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Roll center and bump steer correction, anybody seen anything that fits our cars?

RAAMaudio

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#1
I am going to dig into this as it would be a relatively simple mod that allows me to lower the care more for the track. It can go decently low and still have proper geometry but lower is better, when done right.

I am gong to search to see what the Focus and EU Fiesta cars may of had available but any help would be greatly appreciated.
 


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#2
Hey, any update to this?

And could you educate us a bit on how we can adjust the roll center on the fiesta for some of us new guys?

[wrenchin]

I am going to dig into this as it would be a relatively simple mod that allows me to lower the care more for the track. It can go decently low and still have proper geometry but lower is better, when done right.

I am gong to search to see what the Focus and EU Fiesta cars may of had available but any help would be greatly appreciated.
 


OP
R

RAAMaudio

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Thread Starter #3
On a moderately lowered car there will be no need to adjust it, the key is the ball joint at the bottom of the strut on the front control arm needs to be lower than the inner pickup point, the one connected to the forward end of the arm at the subframe.

There are several main ways of adjusting it, the easiest is using extended ball joints to replace the stock ones, they will normally have spacers so that it can be set according to how low the car is.

Another way is modified steering knuckles, much more difficult, normally not a DIY solution.

A third way is to modify the inboard pickup point but altering the subframe, normally not a DIY solution as well.

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When either of these are done we also need to correspondingly move the rear inboard location up to maintain the correct alignment as it will reduce the castor angle. There are adjustable parts made for that so not as hard to deal with.

And bump steer, which is the ball joint on the tie rod end, at the knuckle, needs to be moved down so the tie rod runs perpendicular to the control arm or steering rack, usually the rack.

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If parts are available the extended ball joints and tie rod ends are far easier to do.

BUT, you need a very good alignment done, the average shop, the vast majority actually, will only look things up in a book that has very broad specs they can go with and it will not end up anywhere near being optimized. One has to pay a race oriented shop a fair higher cost as it takes considerably more time or invest in some alignment tools, you can DIY a very accurate performance alignment with just a few tools and taking time to learn to do it right. I have done my own for decades.
 


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RAAMaudio

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Thread Starter #4
I have not looked into this as my car is performing incredibly well at the ride height I have it set at, any lower is just to much hassle for the street, getting in and out of the trailer, etc....I would have to carefully set it up so I can adjust it for the track and street back and forth all the time which I really do not need to do as it works so well now.

I am going to raise it up a bit and remove the splitter for the winter soon though I will rarely drive it, only on really clear days with clean roads, to much salt used here. This was supposed to be our all around car as sold everything else except our Duramax dually but we will just use it, 2 years old, 18k miles, broken in now, 8,000lb+ 6wd beast that it is:)
 




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