clarified DF brake bias calc examples

Thanks Feuerdog!! Looking forward to applying these new settings to some of my cars. Now, stop working so hard on this and have some fun, you more than deserve it. Your hard work is appreciated.

---

Yet another suspension calculator (V3 based)

woot! hope those with automatic calculators update theirs as well.

again, thanks feuerdog!

---

The crumpet is strong with this one...



**Tango Tuners**

servo101:

woot! hope those with automatic calculators update theirs as well.

again, thanks feuerdog!

Doing that right now :)

---

Yet another suspension calculator (V3 based)

Version 3 Updates are in except for the following:

• Advanced Rebound Stifness options (IE enhancing over/under steer)
• The Aero section

All other calcs for version 3 are in.  If you find issues let me know...

(It's just too late for me to finish tonight, so tomorrow I will get the remaining items out)

 

FD - First of all, amazing update!  Thanks again.   While testing my updates I noticed we started getting off a bit in our rebound settings due to our rounding differences.  Using the guide example, the line for bump stiffness (398 rear springs + 200) x .011 = 6.5 rear Bump Stiffness throws mine off because I am rounding the actual answer of 6.578 to 6.59 (which is nearly 6.6.) and it makes our rebound settings different a bit.  Please advise...seems this would either round to 6.6 or is it a deal where unless it actually makes it to 6.6, we go with 6.5? 

Thanks!

--Croisened

---

qbix:

servo101:

woot! hope those with automatic calculators update theirs as well.

again, thanks feuerdog!

Doing that right now :)

cool!

---

The crumpet is strong with this one...



**Tango Tuners**

servo101:

woot! hope those with automatic calculators update theirs as well.

again, thanks feuerdog!

I will be updating mine to V3 but it wont be a quick update I'm afraid.

I'm bogged down with college work this week, and as this is essentially the "finished" version I want to redo all my formulae from scratch, to make the sheet as efficient as possible.  I could probably crowbar the changes in, like V2, but I wouldn't be happy with it :)

So I'll see what I can get through during my lunch at work, and as soon as I get caught up on my college work I'll spend some time on it in the evening.

So, watch this space.....
Shem

---

My Forza Stuff Including my excel version of Feuerdog's Tuning Calculator V3 Metrics to come

feuerdog:

The 2.9 initial FD setting is just an initial setting,......you HAVE to adjust it to find top speed before you do any f the remaining calcs.

Ah, I assumed it was there or there abouts... I guess it is a case of sometimes it is, sometimes it isn't. I did adjust it anyway but the table for FD ratios using the weight/power wasn't really useful for the car I checked it with.

 

Good work with the V3 calcs though, I'll be sure to check them out and see how they compare to the old ones.

---

My Forza Cars
My Real Car

Great Web Hosting/Design Deals

Hey qbix, what's "downforce comp" short for?

Mach:

Hey qbix, what's "downforce comp" short for?

It stands for "Downforce Compensation". It's based on step 7.2 of the calculator. I think I'll disable this drop down if you haven't specified any downforce to avoid confusion. Soon I'm going to have to re-arrange the layout, but for now I went ahead and made it read "Downforce compen.". Also, I think you'll notice I removed the Porsche variants since they are based on version 2. I will add them back once Carn gets a chance to adapt his calculator to this new version. Thanks!

---

Yet another suspension calculator (V3 based)

I have updated my calculator with the new values from the formulas.

You can download it from the link in my sig.

qbix i saw that you forgot to add the 0.1 to the front Toe when the width of the rear tires are bigger then the front tires.

---

Suspension Calculator Program Download Based on FDv3

qbix:

Mach:

Hey qbix, what's "downforce comp" short for?

It stands for "Downforce Compensation". It's based on step 7.2 of the calculator. I think I'll disable this drop down if you haven't specified any downforce to avoid confusion. Soon I'm going to have to re-arrange the layout, but for now I went ahead and made it read "Downforce compen.". Also, I think you'll notice I removed the Porsche variants since they are based on version 2. I will add them back once Carn gets a chance to adapt his calculator to this new version. Thanks!

I knew what it was, it was just "comp" that had me puzzled here at 5 in the morning because it could mean other things. I came across compensation when I switched your calculator's language from English to Spanish. But thanks for clearing it up

Thanks for the quick work qbix, and to everyone else for thier continuing enthusiasm and support.

- Rounding off - You don't have to round off.  That said, I don't use deciamls when calc'ing springs, but I do use 2 decimal places for damper calcs.  You will get slight variations in damper values based on my rough examples but don't worry about it.  In most cases, and with most people you won't be able to feel a .1 difference.  Qbix, go ahead and use 2 or threee deciaml place calcs, it won't upset a thing, but it may also explain some calcs giving slightly different results.  Again, this is not a even an issue, just a very slight variance.  It's the gross relationships and proportions that are important.

- Porsche calculations - Hopefully, further refinement of these won't be needed this time around, but there may be exceptions.  I spent most of sunday cross checking all of my Porsche variations through the different cars, and in various classes.  There are even some top 500 times on the boards with V3 Porsches now, and I plan on adding some more.  ALL of the Porsche tunes will do Tsukuba in 56 seconds or less in A-class.

- I'll try and get a post up soon to detail every change in the calcs in V3, and maybe a reason for them too.

- The gearing calculator I posted earlier is probably going to be re-scrapped, for at least as long as it takes to see if I can fix it or not.  It definately isn't a good calc.  

 

2. TIRES -
2.1. Set Tire pressures -
a. Set all tires to 29psi

b. Adjust tire pressure for best operating pressures -
1. Free Run five or more laps of Tsukuba.
2. Watch the telemetry screen for tire pressures.
3. Note the pressure increase of the left side tires from lap one to lap five.
4. Adjust the tire pressures so that the tire heats "up" into its best operating pressure and/or temperature.

Advanced Tire Size tuning -
a. For cars with larger rear tires than front tires, add -1% brake bias and add .1 to front toe.

Advanced Tire Temperature tuning -
a. If single tire temperature differences exceed 10 degrees, then increase antiroll bar settings and retest.

Other than a few smaller notes, and a change to the order of the parts tuning, not much has changed here.  It's either too complex to try and come up with anything more advanced or simply not worth the trouble for a basic calculator.

 

 

3. ALIGNMENTS -
3.1. Set Camber -
a. Set camber to -.8 Front/-.8 Rear

Advanced Tuning - Add or remove camber to prevent uneven heating.

3.2. Set Toe -

FF = .1 front/.1 rear
FR = .0 front/-.2 rear
FA = .1 front/.1 rear
MR = 0 front/-.1 rear
MA = .1 front/0 rear
RR = 0 front/-.2 rear
RA = 0 front/-.1 rear

Advanced Tuning - Increase front positive toe to improve turn-in response, decrease to improve stability. Increase rear negative toe to improve rear stability, decrease to reduce understeer.

3.3. Set Caster -
- Set caster to 5.5

Notes: I don't want to get into the details of caster tuning, but it is very closely related to front camber settings, and it shouldn't be adjusted out of the 5.6~6.0 range while used with the other settings. 5.5 caster adds approx. 3 degrees of dynamic camber to the front wheels at full steering lock.

Again no major changes, except for some minor toe tweaks,.......I think.

4. SPRINGS, DAMPERS, and ANTIROLL BARS -
4.1. Find the weight multiplier -
a. Get the weight of the car from the garage screen.
b. Subtract 300 from vehicle weight and multiply by .34
c. This is your weight multiplier - write this number down.
Example FF car: (2600 lbs - 300) x .34 = 782

Advanced Tuning -
- For slightly stiffer suspension add 50 to this result.
- For very stiff suspension add 100 to this result.
- For slightly softer suspension subtract 50 from this result.
- For very soft suspension subtract 100 from this result.

4.2. Find the modified weight distribution -
a. Get the weight distribution values for the car.
Example FF car: 57% front/43% rear

b. Calculate the cars modified weight distribution values by altering the stock weight distribution using the following table:

FF = subtract 8% from the front, and add 8% to the rear.
FR = add 8% to the front, and subtract 8% from the rear.
FA = subtract 5% from the front, and add 5% to the rear.
MR = add 2% to the front, and subtract 2% from the rear.
MA = add 2% to the front, and subtract 2% from the rear.
RR = add 2% to the front, and subtract 2% from the rear.
RA = add 1% to the front, and subtract 1% from the rear.

Example FF car: 57% front (-8%)/43% rear (+8%) = 49% front/51% rear

c. These modified percentages are your modified weight distribution - write this number down.

4.3. Find the Spring value -
a. Weight multiplier x modified weight distribution = Spring value - enter these settings.
Example FF car:
- 782(weight modifier) x .49(49% modified front weight distribution) = 383 Front Springs
- 782(weight modifier) x .51(51% modified rear weight distribution) = 398 Rear Springs

Advanced Tuning - You may need to adjust your ride height. Lower is better, but too low may cause excessive bottoming out. Adjust as needed.

The beginning of the big changes.  This revised weight calc takes into account some complaints of light cars being too stiff, and heavy cars being too soft.  Most cars in the 2500~3000 lb range are for the most part unaffected. 

The weight trnasfer settings are slightly modified, with the biggest change going to the AWD types.  The increase in transfer should assist in fighting some of the understeer that was affecting these cars from V2.  Further tweaking was made with the damper settings to complete this correction.

 

 

4.4. - Find the damper Bump Stiffness -
a. (Spring value + 200) x .011 = Bump Stiffness - enter these settings.
Example FF car:
- (383 front springs + 200) x .011 = 6.4 front Bump Stiffness
- (398 rear springs + 200) x .011 = 6.5 rear Bump Stiffness

Advanced Tuning - For stiffer dampers multiply by .012, for softer dampers multiply by .010

4.5 - Find the damper Rebound Stiffness -
a. Get the Bump Stiffness values for the car.
Example FF car:
- 6.4 front Bump Stiffness
- 6.5 rear Bump Stiffness

b. Calculate the cars Rebound Stiffness values with the following table:

FF - Front Bump stiffness x 1.4 = Front Rebound Stiffness
FF - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

FR - Front Bump stiffness x 1.1 = Front Rebound Stiffness
FR - Rear Bump stiffness x 1.4 = Rear Rebound Stiffness

FA - Front Bump stiffness x 1.3 = Front Rebound Stiffness
FA - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

MR - Front Bump stiffness x 1.3 = Front Rebound Stiffness
MR - Rear Bump stiffness x 1.3 = Rear Rebound Stiffness

MA - Front Bump stiffness x 1.4 = Front Rebound Stiffness
MA - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

RR - Front Bump stiffness x 1.1 = Front Rebound Stiffness
RR - Rear Bump stiffness x 1.3 = Rear Rebound Stiffness

RA - Front Bump stiffness x 1.3 = Front Rebound Stiffness
RA - Rear Bump stiffness x 1.2 = Rear Rebound Stiffness

Example FF car:
- 6.4(front bump stiffness) x 1.4 = 8.9 front Rebound Stiffness
- 6.5(rear bump stiffness) x 1.1 = 7.1 rear Rebound Stiffness

Advanced Tuning -
- Increase corner entry oversteer OR Decrease corner entry understeer = Subtract .1 from the rear Rebound Stiffness multiplier, and recalculate.
- Increase corner exit oversteer OR Decrease corner exit understeer = Add .1 to the front Rebound Stiffness multiplier, and recalculate.

- Increase corner entry understeer OR Decrease corner entry oversteer = Add .1 to the rear Rebound Stiffness multiplier, and recalculate.
- Increase corner exit understeer OR Decrease corner exit oversteer = Subtract .1 from the front Rebound Stiffness multiplier, and recalculate.

4.6. Find the Antiroll Bar settings -
a. Weight distribution x 24 = AntiRoll Bar settings - enter these settings.
Example FF car:
- .57(front weight distribution) x 24 = 13.6 front AntiRoll bar
- .43(rear weight distribution) x 24 = 10.3 rear Antiroll bar

Advanced Tuning -
- For slightly stiffer antiroll bars change multiplier to 33
- For very stiff antiroll bars change multiplier to 44, and decrease caster to 5.4
- For slightly softer antiroll bars change multiplier to 17
- For very soft antiroll bars change multiplier to 12, and increase caster to 5.6

Again, some new calcs here.  Bump stiffness and rebound ratios have changed.  The most important I feel are the Antiroll bar changes and advanced tuning modifiers.  You can solve quite a few different kinds of characteristics with just a slight change in overall antiroll bar stiffness.  Make small changes first and retest as needed.

 

5. BRAKES -
5.1. Set Brake Force -
- Set brake force to 110% with ABS, or 90% without ABS.

5.2. Set Brake Balance -
- Set brake balance to 47% front

Advanced Tuning -
- If rear tires are at least 30mm wider than front tires subtract 1% from brake balance.
- Adjust force in +/-5% increments for best feel, or benchmark performance.
- Adjust balance in +/-2% increments for best feel, or benchmark performance.
- Use friction telemetry screen to determine which wheels are losing traction first and adjust balance accordingly.

No major changes here, just that note on tire size vs. brake bias, which is based on available traction.

 

6. DIFFERENTIALS -
- FWD = 35% Accel./0% Decel.

- RWD = 60% Accel./50% Decel.

- AWD Front = 35% Accel./0% Decel.
- AWD Rear = 80% Accel./70% Decel.
- AWD Split = 25% Front/75% Rear

Note: Gearing, power, and torque won't directly how the diff. work but they will change the feel of it's effects. Keep this in mind while tuning.
Sport differentials are adjustable in accel. only.

Advanced Tuning -
Accelerating oversteer?
- Adjust rear diff. = -5% Accel.

Accelerating understeer?
- Adjust front diff. = -5% Accel.

Braking oversteer?
- Adjust diff. = +5% front Decel. OR -5% rear Decel.

Braking understeer?
- Adjust front diff. = -5% Decel. OR +5% rear Decel.

 Just a couple of slight changes to amplify effects.  The fine tuning aspects still apply.

 

7. AERODYNAMICS(Optional adjustments)-
7.1. Adjust camber based on aerodynamic downforce -
- Add +.1 camber per 100lbs downforce
Example R4 car: 150lbs front/300lbs rear
(150lbs front = +.1) = (+1) + (-.8 camber) = -.7 front camber
(320lbs rear = +.3) = (+.3) + (-.8 camber) = -.5 rear camber

7.2 . Adjust spring value for aerodynamic downforce -
- (Downforce x .15) + Spring value = Adjusted Spring value
Example FF car: 110lbs front/25lbs rear
(110lbs front x .15) = 16 + 383 = 399 front springs
(25lbs rear x .15) = 3 + 398 = 401 rear springs
Note: Do NOT recalculate damper settings after this spring adjustment is made.

Advanced Tuning - For lower compensation multiply by .1, for higher compensation multiply by .2

7.3. Adjust brake bias based on aerodynamic downforce -
a. Subtract front downforce from rear downforce.
Example FR car: 80lbs front/190lbs rear
190lbs rear - 80lbs front = 110lbs positive(rear bias) DF difference

b. Adjust brake bias using the following:
- For every full 100lbs of negative(front bias) adjust brake bias by +1%
- For every full 100lbs of positive(rear bias) adjust brake bias by -1%
Example FR car with 110lbs positive(rear bias) DF difference:
110lbs(positive) = Brake bias 47% - 1% = 46% front brake bias

Edited 7-17-07 to reflect corrections correctly

Here's the new section I mentioned.  It's not perfect, but it may help tame some of the ill effects that high downforce settings can produce.  I'll be looking for alot of feedback on this section particularly.  S, U, and R class cars especially will bear the brunt of these calcs because these cars need high downforces to keep them on the track.  Keep in mind, high downforce will cause increased tire temps, so tire alignment problems need to be sorted out before you go blaming anything else.

Very nice app, CriticalDevil.
Just a minor detail: when you generate  an AWD tuning the "Split" section for the differential reads "Accel" and "Decel" instead of  "Front" and "Rear".

---

feuerdog:

 7.3. Adjust brake bias based on aerodynamic downforce -
a. Subtract front downforce from rear downforce.
Example FR car: 80lbs front/180lbs rear
180lbs front - 80lbs rear = 100lbs

b. Adjust brake bias using the following:
- For every negative 100lbs adjust brake bias +1%
- For every positive 100lbs adjust brake bias -1%
Example FF car:
-85lbs = Brake bias 47% - 1% = 46% brake bias

Example 7.3.a is confusing. In the first line the front is listed as 80lbs and in the second line it's changed to 180lbs. You've also said to subtract the front from the rear, but in the example you've subtracted the rear from the front.

 

Example 7.3.b is also confusing. Firstly the calculation says to use +1% adjustment for every -100lbs. Do we need to round the -85lbs to -100lbs? If not then the adjustment should surely be 0%.

The calculation also tells us to use +1% adjustment for every negative 100lbs. If the -85lbs is to be rounded then the adjustment should be +1%, taking the result of the calculation in the example to 48%.

 

Just wanted to give you feedback on what otherwise was an excellent piece of work

 

Thanks