Circle Track Analyzer User Manual Supplement
Contents
1. for comparisons id Aero Downforce Cross Dynamic Handling Rating of Oversteer or Understeer including the rating and difference between this and the Baseline condition Check Section 3 6 in book Analyze Suspension Handing 2 89 UndeStet Slightly Less Tight for more info on this screen This Dynamic Handing 438 UndeSteer by 147 Handling rating is for the vehicle at the transition point between braking and accelerating no fore or aft acceleration C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Figure A19 Oversteer Understeer Rating Around the Entire Track and Big Bar Soft Spring Starting Pont Suggestions fl Circle Track Analyzer v3 6 Performance Trends LATEMODL 355 B gt Back Graph Print Analyze Suspension Analyze Perf History HelplF 1 es Summam Low Litt Coet Agressive Driving a 2c ja Enge RPM Hig Comments Time Feet MPH AccelGs amp Suspension for the screen below 00 7 00 _ Circle Track Analyzer y3 5 Suspension Analysis Screen LATEMODL 355 Back Options Print Emme Continuous Single Step Ahead Single Step Back Help Suspension Calculations zen is actually right side of car results shown in pink Suspension Calculations with Comments Rule of Thumb Suggestions Std Setup Rule of Thumb Suggestions BBSS Setup Rule of Thumb Adjustments Yank Angle Write ASCII File of BASELINE Wheel Loads 1 Click on Reports then2. A18 Oversteer Understeer Rating BP UE HLE jF Ari LF N mas 487 HP at 6500 from 355 w 390 4BBL roller cam AFR auus Tranzistion Handling Rating for 7 deg Banking Classic Lateral Load Transfer 38 9 Front HEA Oversteer loose Report on Details Help Note Understeer a number above 55 2 is Safer than Oversteer Find Classic Handling Click on Show Dynamic Handling to see comer weights in Transistor and 4 more detailed handling analysis which includes cross weight and aerodynamic effects Click on Show Dynamic Handling to update rating currently 2 74 4 UnderSheer Sulla Wh lie ts nell lap Dynamic Handling rating of 2 74 Understeer which includes cross weight Click here to update the aerodynamic and other effects Note that Dynamic Handling rating and this is completely different than the to display the screen below Classic handling rating which only considers lateral load weight transfer wl Circle Track Analyzer v3 5 Suspension Analysis Screen LATEMODL 355 Back Options Print Reports Help This is a Front View left side of screen is actually right side of car Baseline Title single kevin3 results shown in pink 7 deg Bank Angle a x a 4694RPM Le G 4631 Aerodynamic Downforce loads for both the front and rear axles tires Also include are the loads for the Baseline condition a condition Staic Dy which you have selected to be your 60 Rear Baseline
3. C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Appendix 4 New Features in Version 3 5 Here is a brief listing of some of the features added since v3 2 was released Some we added to later versions of v3 2 and some are new in Version 3 5 e A major new feature is the concept of balancing the Front Lateral Load Distribution FLLD with the rear lateral load distribution This concept can be used to find a balanced setup by adjusting spring and roll bar rates and roll center heights This is discussed in detail below e The Rule of Thumb Suggestions for a good starting point for a setup now includes a suggestion for the rear roll center height This is based on obtaining a recommended FLLD See details below e The program can now do an angled symmetric 4 link rear suspension as used in the late model Mustangs and GM Metric chassis e Added the ability to do Camber Change and Roll Center Migration tables and graphs in the Front Suspension Screen e The Front Suspension Screen now calculates and displays 2 additional suspension characteristics 1 Tire track change tire scrub as the front suspension goes through dive and roll 2 Swing Arm lengths the length from the tire center to its instant center e Changed the name of the Corner Jacking button at top right of main screen to Corner Weights That s because 2 new options have been added letting you do Tire Diameter Circumference changes and weight b
4. Rule of Thumb Suggestions for either a Std Setup or the new BBSS Setup The program will create the report like shown below with spring roll bar stagger anti dive and other recommendations for either type of setup you want to run Aero Downforce Roll 0 11 deg 0 38 Dive 1 52 inches 0 51 Rt Camber 4 97 deg 3 42 Lt Camber 63 deg 1 72 40 Rear Spring Spring 42 Left 52 Cross Friction Circle in Gs Accelerating Aero Downforce D 0 Handling 27 12 UnderSteer Very Much Tighter Handling 274 UnderSteer by 24 38 Baseline is an undetermined car lengths ahead Report is shown in Notepad so you can easily copy and paste email or print it on most any printer E Suspension Report txt Notepad File Edit Format View Help Big Bar Soft Spring BBSS ASPHALT Track Recommendations for LATEMODL 355 These recommendations should work well as a starting point for beginner racers Experienced drivers may want to adjust these specs for their own driving preferences The following recommen dations are based on the current vehicle front and rear suspension and track specs These recommendations are based on rules of thumb
5. find newer versions of Adobe Acrobat and Reader and other PDF compatible programs for viewing the User s Manual RCC RCC and CTA C Performance Trends Inc 2008 Figure A15 Rear Anti Rollbar w Rear Suspension Specs Back File LATEMODL FAB Comments Help Suspension Specs Type Trailing 4rmeCoail Springs Panhard ord E Left Right Left Side Spring Rates Ib in Clic Tire to Centerline in 32 0 25 0 2 0 Spring to Centerline in Spring Angle deg Spring to Axle in Axle to Front Pivot in o fie eft 0 Aight Pnhd Bar to Centerline in Panhard Bar Heights in End of Panhard Bar that Attaches to Axle Roll Bar Roll Bar reg Rate Ib in Roll Bar Length in Axle Mount Ahead of Axle in Help The distance ahead of the rear asle where the anti roll bar attaches to the axle trailing arm assembly via a flexible link IF the anti roll bar attachment i bolted solid to the axle trailing arm assembly enter 0 m Find Front Lat Load Dist Curent Front Lat Load Dist Current Hear Hall Bar Curent Hat Freg Fel 200 Tf f 1 62 98 38 17 f 1 62 Hew Front Lat Load Dist Hew Hear Holl Bar Hew Hat Freg FA Options Adjust For This FLLD Rear Hall Bar This change tends to make the car slightly tighter than its current setup Hote The new settings wou find using this feature may HOT be best pour driving style and could be UNSAFE Click on Help for more intoa For this ve
6. menu item to allow factoring the power curve up or down by a certain percent The option is also available to clean up the power curve should you enter RPM increments out of order or leave blank rows in the data Figure A13 New Commands in the Engine Screen EF Circle Trark analyzer vt 5 Derfarmance Trende FA TFMONL 2551 w Engine Specs latemodl 390 Back File Memel Load From Engine 4nalyzer Comments Help Base E Calculate Power Curve Full Power Curve Add HP Displact Reduce HP CC 582 fszt Re Sort Power Curve Table Clutch Srmaller Clutch Flywheel C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Appendix 5 New Features in Version 3 6 In Version 3 6 we ve broken the Circle Track Analyzer into 3 different programs Roll Center Calculator RCC which does the Front Suspension only Roll Center Calculator Plus RCC which does the Front Suspension and Rear Suspension plus some front to rear balance analysis The full Circle Track Analyzer CTA which does everything the old Circle Track Analyzer v3 5 did plus all these new features Here is a listing of the major new features added in Version 3 6 of full Circle Track Analyzer Note that unless these new features specifically mention Roll Center Calculator they do NOT apply to the Roll Center Calculator versions The program now lets you enter a rear anti roll bar This input changes the front to rear roll stiffness which affe
7. Appendicies Sn SS EEE EEE EE SS ESS Se you highlight various rows by clicking and dragging the mouse in the top Table for the Right Side These selected highlighted rows AND the corresponding rows in the bottom table for the Left side will be graphed If you have selected more data than the Graph can hold you will be told and the top and bottom rows only of what you ve selected will be graphed This screen graphs of Camber in degrees on the vertical Y axis versus either Roll or Dive on the horizontal X axis The data graph here is based on what was highlighted in the Camber table when you clicked on the Graph menu item Data is always graphed for the Left side as well as the Right side for whatever conditions you have selected highlighted If you make graphs of Roll Center Height and Roll Center Left as done if Figure A12 this graph will show the actual location of the roll center and how it moves Height is on the vertical Y axis and Left is on the horizontal X axis Read the labels in the legend at the right side of the graph to see which lines are which colors The graph is always autoscaled which means the program picks the scales for drawing it to display all data with good detail Print the graph on your printer using your Windows default printer by clicking on the Print menu command You can change settings labels and Windows printer setup by clicking on the Options menu command See Figure A13 You can return to the Cam
8. S change this should it not be set exactly as you want Then enter the New Tire dimension and see the effect on Cross Weight Rear and Left percents are not affected by changing tire diameter For the Move Weight tab choose the type of weight change and the amount of weight to change Then type in the Current Location of the weight and or the New Location of the weight after the move Cross Rear and Left percents can all be affected by moving weight Click on Back keep changes at upper left of this screen to return to the main screen while keeping your changes to corner weights tire sizes vehicle weight etc Front Suspension Screen Figure A11 shows some of the new features for the Front Suspension Screen Figure A12 shows an example of the new Table amp Graph feature for calculating Roll Center migration for various amounts of dive and roll Figure A 11 New Front Suspension Screen Features New Table amp Graph features are explained in Figure A12 m Front suspension specs atemodi tal Back Fie Options Edit Suspension Type Shim MEJE Ae Em Comments Help This t front view of suspension Camber Table tually right side of car Roll Center Table Gain based or 1 and 0 deg Roll Other Specs Right Left Swing Arm Length and Scrub are displayed here e e Spring Length Scrub Radius Stc Camber deg Dyn Camber deg King Pin Angle Spindle Angle Rt Swing Arm 47 1 Lt Scrub 207 Lt Swing Arm 55 4 Rt Sc
9. ack Back keep changes Print be Pink represents New Settings Tire Change Hove Weight Teron Static Mew re to Change Right Front Height 50 00 5000 Rear Height What to Change Circumference 00 56 00 58 00 Left ee Ue 58 00 5711 Cross Current Tire Hew Tire Circumference Circumference Lbs zog Help Defimition Chose the type of weight change you want to make Important The estimates made in this screen are based on several assumptions two of the most important being the chassis 1s perfectly stiff and the tres are perfectly stiff The screen in Figure A10 is used to determine how static corner weights change as you make adjustments to the car These adjustments include turning jacking screws to adjust the preload on springs changing tire diameter circumference and moving weight around like ballast Click on one of the 3 tabs at the top to choose your option The first tab Jacking is the same as it was in v3 2 For most all inputs on this screen click on the name or input box and its definition is given in the section at the bottom of the tab page For the Tire Change tab choose which tire to change and which dimension you want to work with The program will then display the Current Tire dimension from the Vehicle specs screen You are allowed to C Performance Trends Inc 2008 Circle Track Analyzer Appendicies SE ESSE SE EEE EE SS SS SSe
10. allast movement to check the affect on corner weights e Screen colors are now more compatible with Windows XP e Added ability to save a vehicle file to or open a vehicle file from a floppy disk or CD with a default drive letter from A to Z selectable in Preferences e New Example files have been added like GM Metric 4 Link Rear Suspension e Added Edit options to the Calculate menu item in the Engine Specs screen The new Edit options let you factor the power curves up or down or re sort the table if there are blank rows or RPM increments out of order FLLD Front Lateral Load Distribution When a car makes a turn weight is transferred from the inside tires to the outside tires However how this weight transfer is split between the front and rear has a huge impact on the feel and handling of the car If more weight transfer occurs on the front of the car the outside front tire is being overworked more than the rear outside tire causing less cornering traction at the front This is more likely to produce understeer or a push Very simplistically if the Front Lateral Load Distribution is 50 that means the C Performance Trends Inc 2008 Circle Track Analyzer Appendicies SSS SS SS SS SS SSS SSS weight transfer split between front and rear is the same and that should produce neutral handling The book Race Car Vehicle Dynamics by Milliken and Milliken with assistance by Terry Satchell discusses this concept in deta
11. ber Table screen by clicking on the Back menu command Figure A 13 Graph Options Menu Graph Options for Making Graphs Graph Labels Use Standard Labels Pig PEE PO Use Labels Given Here fi gpyandayess Piar a i ipini Back Pr Plot Lines CY E l Black amp White C Color Thick Thin Windows Printer Setup Background Color C Black White The Graph Options screen is divided into 4 sections The first section is called Graph Labels Click on Use Standard Labels for standard labels to be printed on the graph Click on Use Labels Given Here and the program will use the labels C Performance Trends Inc 2008 Circle Track Analyzer Appendicies ee ee eae eee ean ee eee SS SSS SSS SSS SSS which you can enter or change Click on any of the 3 text boxes and type in your chosen titles or labels The second section of the Graph Options is called Print Click on Black and White or Color to tell the program how to print the graph Unless you have a color printer you should choose Black and White The program always graphs in color on the computer screen Click on the Print Now button to print the current plot on the printer the same as selecting the Print menu command Click on the Windows Printer Setup button to see the current printer selection or select a different printer for printing the graph The third section lets you pick the line thickness for the Plot Lines eit
12. cts most all of the handling ratings the program will calculate RCC CTA The program now lets you enter both a front and rear aerodynamic Lift Coefficient Many times when you make an aerodynamic adjustment you only affect 1 end of the car like a rear spoiler adjustment This adjustment not only affects overall road holding ability of the car and therefore lap times it also affects handling the tendency to oversteer or understeer CTA only The program has a new Calculation Menu utility called Adjust for the front and rear Lift Coefficient and Drag Coefficient You can choose a type of vehicle modification enter the starting and modified condition and the program shows you how the current lift and drag coefficients would change This way you have an estimate of how certain vehicle modifications would affect the entire aerodynamics of the vehicle CTA only You can now enter more details about the front suspension both for Double A Arms and McPhearson Strut suspensions This added detail lets you locate both the front and rear A Arm mounts on the frame and the angle of the McPhearson Strut when viewed from the side These details let the program more precisely locate where the A Arm attaches to the frame in the 2 dimensional layout They also determine how much Anti Dive is built into the front suspension Anti Dive is the vehicle s resistance to diving the front end due to braking Reasonable starting points for Anti Dive for mo
13. e Rear roll centers being too high High roll centers transfer more weight laterally through the suspension linkages and less through the springs making the springs and roll bar have less effect on this tuning factor You may then want to have the program adjust the C Performance Trends Inc 2008 Circle Track Analyzer Appendicies LSS Se EEE EE EE EE SSS SSS Ses Rear Roll Center to find the FLLD you desire After you adjust the Rear Roll Center and keep this change click on OK Keep then you can go back into this screen and try adjusting springs and or roll bar and they are likely to have more affect If you find settings which you want to keep click on OK Keep and they will be loaded back to the vehicle specs screen For the Front and Rear Roll Center Heights for some suspension types you must make a mental note of this setting and go back into the Front or Rear Suspension Screen and try various setting to arrive at this height The program can not make this change automatically for you Fig A9 Other Features using the FLLD Concept At the top of the Analyze i Suspension screen these w Circle Track Analyzer v3 9 Suspension Analysis Screen LATEMODL 355 r 3 reports are all improved Back Back keep changes Options Print etnies Continuous ffnge Step Ahead Single Step Back S This is a Front View left side of scl Suspension Calcaf ti j USING the FLLD concept Suspension C4lculations with Comments Rule of Thumb Sugge
14. eral ways to obtain a certain Front Lateral Load Distrbution percentage 3 Click here to have program find new settings 1 Pick what to Adjust 2 Select the FLLD you want The program will default to a typical value based on your car s weight distribution 4 Click here to have program save these new settings Load Dist 150 7 180 1 75 7 1 68 Hew Front Lat Load Dis New Rear Springs Options Adjust For This FLLD This change tends to make the car slightly looser Hote The new settings you find using this feature may NOT be best your driving style and could be UNSAFE Click on Help for more mfo For this vehicle s Front Wit of SOLO 55 0 5 higher would be a suggested setting OK Keep Help Cancel Print The new settings you find using this feature MAY NOT BE THE BEST AND COULD BE UNSAFE USE YOUR JUDGEMENT when making adjustments based on this concept To reduce the possibility of using very strange settings the program will calculate the average front and rear natural frequencies for the springs If these frequencies are significantly different than those typically used the program will warn you Typically the front natural frequency will be in the range of 1 4 to 2 0 and the rear will be 1 to 5 points lower than the front For many vehicle combinations the program can not find settings to match your requirements Many times this is due to the Front or especially th
15. ference in agger in Tread Width in Traction Factor Hel The ie ioh ie vehicle with the driver in pounds p 20 Back Help Print Printer Setup poso e C a5 Rear deck of car Circle Track Analyzer Appendicies Click on the Adjust button for the screen shown below Program now has both a front and rear lift coefficient to split the aerodynamic down force between the front and rear tires Help Cancel Print C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Figure A17 More Front Suspension Details Enter both measurements for both front and rear Kl attachment points on frame Back File f Suspension Type Shim Table amp raph Comments Help w Front Suspension yecs later E a i The calculated 2 D mounting Right lt Height Dey point used by program is Nee Close this a FA shown here with the current screen b 16 5 e 2 D mounting point used by C I0 Load the program from the screen d a below l Fi Click here to use these new l B 2 D points in screen below Ties Load Calculated Mount Load o 0 5 Curent Mount 85 o P En Calculated Anti Dive ae Lower Frame Pivot 85 NO Upper Spring Pad h9 Click here on Show 71 25 575 Lower Spring Pad Details button to open i l AS screen shows above Length Angle Length Angle Upper Arm Dim Lower Arm Dim C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Figure
16. her thick or thin The fourth section lets you pick the color for the Background Color of the graph either black or white Click on OK to return to the Graph Screen with your changes in effect Rear Suspension Screen Figure A14 Symmetric Angled 4 Link Rear Suspension New Type is available of w Rear Suspension Specs Metric 4 Link Symetric Angled A Link Back File Comments Help Suspension Specs Top iew Right Side Type Sumetric Angled 4 Link Left Right Spring Rates Ibin Tire to Centerline in 0 0 3 aain im beaches ae Spring Angle deg Spring to Axle in Wheel Rates Rear View Bump 200 Axle to Front Pivot in ie Axle to Rear Pivot in 4 Link Side View To Cel Ht To CL at r ehas es Help Click on down arrow button to pick a Typical Example of A rear SUSpension of a general design to Use Specs Below where you can enter Your own specs p 51 Roll Center Ht 16 7 Roll Center Right 0 0 C Performance Trends Inc 2008 Circle Track Analyzer Appendicies ae see a ee ee eee eee cee enn ee ee SS SSS SSS SSS SSS The new Suspension Type of Symmetric Angled 4 Link lets you find the roll center and roll stiffness of rear suspensions found in several vehicles including GM Metric and later model Mustangs Because it is only for symmetric layouts you will only enter measurements for 1 side and they will be used for both sides Engine Screen Edit options have been added to the Calculate
17. hicle s Front wt of 50 02 55 02 Se higher would be 4 suggested setting OF sSFeep Help Cancel Print Circle Track Analyzer Appendicies Roll bar drawn to your specs here in green Top View wheel Aates ae 150 Rear View Set to Yes and you can enter rear roll bar Specs Bump 180 Roll 159 Roll Center Right 0 0 Click here to Calculate a roll bar rate from other inputs You can also find a rear roll bar rate to give a desired handling rating Front Lateral Load Distribution FLLD C Performance Trends Inc 2008 Figure A16 Front and Rear Aerodynamic Lift Coefficients w Vehicle Specs General Vehicle Specs Total Weight with Driver Ibs Hear 50 CI Corner Weights eco co Cross E 5 cic Standard Duty ka Type Use Specs Below Drag Coefficient 42 Height of C G in Wheelbase m Rear Axle Ratio Rear Axle Type Aerodynamics Lift Coefficient front Lift Coefficient rear Frontal Area sq ft w Calc sero Adjustments Drag Coef Change Lift Coef Change front Lift Coef Change rear Current Condition Deck Spoiler Length Deck Spoiler Height Angle 0 flat 90 up Hew Condition Deck Spoiler Height Angle 0 flat 90 up Notes This adjustment is based 003 Transmission Type Std Duty Manual Ratio of Trans Gear Used fs Rear Wheel Tie Sp cs Type Typical Macing Tire average traction Avg WheelX Tire Wt Ibs Left Right Ciop
18. il This concept is similar to the idea of balancing the front and rear roll angles presented in recent magazine articles Figure A7 shows the program displaying the FLLD for the current vehicle currently 43 4 which would tend to oversteer during the transition between releasing the brakes and going to the throttle at the apex of the turn transistion between braking and power During braking and under acceleration the weight transfer 1s much more complicated and the FLLD concept can not be as easily applied Figure A7 New Options at Main Screen Corner Jacking brings up screen of Figure A10 E Circle Track Analyzer v3 5 Performance Trends LATEMODL 355 Tak File vehicle Results Help Preferences Reg To Kevin Gerbgen ee Open ehicle Library Calculate Lap Times Find Best Gear Ratio 4 FLLD value for this car is shown here with a description of what it nee oe eye tay means Click on details for more 50 rear 58 left 58 cross info on this tuning parameter including more complete vehicle calculations Rear Susp File latemodl tab for ailing ArmsCail SpringsPanhard or NB ar Hes Suspension Track 64 0 Lt Spring 150 Transistion Handlin i Running Conditions Lateral Load Transfer 44 4 Front some oversteer loose _Details Note Understeer a number above 50 ts Safer than Oversteer Fing Help Comments Move mouse ower item For show All Comments description to be given here Click on Help in menu
19. line For more detailed info on options Super Late Model on a 172 mile track with fabricated front and rg suspension 467 HP at 6500 from 355 w 390 46BL roller cam AFR heads Find button brings up screen of Figure A8 to let you quickly find combinations producing different FLLDs Figure A8 is displayed if you click on the Find button shown in Figure A7 This Find FLLD screen lets you find a certain Front Lateral Load Distribution FLLD which can be a good indication of how the car will handle at the apex or transistion of the turn no power no braking C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Pick the Adjust factor to tell the program what vehicle component s you want to adjust Enter your Figure A8 Find Front Lateral Load Distribution Screen obtained by clicking on Find button in Fig A7 m Find Front Lat Load Dist Eg desired For This FLLD then click on the Find Now button For perfect theoretical Balance the FLLD should be 50 However from experience Milliken suggests a target starting point FLLD value of 5 percentage points higher than the percent weight on the front tires 100 Rear Wt Front Wt By default the program will load in this value but you can change it to anything else you want Higher FLLDs tend to make the car tighter with more understeer Lower FLLDs tend to make the car looser with more oversteer There are sev
20. ondition as a Baseline you can compare your current conditions to a saved Baseline This is the same as what is described in the preceeding paragraph except it is done at all locations on the track This is also the same as the Analyze Suspension feature in previous versions except now it includes the front and rear aerodynamic downforce and the handling rating CTA only e The Rule of Thumb Suggestions for a good starting point for a setup now includes suggestions for a Big Bar Soft Spring BBSS setup The BBSS theory is you use significantly softer front springs to better handle bumps in the track and to lower the car in the corners for less aerodynamic drag and less weight transfer inside to outside Then to counteract the additional roll these soft springs would allow the anti roll bar is stiffened significantly Other adjustments include a much stiffer than typical right rear spring paying more attention to Anti Dive and shock valving CTA only e Improved the Tire Scrub calculation for a Double A Arm front suspension how much sideways tire movement there is during dive and roll RCC RCC and CTA e Refined the calculations for suggested spring rates for Starting Point Suggestions report CTA only e Program is now more compatible with Windows Vista and Windows 7 RCC RCC and CTA e Program is now better at remembering a printer or printer orientation changes RCC RCC and CTA e Program is now better at
21. rows and 11 columns Your inputs may be changed if a combination produces more than these limits When you are satisfied with the Preview click on OK Exit Click on Cancel to close this menu and return to the original Table layout Note If you change the Table specs any previously saved baseline conditions will be lost because that baseline has different increments for columns and rows which would not match up to the new increments you have selected C Performance Trends Inc 2008 Figure A 12 Roll Center Table and Graph wi Roll Center Table Heimi amp Offset Leli aol Bad Print Crptiorns Baseline show sawed rets RC Height A 31ers oe Dive inches 2 00 new 2 00 base 2 00 mer 2 00 bare UIE re LD Eee 2 Dittenence 2 00 400 Click on Options for screen to the right to choose increments for dive and roll for table Circle Track Analyzer Appendicies Click on Graph to make graph mas as shown below Data in Rows Starting Dive inches Ending Dive inches Dive Step Size Starting Roll degrees Ending Roll degrees Roll Step Size Preview Dive Srowe s r columns columns Maxinum of 10 rows by 11 OKE xit Help Cancel Print RC Location for Roll degrees 3 00 to 3 00 Baseline Symetric d a r J i 1 RC Offset Left left side graph nght side car like Front Suspension Screen C Performance Trends Inc 2008 Circle Track Analyzer
22. rub 092 Roll Bar Rate Ib in Roll Bar Length in Roll Center height 1 5 Roll Center Left _5 Static Layout Dimensions Show Dive amp Roll Right i z 7 Upper Ball Joint a Yez Upper Frame Pivot Dive inches Roll deg Draw fT SS Bia O No Lower Ball Joint Lower Frame Pivot Upper Spring Pad Lower Spring Pad Upper Arm Dim Lower Arm Dim Help definition Distance from car centerline to the center of ball joint on Upper arm on Aight side in inches For ease of consistent measurements for front and rear use the center of the drivetrain engine trans rear asle as the car s centerline p 31 C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Lt and Rt Scrub shows in Figure A11 is the amount the tire moves out from the center of the car as it goes through the amount of dive and roll you have specified Lt and Rt Swing Arm Length is the distance from the center of the wheel tire to its instant center Long lengths indicate that camber will change little with dive and or roll Camber Gain will be low Table amp Graph If you click on Table amp Graph at the Front Suspension Screen you will obtain a screen similar to to the top picture in Figure A12 This screen shows you 2 tables of Roll Center Height and Roll Center Left distance left of center for a set on Dive and Roll combinations Distances right of center are labeled as negative Negative in not bad it is just a wa
23. st all circle track asphalt cars in the 2000 3500 Ib range are 10 on the Right Front and 5 on the Left Front RCC RCC and CTA We ve taken the concept of balancing the Front Lateral Load Distribution FLLD with the rear lateral load distribution a step farther We ve developed a Performance Trends exclusive called Oversteer Understeer rating It is based on how evenly the tires on the 4 corners of the car are loaded If they are equally loaded left to right and loaded front to back the same as the front to back weight distribution we say that is a 0 Oversteer rating or Neutral handling Several C Performance Trends Inc 2008 Circle Track Analyzer Appendicies SSS SSS ee factors go into this rating including banking forces aerodynamic forces dynamic weight transfer left to right and front to back CTA only e You can display the actual wheel loads for the car in transition on the track at the point where you are neither braking or accelerating It is at this point where the program determines the Oversteer Understeer rating described above For this transition condition you can also save a baseline condition for comparison to some modification you have made to the vehicle This way you can actually see the effect you modifications will have on wheel loads and the handling rating CTA only e The oversteer understeer rating is displayed as the car goes around the track on the Analyze Suspension screen By saving a c
24. stions Rule of Thumb Adjustments write ASCII File of BASELINE Wheel Loads Suspension Report td Notepad File Edit Format View Help Your current rear roll center height is 12 68 inches above ground A good starting point for Front Lateral Load Distribution FLLD For a car with 56 68 Front weight distribution would be 55 6 This is based on the Rule of Thumb that FLLD should be 5 higher than the Front Wt 4 To obtain this with the recommended spring rates The Rear Roll Center Height should be 12 68 inches above ground The new v3 5 Transistion Handling Rating options on the main screen will let you adjust other specs to obtain this or other FLLDs Ln 54 Col 1 E Suspension Report txt Notepad File Edit Format wiew Help Distance Behind Front Axle in Distance from Vehicle Centerline in Left Comments Your FLLD of 43 4 is Much Lower than typically used A suggested starting point is 55 Front Lateral Load Distribution or FLLD This is based on adding 5 percentage points to this vehicle s 56 Front Weight Distributi Ln i Col 1 C Performance Trends Inc 2008 Circle Track Analyzer Appendicies Figure A9 shows 2 reports which now also include references and suggestions based on balancing the FLLD Corner Weights Figure A10 Corner Weight Screen from Clicking On Button in Fig A7 Two New Options in Version 3 5 w Circle Track Analyzer v3 5 Corner Jacking Screen LATEMODL 355 B
25. y to indicate right the opposite of Left You could have also chosen to do a Camber Table Then the top table would be for the Right side and the bottom would be for the Left side You can also select to have a Baseline condition displayed in the Table Show Baseline Data This is useful to compare 2 different suspension layouts A Baseline is some previous condition which was shown in the Table To save the current Table as a Baseline click on Baseline then Save This Data as Baseline The program will ask you for a Comment to describe the Baseline condition This Comment will be printed with the Table when you print it if you are Showing the Baseline condition This comment can also be edited by clicking on Baseline and then Baseline Comment After saving a baseline Table you could close the Table by clicking on Back in the Menu Bar make a change in the suspension and create the table again by clicking on Table amp Graph You would produce a Table like in the upper left of Figure A12 Click on the Options menu item and select Specs for Table Rows amp Columns to change the Dive and Roll increments and which is used for rows and which is used for columns You will obtain the menu shown in the upper right of Figure A12 As you change the specs in this menu the Preview at the bottom changes to show what the Roll and Dive increments and the general layout of the Camber Table will look like The program allows only up to 10
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