Hephaestus RC Tune Up Spreadsheets
04-09-2015 | 06:18 AM
#76
I'm going to send MIP an email to know if they will produce the Bypass1 for16 mm shocks edit/ coming soon /edit, I am more confident in their design (I want to choose piston hole size and number and a staggered config, unfortunately seems neither do).
| + YouTube Video | |
Last edited by 30Tooth; 04-09-2015 at 06:36 AM.
04-20-2015 | 11:57 AM
#77
New version is up, there's a new sheet called Susp. Freq. Graph. That way you can match easily front and rear springs 
automatically calculates from weight bias/spring and MR changes in the main sheet.
I've seen more spreadsheets, some of them way with more pro looks, tire deflection equations, advanced dampening, sway bar and bushing flex(!), advanced weight transfer equations... amazing work. The spreadsheet I present here is a condensed and to the point version aimed specifically at increase know-how and efficiency. Expect a 10% deviation in results.
In conclusion, start by matching shock pistons to Motion Ratio, then setup evolution is much more easier. Don't try to understand where roll centers should be! The important thing is: whenever they are, if the CoG has enough leverage in them, it will create roll and therefore grip no matter track surface or tire friction potential.
automatically calculates from weight bias/spring and MR changes in the main sheet.I've seen more spreadsheets, some of them way with more pro looks, tire deflection equations, advanced dampening, sway bar and bushing flex(!), advanced weight transfer equations... amazing work. The spreadsheet I present here is a condensed and to the point version aimed specifically at increase know-how and efficiency. Expect a 10% deviation in results.
In conclusion, start by matching shock pistons to Motion Ratio, then setup evolution is much more easier. Don't try to understand where roll centers should be! The important thing is: whenever they are, if the CoG has enough leverage in them, it will create roll and therefore grip no matter track surface or tire friction potential.
Last edited by 30Tooth; 04-30-2015 at 03:26 PM.
05-01-2015 | 12:34 PM
#78
Just piggyback the amazing work from the shock dyno thread (link in the first post, sources section) on the spreadsheet, it's v5 now.
The way it works is: you enter the average height your car drops in the track and see if the displacement line goes over the amount of droop your car has. Example: a 0.030m displacement and having 0.029m of droop means the chassis bottomed out. I'm researching ways to input acceleration to know how the suspension reacts to bumps and if the tires leave the track surface.
The way it works is: you enter the average height your car drops in the track and see if the displacement line goes over the amount of droop your car has. Example: a 0.030m displacement and having 0.029m of droop means the chassis bottomed out. I'm researching ways to input acceleration to know how the suspension reacts to bumps and if the tires leave the track surface.
06-18-2015 | 07:40 AM
#80
Roll center height/couple and "slope" and go-faster stuff.
Had a brain storm last night...Here's a couple things I want to share with you:
- Some cars just have a tendency to roll more on one end than the other, most drivers just change spring or damping and end up with a ill driving car. They don't know what is causing the roll.
Weight transfer - which is only affected by CG height, the amount of force applied and vehicle track or wheelbase depending on what you want to calculate - is the most important dynamic in vehicle handling. You can't change weight transfer with springs, roll bars or roll center tuning! Only by altering CG height, widening or shortening the track (vehicle's track not the track itself) or wheelbase again depending if you are looking into side to side weight transfer or front to back and vice versa weigh transfer. Roll center tuning, springs, roll bars and suspension geometry change the rate the weight transfer happens.
With that said, to have a balanced car in roll resistance and ride resistance (which means the front and rear suspension works the same distance when under side to side and up-down forces respectively and not correlated) only through springs and roll bars masks another characteristic, roll couple. Example, a car with 50-50 weight bias has it's CG in the middle, which means both front and rear wheels are subject to the same weight transfer force when turning. If the springs are balanced regarding ride resistance but the suspension still dumps in turns, increasing front damping/roll bar thickness is not the solution. Imagine looking at the side of the car and a line connecting the two roll centers, if the line is tilted to one side it means that end will roll more and twist the other suspension, increasing tire load (imagine sitting in a one legged chair and tilting a bit to the front, if you keep both foots closer together in front of you, you have to exert greater force in the ground to not fall). Let that sink in, a bit confusing isn't it?
So, softening the rear roll stiffness increases front tire load and vice versa! If you change the front roll stiffness the effect is less profound because the CG height is lower in the front so the effect in the rear is lower! That's why it so important to have the rear RC and roll stiffness in the right place in the grand scheme of things. That's why the only thing my spreadsheet lacks is roll center height but with the information provided in this post you can tune by eye balling which end rolls more after balancing front and rear ride and roll resistance through the spreadsheet.
In the end, you will end up with a car that provides maximum consistent tire loading through the turns, where both ends will work together instead of fighting each other. Now, how much roll/ride resistance, RC height, weight and weight bias? That's up to available grip and track conditions.
Had a brain storm last night...Here's a couple things I want to share with you:
- Some cars just have a tendency to roll more on one end than the other, most drivers just change spring or damping and end up with a ill driving car. They don't know what is causing the roll.
Weight transfer - which is only affected by CG height, the amount of force applied and vehicle track or wheelbase depending on what you want to calculate - is the most important dynamic in vehicle handling. You can't change weight transfer with springs, roll bars or roll center tuning! Only by altering CG height, widening or shortening the track (vehicle's track not the track itself) or wheelbase again depending if you are looking into side to side weight transfer or front to back and vice versa weigh transfer. Roll center tuning, springs, roll bars and suspension geometry change the rate the weight transfer happens.
With that said, to have a balanced car in roll resistance and ride resistance (which means the front and rear suspension works the same distance when under side to side and up-down forces respectively and not correlated) only through springs and roll bars masks another characteristic, roll couple. Example, a car with 50-50 weight bias has it's CG in the middle, which means both front and rear wheels are subject to the same weight transfer force when turning. If the springs are balanced regarding ride resistance but the suspension still dumps in turns, increasing front damping/roll bar thickness is not the solution. Imagine looking at the side of the car and a line connecting the two roll centers, if the line is tilted to one side it means that end will roll more and twist the other suspension, increasing tire load (imagine sitting in a one legged chair and tilting a bit to the front, if you keep both foots closer together in front of you, you have to exert greater force in the ground to not fall). Let that sink in, a bit confusing isn't it?
So, softening the rear roll stiffness increases front tire load and vice versa! If you change the front roll stiffness the effect is less profound because the CG height is lower in the front so the effect in the rear is lower! That's why it so important to have the rear RC and roll stiffness in the right place in the grand scheme of things. That's why the only thing my spreadsheet lacks is roll center height but with the information provided in this post you can tune by eye balling which end rolls more after balancing front and rear ride and roll resistance through the spreadsheet.
In the end, you will end up with a car that provides maximum consistent tire loading through the turns, where both ends will work together instead of fighting each other. Now, how much roll/ride resistance, RC height, weight and weight bias? That's up to available grip and track conditions.
07-03-2015 | 06:55 AM
#82
With the recent breakthroughs I have been researching a lot about ride height.
This is a first tier adjustment, being it changes two suspension geometry laws, CG height to ground and roll center static height. Generally speaking you want as much ride height as you can get away with because:
-with more CG height comes more weight transfer, therefore available grip;
-more suspension/chassis clearance.
Now, having different ride height front to back is a mean to fine tune roll center height at least in 1/8th cars, 1/10th can fine tune roll center in cars with vertical ball studs. I've found time and time again that a lower ride height doesn't provide more grip, on the contrary. Very useful adjustment in high grip track surfaces!
Another thing with ride height is that you could neutralize the change in roll couple (difference between CG height and static roll center height) and keep the static roll couple approximately the same distance but could locate the roll center too low or too high depending if you are lowering or increasing ride height.
Funny thing, if you could move the roll center height closer to CG height even a lifted Savage could have zero suspension roll!
This is a first tier adjustment, being it changes two suspension geometry laws, CG height to ground and roll center static height. Generally speaking you want as much ride height as you can get away with because:
-with more CG height comes more weight transfer, therefore available grip;
-more suspension/chassis clearance.
Now, having different ride height front to back is a mean to fine tune roll center height at least in 1/8th cars, 1/10th can fine tune roll center in cars with vertical ball studs. I've found time and time again that a lower ride height doesn't provide more grip, on the contrary. Very useful adjustment in high grip track surfaces!
Another thing with ride height is that you could neutralize the change in roll couple (difference between CG height and static roll center height) and keep the static roll couple approximately the same distance but could locate the roll center too low or too high depending if you are lowering or increasing ride height.
Funny thing, if you could move the roll center height closer to CG height even a lifted Savage could have zero suspension roll!
07-31-2015 | 01:10 PM
#83
New lite version is up, anything deemed low priority was deleted but the good stuff was improved, expanded and corrected. Some stuff I learnt this past months made me cut most of the shock tuning stuff because I believe anyone with enough eyesight can see what the car is lacking after tuning through the spreadsheet. As always, any question, improvement or critic I'm all ears.
08-28-2015 | 07:01 AM
#84
Just a small setup tip. I've been curious about the Batlle's MBX7 World Champion setup and my testing shows that a way lower front end helps tremendously in on power traction. Any of you with MBX7's or just lacking on power traction try running the front 2-3 mm lower than the rear.
08-28-2015 | 12:07 PM
#85
Tech Master
iTrader: (5)
Joined: Jun 2012
Posts: 1,876
I can't get my head around the spreadsheets. I'm not sure if you can do this, but can you plug in all the info into one of the spreadsheets and give me a good starting set up for an RC8B3 (the new Associated nitro buggy)? I'm helping a friend get his Buggy dialed in. I'm also keeping in mind your other thread.
08-28-2015 | 02:53 PM
#86
I can't get my head around the spreadsheets. I'm not sure if you can do this, but can you plug in all the info into one of the spreadsheets and give me a good starting set up for an RC8B3 (the new Associated nitro buggy)? I'm helping a friend get his Buggy dialed in. I'm also keeping in mind your other thread.
Sure can, I need:
-front and rear arm length, the front is harder but measure from center of inner hinge pin to middle of lower pillow ball;
-weight bias in grams
-the whole shock dimensions I explain how to measure in the first post;
-front and rear ride height.
That is enough to know what setup I should recommend. One thing I want to ask you, how can I improve the spreadsheet for you?
08-30-2015 | 12:46 AM
#87
Tech Master
iTrader: (5)
Joined: Jun 2012
Posts: 1,876
Cool. I will try and get that info to you, but it will be a while as I don't have the car in my possession.
As far as the spreadsheet goes, I haven't really put the effort in to try and figure it out mostly due to lack of time. When I get time, I will dive into it!
As far as the spreadsheet goes, I haven't really put the effort in to try and figure it out mostly due to lack of time. When I get time, I will dive into it!
09-21-2015 | 03:57 PM
#89
My job is keeping me very busy, but I've not forgot this thread and the people I help.
TO DO LIST:
-Add sway bar stiffness calculator to final version spreadsheet;
-Glossary!
-More tips, have some about roll bars.
One very important part of the whole setup dynamics is acknowledging that all buggies can be fast. Doesn't matter suspension geometry or chassis width/flex/cut outs. These can be changed to alter feel or tune to a certain driving/track characteristic.
I'm reading again that gentleman are having issues with on power traction on the RC8B3 and other new gen buggies. Some tips:
Assuming a mechanically sound buggy and running level rear arms with ground, how are the rear tires wearing? More than the front tires? On the inside, outside or center of the thread? Typically having on power oversteer is a symptom of rear wheel rolling too much and can be cured by lowering the inner camber link position on the rear shock tower (effectively decreasing rear roll couple); running a thicker rear anti roll bar and/or stiffer spring in the rear. Anti squat works if the buggy squats too much on acceleration and causes the wheels to gain camber, the other adjustments work if you have to wait for it to finish the corner before accelerating. Running a less aggressive front end works too but it's your call if you want to mess with the front end.
I also saw that the stock rear camber link length is long, coupled with lot's of roll it can cause the rear tires to loose camber and then the buggy rides on the sidewall. A short rear camber link cures that issue but beware the buggy might roll more now that has more available grip!
TO DO LIST:
-Add sway bar stiffness calculator to final version spreadsheet;
-Glossary!
-More tips, have some about roll bars.
One very important part of the whole setup dynamics is acknowledging that all buggies can be fast. Doesn't matter suspension geometry or chassis width/flex/cut outs. These can be changed to alter feel or tune to a certain driving/track characteristic.
I'm reading again that gentleman are having issues with on power traction on the RC8B3 and other new gen buggies. Some tips:
Assuming a mechanically sound buggy and running level rear arms with ground, how are the rear tires wearing? More than the front tires? On the inside, outside or center of the thread? Typically having on power oversteer is a symptom of rear wheel rolling too much and can be cured by lowering the inner camber link position on the rear shock tower (effectively decreasing rear roll couple); running a thicker rear anti roll bar and/or stiffer spring in the rear. Anti squat works if the buggy squats too much on acceleration and causes the wheels to gain camber, the other adjustments work if you have to wait for it to finish the corner before accelerating. Running a less aggressive front end works too but it's your call if you want to mess with the front end.
I also saw that the stock rear camber link length is long, coupled with lot's of roll it can cause the rear tires to loose camber and then the buggy rides on the sidewall. A short rear camber link cures that issue but beware the buggy might roll more now that has more available grip!
Last edited by 30Tooth; 10-15-2015 at 07:44 AM.