The Suspension Build Guide For Your S12

This is a basic outline for those looking for suspension info on various setups.
Please read this carefully. If you have questions, Please copy what you have questions on, start a new thread, paste, and ask your questions there.  [thanks, moderators]

***The "///" denotes the alternative, meaning OR.***

If you want to stick to S12 suspension parts:

There are SSC/Canuck lowering/performance springs available for STOCK S12s. See http://club-s12.org/v3/index.php?topic=7848   for more details.  For shocks/struts to use with these springs, look further down in the Shock/Strut part of this post.

Those not wanting the S13 front conversion but still yearning for coilovers, you can use Ground Control front components and MR2 (SW20) struts with the stock S12 strut tubes. For details on the MR2 shocks, see the Shock/Strut part of this post.  There are universal collars/perches available that will work if you don't like GC. I would recommend running a progressive spring or main spring/helper spring combo but just a main spring will be fine.  For the rear coilover setup, look here, page 2: http://club-s12.org/v3/index.php?topic=18579

If you want S13 coilovers, you have a few options:

Option 1:
S12 Setup
-S13 balljoint
-S13 spindle
-S13 5-lug conversion hub /// -stock S13 4-lugs
-S13 Brake caliper hoses (Optional, but recommended as the S12 hoses stretch a little tight)
-S12 stock control arm/tension rods
-S13 tie rods, and 1995 ford escort tie rod ends /// S12 tie rods, A1 tie rod ends (http://shop.a1racing.com/dgt100.aspx)

Option 2:
s12-S13 hybrid
-S13 balljoint
-S13 spindle
-S13 5-lug conversion /// -stock S13 4-lugs
-S13 Brake caliper hoses (Optional, but recommended as the S12 hoses stretch a little tight)
-S12 stock control arm
-S13 tie rods, and 1995 ford escort tie rod ends /// S12 tie rods, A1 tie rod ends (http://shop.a1racing.com/dgt100.aspx)

Option 3:
s12-S14 hybrid
   -S14 balljoint
   -S14 spindle
   -S14 SE hubs(5-lug) /// -s14 non SE 4-lugs
   -S14 Brake caliper hoses
   -S12 stock control arm

Option 4:
S13 setup
   -s13 control arm
   -s13 spindle
   -s13 Brake caliper hoses
   -s13 5-lug conversion hub  /// -stock S13 4-lug

Option 5:
S14 setup
   -S14 control arm
   -S14 SE spindle/hub(SE S14s are 5lug) /// -S14 non-SE 4-lugs
   -S14 spindle spacer(with S13 strut bolts) /// -drill out S13 coilovers to use accomodate larger S14 spindle
                 bolts

Option 6:
S13/14 hybrid
  -S13 control arm
  -S14 balljoint
  -S14 SE spindle/hubs  /// -S14 non-SE 4-lugs
  -S14 spindle spacers(with S13 strut bolts) /// -drilled s13 coils.

If you use S14 front spindles, might as well use S14 coilovers, if you can source it. If not, use S13 coilovers and mix and match S13/14 stuff for 5 lugs. You cannot use any S14 hubs(4/5-lug) on S13 spindles. S13 hubs go to S13 spindles and S14 hubs go to S14 spindles.

Megan Racing S12 SPECIFIC Coilover Kit
Technically, its not 100% for an S12- you NEED to do the S13 front conversion, as detailed above.  The Megan kit is essentially a normal S13 Megan kit that has been modified in the rear for our suspension, but otherwise the S13 knuckle/spindle will need to be installed, as detailed in Options 1, 2, and 4.  This is the easiest and most convenient way to go if you are planning S13 front conversion. You can also adapt S13 rear coilover shocks to run a full S13 coilover set of your choice. You can use my rear suspension setup for ride height adjustment or just a spring length of your choice.  Check Megan's website for the pics/details of the kit.


****OTHER REQUIRED ITEMS**** YOU ALSO NEED THESE TO CONVERT!!
-S14 tension rod brackets(you'll need to slot out a hole to fit the S12 chassis)
-S13 tension rods(stock/aftermarket)
-A1 racing tie rod ends OR S13/s14 tie rod inner/outers combo, respectively.
-S13/S14 sway bar with endlinks/mounts /// -S12 swaybar with washers and two longer tension rod bolts(one for each side)

--------------------------------------------------------------

Brake Upgrades

Brake upgrade for 5-lug with STOCK S12 suspension
- S12 MK2 SE V6 struts/springs

- Z31 87-89 turbo front hubs(for slip on rotors) and wheel bearing
- Z31 87-89 turbo front rotors
- Z31 87-89 turbo front calipers
- Z31/S12/S13 lines, SS or rubber

Alternative brakes for the SE V6 WITH Z31 hubs for slip on rotors
- S13/s14/q45/j30/z32 front Calipers
- matching rotors
- Z31/S13/stock brake lines /// -S13-Z32 front conversion lines for Z32 calipers
- washer to space calipers out .170" to center the caliper to rotors

Brake info for S13/s14 front conversion(this applies AFTER you have converted)
If you use the Z32 4pots, you will need a Z32 master cylinder -and- Z32 front brake conversion lines for an S13. The z32 piston diameter is 1" or 1 1/16". If the stock S12 master cylinder size says 15/16" on it(most are), then the Q45/J30 brakes will work fine. As for brake lines, stock S13 lines will bolt up to q45/j30 calipers. You can get Z31 SS lines (ebay ones don't hold up too well) and they will bolt right up to the front and rears(make sure it is 6 pieces, 2 front 4 rears).

For the stock SE V6ers, they can run Z31 SS lines all around.

Brake option #1:
Z32 Front brakes
- Z32 Master cylinder 1" or 1 1/16"(15/16" is fine but will give a slightly mushier pedal feel)
- S13 Z32 front brake conversion line
- Z32 rotors(matching calipers)
- IF 4-LUG! --- Redrill rotors

Brake option #2:
S13/S14 calipers
- S13 master cylinder 15/16"(if stock is 15/16" not required)
- S12/S13/S14/Z31 front lines(stock rubber or SS)
- S13 rotors for 4lug /// -S14 SE rotors for 5 lug

Brake option #3:
Q45(90-96)/J30(93-97?, recheck before ordering) front calipers
- S13 master cylinder 15/16"(if stock is 15/16" not required)
- S12/S13/S14/Z31 front lines(stock or SS)
- Q45(90-96) /// J30(93-97) front Calipers
- Q45/j30 rotors
- IF 4-LUG! --- Redrill rotors


----------------------------------------------------------------------

** Z31 Rear ** Conversion

+++Z31 vented REAR brake swap
- Z31 87-89(na/t) rear control arms
- Z31 87-89 axles(my stock 6-bolt s12[r180] axles bolt up to Z31 arms, R200 axles should too.)
- Z31 87-89 calipers/rotors
- Z31 SS/stock lines(2 front, 4 rear)
+++Try to get this as a set, it'll make your life EASIER!

Ok Some background info. Before everyone though that Z31 87-89 arms and S12/Z31 84-86 arms were identical except the hubs. WRONG. The actual Z31 87-89 arm is different. It has been confirmed by 200sxkit car that the rear arms are infact different. The mount for the hubs are pushed out 10mm to accommodate for the taller vented rotors. The rear hubs used among the 84-89 Z31s are probably all the same. So if you want vented brakes on the rears, BUT wish to retain 4 lug, get your rear 4-lug hubs and swap them over to the 87-89 Z31 rear arm. Then redrill your Z31 vented rotors to fit on your 4-lug hubs. DONE!  Obviously, if you want 5 lug, just get the 87-89 Z31 arms, and bolt them on, no hub swapping needed.

If you find a way to get 87-89 Z31 vented rear rotors on stock S12/84-86 Z31 arms, please let me know. I have an idea, listed below...

Z31 vented brake info/tech:
!!USE AT YOUR OWN RISK!!
My theory to run the vented brake rotors/calipers on an S12/Z31(84-86) RCA is to get a hubcentric 10mm spacer(that fits inside the vented brake rotors and centers it) to space the rotor out 10MM and the vented brake calipers should bolt up to the S12/Z31 84-86 arm. If you're 4-lug, just redrill the vented rotors to 4-lug.
!!THIS IS NOT CONFIRMED, USE AT YOUR OWN RISK!! If you have tried this and it does work, please let me know and post me some pictures so I can make sure. Thanks!

--------------------------------------------------

SHOCKS/STRUTS

I recommended to run all four of the same shocks because they are valved similarly. If you run Illuminas in the front and Konis in the rear, the Konis are going to have much better dampening characterstics so the rear is going to be much more stable over bumps. The car itself is going to be upset when going over bumps because the fronts won't react the same as the rears. It's not about how it FEELS, but how the car actually reacts. Remember that these adjustments are rebound and NOT bound. When you adjust the knob, you're actually adjusting how it reacts to the bumps in the road. Think of it this way, bound prevents the spring from compressing and rebound prevents the spring from expanding. Bound is what makes a car feel JDM super rock hard solid. However you want the car to feel is all preference. Whether you actually gain some sort of performance enhancement* is another story.

*I meant this in a sense of actual faster lap times and/or faster speeds through a corner. This really all depends on what YOU want the car to do. A drag race setup is not the same as a road course setup. Same applies for drifting/street driving/etc.

That said...
For stock S12 front suspension...

- 280zx shocks in the front, Z31 in the rear is the general setup.  BUT that only limits you to Tokico Illuminas because there are no KONI Yellows or KYB AGX for that COMBO (there are KONI Z31s but no Koni 280zx, AGX neither.) 

- The next thing to do now is to run SW20 MR2 rear shocks (in the front S12 strut tube, according to Gerrybg) and Foxbody Mustang rears (in the rear of the S12). Then you'd have a selection of KONI and AGX shocks available.

- Using SW20 MR2 front strut inserts in the front will require sectioning the strut tube but in return you get a shorter shock/stroke for the super lowered cars(good with GC/sleeve setup).  Less chance of hitting the bumpstops this way.  Foxbody Mustangs also have a shorter stroke and shock so that helps on lowered cars too.  One more thing, if you go Konis, run all 4 Konis, same applies to the AGXes.

- For the info on using the MR2 front strut insert and shortening the housing, check my suspension thread linked below and look on page 3, Gerrybg details the situation.

----------------------------------------------

My Suspension Thread:
Here is the link to my suspension thread.  http://club-s12.org/v3/index.php?topic=18579  I will update it every so often when I get more money and more parts. I have the rear suspension height-adjustment on page 2. If the solid axle guys want rear height adjustment, then I'm going to need specific information and pictures. Just contact me if you're willing to help out and experiment.

Will update as info becomes available.

If there is any missing info or errors, let me know and I'll correct it. I hope this clears up A LOT of brake info. Lastly, I'm not responsible for any errors this contains, whether it be parts not bolting up or requiring more parts. My Front and rear suspension setup bolted up fine, it might not be the same for you. You need to do your own research before buying anything. Use this guide at your own risk.

-mod_mastaz

Update 01-21-09
Sorry guys I haven't updated this in a while. Thanks to Sterling for cleaning this up for me too. Anyway, I forgot to mention that you can run Z31 front inserts into the S12 strut tube also. I don't know if it was the turbo or na shock that fits, because one was 10mm larger in diameter than the other. Anyway with that said, you can run all 4 Konis and Canuck springs or whichever in your stock S12 setup and be on your merry way.

Was your unlisted idea to use 4 lug rear spindles with the Z31 rear arms for the vented rear discs? If so, then yes, you can swap in the 4 lug spindles, drill the rotors, and still use the Z31 control arm.

The spindle shafts are all the same size for 84-88 IRS S12's, and for all 84-88 Z31's (turbo or otherwise). The only part different is the CV shaft companion flange that bolts to the spindle.

I was thinking of using the vented rear calipers and rotors on a regular non vented 84-86 Z31//S12 rear arm. Not sure it it'll work, cuz I didn't want to figure it out. I just put my stuff on and I was done with. Maybe someone could experiment with my idea or something.

Just want to add... if doing the TRX series 3 rear disk brake upgrade for/from the solid axle drums, you need to also upgrade the master cylinder. To either stock all disk S12 , non ABS S13 or S14/15.

About the solid rear axle, I don't know because I haven't seen it or have been able to measure/compare parts. I would just take a guess at the AE86 rear struts or something. Measure the spring diameter or the spring seat/perch diameter and you'll probably be able to find springs in  those sizes.

They won't work though. I checked.

Hrm... If you have any pictures of the rear axle, post some here please. I wanna see where the shock is bolted to subframe and the chassis. Measure the width of the bottom part of the strut too. How wide is the spring perch/seat anyway? The chassis and the subframe perch I mean. Pictures here would help too.

So lets see, to get the megan coilovers to work at the front this is all i need?

++S13 setup
-s13 control arm
-s13 spindle
-s13 5-lug conversion hub or -stock s13 4-lug hub

OR

-s13 balljoint (to press into S12 control arm)
-s13 spindle
-s13 5-lug conversion hub or -stock s13 4-lug hub

Did i get it?

[moderator edit:  Yes]

Thanks Julie. Do you have pix of the strut mount for the solid axle? And  does anyone happen to know the spring's inner diameter and uncompressed length?

There has been a few solid axle people for rear ride height adjustment. Ground Control custom makes these, check the product advertisements section on this forum for the info.  if not I'll figure out something when I can get all the information I need.

hey im not yet too experienced with chassis modifications and tuning...

i have stock SE V6, 5 lug, full discs... what should i be looking to upgrade with? i wanna keep the stock 5 lug... brakes are cool for now too. i really just want to (as simply as possible) lower stiffen and stabilize this old loose chassis. so what parts should i be looking for and from what cars? thanks a million

btw i have a full set of stock s13 struts layin around. not sure if they would be any help... also ill probly be taking some other chassis components out of my s13 soon to replace with aftermarket so im not sure if stock s13 stuff would be upgrades for the s12 or not...?

If you're looking for something basic, just run Canuck springs and Tokico Illuminas shocks/struts, 280zx front and Z31 rears. Or you can run AGX MR2 rear strut inserts(in the front) and AGX Foxbody shocks in the rears(you'd have to look more into the front setup because I'm not EXACTLY 100%). Just remember to use your S12 rear mounting hardware if you use Z31 Illuminas. Poly bushing kit for a Z31 and also poly filling your diff mount. Addco sways bars are also available. That's pretty much the gist of it. If there is anything more then you'd have to search around. PM if you need some extra info on the S13 swap AFTER you have read the first post. Thanks!

to use q45 or j30 calipers can you use s13 spindles and hubs with that?

Canuck springs? what are they and where would i get them lol. So you're saying to get illuminas for a 280zx for the front, and illuminas for z31 in the rear. right?

Doug, to use the q45/j30 calipers, you would need to do the S13 conversion. You have a choice of doing the FULL conversion, or just using the s13 coilover/spindle/balljoint.

Frosti, Canuck springs are lowering springs for S12s. Tokicos Illuminas are shocks. You would use the shocks from the front of a 280zx and 300zx rear(z31).

http://club-s12.org/v3/index.php?topic=7848
For the springs. You'd have to find your shop for the shocks.

agx's are hella too soft (imo)

Front or rear?

What are your spring rates?

DeathAndMajesty
Front or rear?

What are your spring rates?

Honestly if the shocks up front are significantly softer, the rear will feel sloppy. Does the ass end feel floaty over rough pavement?

SSC might not be enough drop for the mustang rears.

I recommended to run all four of the same shocks because they are valved similarly. If you run Illuminas in the front and Konis in the rear, the Konis are going to have much better dampening characterstics so the rear is going to be much more stable over bumps. The car itself is going to be upset when going over bumps because the fronts won't react the same as the rears. It's not about how it FEELS, but how the car actually reacts. Remember that these adjustments are rebound and NOT bound. When you adjust the knob, you're actually adjusting how it reacts to the bumps in the road. Think of it this way, bound prevents the spring from compressing and rebound prevents the spring from expanding. Bound is what makes a car feel JDM super rock hard solid. However you want the car to feel is all preference. Whether you actually gain some sort of performance enhancement* is another story.

*I meant this in a sense of actual faster lap times and/or faster speeds through a corner. This really all depends on what YOU want the car to do. A drag race setup is not the same as a road course setup. Same applies for drifting/street driving/etc.

mx73 cressida rear springs are a direct fit, thus ae86 springs do as well....

im unsure of spring rates and such, just thought id let you guys know its confirmed, not on height though

This is for IRS models.

...what would be the easiest place to find the .170" spacer??..anyone have a pix of the spacer??...i'd like to try a q45 or j30 front brake conversion on my 88 SE as those are easy to find in the yards...THX,MIKE

Just bring a vernier caliper with you to measure the washers you're going to buy. A hardware store should have different thicknesses and sizes for you. Make sure you get the highest grade you can find. I got this info off RedZ31's site so you can find more info there. He just used a washer too I believe.

After installing my front megan coilovers i TRULY know what you must do to get them installed. I consider myself more than lucky to acquire a whole front subframe/suspension from a good friends parts s13 for the price of a case of beer.

s13 tie rods inners/outers(s12 are too short)
s13 spindle(for the coilover to mount properly)
s13 brake lines(s12 have the block fitting rather than threaded)
S13 rotors(to acompany s12 calipers)
S13 calipers(s12 wont bolt up to s13 spindles)
s13/longer sway bar endlinks i will also be using an s13 sway bar and moounts because the s12 bar with s12 endlinks gets way to close to the tension rod and will most likely make contact when the suspension is compressed

s12 caliper shown against s13 spindle.

s13 seen left s12 right difference can be seen in mounting size as well as the brake line difference

i have a v6.arent the q 45/z32/and j30 front calipers bolt on?thats what i was under the impression of.

i added some pictures check it out

i would assume naturally the q45(being the v8 beast it is) does not have the same size caliper as a s13.and more than likely will fit.

what is the bolt spacing on the caliper? if its 100mm on the hub/ axle you could use the 4 piston nissan skyline ?

Yes, you can run Z32 brakes on the S13 spindle.

For the V6 strut tubes, you'll need to get Z31 88-89 turbo front hubs and Q45 rotors/calipers for it to work. The stock V6 rotors are behind the hub and bolting on just the q45 calipers won't work.

im using s13 spindles as you can see because i have s13 front coilovers oem brakes will not fit on the s13 spidnles

So a stock SE can take non turbo rotors from a 87 z31 correct? Front and back?

Brake upgrade for 5-lug with STOCK S12 suspension
- S12 MK2 SE V6 struts/springs

- Z31 87-89 turbo front hubs(for slip on rotors) and wheel bearing
- Z31 87-89 turbo front rotors
- Z31 87-89 turbo front calipers
- Z31/S12/S13 lines, SS or rubber

Alternative brakes for the SE V6 WITH Z31 hubs for slip on rotors
- S13/s14/q45/j30/z32 front Calipers
- matching rotors
- Z31/S13/stock brake lines /// -S13-Z32 front conversion lines for Z32 calipers
- washer to space calipers out .170" to center the caliper to rotors

Could i use a 4 lug z31 hub and still run j30 calipers?

No. You need the V6 strut tube first off to use the calipers, then you need M30 front hubs for 4lug slip on J30 rotors. The Z31 hubs are in front of the rotor and the S12 4 cylinder strut tubes have the wrong spacing for the newer style calipers.

awsome thanks for the help

I've run into an issue with the 87 Z31 brakes I'm trying to install, finally got them on the front but I realized that in the rear its impossible to use them as the metal piece (not the caliper) that goes around the rotor doesn't clear the vented rotors (my stock rotors are not vented I've come to find . So would using the rear calipers and I guess I'll call them caliper brakets from a 87 Z31 solve this problem?

Maxpow, I'm assuming this is your setup.

Z31 front brakes on SE tubes. Remember to swap to the Z31 rotors too if you haven't already.

The rears, Z31 vented rotors on stock calipers and stock control arms. THIS WILL NOT WORK. You need need the entire arm for this setup to work, cuz you're gonna be doing more work trying to convert it.

If you can't get the arms, then you're going to need:
Z31 vented dust shield(you can go without this, just remove your old one)
Z31 87-89 vented rear calipers
2x 10mm hubcentric spacers for the ROTOR(NOT TYPICAL WHEEL SPACER. It will need to be custom machined! You have to measure the ID of the rotor and the OD of the hub where the rotor seats to) This will push the vented rotor out 10mm because the Z31 arms have the hubs pushed outward to clear the caliper bracket.

I don't know what else you're missing, but it seems like you only got the rotor, which isn't anywhere close to a rear brake upgrade. I need more info on your setup before I can help you. The above list is just a general list, you might need more specific parts. Honestly, if you can go without the rear brake upgrade, I'd recommend not to upgrade because it doesn't make that much of a difference for the work you're going to have to put in.

And so you know, I haven't done this conversion. I just swapped my entire arm to the Z31 vented brakes. You're going to need to do some measuring on your part to make sure you can get it to work.

mod_mastaz
Maxpow, I'm assuming this is your setup.

Z31 front brakes on SE tubes. Remember to swap to the Z31 rotors too if you haven't already.

The rears, Z31 vented rotors on stock calipers and stock control arms. THIS WILL NOT WORK. You need need the entire arm for this setup to work, cuz you're gonna be doing more work trying to convert it.

If you can't get the arms, then you're going to need:
Z31 vented dust shield(you can go without this, just remove your old one)
Z31 87-89 vented rear calipers
2x 10mm hubcentric spacers for the ROTOR(NOT TYPICAL WHEEL SPACER. It will need to be custom machined! You have to measure the ID of the rotor and the OD of the hub where the rotor seats to) This will push the vented rotor out 10mm because the Z31 arms have the hubs pushed outward to clear the caliper bracket.
I don't know what else you're missing, but it seems like you only got the rotor, which isn't anywhere close to a rear brake upgrade. I need more info on your setup before I can help you. The above list is just a general list, you might need more specific parts. Honestly, if you can go without the rear brake upgrade, I'd recommend not to upgrade because it doesn't make that much of a difference for the work you're going to have to put in.

And so you know, I haven't done this conversion. I just swapped my entire arm to the Z31 vented brakes. You're going to need to do some measuring on your part to make sure you can get it to work.

Does anyone know which z31 strut tubes fit our cars?  turbo or n/a?  I'm looking at getting some Bilsteins HDs or Konis and the Turbo and na dampers have different part #s.

You want 280zx struts for the front, not Z31.

Z31 shocks will work for the rear if you have IRS.

You can run the Z31 front shocks. The 280ZX ones are like stock length, so if you have Canucks lowering springs, the Z31s are actually better fitting because they are slightly shorter. I don't know which insert is the right one. If you look on the Z31 forums you can find out which one is 10mms larger or not. I would think the Turbo ones are 10mm larger so check around before ordering anything.

ok this is going to sound very noobish, because it is  
could you use the v6 5 lug instead of the s13 4 lug, and whhich one will give you the most angle/aftermarket support?
and would it be best to swap in a s13/s14 subframe

S13 4 lug is best, SE parts are no different than 4cyl parts besides overall thickness and its 5 lug.

S13 gives aftermarket and angle, and you can buy 5 lug rotors and hubs to convert the S13 items to 5 lug.

im kinda confused, i dont want to do the s13 4 lug because im getting a realy good deal on some 5lug wheels and im on a budget so i couldnt affort to do a 5 lug conversion, so is there any way i could use the se 5 lug

Troskinatorim kinda confused, i dont want to do the s13 4 lug because im getting a realy good deal on some 5lug wheels and im on a budget so i couldnt affort to do a 5 lug conversion, so is there any way i could use the se 5 lug

i dont want s14 stuff because i already have se 5 lug, is there any way to modify it to work? and sorry for the dumb question, im not good with suspencion stuff

Yes you can use the se 5 lug set up but you need the whole strut because the se calipers have wider mounting points so the struts have wider caliper mounts to suit, so your ca20 brakes won't mount to the strut and also won't work with the se rotors.
So in short find complete struts brakes and hubs off an se.

For the rear use the se trailing arms. (You can swap out juts the rear 5 stud hubs, but it is such a shit job getting them out, (I know I've done it) you are better off just swapping the whole trailing arm complete with hubs brakes etc). Hope that answers your question.

I'm going for the s13 setup, but I have a question, will I be able to put in the original s13 coilover, because the diameter of the spring of the s13 is bigger, and the spindle can't pull of a compleet turn.
Am I doing something wrong or should I take upgrade (adjustable) coilovers?