Eyris6:

How does ride height factor into all of this? If you lower the ride height will it throw off the spring calculations, or should you do all these and then go ahead and lower the ride height as low as you can for a certain track?

So far, height doesn't really seem to affect too much,.....especially with the spring values we are using here.

I personally never use less than about 2 inches of ride height, but there are very few cars that can actually go that low.

I haven't done tests yet on how an undersprung car handles bottoming out.

Here's what I have so far,......Dump it, low as you can go.  Go race Sebring and do the big bumpy sweeper at speed,....if the outer suspension travel goes red and stays there for more than a few successive flashes of red(telemetry screen), then you need to raise that end up a few tenths and test again. 
The alternative to raising the ride hide is stiffening the suspension, but there are always compromises to keep in mind.  Stiffer can equal twitchier in some cases.

---

FM3 Suspension Calculator
http://forums.forzamotorsport.net/forums/thread/3073197.aspx

iPhone Suspension Calculator
http://forzatune.com/

Learn about Tuning at DIY RaceTuning
http://diy-racetuning.net/

RevDrew:

...understeer problems with the FF cars? I figured out how to dial it out of the RWD cars by tuning the diff, but I haven't had the same success with FWD.

Here is something you can try.

The object is to defeat the throttle understeer by exaserbating the lift off oversteer.  The following is the steps I took with the Golf GTi Mk5...  (remember - get your spring and damper numbers After you have made all other upgrades.  Any upgrade that changes the weight will change those numbers as well.)

• reduce front ARB, springs and dampers by 1%
• increase rear ARB springs and dampers by 2%
• lower pressure of front tires in relation to rear tires.  I use 29/30
• set diff Accel to 64
• set diff Decel to 32
• brake bias to 48% front.  Pressure to taste, I use 106
• Note: you may want to decrease front rebound damping another tenth - this will slow the recovery of the suspension from the turn in weight shift.

With these settings I can drive right through the apex and out without lifting.  The second turn of Maple Valley for instance, set up is nothing more than a slight lifting off the throttle, this is enough to swing the weight forward and out as you turn in.  Then it is pour on the coal, through the apex and out the other side, you will come close to the rumble strip on the outside, but it will make it, and you will leave the competition in the dust with that single move.

Disclaimer: the suspension numbers are only for a C class Golf GTi Mk5 with 245 ft/lb torque and weighing 2577 lbs, and only the width and rim tire upgrades.  For other cars, the numbers would be similar, but different

$

---

Forza-Tuning

Agree about the wheel rates...  You also bring up another interesting point about frequencies...  Not sure if it would be feasible, or even advantagous to try to calc freqs in this game... but one could probably make some assumptions on unsprug mass at each corner and do some sanity checks. 

I have been playing around with setting up suspension frequencies between 1.9 and 2.2 and it has been working pretty well so far.  I have also tried subtracting 10-15% as a generic modifier for unsprung weight but this may be beyond the scope of the game so I haven't felt the need to continue doing it.  I haven't been tuning a lot of cars, but rather focusing on a few because it takes so long!  I found that the Viper GTS ACR spring rate reflects a suspension frequency of 1.89 using the spring rate number from the slider and the axle weight based on the weight of the car and static weight distrubution.  This was with the sport weight reduction and a total weight of 3,242 lbs.  I am currently on the road so I don't have all of the numbers in front of me but I thought it interesting that the numbers from the game worked out to be very realistic when used in a "real world" equation.  I am going to keep playing with this and see if I can further enhance the handling of other cars based on track conditions.  My Viper is turning out to be rock solid in both A class and S class.  I'm not quite done with it yet though!  The biggest limitation for the car seems to be my driving ability.  I am yet to explore other cars with as much detail as I have with my "test-bed" Viper but I am looking forward to producing some more data.  Some light bulbs are definitely coming on!

Yep, thats a FFR, although not a spec racer.  Its actually one of the first FFR cobras on the road.  Ive owned it for about 10 years now.  Its a classic ;)   

You might like my new project:

Now I am green with envy.  I have actually run across your site in the past.  The GTM is very cool and I find myself drooling frequently over the brochure.  I am yet to see one in real life but hope to get the chance some time.  It will be a prerequisite prior to buying the kit.  One of these days, one of these days....

Take care

Would it be a valid test of setup (comparing one setup with another) to have one of the "expert" A.I. drivers like M. Rossi drive the car and record lap times?  I'm thinking of giving him/her a strong car and setting the other A.I.s to minimum skill level

---

Please bring back System Link & Local Scoreboards, fix frame rate issues, complete multi-screen operation (especially Point-to-Point and replays), allow tuning in Lobby, and move the split time back to where it was easily seen and readable.

feuerdog:

Wickedneoq:

So far, I'm cool with everything in this except dampers, I'm still maybe a bit confused as to why bump damping is a higher value than rebound damping, but when I use it the way the calculator explains, it actually helps performance, so maybe I'm feeling uneasy over nothing!  D-:

After rereading,...... http://www.theoryinpracticeengineering.com/drift_mag/basic_damper.pdf

...it seems I have to eat my previously, retracted statement which was apparently correct in the first place, and replace it with what I have already corrected in my most recent revision and post of said statement. Um,....nevermind.

You are correct and I am confused.

Compression(bump) damper values should be lower than rebound damper values.

My rethink based on what I read in Miliken's suspension dynamics book was somehow inverted and possibly confused with damper velocities, .....or something.

Regardless,.....after some of the damper testing I did last night(max. comp. vs.zero rebound and zero comp. vs. max. rebound), it still seems as though too high a rebound heavy ratio will cause pack-down issues.  However, since Sebring is our only really rough track, and only in one section, the optimal ratio might not be too far off from what we have now.  There is no perfect ratio anyways, thats why we are tuning to begin with.

As far as the calculator is concerned, i'll leave it alone for now.  I'll just have to add this issue into my list of things to test and confirm.  It seems to work ok, so theres no immediate need to change anything just yet just for the sake of realism(It kills me to say that, btw).

I need to reresearch this and double confirm to be sure..

This is the problem with rushing things before they are ready,........my mistake.

 

Ran some more tests last night.....

Damper ratio - I took the 50/50 weight AWD 206 and setup two balanced setups for it.  One was 8 bump/4 rebound and the other was 4 bump /8 rebound.  I haven't run the car yet so it was going to be a straight judgement call on how it handled.  I took it to Tsukuba and ran about 20 laps, swapping out the setup every few laps to compensate for any tire heating issues, and to compare fairly.

The high bump car had a more immediate response feel, but it also seemed more harsh.  It required a sensitive transition to be fast turning in, but it did exit well(I like getting AWD's loose).

The high rebound car had a softer overall feel, but it could be pushed harder and would absorb mistakes a little better, turn-in feel was more progressive, and exit was easy to control,.....it made the car feel underpowered at times.  For this very reason I think the high rebound car is a superior choice.  It's based purely on feel, but personally, and for beginner tuning purposes, this is the better choice for stable and predictable control.  I'm working on the new calcs now so this change is a definate.  I know it's reversal of tuning but it should benefit everyone in the end.

I test and ran an A-class Ferrari 355 Challenge on the Mugello endurance race last night too.  20 laps of damper, spring balance, and gear tesing, followed by actually running the full 25 lap race, for a nice 400k+ reward.  Anyways, the firm rebound ratio worked, and it also confirmed for me the balance of the 355,....I love how this car handles.  I managed a 1:47.xxx lap time, but it's probably got at least another second or two of potential, especially with a manual trans.  And that would put it in the top 100 for the class.

Speaking of handling, I finally got some time to test my Porsche GT3 911-997 on Maple Valley.  This thing handles great even without tuning.  I did manage to squeek it up a little bit, but I haven't fully balanced it yet.  I need more time to loosen it up.

 

I found an interesting way to test the caster/dynamic camber relationship too.

1. Set your camber and toe values to zero, and your caster to 5.5

2. Go to a nice flat section of Sebring and park,.....open your telemetry screen for tire camber angles.

3. Turn you wheel and watch how caster affects you camber based on turn angle.  This is a handy reference for tuning camber and caster together.

 

The other revisons and updates are coming together, hopefully this weekend.  Sunday will be a full on Forza testing day for me.  So expect some updates and changes then.  

 

---

FM3 Suspension Calculator
http://forums.forzamotorsport.net/forums/thread/3073197.aspx

iPhone Suspension Calculator
http://forzatune.com/

Learn about Tuning at DIY RaceTuning
http://diy-racetuning.net/

Redshirt, your web calc is reversing all the front and rear values when RA is selected.

Btw, thanks for all your work on this handy tool.

VERSION 2 BETA

The new calculations are written below, but as usual, some testing needs to be done.  This version will replace the original version once the results from your tunes are verified.  This will handle a bit differently, but the stability, and performance is still there, and actually better in my opinion.

Try it out.

 

Forza Motorsports 2

Suspension Setup Calculator

Version 2

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 esier to drive, and faster too.  Enjoy!

 

 

PURPOSE - Why use this guide?

- What it might do you for you

          -  help drivers and tuners by giving them a way to tune or retune thier 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, independantly 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 acheive 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 alot of time, and some money, to learn more about damping, automotive vehicle dynamics, and racing car tuning in general.  In the end it's all about fun.  If this guide can provide you with a car that is fun and easy to drive then my work here is done.

 

 

  

SUSPENSION SETUP CALCULATOR

 

1. Before you begin.

2. Springs, Dampers, and Antiroll Bars

          - Springs

          - Antiroll Bars 

          - Dampers

                   -Bump Stiffness

                   -Rebound Stiffness

         

3. Alignments

          - Camber

          - Toe

          - Caster

4. Tires

5. Brakes

6. Differentials

 

 

         

 

 

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.

- to know....

          a.  The weight of the car, and what the weight distribution values are for front and rear.  These are found in the game.

          b.  These 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.  SPRINGS, ANTIROLL BARS, and DAMPERS -

2.1. Find the weight multiplier -

a. Get the weight of the car from the garage screen.

b. Multiply the weight of the car by .3

c. This is your weight multiplier - write this number down.

Example FF car: 2600 lbs x .3 = 780

 

Advanced Tuning - To stiffen the suspension multiply by .32, to soften the suspension multiply by .28

 

 

2.2. 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 with 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 4% from the front, and add 4% to the rear.

MR = add 2% to the front, and subtract 2% from the rear.

MA = no change.

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.

 

 

2.3. Find the Spring settings -

a. Weight multiplier x modified weight distribution = Spring value - enter these settings.

Example FF car:

- 780(weight modifier) x .49(49% modified front weight distribution) =  382 Front Springs

- 780(weight modifier) x .51(51% modified rear weight distribution) =  397 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.

 

 

2.4. Find the Antiroll Bar settings -

a. Weight distribution x 25 = AntiRoll Bar settings - enter these settings.

Example FF car:

- .57(front weight distribution) x 25 = 14.2 front AntiRoll bar

- .43(rear weight distribution) x 25 = 10.7 rear Antiroll bar

 

Advanced Tuning - For stiffer Antiroll Bars multiply by 35, for softer Antiroll Bars multiply by 15

 

 

2.5. - Find the damper Bump Stiffness -

a. (Spring value + 200) x .011 = Bump Stiffness - enter these settings.

Example FF car:

- (382 front springs + 200) x .011 = 6.4 front Bump Stiffness

- (397 rear springs + 200) x .011 = 6.5 rear Bump Stiffness

 

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

 

 

2.6 - 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 1.5 = 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 1.5 = Rear Rebound Stiffness

 

FA - Front Bump stiffness x 1.5 = Front Rebound Stiffness

FA - Rear Bump stiffness x 1.1 = Rear Rebound Stiffness

 

MR - Front Bump stiffness x 1.2 = Front Rebound Stiffness

MR - Rear Bump stiffness x 1.3 = Rear Rebound Stiffness

 

MA - Front Bump stiffness x 1.3 = Front Rebound Stiffness

MA - Rear Bump stiffness x 1.2 = Rear Rebound Stiffness

 

RR - Front Bump stiffness x 1.3 = Front Rebound Stiffness

RR - Rear Bump stiffness x 1.4 = Rear Rebound Stiffness

 

RA - Front Bump stiffness x 1.4 = Front Rebound Stiffness

RA - Rear Bump stiffness x 1.3 = Rear Rebound Stiffness

Example FF car:

- 6.4(front bump stiffness) x 1.5 = 9.6 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.

 

- For faster weight transitions lower both of the multipliers by .1

- For slower weight transitions increase both of the multipliers by .1

 

 

 

3. ALIGNMENTS -

3.1. Set Camber -

a. Set camber to -.8 Front/-.8 Rear

 

b. Adjust camber based on aerodynamic downforce.

- +.1 camber per 200lbs downforce

 

Example R4 car with 150lbs front/300lbs rear

- 150lbs front downforce = -.8(front camber) + .0 = -.8 front camber

- 300lbs rear downforce = -.8(rear camber) + .1 = -.7 rear camber

 

 

3.2. Set Toe -

FF = .1 front/.1 rear

FR = .0 front/-.2 rear

FA = .1 front/.1 rear

MR = .1 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. TIRES -

4.1. Set Tire pressures

Set all tires to 29psi(2.0bar)

 

 

Advanced Tire Pressure tuning -

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 front and/or rear "down" so that the tire heats "up" into it's best operating pressure and/or temperature.

 

 

 

5. BRAKES -

5.1. Set Brake Force

a. Set brake force to 110% with ABS, or 90% without ABS.

 

5.2.  Set Brake Balance

a. Set brake balance to 47% front

 

Advanced Tuning -

- Adjust force in +/-5% increments for best feel or benchmark performance.

- Adjust balance in +/-2% increments for best feel, stability, or benchmark performance. 

 

 

 

6. DIFFERENTIALS -

- FWD = 40% Accel./0% Decel.

 

- RWD = 65% Accel./55% Decel.

 

- AWD Front = 30% 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 changes the feel of it's effects.  Keep this in mind while tuning.

 

 

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.

 

 

 

 

FEEDBACK -

TEST DRIVERS WANTED! 

I obviously can't test every combination of possible car and part in the game, and i've had a hard time finding the time to test the cars that I have tested, so I need your help.  Try the calculations, give the setups a chance, and see what you think

 

Your feedback will help me fix anything i've missed, or need to adjust. 

 

If the calculations work for you, or even if they don't, i'd like to know.  Post in this thread and let me know the details.  Be as specific as possible.

 

PLEASE specify wether you are using Version 1 or Version 2!

 

 

 

Changes from Version 1:

- Highlighted certain purposes of the calculator.

- New weight disribuion modifier mutipliers.

- New Antiroll Bar, Damper, Camber, Caster, and Toe settings or notes.

- New differential settings for RWD and AWD.

- New simlified tire and brake settings.

- Changed some colors and formatting.

- Added note about Ride Height under Springs.

Corrections:

- 6-17-07 - Typo on spring calculation, stock multiplier should be .011 not .012.

- 6-20-07 - Added parenthesis to bump stiffness operation - no change in settings.

 

---

FM3 Suspension Calculator
http://forums.forzamotorsport.net/forums/thread/3073197.aspx

iPhone Suspension Calculator
http://forzatune.com/

Learn about Tuning at DIY RaceTuning
http://diy-racetuning.net/

feuerdog:

The high bump car had a more immediate response feel, but it also seemed more harsh.  It required a sensitive transition to be fast turning in, but it did exit well(I like getting AWD's loose).

The high rebound car had a softer overall feel, but it could be pushed harder and would absorb mistakes a little better, turn-in feel was more progressive, and exit was easy to control,.....it made the car feel underpowered at times.  For this very reason I think the high rebound car is a superior choice.  It's based purely on feel, but personally, and for beginner tuning purposes, this is the better choice for stable and predictable control.  I'm working on the new calcs now so this change is a definate.  I know it's reversal of tuning but it should benefit everyone in the end.

Very cool... that's what I would expect.  While a perfect lap with each setup may be very close... The easier setup to drive will generally win.  The "slower" feeling is actually good.  Its interesting how a smooth flowing lap may feel slow, but is actually the fastest.

Im going to post a section of the Koni Tuning Guide for road racing.  This should be helpful for those who want to dial in their shocks exactly for a given car. 

David

 

Except originally taken from the Koni Racing Shock Tuning Guide: http://www.bimmerhaus.com/tech/shocktuningTN.html

Adjusting The COMPRESSION (Bump) Damping Control (Very Important to do this FIRST!)

Bump damping controls the unsprung weight of the vehicle (wheels, axles, etc.). It controls the upward movement of the suspension as when hitting a bump in the track. It should not be used to control the downward movement of the vehicle when it encounters dips. Also, it should not be used to control roll or bottoming.

Depending on the vehicle, the ideal bump setting can occur at any point within the adjustment range. This setting will be reached when "side-hop" or "walking" in a bumpy turn is minimal and the ride is not uncomfortably harsh. At any point other than this ideal setting, the "side-hopping" condition will be more pronounced and the ride may be too harsh.

STEP 1: Set all four dampers on minimum bump and minimum rebound settings.

STEP 2: Drive one or two laps to get the feel of the car. Note: When driving the car during the bump adjustment phase, disregard body lean or roll and concentrate solely on how the car feels over bumps. Also, try to notice if the car "walks" or "side-hops" on a rough turn.

STEP 3: Increase bump adjustment clockwise 3 clicks on all four dampers. Drive the car one or two laps. Repeat Step 3 until a point is reached where the car starts to feel hard over bumpy surfaces.

STEP 4: Back off the bump adjustment two clicks. The bump control is now set. Note: The back off point will probably be reached sooner on one end of the vehicle than the other. If this occurs, keep increasing the bump on the soft end until it, too, feels hard. Then back it off 2 clicks. The bump control is now set.

Adjusting the REBOUND Damping Control

Once you have found what you feel to be the best bump setting on all four wheels, you are now ready to proceed with adjusting the rebound. The rebound damping controls the transitional roll (lean) as when entering a turn. It does *not* limit the total amount of roll; it *does* limit how *fast* this total roll angle is achieved. How much the vehicle actually leans is determined by other things such as spring rate, sway bars, roll center, ride heights, etc.

It should be noted that too much rebound on either end of the vehicle will cause an initial loss of lateral acceleration (cornering grip) a that end which will cause the vehicle to oversteer or understeer excessively when entering a turn. Too much rebound control in relation to spring rate will cause a condition known as "jacking down." This is a condition where, after hitting a bump and compressing the spring, the damper does not allow the spring to return to a neutral position before the next bump is encountered.

This repeats with each subsequent bump until the car is actually lowered onto the bump stops. Contact with the bump stops causes a drastic increase in roll stiffness. If this condition occurs on the front, the car will understeer; if it occurs on the rear, the car will oversteer.

STEP 1: With rebound set on full soft and the bump control set from your earlier testing, drive the car one of two laps, paying particular attention to how the car rolls when entering a turn.

STEP 2: Increase rebound damping three sweeps (or 3/4 turn) on all four dampers and drive the car one or two laps. Repeat Step 2 until the car enters the turns smoothly (no drastic attitude changes) and without leaning excessively. An increase in the rebound stiffness beyond this point is unnecessary and may result in a loss of cornering power. Note: As with the bump settings, this point will probably be reached at one end of the car before the other.

However, individual drivers may find it desirable to have a car that assumes an oversteering or understeering attitude when entering a turn. This can be easily "dialed-in" using slightly excessive rebound settings at either end.

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

David

The calculator tool that has been mentioned only calculates part of the calculations right? I assume this as owner of the thread is still making revision to the calculations. I have read the post and understand most of it. I just wanted to know if the online calculator is needed as well as the tutorial or do we use just the tutorial or what?

Thanks
Jads

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[Mod edit: Sig size exceeds forum limits, 480x115 pixels max - D]

When using this newest set of calculations, if I try to do a "stiff setup" I'm getting Rebound Values that are higher then I can enter into the game.  Am giving my Mercedes CLK-GTR a test run as we speak with your new numbers.

---

Suspension Calculator Based on feuerdog's guide: (Now Does Metric!)
http://fm2calc.ruinedmylife.com

In all seriousness, there's two options you can take:

- Keep the old values, because I'm using "bump > rebound" values to very successful runs in my '69 Camaro SS.  Some of the stock setups in the R Class cars even show this at work, and they handle quite well.

- Just swap the two values.  I know this would require some testing, but it seems viable.  Really high rebound stiffness makes the front end too stiff on the Camaro, causing the car to bounce uncontrolably, losing steering.  That's just what I've experienced at least, especially at Road Atlanta, where even tapping a curb can spell disaster if done incorrectly.

---

[RCKT] - RCKT Racing Nova Scotia
Member of SimRacingHD.com's Forums
Open-wheel and sprintcar simulator racer

WOW!
You guys take this pretty serious!

I can imagine you guys sitting down playing forza with a freakin calculator, calculating your power to weight ratios and perfect settings for weight distribution and all of that.

I do see the logic behind it.
But seriously, think about it. Its a game!

You play games not calculate them!

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wow that looks complicated and very detailed, I'm on vacation in Colorado right now, but when I get back to North Dakota (where I live), I'll give this a shot, I'll let you know how it works.

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[Mod edit: Sig size exceeds forum limits, 480x115 pixels max - D]

BENZO wrote:
WOW!
You guys take this pretty serious!Surprise

# I can imagine you guys sitting down playing forza with a freakin calculator, calculating your power to weight ratios and perfect settings for weight distribution and all of that.

I do see the logic behind it.
But seriously, think about it. Its a game!

You play games not calculate them!

***
QFT

A VERY REALISTIC GAME.....Everyone wants to be the "Best" ... heh its fun

BENZO:

WOW!
You guys take this pretty serious!

I can imagine you guys sitting down playing forza with a freakin calculator, calculating your power to weight ratios and perfect settings for weight distribution and all of that.

I do see the logic behind it.
But seriously, think about it. Its a game!

You play games not calculate them!

Heh!  yeah, so true.  You should see the stack of books and notes that I have accumulated while figuring all this stuff out.  It's a fire hazard to say the least.

I didn't want to make a calculator, I needed to make a calculator.  I hate math.  The need arose form enjoying racing cars and then getting my butt handed to me online by kiddies who didn't know how to drive or tune.  So I taught myself everything I could about suspension dynamics,......when I realized how complex it was(alot more complex than my calculator) I decided to make a cheat sheet.  Thus was created my first calculator.  I've made probably 7 or 8 variations of this calculator since FM1 came out.  It's not meant to be complex,......but the nature of suspension tuning makes it that way.  This is just a generic calculator,....real racing teams spend millions of dollars on racing telemetry analysis, and tuning and then spend years refining what they learn. 

FM2 is just a game?!  Pfft!  Nah,...this is a full time hobby.

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FM3 Suspension Calculator
http://forums.forzamotorsport.net/forums/thread/3073197.aspx

iPhone Suspension Calculator
http://forzatune.com/

Learn about Tuning at DIY RaceTuning
http://diy-racetuning.net/

Well said feuerdog ...

iammatt00:

When using this newest set of calculations, if I try to do a "stiff setup" I'm getting Rebound Values that are higher then I can enter into the game.  Am giving my Mercedes CLK-GTR a test run as we speak with your new numbers.

Which calcs?  The whited out ones?

I need more details:  Car weight, weight distribution, and drivetype please. 

 

Hmmm,...yeah you may have found an issue.

The heaviest car I have tested is a fully loaded AWD Bentley GT @5400lbs

With a weight modifier of 1620 and a front spring pecentage of 62, we get a spring of 1004lbs.

The bump on a 1004 is over 20,...rebound would be well over 30,.....not good.

I'll have to reformulate based on the rebound,.....damn, back to the drawing board.

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FM3 Suspension Calculator
http://forums.forzamotorsport.net/forums/thread/3073197.aspx

iPhone Suspension Calculator
http://forzatune.com/

Learn about Tuning at DIY RaceTuning
http://diy-racetuning.net/

VaporATX:

Redshirt, your web calc is reversing all the front and rear values when RA is selected. Btw, thanks for all your work on this handy tool.

Thanks for the Catch!  I haven't played Forza2 since Tuesday night and won't be able to until Sunday.

I had reversed the front / rear weight variables in the RA section.

Fixed as of now.

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Online Forza 2 Suspension Calculator
http://www.redshirt1701.com/Forza2/suspensioninput.cfm
Based on Suspension Guide by Feuerdog
http://forums.forzamotorsport.net/forums/1/256899/ShowThread.aspx