The moonface roll center adjusters do move the pivot point where the lower control arm connects to the hub. If you shorten the distance between the lower control arm and the hub which the shorter adjuster do then you will need to legnthen your damper to keep the same ride height. By legnthening the damper you are changing the angle between the outside hub pivot point and the inside chasis pivot point. You are also changing the angle of the upper control arm since bothe arms are connected by the upright. The change in angle of the 2 control arms raises the instant center and therefore the roll center.

 

Yes...

No, your upright is always in the same position relative to the ground, and if your ride height remains the same, your chassis remains in the same position relative to the ground. The pivot points are fixed on the inboard, relative to the chassis, and on the outboard, relative to the upright. So nothing is changed.

The upper arm pivot points would remain fixed for the same reason above...

 

Dayum this is an interesting thread...for real..

I might even learn something from a Forum Thread

 

Yes....You're right. The upper control arm angle won't change.

 

so kuah, what do you and the gang at SPL have up your sleeve for the front geometry--if you even feel there is anything to gain there?

 

I just got a call back from a firend who has a suspension program and the program confirms what you are saying Kuah. These will not change the roll center at all. After studying the suspensuion in the garage I see what your saying.

So am I right that these won't roll center? $500 for parts that don't work?

 

Well there's always something to be gained, I don't think any racer will stop looking for that last edge We did recently release the outer tie rod ends for bumpsteer adjustment, but otherwise progress is slow, I have ideas but not enough time/resources for development. Right now we are working on the v2 front upper arms, hopefully next year the economy will turn around and we can really get going with new products

 

Jet,

Do you not think these made any difference at all? I can't really comment on roll centre, but my handling definitely changed for the better upon fitting these.

 

I think if the coilover needed to be extended, then it obviously moved the arm and changed the geometry. If you are noticing a dramatic difference, it certainly works.

 

But didn't you get an alignment after installing these moonface devices? Don't you think the alignment had any effect at all??? Maybe you were so far out of spec that you didn't know until now that you are back to spec??? Just a thought.

 

I know I just had these installed on my own car ~2 weeks ago. My alignment had previously been done in May, just before Z days.

My before and after alignment specs.

May 2008 Specs

Front

Camber - Final (after alignment done May '08)

FL FR
-1.5 -1.6

Toe - Final (after May '08 alignment)

FL FR
.000 .001


These were my specs when the car was put on the rack October 2008

Front:
Camber - Initial (before RCA kit installed, before corner balancing done)

FL FR
-1.59 -1.64

Toe - Initial

FL FR
.004 .006

Camber - Final (after installing the RCA kit, camber and toe both had to be readjusted, this is where my car sits now)

FL FR
-1.29 -1.45

Toe - Final

FL FR
.003 .002

Cusco camber arms (set to max positive both sides, unmodded) , HKS RS coilovers. I think I posted front height from centerline to ground earlier in this thread so you can see what height I'm at.

 

Adam, are these adjustments made with you in the car? That would explain the differences I see in the Left to Right comparo.

 

I wasn't in the car, someone else there was who's basically same weight as me. Keep in mind though that the Cusco arms have fixed adjustment points, its not like an open slot. So, it sorta ends up where it ends up - so not uncommon for there to be small differences side to side

 

Yea I did, but had a few days before i had the alignment where i noticed a dramatic difference.

 

Now we're talking. This is exactly the kind of discussion that people should push for before taking the jump.

I would comment but the discussion between Jet and Kuah is very thorough. Interested to see further developments.

 

Could you elaborate on your findings just a bit more perhaps? It was "better" just doesn't cut it for me... Please explain what your car was doing wrong before the mod and how the mod helped.
Ex. Every time I made a sharp 90 degree turn > 20 mph the tires would squeel and now it hooks likes its on rails. etc..

 

Sorry i can't be more technical but for me my front end was very 'twitchy' which i believe is bumpsteer. The faster i was going, the more noticeable it was. My front end seemed to dance about all over the place over rough ground which was instantly eliminated after fitting these. I could instantly drive faster and under more control, long sweeping bends which i previously could only take at 100mph now was comfortably taking them at 140mph. (albeit i could take them at 140 on standard suspension).

Also i was experiencing understeer on rough ground where i was pretty netural on a smooth surface which has also disappeared.

The turn in response is much sharper at all speeds and the car overall seems very precise.

Ultimately i am very happy with these and would recommend them to anyone who's car was handling like mine.

Hope that helps.

 

Thanks for breaking that down. That makes much more sense. I appreciate it. Are you using sway bars at least, because for a stock suspension, that a pretty aggressive pace 140 mph.

 

No probs,

Oh i am running a full setup now, Tein Flex Coilovers, Hotchkis Sways, Custo A Arms, SPC Rear Camber and Toe Kit, Power Grid Endlinks and these Moonface things.

 

So from what I gather Colin, the moonface upgrade was your last and most recent suspension mod, afterwhich you noticed an immediate change which was further improved after you got your alignment checked/corrected. Thank you.

Question: did the powergrid endlinks do anything for you? I am suspicious about those too.
Another waste of $$$ or useful mod? Curious about your (or anyone's) feedback on those too.