This is the roll center, suspension pickup, and steering angle modification thread.

[nieko]

Def, you said the rear doesnt get as messed up as the front, which i believe is true.

But, is this really not THAT bad?

This is after i installed the PBM subframe risers, which i did notice a HUGE difference in how my car felt.

I was reading on how to adjust the traction rod properly on NRR and that is how i did it but my LCA rubs slightly against the mouting bracket and makes an annoying ass squeaky sound.

doesnt ever bind, but it is slightly rubbing.

Sorry this post was kind of all over the place but im just trying to figure out what my best options are for all this roll center fun.

If your front spindles come out and i only need a RLCA or something for the rear to fix what is neccesary then that would be fantastic haha

[xpertsnowcarver]

^^ That's how my suspension looks right now. Soooo, I'll be raising my car back up to near stock height, while I save dinero for S14 subframe to modify.

Originally Posted by Def

My crystal ball says waiting is a good idea if you want to correct your front geometry to any large extent.

That's what I'm doing.

[Def]

Originally Posted by SoSideways

I think the high KPI angle and the caster help to give the negative camber when the wheel is turned in, and positive camber when the wheel is turned out.

Other than that, I can't really think of a reason why there would be such a high KPI angle.

BTW - the steering axis inclination(our cars don't have kingpins) is from the upper strut pivot to the balljoint pivot. The funky angle the upright balljoint taper has really doesn't seem to serve much purpose other than maybe an attempt at keeping the balljoint together if it's super worn and has 300k miles on it and you go into a corner(by putting a vertical load on it).

The upright will still rotate about an imaginary line from the strut upper mounting point to the balljoint point, so that angle almost seems arbitrary...

[Def]

Originally Posted by nieko

Def, you said the rear doesnt get as messed up as the front, which i believe is true.

But, is this really not THAT bad?

This is after i installed the PBM subframe risers, which i did notice a HUGE difference in how my car felt.

I was reading on how to adjust the traction rod properly on NRR and that is how i did it but my LCA rubs slightly against the mouting bracket and makes an annoying ass squeaky sound.

doesnt ever bind, but it is slightly rubbing.

Sorry this post was kind of all over the place but im just trying to figure out what my best options are for all this roll center fun.

If your front spindles come out and i only need a RLCA or something for the rear to fix what is neccesary then that would be fantastic haha

Well, looking at the rear suspension, you likely have your rear roll center still above the ground. The front at the same ride height is going to have a roll center FAR below the ground. So like I said, the roll center height and migration isn't near as bad on the rear as the front.

[GSXRJJordan]

Originally Posted by Def

BTW - the steering axis inclination(our cars don't have kingpins) is from the upper strut pivot to the balljoint pivot. The funky angle the upright balljoint taper has really doesn't seem to serve much purpose other than maybe an attempt at keeping the balljoint together if it's super worn and has 300k miles on it and you go into a corner(by putting a vertical load on it).

The upright will still rotate about an imaginary line from the strut upper mounting point to the balljoint point, so that angle almost seems arbitrary...

Exactly! The last time someone was talking to me about kingpin angle and S-chassis, I did a double-take... So when designing new LCA's and hubs, that angle need not be kept. I guess if you were making LCAs and keeping the stock hubs without adding or moving material to change the pickup, you'd have to keep it to keep misalignment down.

Originally Posted by Def

Well, looking at the rear suspension, you likely have your rear roll center still above the ground. The front at the same ride height is going to have a roll center FAR below the ground. So like I said, the roll center height and migration isn't near as bad on the rear as the front.

Interesting.

[Def]

Originally Posted by GSXRJJordan

Exactly! The last time someone was talking to me about kingpin angle and S-chassis, I did a double-take... So when designing new LCA's and hubs, that angle need not be kept. I guess if you were making LCAs and keeping the stock hubs without adding or moving material to change the pickup, you'd have to keep it to keep misalignment down.

Yep, that angle also axially loads the joint, which is not great for a spherical bearing.

[Jonnie Fraz]

Originally Posted by Def

BTW - the steering axis inclination(our cars don't have kingpins) is from the upper strut pivot to the balljoint pivot. The funky angle the upright balljoint taper has really doesn't seem to serve much purpose other than maybe an attempt at keeping the balljoint together if it's super worn and has 300k miles on it and you go into a corner(by putting a vertical load on it).

The upright will still rotate about an imaginary line from the strut upper mounting point to the balljoint point, so that angle almost seems arbitrary...

Sorry I was searching for the terminology

[SoSideways]

Somewhere I was reading up, they did mention that not all the cars have kingpins, or the ball joint acts as the kingpin or something. Oh well, I'll revise my terminology

Anyway, I'm just going to copy and paste my findings from last night's 2.5hrs of messing around on the front suspension yet again from the post I made over on NRR.

Originally Posted by Def

As long as you've got about 1 diameter of the pieces engaged(threads) you're fine.

So the 16x2 mm rod end needs 8 full turns engagement. Etc

Thats conservative but a good rule of thumb on "stronger" materials like steel.

OK so I measured the diameter of the big adjuster piece that the rod end screws into on the FLCA, and it was 1" in diameter.

So I measured 1" up on the threads, and turns out, 1" of threads would basically make that adjuster useless, because there's only like 1.75" of threads total, and I couldn't really move it out much at all.

The rod end had more adjustment than that piece. With 8 full threads engaged, it stuck out quite a bit, which was helpful.

So I basically messed with the angle of the FLCA, and got a little more angle out of it by tilting it slightly forward. I did this by placing a washer between the rear hole (lawl) on the FLCA and the tension rod to space it up.

This allowed for a tiny bit more articulation before binding, but the reality is, the FLCA's angle is still not the same as the knuckle's, thus it binds.

I then looked over at the practically brand new stock arms to see why stock arms would work fine still for guys that are uber slammed, and it is because the stock ball joint actually allows for quite a bit of articulation, a lot more than the current FLCA setup.

So, I came to the conclusion that:

1) I need to take the bearing out of the arm and open up the bearing mount cup lip up top a bit more. Right now it's at 1-3/8, I would imagine that if I could find a step drill that has one size up on that, then drilling through the 1-3/8" step and creating a chamfer with the next step up will more than likely do the trick here.

2) I need to find a c-clip with a smaller I.D. so the c-clip does not become the next culprit in line to get binded up.

3) Because of the coilovers I am using, I have to figure out if I can find a nut that will extend the hex part up a little bit so the hex part does not bind up on the bearing cup part. I am currently running Stance GR+ coilovers.

If I can get all 3 of those things done, then I will have eliminated all the binding issues, and the only thing left to do at that point would be to cut off more of the endlink mounting bracket on the FLCA so the tie rods don't hit it.

I might straight up get it completely cut off and then worry about an endlink mounting solution later, as the current bracket is huge and in a weird spot.

[nieko]

Maybe i am the only one that didnt know this but....

the Driftworks offset spacers will not work with the SPL outters and z32 inner setup.

shit is too long and i have mad toe in with everything screwd all the way in.

I am going to cut the tie rod a little shorter and the spacer that connects the heim joint and the tie rod to make it shorter.

i will either fail miserably or succeed hahaha

updates tomorrow.

[SoSideways]

Well... that should have been common sense lol

The Z32 inners + SPL outters will get you to be able to get some toe out or zero toe, and by adding another like inch to it, what did you think was gonna happen? lol

Anyway, no real updates from me, other than I'm going to grind the spacer down a little where it will sit on the spherical bearings on the FLCA, and I might even grind down the lip on the bearing cup to get a little more room up top.

I'm also going to use a bigger snap ring to get a little more clearance on the bottom.

With these steps, I feel I should be able to get rid of the binding issues I've been having, at least with the FLCA. Might still bind up top at the camber plate though.

[!Zar!]

How much is the Driftworks offset spacer? Last time I payed attention to it, it wasn't for sale yet. That's why I was going to just go with the Dmax spacer; even though it isn't offset.

[nieko]

Im pretty sure you can go on driftworks.com and order it?

Brian Rogers posted his up for sale a few days ago and i saw them and snagged them up.

i think after shipping and everthing from england it comes out to like 250 ouch...

not what i paid though for sureee.

and they arent perfectly froward, they are a slight bit pointed up too.

so i guess that corrects a little bit more bumpsteer also?

[nieko]

New update... after i did the cutting i needed to do to get it to align right.

i bolt everything up, everything is cool.

but for some reason... i get ASSHOLE angle.

i used to get WAY more angle... now i cant even make a u-turn on my street.

wtf....

[GripTerror]

wow your ass has angle? lol

[nieko]

no bro.... THATS THE POINT, i dont get any angle anymore lol

[Def]

Do the driftworks spacers let the rack go all the way to full extension, like a 6-7mm spacer on the inner tie rods does?

[nieko]

it looks as if it does yes.

but i get less turns on my steering wheel then before also.... so its clearly not.

maybe the fat spacer actually hits the rack itself, not letting it go in all the way?


My rack wasnt centered perfectly, so i did that today and got my alignment done.

it IS better, but still not as much angle as before... i cant make u-turns on my street damnit. LOl

probably going to end up modding my knuckles, even though i was trying to hold on and buy your stuff.

have a comp next weekend and then ASB in july though... FUCK

[JeremyR]

Originally Posted by nieko

maybe the fat spacer actually hits the rack itself, not letting it go in all the way?

take the boot off and check and see? can you still hit the bumpspots??

i was planning to run these with the PBM SAK to stop the rack from over centering and binding...so im really interested in whats going on with yours.

[SoSideways]

Its probably because your tie rods are real short now, thus your tie rods hit the lower arms quicker than before.

I'm pretty sure that's what's happening.

[nieko]

no...

with my old setup, my tie rod ends would hit my LCA all day long lol there is basically a little notch in my control arm from them hitting.

now theyre like an inch and a half away from hitting.

wtf?

I also have less turns side to side on my steering wheel.

basically the spacers arent letting the rack fully extend each way... how annoyying.

[PoorMans180SX]

You have an S13 or 14?

Because if you have a S13, you should have just gotten S14 LCAs.

[nieko]

I do have an s13.

but how are s14 lcas gunna prevent me from going over center?

[PoorMans180SX]

They wouldn't have, but they would have let you run the tie rods at the length you had them.

Therefore keeping your angle and the spacers.

[Def]

Originally Posted by PoorMans180SX

You have an S13 or 14?

Because if you have a S13, you should have just gotten S14 LCAs.

More than a few people have measured the S13 and S14 FLCA and found them to be the same length. I think the track difference might come from the front subframe. It's the same way in the rear.

[nieko]

UPDATE.

These either DONT work for s13. or i have some random rack of some sort.

Basically, the reason my steering rack wasnt centered anymore, and i got shit angle was because these spacers hit the rack and dont let it go in far enough.

but hey, driftworks thought about that, on one of the spacers, there is added material and the big part of the spacer is a little thinner.

Oh, stupid me, I put the spacers on the wrong side, let me swap them to fix all of my problems.

So I take them off and try to swap sides so they will actually work the way they are supposed too.

WRONG.

The pins on the spacer that mate with the rack line up but put the spacers pointing in the wrong direction.

And my drivers side spacer doesnt get tightened all the way.

meaning, fully tight there is play because the bolt is too long or something.

cool.

i emailed driftworks to see whats up, ill let you guys know what they say.

[nieko]

This is what im talking about.

These are the spacers



Here is the drivers side of my steering rack.



So basically, the spacer on TOP in the picture above should go on the drivers side because of how the rack is correct?



INCORRECT. That is how it sits when i put the spacer on the drivers side, and it doesnt get tightened all the way.

So lets try putting the other spacer on.



Cool, it looks how it is supposed to look, but wait..



the fat spacer hits the rack before it goes in enough.

[nieko]

This picture on the front page is the drivers side i am assuming by where the LCA is and which direction the tie rod is offset.

His rack CLEARLY looks different then mine.....

I am confused and lost. Someone please give me some clarity.

[Jonnie Fraz]

Right hand drive vrs left hand drive?

[nieko]

Holy shit i bet that is the problem....

fucking lamesauce 9 billion, i dont know why i didnt think of that.

well, since i ended up cutting my tie rod setup to make these work and now i cant go back to that because ites too short.

could i just make 2 little slots on the rack so i can make the spacer work?

[nieko]

You should probalby write that on the first page bro....

offset spacers are for the RHD onlyyyy lol

i will be making my own notches in the rack tomorrow to make these work.

cool story.