Extended Ball Joints


This is my kinda thread. :nice:

I've got some CAD models that depict geometry changes quite well, I might dig them up later on, don't think they can show what RCAs do (or don't do) though.
 
Hmm I wish I knew how to work with the CAD drawings as that would make them much better and understanding.
 
WAIT!

I think I just punched my self in the face, but are the Lower Ball Joints on the Knuckle Pointing down? Or are the on the LCA Pointing up?

I think I just screwed up big time :(
It seems the Lower Ball Joint on the Honda's Front Suspension is on the Knuckle Pointing down. So in turn these actually are Roll Center correcting Ball Joints. Pls excuse my mistake as I was imagining the Ball Joint being on the LCA pointing upwards.

I just noticed this after looking at the small picture on the side that J's Racing provided. The Ball joint is facing Downwards so they actually would space the Pivot point down correcting the Roll Center.

Pls excuse this mistake as I come from the S-Chassis world where our LCA houses the Lower Ball Joint and not the Knuckle.

I'll label this as a fail.......

This can be deleted and rep taken back.




FAIL!
 
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I know someones gonna come in here and give me **** and call me an idiot but eh, it was a honest mistake, I thought the Ball Joints were Facing up from the LCA not Facing down from the Knuckle.

Again sorry for the confusion and mis-information.


Pls delete thread and if need be take back the given rep for this.
 
even if you were wrong its all relevant discussion and provokes people to think about this
 
I suppose but I know I caused some confusion because I was looking at the Ball Joint in the opposite way that it was used in the Honda's Application. But I guess if you folks feel it's relevant the thread can stay open, but I'll delete the mis-information and leave the thing that are relevant such as the negative affects n such.

kept the first post.
 
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Still useful info in this thread regardless, seems like an easy mistake to make, you certainly had me fooled into thinking they were that way up, despite me having replaced mine last year!
 
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:lol:

Having actually purchased and fitted "roll centre adjusters" I can safely say they have made a noticable difference to handling

Front feels alot flatter and more planted and steering seems to be easier also (more noticable on my car as it does not have PS fitted)
 
Yes I remember you saying they made a noticeable difference.

Just been fiddling around with the CAD diagram, plotted camber curves for stock ride height and lowered 2" and the lowered one seems to have the better camber curve. Interesting...
 
Talking of ride heights, will give you a laugh

Fitted my new coilovers last night, fronts are set as high as i can safely run them and top of tyre is in line with the arch :lol:

You seen the PIC spherical RTA bushes? They are offset to apparantly rectify rear roll centre!
 
stevenEK9 said:
Talking of ride heights, will give you a laugh

Fitted my new coilovers last night, fronts are set as high as i can safely run them and top of tyre is in line with the arch :lol:
Click to expand...

Good thing you won't be needing suspension travel with those rates! :wow:
 
stevenEK9 said:
:lol:

Having actually purchased and fitted "roll centre adjusters" I can safely say they have made a noticable difference to handling

Front feels alot flatter and more planted and steering seems to be easier also (more noticable on my car as it does not have PS fitted)
Click to expand...

Good Feedback. Can u post pics. Want to see the ride height. Have u done a shalom time attack? I think your car has a roll cage right?
 
have the bc rca and look good piece of kit.Havent drove car yet but will update on how it handles
 
johnny_9 said:
Good Feedback. Can u post pics. Want to see the ride height. Have u done a shalom time attack? I think your car has a roll cage right?
Click to expand...

Will be pics of my car up this weekend as it's looking more like a car now

Shalom time attack? Not a clue what you mean so going to say no.... Yes i have a roll cage :)
 
Here's my diagram, it's not accurate but I think it makes a fair representation of EK front geometry.

Rollcentre1.jpg


Everything can be altered on it and the roll angle can be entered to plot the camber curves. They aren't accurate by any means, but give a vague idea what is going on.

I plotted 3 curves, one at 'stock ride height', one dropped 2" with the static camber corrected to 1deg and the third dropped 2" with the lower ball joint located 1" down and camber corrected back to 1deg static.

My fairytale results:

Cambercurve.jpg


Stock appears to have the worst curve, shown as the steepest drop off with regards to roll angle, and the 2" drop has the best, maintaining the most camber for any given roll angle.

Interestingly, the RCAs seem to make the camber curve worse, although not quite as bad as stock. They do raise the roll center from 1.8" to 2.9", which obviously has its benefits regarding roll angle.

Once again, I fabricated this all in my head, so feel free to pick holes in it. I'll probably revise it over the next few days as I pick up my own errors, I've already spotted one... :nice:
 
^I understand that your CAD is just a Generic representation which is great and much better then I could do, but there's alot of precision that needs to be taken into account in order to get a decent "Ball park" number.

Things that need measurements.

Front UCA Length
Front LCA Length
Knuckle
- Ball Joint Distance/Relation to the Spindle/Hub
OD of the Tires
Offset of the Wheels


Now I just want to say I'm not attacking you, just pointing out some thing to help better ourselves.

Cambercurve.jpg


You said it started from -1* of static Camber but it looks like it's starting from 1/8" or .125"

Also to give a better representation I would allow/show at least 2" of Suspension travel as oppose to your 1" you have shown. Because if my math serves me correctly the lowered vehicle will turn Negative Camber into Positive camber within the next 1-2" of travel judging by the Slope/Curve of the Red/Lowered Line.

I also think that you should start from the 0 and work your way up as the Suspension compresses cause Starting from 1" and working your way down pass 0" as the suspension compresses will kind of throw you off, at least it would me.

Also Caster plays a pretty decent part in Camber Gain, though in a straight line it doesn't but when the wheel is turned it can change up the Camber numbers a decent amount.



Just my thoughts I'd throw out there.
 
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You are talking about camber gain with relation to deflection/bump/jounce/compression (whichever term you use), I am going with relation to roll here, whereby the outside wheel negative camber will decrease. All three start at the same point, 0 roll (X axis) and 1deg camber (Y axis), and the negative camber drops off at varying rates depending on the geometry.

I understand the need to be exact, however I made a few tweaks here and there and overall, the trends are the same, just the absolute values are not accurate. Things like the tyre radius and knuckle height are correct, the height of the lower inboard pivot was ballparked off of my car parked in the carpark (I know the span of my hand is roughly 8", so can guestimate around that), things like the width of the inboard parts are assumed with relation to nearby parts I have measured on the car (track width, distance between ARB mounts etc) and the rest is sort of jigged about till it looks right.

Overall, an inch here or there will obviously change the absolute values, but trends remain the same, this was originally set up as a single seater with vastly different geometry, and it would still show the same overall trends with regards to the effect of ride height on the camber curve.

Caster does throw an interesting curveball into the matter, something I want to get round to modelling but that will take a 3D model and probably more time than I can really spare at work!
 
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as good as it is mocking everything up in theory, the best way to learn if these parts work and how different geo setups work is to go and actually put it into practice

i've learnt so much about how my car handles by driving it and making subtle adjustments now and again
 
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