Adri_s2k

Hi ya

I installed today the J's Racing roll centers (front and rear), for the rear all is fine, but not for the front
Mine is the old model that includes the golden plates:



Once installed the front (golden plates too) it raised the steering rack so is no longer in their correct height now.
I have front antibumpsteer spacer fitted and I also raise my front springs a little bit (I'm on Tein Flex coilovers).

So my question is, how I get back to the correct height for the steering? I must remove the spacer from the steering rack?

Many thanks

s2000Junky

Its a compromise, so which do you care more about, bump steer possibility or roll center position? If you’re not sure, get some drive time and see how it feels. Toe alignment shouldn’t be effected as long as and you measured the ride height and adjusted the coilovers to regain the before ride height after install. What is your ride height? If your 13" hub to fender or higher, you shouldn’t be experiencing any perceivable bump steer anyway, so probably moot. You can run up to 20mm rack spacers to help if your running only 15mm fyi.

RedCelica

You did an alignment after the install?

Adri_s2k

Height is around 14" (35cm) and after a quick ride I didn't feel too much difference at all, just a bit "free" steering wheel than before.
The golden plates should be there, right?
I believe the spacers I have are the smallers ones.
Does anybody being in same situation?

Adri_s2k

Yes, no problem.
0º toe

User 121020

I don't understand the issue. The J's Racing RCA lowers the lower control arm relative to the knuckle. Once you adjust the spring perches to restore the ride height to the original position, the knuckle, steering linkage and steering rack would all be in the same position as the pre-RCA configuration. The RCA would have a slight impact to the suspension curves throughout the range of travel, but I don't see this being a huge deal. Am I missing something here?

s2000Junky

14" ride height is questionable on needing any of these bump steer or roll center provisions to begin with in my experience. If your roll center adjusters are offset for more negative camber then sure, I get its value. At 13" ride height I max out the front camber for track at -2.5 with max 6.8 caster, so offset camber joints have their place if you want more then this, certainly at a higher ride height. I do run a 20mm rack spacer to help bring the tie rods back closer to parallel, however I never really experience much in the way of bump steer without them, probably because suspension travel is rather still and minimal, but easy/cheap mod just made sense to do. I don't run any roll center adjustment, don't feel its necessary to the handling of the car currently with my spring and sway bar balance and ride height.

Adri_s2k

After a spirited drive in the mountains these weekend I didn't feel nothing wrong and uncomfortable at steering.
So maybe the need should be a bigger spacer (20mm) as im with 12mm one.
I'm -3 front camber and max caster (around +7) and of course 0 toe, 255 tyres all around so I really feel a improvement in quicker cornering with more front camber than the rear.

I need RCA as with my ride height I cannot reach much more than -2 camber at the front, I even feel more comfortable and safe straight drive and cornering with front and rear J's Racing RCA

s2000Junky, are you running non-staggered?

thomsbrain

Roll center adjusters are not the same as camber adjusters. The J's kit achieves extra negative camber without the spacer plates, and adds roll center correction to the existing camber correction when you add the plates. If all you wanted was more camber you should have run them without the included spacer plates.