Extended Ball Joints


The reason I like this stuff is because I am designing my own single seater autotest car. In a project like this testing isn't an option, I don't have a big budget to try out things so it has to be right first time when it gets built. Because of this, I need to do the maths so I know how everything works and I can, as near as possible, predict how the thing will perform. All this theory work is massive overkill and pretty pointless for a road/track car, as you say, simply driving it is a much better use of ones time!

I simply transfer the theory stuff I do over to the Civic because I can, it usually whiles away a few hours at work when things are slow. At the end of the day, it's just my daily hack that I happen to autotest once a month a do maybe one trackday a year in.
 
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Fixed the error I spotted last night, seems the RCAs do improve the camber curve after all:

Cambercurve2.jpg


They also rasied the RC up to 3.89, higher than before.

However, plot the camber against deflection and they aren't so good:

Cambercurve3.jpg


This is of course mitigated by the fact that if you are running RCAs then you are almost certainly using stiffer rates in conjuction with the lower ride height so deflection will likely be less than stock anyway.
 
very interesting stuff guys
ill see if i can draw the civic up on wingeo3 which is a motorsport program which you can pretty much plot out the cars entire geometry and play around with heights etc and it will re adjust everything and give you results
it also allows you to induce scenarios such as bump rebound etc
kozy in your deflection against camber graph i wouldnt necessarily say it was a bad thing as it is inducing more camber as you roll which in speaking should be good also that can be explained by the fact that using the rca you in effect distance the top arm which is shorter in length to the bottom arm which is longer and as a result as the bottom arm deflects upwards the upper arm is already traveling within its curve resulting in a larger camber gain as deflection increases.

i suppose on a soft road suspension set up it can be negative effect but on a track based car or fast road setup the smaller deflection offered by the harder suspension will greatly benefit from the increased amount of camber gained per mm of deflection as it will strictly theoretically speaking equate to the same amount of camber gain over a standard setup on soft suspension
im not sure if i am making any sense but this was written quickly as im in work and not really supposed to be on forums :D

peace
-si-
 
sie2050 said:
kozy in your deflection against camber graph i wouldnt necessarily say it was a bad thing as it is inducing more camber as you roll which in speaking should be good also that can be explained by the fact that using the rca you in effect distance the top arm which is shorter in length to the bottom arm which is longer and as a result as the bottom arm deflects upwards the upper arm is already traveling within its curve resulting in a larger camber gain as deflection increases.
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The deflection plot represents jounce but no roll, so it is gaining camber as the car pitches forwards under braking, which is bad as camber reduces straight line traction. The increased camber 'retention' (or reduced camber loss) with the RCAs as shown in the camber vs roll plot shows what you describe, and yes, that would be a good thing!

Interested in that wingeo program, is that something I would be able to get hold of? Been trying to get ADAMSCar for a while to no avail. :(

sie2050 said:
im not sure if i am making any sense but this was written quickly as im in work and not really supposed to be on forums :D
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Hehe, same here!

Anyone ever fitted these RCAs on a non slammed car?
 
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if that graph is relating to dive under braking then im pretty sure it can be negated as if the rcas are used as designed such as during heavy motorsport use then the whole set up of the car can nagate any dive which would result in the instability which you are concerned about such as rebound settings on rear shocks/ compression on the front shocks and multiples there of also the weight spread of the car between front rear splits and left right splits also diagonal splits all come into play but by default there will always be some sort of pitch during hard braking and by flaw of design there is not much that can be done. also the double wishbone design in itself is a compromise of straight line stability and cornering ability mainly sacraficing straight line for cornering grip but the negative effects can only be seen under certain extremities such as like you say under hard braking etc
that is talking strictly theoretically
but as stated before if the car is setup for track use then the stiffness of the setup will depict wether or not the suspension will build enough camber to negatively effect it
another factor would be tire deflection but thats a whole different kettle of fish lmao

-si-
 
and about your question on wingeo its a very expensive program which ive only seen in uni where im studying motorsport engineering

the program is called mitchells wingeo3 i think, im pretty sure someone has uploaded it to the net at some point so best bet it to have a search ive not tried really as ive never needed it outside of uni

-si-

heres a link to their site i think
 
sie2050 said:
if that graph is relating to dive under braking then im pretty sure it can be negated as if the rcas are used as designed such as during heavy motorsport use then the whole set up of the car can nagate any dive which would result in the instability which you are concerned about such as rebound settings on rear shocks/ compression on the front shocks and multiples there of also the weight spread of the car between front rear splits and left right splits also diagonal splits all come into play but by default there will always be some sort of pitch during hard braking and by flaw of design there is not much that can be done. also the double wishbone design in itself is a compromise of straight line stability and cornering ability mainly sacraficing straight line for cornering grip but the negative effects can only be seen under certain extremities such as like you say under hard braking etc
that is talking strictly theoretically
but as stated before if the car is setup for track use then the stiffness of the setup will depict wether or not the suspension will build enough camber to negatively effect it
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Totally agree... ;)
Kozy said:
This is of course mitigated by the fact that if you are running RCAs then you are almost certainly using stiffer rates in conjuction with the lower ride height so deflection will likely be less than stock anyway.
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It's not really a problem at all for the reasons mentioned, as you say you will always be trading lateral for longitudinal traction so best just strike a good balance.

sie2050 said:
and about your question on wingeo its a very expensive program which ive only seen in uni where im studying motorsport engineering

the program is called mitchells wingeo3 i think, im pretty sure someone has uploaded it to the net at some point so best bet it to have a search ive not tried really as ive never needed it outside of uni
Click to expand...

Yes had a search, looks like a bit of a pain to get hold of though! I would like to see how you get on with mocking up a Civic on it and what sort of results you get from it, would be good to see how my model stacks up to proper software (it's probably way off). I take it from your location you are studying at Swansea?

Are you involved with FSAE?
 
yer kozy i study at swansea met not the actual swansea uni did a year in swansea uni but sitting in a class of over 150 looking at a white board while some ******* writes a load of **** and mumbles to himself just didnt do it for me so i switched (i was doin materials engineering then but now motorsport)

by fsae i assume you mean formula student?
no im not involved with them with the course im doin unless your doing Beng theres not much point as its mainly a big project for your dissertation
and its also mainly nerdish lads there that think they know more than you and are mainly f1 wannabe technicians i went to one meeting and they just fobed me off as a nobody so i didnt see the benefits of it for me on the whole, as much as i like circuit racing its not my main focus as in reality getting a foot in the door to circuit racing is nigh on impossible unless your in the know or an insane genious at it id rather concentrate my efforts on a more variable range such are rallying or road racing.

i also help run my mums takeaway almost every night of the week so doing almost 18 hour days i flat out refuse to get up at half 6 to go join a bunch of "professionals" in making a glorified go kart lol's not a dig at anyone who does it but the bunch at my uni are pretty narrow minded and are dreamers in the way they put their ideas to use

anyways bk to the topic on the roll centre adjusters

tbh they dont really adjust your roll centres but merely correct it after you have lowered you car if you really want to see the benefits then you should match the change in roll centre proportionatly to the change in ride height so say you drop your car 60mm then you should adjust your roll centre x amount in relation to the wheel leavarge ratio(i think) etc which takes into account the length of each wishbone, degree of movement, and a host of other things i have all the calcs at home and in uni but for the general masses the rca kits will do the job without the head ache of doin lots of calculations.

hope my input has been insightful and mayb even helpfull
sorry for late reply kozy in work and everyone wants food between 7 and 9 lmao

peace
-si-
 
Haha, I understand your prejudices against the FSAE lads, I was never involved with them personally but I heard many people that were and they all said similar things. :D
 
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