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

[drift937]

18x10 15 offset. im going down to a 18x8 or 17x8 or 9

[Csomme]

Some more pictures of your setup, like from a couple different angles?

[Motary]

Caster reducing top mounts?

[drift937]

i am waiting on my new coils to show up then ill post more pics. i guess you can say it reduces caster. but it really doesnt matter once your already turning. when you over think shit is when it starts messing up

[ridesnowx4]

Originally Posted by Croustibat

je suis partout :d

Moi aussi!

[Steugen]

I have gone thrue all 120 pages, but Im still not sure about my one question. For a full out race car with modified wheel arches, which hub setup is the best for me? I of course need to go as low as possible without messing up the geo. Driftworks claim that the loss of ackerman does not matter much in a race car, so they highly recommend their Geomaster2 for my race car (of course)..

[JaredP]

finally all done reading through this thread...ton of great info! big thanks to poormans180sx for starting it..as well as everyone else who has helped spread a wealth of great information!

just a couple questions:

1. i saw the pic dan posted about changing ackerman, but i was under the impression it was changed via the tie rod mounting arm on the knuckle? looking at this pic:

you can see how the arm angles back in towards the vehicle. i thought if you made that straighter instead of curved it would lower your ackerman, is that wrong? or is that another way to do it.

2. i have tein s13 "super angle" tie rods...does anyone know if those are longer than oem itr's? i havent taken them off to measure, just wondering if anyone knows off the top of their head

3. modded the knuckle on my roommates car, turning all the way to the right, the drivers front wheel comes within millimeters of the swaybar, and almost hits the frame on full left. the right front tire however comes nowhere near either. is this just a recentering of the rack needed? its aligned, and everything is even, just wondering what the issue could be

4. does anyone make caster-adjustable top plates for stance coils? i have gr+pros and want to adjust caster for contact patch etc. and dont want to have to buy all new coils (but will if i have to in the future). also, the dust boot on the rear coils is torn. they need to be driven on (yes now, in bits of snow), will they be ok? will be cleaned regularly

5. last but not least, to dan. i know you said your rear knuckles arent set up for z32 brakes, and i agree with your reasoning, but is there any chance in the future of some type of adapter/differing design for the larger caliper/rotor? all else fails i imagine someone could just build an adapter bracket

[Motary]

1. If you move the outer tie rod pickup point outside, you decrease ackermann angle

2. No clue

3. How did you move the tie rod pickup point?

4.Stance makes them


Steugen - Ackermann angle is commonly reduced on race cars, on high speed tracks anti-ackermann is also used. On tight tracks reduction in ackermann geometry will make the car understeer more



Link: click me

[JaredP]

thanks motary! tie rod pickup was shortened, dropped, and slight reduction in ackerman (by rewelding "straighter").

thanks for the link to the stance caster plates too. if my coils last through the next couple months of winter (which they should with reg cleaning) i'll look into getting them. i was on stance's site a few days ago and didnt see them

[Motary]

By straighter do you mean that you moved toward outside? How much did you move it?

[godrifttoday]

Can someone just make a perfect kit allready

[PoorMans180SX]

Originally Posted by Steugen

I have gone thrue all 120 pages, but Im still not sure about my one question. For a full out race car with modified wheel arches, which hub setup is the best for me? I of course need to go as low as possible without messing up the geo. Driftworks claim that the loss of ackerman does not matter much in a race car, so they highly recommend their Geomaster2 for my race car (of course)..

Driftworks are going to be cheapest and best for you since you're in Norway.

Originally Posted by godrifttoday

Can someone just make a perfect kit allready

I think you're joking, but obviously there is no "perfect" solution. PSM and Driftworks have the best kits on the market, but there is compromise in everything suspension related.

[JaredP]

Originally Posted by Motary

By straighter do you mean that you moved toward outside? How much did you move it?

yes towards the outside. if i remember right, we cut the arm 1 3/8" from the very outside, and rewelded it in line with the rest of the pickup point, so that it didnt curve. along with shortening, it was likely moved 1/4" outwards

[Motary]

So you moved it 1 3/8 of an inch to the inside and 3/4 of an inch to the outside?

[JaredP]

1/4" to the outside. like this:


cut along the red line (to shorten) and rewelded in line with the green for less ackerman. not a very scientific way around it, just messing around with an extra set of knuckles. he likes them alot except that one issue

[initial_jc]

may you guys can help me since you guys atually seem to do suspension work and not just regurgitating what you saw somewhere else.

I recently installed some KW v3's and a spl ruca along with 18x 10 rims in the rear of my s14, and I know rightrear coil is blown.

But i hear a wobbling sound like a my rotor is rubbing, and i also hear like a click sound at low speeds.

Ive tried to tighten the tophat, torque all arms, replaced brakes and rotors, but i cant get rid of the sounds and im starting to become ocd, so i want it to be perfect any ideas?



I also ordered my spl tierods, wont install untill i get z32 inners

[SicBastard]

Originally Posted by initial_jc

may you guys can help me since you guys atually seem to do suspension work and not just regurgitating what you saw somewhere else.

I recently installed some KW v3's and a spl ruca along with 18x 10 rims in the rear of my s14, and I know rightrear coil is blown.

But i hear a wobbling sound like a my rotor is rubbing, and i also hear like a click sound at low speeds.

Ive tried to tighten the tophat, torque all arms, replaced brakes and rotors, but i cant get rid of the sounds and im starting to become ocd, so i want it to be perfect any ideas?



I also ordered my spl tierods, wont install untill i get z32 inners

Your rotors can warp really easily. But the clicking could just be a normal sound from your twin tube dampers.

[initial_jc]

Its so annoying, I thought it had something to with the strut mount.

[SicBastard]

Originally Posted by initial_jc

Its so annoying, I thought it had something to with the strut mount.

It still may be the mount, but I remember an old SCC article where they reported a strange and annoying clicking coming from their KW dampers, that KW said was normal. In the end they just conlcluded that race parts aren't designed for NVH, and that the minor annoyance was worth the performance.

[initial_jc]

Cool at least Im not crazy. Im going to try to find the link

[Karlitos]

Hey Motary,

I know this is related to a while back but anyways, what suspension 3d program did you use? I recently got access to WinGeo3 in my personal computer so Im starting to play around with it for FSAE. Id like to soon measure s14 points and plot them in.

Thanks

[Motary]

I used susprog3d, it is what we have at college and if you want to buy a license there is a 50% discount for students

Problem with susprog is that you can't calculate toe settings for more than 35 degrees of steering, I've been trying to make a drift specific knuckle for a friend of mine and so far I've come up with this kind of steering:



Toe out in turn has been decrased from 15.52 degrees to 2.59. I still have some development left to do here.

[S13Fullock]

so basically you can find tune your anckerman by adding and removing sapcers between the ball-joint and the knuckles....so i could make myself zero anckerman knuckle and from there i can just drop my roll center using spacers and it will ad anckerman again so you dont really need perfect spec knuckles...

[Motary]

No, that is how you fine tune bumpsteer. Wisefab tunes ackermann with spacers, but their balljoint pickup point is oval so a washer locks it in place.

[S13Fullock]

with stock knuckles if you ad the same amount of spacing at both pick-up point tie rod and lca you will be adding anckerman ... so if you already have aftermarket lca and tierod end its an almost free option...

http://www.gtfactory.jp/cms/e107_fil..._lcaandack.jpg

its pretty easy to understand with this picture

so what you do is cut and re-weld the tie rod pickup point (witch is the yellow line) to the zero anckerman location (witch is the green line) and then by adding and removing spacers between both pick-up point you can fine tune your anckerman by what ever amount you want. do you understand?

[PoorMans180SX]

Yes, that is all true.

[prego]

anyone out there using a progressive sway bar and find it hangs too low?

[e1_griego]

I can take a pic of mine if you want, it's not too low.

[prego]

yeah that would be good the main part of my bar hangs below my nismo power brace, my car is low but has driftworks knuckles and psm lower control arms so my arms are level

[s13 loverr]

Does anyone know if psm's rear knuckle will work with a dual caliper setup? I know they got dirftwerks knuckle to work with these I'm pretty sure PSM said that it works with a dual caliper setup, but I wanted to verify.