Im about the same (with a little bit of rake) and can't imagine going much lower either. Random1 is pretty slammed as I recall so obviously it can work for some

 

I certainly can see the benefits of going lower. Jim took 2nd at Nationals with the lowest S2000 there... period. However, like it or not, his car was far from legal as a result. His fenders were very flared (Outside profile changed drastically), as a result of that amount of lowering. I'm sure it's course dependent though. I.e. I am not comfortable lowering the car anymore than it is because we have some venues that have so much elevation change I would.., and have, damaged my fender as a result. At the moment, the car is legal... but it's not as pretty as it used to be...

 

you 100% sure of this? ...i am not, but i think you could be wrong. the shim is changing one of the pivot point locations with respect to the hub. but since it does not change the upper location, i always wondered what it could be doing to the geometry. so, i always hoped someone technically knowledgeable would comment on this (maybe antonov if he reads this). but i do think it affects roll center in some way, but perhaps not in a beneficial manner. maxrev has commented on the rear kit having the same effect as what josh said, "settling" the suspension. however, i heard rumors from others he has since removed it, so i dunno.

i have both on my car (12mm rear kit, not the 20mm), and i can't say i feel a difference, though i did not try to do before and after tests.

so, when josh posted what he wrote here, i was really curious if he knew that the "rca's" actually hurt the car, cause i would believe that. but for now, i still have them on. i think my car is lowered pretty close to 2", maybe less. so i'm on that border-line j's racing recommends.

EDIT: i did some searching and came across this:

https://www.s2ki.com/s2000/topic/546...t/page__st__50

they are talking about the rear rca, but if i remember how the suspension is arranged, i think the concept is similar with the front spacer talked of here, which basically moves the arm lower relative to the hub (hope i'm not wrong). so, this is what antonov said in that thread:

"As far as I'm concerned, the benefit of modeling the suspension is being able to determine what toe changes take place during travel. The roll-center is easy enough to determine just by looking at the lc-arm. The addition of RCA no doubt brings the RC closer to the CG. My concern is what it does to the bump steer."

so, it sounds like, yes, the j's shim does indeed change the roll center... i'm just still not clear whether the suspension geometry is bettered or worsened by it.

 

I don't know the effects off hand, but it could raise the instant center and the kinematic center, but to know for sure you need to analyze the geometry in 2 or 3 dimensions.

 

I don't believe that it (spacer) does anything to the roll center. It does NOT change the relationship of the spindle to the pivot point it merely spaces the pivot point further from the control arm. Remember that you can draw a line from the inner pivot to the outer and that is what (in conjunction with the line from the pivot points of the upper control arm) determine the roll center. For the're to be a change in roll center you would have to move the ball joint further away from the spindle not the control arm.

 

Sorry... Not sure what you mean as it does move the ball joint further from the spindle. That joint then attaches to the control arm. Unless I am using the wrong terminology?

EDIT:

Here's a pic:


In that picture, the J's joint is #4, and the spacer goes between that and the knuckle. The joint #4 is also attached to the control arm #11/12. As you can see, adding the spacer between #4 and the knuckle lowers the joint, moving it lower from the "spindle" or where the knuckle is.

Do I have something wrong?

 

Nope, I was wrong. For some reason i was thinking that it bolted to the control arm...

 

I've been running the SPC adjustable ball joints for about 4 years now. Their best feature is they allow addition of both camber and caster. If you angle the slot about 40 degrees toward the rear you will increase both as you slide the ball joint inward. I run mine full in with -3.5 camber and around 7 degrees of caster. After setting them full in and torquing the big 27mm top nut to 120 ft-lbs I scratch index marks around the top nut so I can see that it hasn't moved and I've never had one move.

A friend recently had a set installed and his shop stripped the threads on the big top nut. They set them for full in and welded them in place so some have had issues with them.

Another problem with the adjustable ball joints is the points hit you take with NASA in performance touring or time trials. You take no points with the J's part.

Even so I'd buy another set of SPCs if I needed to.

 

Maybe they changed the initial ruling. When the adjustable ball joints sh1t storm hit NASA National said non-adjustable camber ball joints are ok because the CCR gives permission for camber plates with no points. But our ball joints were adjustable so we had to take points. That may have changed.

 

Has anyone found a place to buy J's racing S1 or S2 joints that can ship in a reasonable amount of time?