I've been browsing some products online and came across Ikeya Formula's Roll Center Adjuster, which restores the roll center above ground after a car has been lowered. The only problem is that they only offer fitments for the FD.

Elsewhere on the froum, I heard of 1st gen roll center spacers being available as well. My question is, does anyone make something similar for us 2nd gen guys?

 

http://www.awrracing.com/pages/rx/rxsusp.html

Roll center blocks.

 

ooh =)

Too bad it's not for sale on the website....I guess I'll be calling Tony tomorrow to see if they have any for sale.

 

Do you know what they even do?


-Ted

 

Raise the roll center from below ground after the car has been lowered, thereby reducing the roll couple? That's just my theory, at least.

 

In layman's terms?


-Ted

 

prevents excessive body roll from lowering the car, since the roll center is possibly lowered more than the center of gravity, thereby elongating the arm that the car rotates around.

The product that I'm looking for would raise the roll center back above ground to shorten the roll couple and therefore reduce body roll. I'm hoping the AWR product does just that.

 

On most suspensions (ours included) when you lower it the immaginary point about which the car rotates when cornering (roll center) gets lowered more than the center of gravity of the car. This gives the acceleration forces a greater lever to push against, causing more body roll. Roll center blocks will raise the roll center by moving the outer pivot point of the front suspension downwards, this moves the arm closer to it's original angle, thus restoring the suspension geometry and raising the roll center back up.

On a side note, changing the camber of the rear wheels also changes the roll center, but they're permanently linked AFAIK.

 

changing the camber by adjusting the subfame link? or by using the links on the control arm?

 

So how do you adjust roll center on our MacPherson struts up front without trashing the original type suspension?

To the OP, are you building a race car or something?


-Ted

 

http://www.ikeya-f.co.jp/en/index.html

I guess that's the best example of what I'd like, I'm not sure how the AWR product works. I'm not building a race car, I'm just trying to dial out some of the body roll that I have after lowering the car 1.5 inches front and back, I didn't think the roll was going to be as excessive as it is.

Even though the picture on the website shows double a-arms, i think they have them for strut-type suspensions as well.

 

It's a bit tougher with the MacPherson front struts...

Why not just get larger stabilizer bars?


-Ted

 

to me, anti-sway bars feel like a bandaid for this problem, because the long roll couple will still be there. Raising the roll center will solve that problem, plus any sway bars added afterwards would tighten up the body even more, it's not as if one mod negates the use of the other.

 

Just got off the phone with Tony from AWR,

He says they're still testing a new design for the roll center blocks and they will for the next while to make sure that the part is street-worthy. I can't wait to see his finished product. My guess is that his product raises the roll center up, but finding the optimal height of the car is still unknown at this time.

If I could have one product that'll probably not exist, it would be on that fixes a roll center in place, while the height changes.....that would be totally sweet.

 

In the rear the angle of the suspension arm dictates both camber and roll center because it's calculated from the angle of the control arm pivot points. This means that unless you build yourself a new arm with camber seperately controlled from the control arm pivot points (a twistable arm in effect) then you're stuck with whatever it happens to be.

http://e46m3performance.com/tech/transfer/pg-2.htm
http://e30m3performance.com/tech_art...ter/page-2.htm (click on the link labelled "Semi-trailing arm ROLL CENTER for raised outer pickup point.")

 

For frot roll center raising on our FC's all you need to do is lower the outer ball joint by seperating it from the stock point in the spindle. Make something to go into the spindle where the ball joint did and also mount the ball joint, aka a "spacer" and your done. Well easier said than done... We have some that we made for some vintage racing Alfas,(double A arm but they do pretty much the same thing while improving the camber gain, we put them on the top arm/ball joint). I was working on some for my car but I can build entire new struts/spindles and do the same thing.

 

That's not such a bad thing is it? At least the rear roll center is not height dependent and by adjusting the camber, you adjust the location of the roll center. Obviously, it's not optimal to base your settings off camber, but it's better than having 3 individual variables and having to control/compromise all three.

 

Well yea, not necessarily bad, just not adjustable.