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

[swiftmini]

The setup i run now has identical components to the setup i ran before. Its just the way i have set everything up is different.

before i had -5* camber and 5* caster, geomaster knuckle with the included angle reduced and with a 245 40 17 ad08

now i have -5* camber and 9* caster, geomaster with normal amount of geomaster included angle and with 215 45 17 toyo road tyres

too be honest both worked well for me, but the camber gain of each setup was night and day different

My R32 pictured below has the top mount fitted to get maximum camber and caster


and my s14 is also fitted the same way, but the top mounts need machining for more caster.


Ive added camber at the top to help stay away from over centre

[Bink Industries]

yah the knuckle i build you dont have to worry about over centering. leave the camber plates rotated in the normal fashion and you get 52 degrees of angle no over centering and a good ackerman reduction, 5 degrees at full lock (on my car, need to confirm caster angle). no rack offset spacers no funny stuff just a part that works. confirming angles on another car tomorrow with my knuckle.

[Bink Industries]

heres my cut knuckle.

4130 chromoly inserts laser cut and cnc bent at a local shop
I TIG welded, pre heated and peened after welding and then cool in sand over night.

this is my prototype so I have cleaned up the fit considerably since these knuckles.

did some testing at the track, reverse enteries were no problem at all. (still confirming numbers and angles of everything on the test car)

driver reports great steering feel and the steering quickness feels good not to fast. car doesn't want to get stuck at lock of feel sluggish. Just let go of the wheel and the car self steers the other way.

got the car over a foot in the air at a jump at the balcony, inspected for any stress cracks on the knuckle and everything looks beautiful. super strong when welded correctly

[Motary]

Originally Posted by PoorMans180SX

What's the difference between your front and rear stuff and Wisefabs? It seems your knuckle has more caster trail in the front, what about the rear stuff? It looks extremely similar to the uninformed eye.

My front is narrower, scrub radius is smaller, maximum lock is 60 degrees (srsly 60 not advertised 60, unlike many other companies), caster trail is roughly the same (visual appearance might be confusing) it is not a track only setup and features one steering hole for reverse ackermann and one close to 100% as I could make it.

Rear is double wishbone instead of multilink for simplicity sakes. I later discovered double wishbone has half as steep anti-squat curve too, however but you can't really mess around with it as you can with a multilink.

N8 of S-Empire - I spot a one piece lower control arm there too
Lovely how modified the stock uprights

[Bink Industries]

Originally Posted by Motary

N8 of S-Empire - I spot a one piece lower control arm there too
Lovely how modified the stock uprights

I will post pics of my lower arm later.

[e1_griego]

So I have the custom spindles that I've posted earlier in this thread that offer ~33mm of roll center correction and quicken the steering to 2.25 turns lock to lock.

For the new s13 I've put together I'm eyeballing the PBM spindles, but I don't really need "hellaangle" or anything. I'd just like the RCC and the quicker steer. Running stock FLCA,steering stops and tie rods I shouldn't have any problem running these spindles and getting what I want, correct?

[derass]

you would likely need longer inner tie rods to reach the relocated pickup on the knuckle. you might be able to get away with just extending out adjustable outer ends (SPL etc.)

also i would make sure that the steering angle is limited where you want it. im might not be important if you're not drifting, seeing as you wounldnt be at full lock, but i would still make sure you're not contacting the frame rail or tension rod/sway bar

[PoorMans180SX]

Flipped my brackets and pulled a collar today, as well as moved my camber plates to the middle, reducing caster.

Got the camber down to -6ish, and it raised the car some. Looks like I'll have to pull the last collar to get ride height where I want it. Kei-offices are definitely not meant to go low.

There is even more angle now, believe it or not. TDP is also sending me their 100mm RC correction shanks

[thefro526]

Originally Posted by PoorMans180SX

EDIT: What we're all trying to say here is that you can alter the tires relationship with the steering axis by using the knuckle/lower bracket. This changes how the wheel sits at lock. This doesn't alter the camber change. It alters the angles through which the camber changes. Does this make better sense now?

Example:

Take a tire that is parallel to the KPI, turn it to 60 degrees. There will be a certain amount of camber change.

Take the same tire, and use the knuckle to add 2* more camber. The camber change is still the same, but now the tire sits differently in the arch at 60 degrees of lock because of angle at the knuckle.

I wish I had been able to phrase this so eloquently when writing my previous rant.



Well played sir, well played.

[GKTECH]

our billet rear knuckle prototypes have been machined up and we've started on our new R-chassis knuckles which I believe will also fit the Z32's.

Overlay of the S-chassis knuckle and the R-chassis knuckle:



and our rear knuckles being fitted up:

[Tulok]

If I started with stock suspension and coil-overs and didn't lower the car too much, wha is the most important thing to change first? I've read like 50 pages but I'm still not grasping exactly what the enemy is, so to speak.

[SicBastard]

Originally Posted by Tulok

If I started with stock suspension and coil-overs and didn't lower the car too much, wha is the most important thing to change first? I've read like 50 pages but I'm still not grasping exactly what the enemy is, so to speak.

Tires......

[PoorMans180SX]

Originally Posted by Tulok

If I started with stock suspension and coil-overs and didn't lower the car too much, wha is the most important thing to change first? I've read like 50 pages but I'm still not grasping exactly what the enemy is, so to speak.

Subframe bushings and tension rods. Both bushings are huge and suck at doing what they're supposed to.

[Silvi]

Originally Posted by GKTECH

our billet rear knuckle prototypes have been machined up and we've started on our new R-chassis knuckles which I believe will also fit the Z32's.

Overlay of the S-chassis knuckle and the R-chassis knuckle:



and our rear knuckles being fitted up:

the S-Chassis rear knuckle will work with the stock calipers and stock rotor?

[GKTECH]

Originally Posted by Silvi

the S-Chassis rear knuckle will work with the stock calipers and stock rotor?

Yes they will/do. The mounting plates are interchangeable so you can easily swap out for different setups. This setup shown is exactly the same position as the factory rear knuckle to suit 2 oem calipers with the corresponding rotor. We will also have some Wilwood options.

[[email protected]]

Originally Posted by PoorMans180SX

Flipped my brackets and pulled a collar today, as well as moved my camber plates to the middle, reducing caster.

Got the camber down to -6ish, and it raised the car some. Looks like I'll have to pull the last collar to get ride height where I want it. Kei-offices are definitely not meant to go low.

There is even more angle now, believe it or not. TDP is also sending me their 100mm RC correction shanks

Max angle is at 5 degrees negative camber.

Robbie

[Motary]

Do GKTech have different kinematics compared to stock other than adjustable pivot point for toe arm?

[GKTECH]

Originally Posted by Motary

Do GKTech have different kinematics compared to stock other than adjustable pivot point for toe arm?

They do however nothing major. Ie. We moved the camber arm mount inward a little and some other slight changes (a few mm)

[GKTECH]

They fit

[GKTECH]

[NotLowEnough]

hey guys, i have a super quick question and probably a stupid 1 but what gauge metal do i need to extend my flca's? thanks

[Guilty1s]

1/8" seemed pretty standard

[KoukiMonsta]

Been doing some research since I have replaced all suspension arms and the car needs alignment soon.

My main question is in the rear traction arm. I am not confident in the alignment shop handling this. Can someone with a very low s13 measure center to center their traction arm? I figure that will be a good start for me to get it in a good spot.

What kind of extra length are we talking about here vs stock?

Hate to thread jack, but you gurus can provide the best info.

Input appreciated

[Guilty1s]

Originally Posted by KoukiMonsta

Been doing some research since I have replaced all suspension arms and the car needs alignment soon.

My main question is in the rear traction arm. I am not confident in the alignment shop handling this. Can someone with a very low s13 measure center to center their traction arm? I figure that will be a good start for me to get it in a good spot.

What kind of extra length are we talking about here vs stock?

Hate to thread jack, but you gurus can provide the best info.

Input appreciated

I read somewhere that you need to extend it the same length for length that you extend your camber arm. There is research on it somewhere and it is found that is best, but like all suspension setups, it is subject to opinion and preference.

[az_240]

Originally Posted by KoukiMonsta

My main question is in the rear traction arm. I am not confident in the alignment shop handling this. Can someone with a very low s13 measure center to center their traction arm? I figure that will be a good start for me to get it in a good spot.

What kind of extra length are we talking about here vs stock?

Pretty sure this was just discussed but stock traction rod center to center is 8.25". Stock RUCA is 12" center to center. Some dudes on NRR with stock knuckles like to extend each by ~.25" and adjust camber with the eccentric bolt but there are still variables/preferences that go into this so it's not a end all number.

[SicBastard]

Originally Posted by az_240

Pretty sure this was just discussed but stock traction rod center to center is 8.25". Stock RUCA is 12" center to center. Some dudes on NRR with stock knuckles like to extend each by ~.25" and adjust camber with the eccentric bolt but there are still variables/preferences that go into this so it's not a end all number.

I second that, go find the NRR thread where the camber and toe curves were actually ploted with different measured length arms.

[tobroketobuildarealcar]

New S14 bumpsteer graphs - Nissan Road Racing Forums


This is it

[KoukiMonsta]

I looked at that graph last night, I was tired and didn't take it all in.

I did not realize there were three traction arm measurements, was only paying attention to ruca stuff. My mistake.

Now honestly I do not know what I want my curve to look like, considering I have not been into this whole suspension thing very in depth before. But lately I find it quite interesting...eventually I'll read this whole thread.

Ninja edit, as stated quite bluntly below 'minimize toe out under travel' I think I'm getting somewhere. Thanks a lot.

[tobroketobuildarealcar]

You always want the setup that causes the least toe out with suspension travel

[conrad_s13.5]

Random question.
All tierods with lengths listed on the first page have the same thread pitch at both ends right?

Just only want to buy these once

p.s. its awesome that I can just go to the first page of this thread to see which parts I need for which desired setup