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How To: 5lug Conversion, And Home Made Coilovers

Started by JasterM5 · Jun 2, 2006 · 50postsSMF 2010–26

JasterM5Jun 2, 2006, 4:28 pm · #1

Ok, so I'm deciding what I want to do with my rear suspension since its so disgusting. I'm building a full drift car which i eventually want to get into seriously. The only thing holding me back at the moment is the car. I can get into an s13 and drift the crap out of it, but I want my s12.

A buddy of mine came across a post on ziptied.com about a guy who swapped in an S14 Rear subframe into his Z31. The guy is amazing with his work and does it all himself in spare time. Easily one of the nicest z31's ever. So anyway, I know our rear subframe is EXTREMELY like the Z31 if not exactly like it. Below I'm gonna re-create his post with his picture because you have to be a member of ziptied to see the posts and they have a weird application for membership.

Now it's time for semi-trailing arm ----> S14 multilink swapu!!!
Remove tired Z31 stuff and throw away.
[attachmentid=30]
Gratuidous "hey look, I got parts" pic.
[attachmentid=34]
Your standard S14 subframe. Pink dots indicate the locations of the old mounting points on the car when installed.
[attachmentid=24]
See.
[attachmentid=27]
Yes, that IS a nissan part sticker stil on the subframe, and yes, that IS rust on the subframe. Welcome to the salt belt. Hey, check out this beam on the frame that just so happens to be in the right place. Dope.
[attachmentid=28]
The modified subrame. Now with solid front mounts extending out. Note tabs I welded to the back to bolt up to the old mount temporarily. I'll eventually weld the rear S14 mounts solid and mount them on studs welded to that cool beam. I threw a KAAZ 2 way in there too, cause I heard it helps make drifts.
[attachmentid=25]
This picture shows a spring mount that will never be used again, and areas I needed to bash in, notch, reweld to get this stuff as far up into the car as possible.
[attachmentid=26]
Suburban Driveline made me this driveshaft. It's longer, stronger, and lighter than stock. It also sodimizes the rubber S14 one.
[attachmentid=33]
Lower it down, and ......awww shit. (coilovers at min and max height)
 [attachmentid=29]
This is my solution for the rear. I think it should stop a .50cal round. Removed the top mounts from the sustec pro's and now they live inside gas pipe.
[attachmentid=31]
Overkill, maybe, but I'm trying to cover as much surface area as possible to distribute the load. Remember, this used to be the shock mount, now it carries the weight of the car.
[attachmentid=32]
[attachmentid=35]

I'm currently in the process of buying an s14 subframe and finding out what needs to be done. This conversion would allow full adjustability of toe, camber and of coarse the ability to run coilovers. Also the s13 coilover and s14 coilovers are exeaclty the same with the exception of the length(s13 are shorter than s14). I think running S13 coilovers would be the better route to make the ass sit lower.

If anyone has any thoughts or question please post them up as its always good to get a few opinions and different angles.
rageJun 2, 2006, 5:31 pm · #2

ive seen that thread on ziptied, aswell. pretty neat.

sam31183Jun 3, 2006, 1:23 am · #3

If i remember right, needcafors13 saw this exact post and attempted to recreate it on his s12. But there was an hump or something in the s12 body that was different from the z31s body that prevented the s14 rear subframe from going in right. If memory serves me right he said it could be done, but you would need to do alot of fabricating to get it to work right. There is an guy on this forum from uk or something with a silver hatch that he put onto an rotissere(sp?) and fabbed on an s13 or s14 rear end. Also I belive another member on the forum with an red notch with an sr in it that has done an similiar setup....i remember he did make up some real hardcore strut towers for his car tho. He is also running all megan racing coilovers. But I cant recall his name.

rageJun 3, 2006, 5:44 am · #4

ya, the problem with s12's is the strut towers are smaller in diameter, so only a strut can fit in it. you need to cut it out and make another for coilovers.

JonBMar 28, 2010, 6:02 pm · #5

I'd say no. I solid-bushinged my car so my ride is harsh and there's alot of feedback/road noise. But my steering wheel doesn't wobble or anything. It has in the past, but just from loosing skick-on wheel weights.

It's pretty much still done by the Nissan engineers. The Z31 is pretty much the same as the S12, it just had bigger brakes(it's heavier). Any new noise/harshness will be from the spring plate, shock, and spring choices you make; that's not nissan engineering.

The S13 front end allows for a greater choice of after market parts. It's similar in weight to the 200, so it's breaks are good, and there's alot of parts interchange with bigger nissan vehicals and later "S"s with performance 5-bolts and bigger breaks. It seems to be the more popular swap.

My Z31 front struts stretched my wheel base a bit if I'm not mistaken.

Johnny_boiMar 28, 2010, 7:05 pm · #6

i took it on the freeway last night rode good but it can be better

Johnny_boiMay 8, 2010, 9:15 pm · #7

the follow up on the conversion/ feedback

well been riding on these for 2000+ miles with little to on problems had to roll the fenders, they were cuttin my tires.

im running qa1 10in 350lbs in the rear with no adj. prech. soon to be tho.

camber plates are a real good idea, plan on getin some, as soon i have the green back to do it

without camber plates and top hat needle bearings there will be spring binding here and there

falkhenAug 11, 2010, 4:00 pm · #8

here is related thread with more info including this
http://www.z31performance.com/forum/viewto...hp?f=2&t=22
http://www.ziptied.com/forums/index.php?topic=6734.0

EightySix200SXAug 11, 2010, 5:17 pm · #9

mod_mastaz will most likely chime in on this.

mod_mastazAug 12, 2010, 10:25 am · #10

Good luck guys! Just strengthen the rear frame rail where the rear mounts go and redo the front mounts on the s14 subframe. Hammer out what you can and even drop it a bit, but try to keep subframe as close to the body as possible. Use the FSM for body measurements and keeping the subframe sitting the way it's supposed to be originally(think pinion angle but for the entire subframe, if that makes sense). You can also run tiny custom shocks and 1.8" OD springs if you don't want to make a new tower, might as well at this point. Anyway, that's what I'd start with when I do my rear conversion down the line. Have fun!

IggyEGuanaAug 12, 2010, 11:26 am · #11

check the rules

2010 Formula Drift Rulebook (excerpt)

3.2 ENGINE & TRANSMISSION
3.2.1 Modifications
3.2.1.1 Engine, transmission, ECU and/or final drive modifications are free,
but only the rear wheels may propel the vehicle.

3.2.1.2 Engine and radiator catch tanks with a minimum capacity of one (1) quart each are required and securely fastened and sealed in the engine compartment.
3.2.1.3 All fluid systems must be free of leaks.
3.2.1.4 All cars must be equipped with an on-board starter and power supply
which must be in working order at all times
3.2.1.5 All vehicles must be equipped with a functioning reverse gear.
3.2.2 Traction Control
Traction control and other non-specified "driver aids" are not allowed. Wheel
speed sensors must be removed.
3.3 CHASSIS & SUSPENSION
3.3.1 Basic Chassis Design

The vehicle chassis, frame and / or uni-body must remain unmodified between the vertical planes created by the original forward most and rearward most suspension mounting points unless otherwise specified in these rules. Uni-body or chassis may be seam welded.
3.3.2 Suspension Design

The basic OEM suspension design type may be freely modified. The original suspension mounting "pick-up points" must remain in the stock, unmodified location.

3.3.3 Modifications of the stock, OEM firewall and transmission tunnel are allowed
as follows:
•
Dimension A: Tunnel Width May be no wider than 18 Inches
•
Dimension B: Minimum dimension of 10 inches between the bottom of the
windshield and the top of the transmission tunnel.
•
Dimension C: Modifications of the driveshaft tunnels behind the transmission
tunnel taper vertical plane should not exceed an overall width of 10 inches.
•
Dimension D: Modifications to driveshaft tunnels behind the transmission
tunnel taper vertical plane should not exceed an overall width of 10 inches.
•
Taper Length: (from the firewall to the end of the transmission tunnel into the
beginning of the driveshaft hump) may be no longer than 36 inches.
•
No part of the engine casing may cross the vertical plane of the original
firewall into the transmission tunnel.
•
No other modifications may be made to the vehicle chassis, frame, or uni-
body unless otherwise specified in these rules.

•

Any holes in the firewall must be of the minimum size for the passage of controls and wires, and must be completely sealed to prevent the passage of fluids or flames from the engine compartment to the cockpit.

3.3.4 Front cross member and/or front or rear sub-frame

Front and rear sub-frames and cross members must be stock and available on the exact model that is competing in Formula Drift. The subframe must also be mounted in the exact stock location, without being moved in any plane.

Front subframes may only be modified to directly allow for oil pan / starter clearance and steering rack relocation. The front subframe must retain intact on at least one major member on one face that spans the entire width of the subframe, thereby keeping the original dimensions of the subframe intact. Any other modifications, cutting, welding, strengthening, etc is not allowed.

Rear subframes may only be modified to allow for mounting or relocating a differential. The rear subframe must retain at least one major member that spans the entire width of the subframe, thereby keeping the original dimensions of the subframe intact. Any other modifications, cutting, welding, strengthening, etc is not allowed.
3.3.5 Modified or aftermarket suspension parts
Modified or aftermarket suspension parts, including hubs, are allowed.
3.3.6 Steering
Modifications of steering components (steering rack, tie rods, etc) are free.
This includes mounting the steering rack to the front subframe.

falkhenAug 12, 2010, 2:28 pm · #12

in that thought process "Rear subframes may only be modified to allow for mounting or relocating a differential"

Modification to allow the install of R230 LSD So equipped to Q45/Z32 turbo...hmmm

in consideration installing subframe from S13/S14/S15/Z32(N/A/z32(T) so that you can install  R230 LSD is that enough rational to meet an exception?
although not factory equipped. becuase you are mount and or relocating a differential.

front and rear sub-frames and cross members must be stock and available on the exact model that is competing in Formula Drift. The subframe must also be mounted in the exact stock location, without being moved in any plane.

2x competing cars of same model "exact model that is competing in Formula Drift"
stock S13/S14/S15/Z32(N/A/z32(T) subframe swapped with no welding to it.
the wording is not very clear.
it did not say "as so equipped OEM per specified model year vehicle" its implied leaving flexibility.

need a grampa clause in there for older cars.

D-sport S12Aug 12, 2010, 4:49 pm · #13

to get the best answer, you are probably better off messaging fomula d, whoever there and finding out if you can do that. I have a very good idea for our RCAs. It would also include a toe adjustment. I will see if i can draw something up quite shortly.

sam31183Aug 12, 2010, 5:19 pm · #14

local guy to the pacific northwest had a skyline rear subframe in the back of his s13 and had to switch it back out to a rear s13 subframe night before fd seattle so he could compete....(nikolay) Atleast that is what i have read online...not sure if the car actually went through tech, or if they changed it before hand.

IggyEGuanaAug 12, 2010, 8:38 pm · #15

ya they leave it kinda vauge in parts for sure.  anything is worth a shot.  imo the way to do it is drift with a SRA car and avoid that headache altogether or mod the rear arms (not subframe) to correct the geometry.  could get some adjustment with threaded heim joint ends too.  in fact since suspension mods are free in the rules u could build comepletely new arms from DOM tube and do all kinds of fancy adjustability.

D-sport S12Aug 12, 2010, 9:11 pm · #16
IggyEGuanaya they leave it kinda vauge in parts for sure.  anything is worth a shot.  imo the way to do it is drift with a SRA car and avoid that headache altogether or mod the rear arms (not subframe) to correct the geometry.  could get some adjustment with threaded heim joint ends too.  in fact since suspension mods are free in the rules u could build comepletely new arms from DOM tube and do all kinds of fancy adjustability.

that's pretty much what i was thinking for the LCAs. Heim joints and DOM tube. You could makes some super nice LCAs. I need a good mig and a few other thing, get a good design made up and make some dope LCAs
CamInHeadAug 13, 2010, 9:06 pm · #17

TBH, for all the work involoved you may as well just drift an S13/14 and be done with it. Personally, I think there's nothing wrong with the S12 IRS save for the camber when lowered, which can be fixed, and unsprung weight. Those seni-trailing arms are bloody heavy.
I've seen an Escort Cosworth with some custom arms and rose-jointed pivots and it looked to be a decent set-up.

tuhsty s-12Aug 15, 2010, 5:28 am · #18

in my opinion i would stick with the stock rear end.. camber can be fixed.. and u can get creative and have a pinion machined from a short nose diff to go with a 4.3/4.6 ring gear.
 im actually in the process of doing and s13 rear end conversion on my car... but if i had the choice agen i would stick to stock... cuz there is no turning back....there are a few thing that needs to be cut n massaged so to speak... i dont have any pictures tho...but my subframe rite now is mounted.. jus waiting on sum s13 shock towers to complete the set up.

i wont discourage u from doing it though cuz once done rite would make for a sweet setup.

falkhenAug 16, 2010, 1:37 am · #19
local guy to the pacific northwest had a skyline rear subframe in the back of his s13 and had to switch it back out to a rear s13 subframe night before fd seattle so he could compete....(nikolay) Atleast that is what i have read online...not sure if the car actually went through tech, or if they changed it before hand.
 

Randy: fixed the problem.
I was talking to him about all the time...
 this is getting off topic thanks to iggy.  your topic however is important just not on this thread...

Good luck guys! Just strengthen the rear frame rail where the rear mounts go and redo the front mounts on the s14 subframe. Hammer out what you can and even drop it a bit, but try to keep subframe as close to the body as possible. Use the FSM for body measurements and keeping the subframe sitting the way it's supposed to be originally(think pinion angle but for the entire subframe, if that makes sense). You can also run tiny custom shocks and 1.8" OD springs if you don't want to make a new tower, might as well at this point. Anyway, that's what I'd start with when I do my rear conversion down the line. Have fun!

not many would think of the pinion angle as issue, but I was into Mini trucks and before i had the frame C-notched had problems with Pinion angle Roll up.
 blew out the trany seal 2x times and 1 u-joint.

does any one have measurements for the SuB-frame chassis mount points i got about 46.75" but i didn't have any one helping me so it maybe off.
8SixS12Aug 17, 2010, 5:50 pm · #20

Question: On the s13 setup, couldn't you just cut off enough of the spring perch to accomidate a slip on coilover sleeve?  I would think that would be alot simpler and wouldn't require any welding right?  Or am I just not taking into account the s13 strut length?

DeezusAug 17, 2010, 10:19 pm · #21

im guessing you would have to weld it, having a slip on perch like that and not having it welded tight would just seem dangerous.

8SixS12Aug 18, 2010, 7:59 pm · #22

That's how all coilver sleeves are.  Not welded.  They just slip over the strut and the weight of the vehicle and spring tension hold them in place when the strut assembly is put back together.  Let me re-read that section.  I may end up answering my own question.

8SixS12Aug 18, 2010, 8:44 pm · #23

Nope, still don't see the need to cut the s13 strut.  Any ideas?

EightySix200SXAug 18, 2010, 8:56 pm · #24

U need to cut the s13 strut because the sw20 inserts are shorter.

I'm running similar setup only with 280zx sleves and using stock s12 tubes 40mm needs to be sectioned out. U can weld the sleve to the tube if u have steel sleves but most are aluminum that's where the perch comes into play. I was gonna do helper springs but it isnt needed I don't have that much travel. They would be nice. I also have a needle bearing integrated into. He upper hat so tube assy dosent bind when turning. They sell lower thrust bearing also that go underneath the spring itself

sam31183Aug 18, 2010, 9:14 pm · #25

you could also just make a spacer then put it in the bottom of the tube that the strut could sit on...but i mean...it matters how short a spring your running...i would also imagine the car will sit lower in the front with the strut tubes sectioned. I am running the cm spring/agx combo and i just made a spacer inside the strut tube and drilled out my factory top hats so the larger sw20 strut tube top would be able to fit through the hole...

EightySix200SXAug 18, 2010, 9:25 pm · #26

the spacer defeats the purpouse to get lower. i can slam the shit outta my car (not that i would) but as low as i am not i can still drop pretty far and have maintain a good amount of shock travel. but everone has theyre own method. its cool too cuz we all have something different to bring to the table.

johnnyboi- hey so ur running 350lb all the way around? cool setup 200sxkitcar has a similar setup with sectioned s13 tubes on s13 suspension componments. its pretty legit (no thread jack intended)

sterling setup s13 tubes
posted image
posted image

my setup s12 tubes:
left: sw20 shock w/ shortend tube///right: s12 tube (non shortend for comaprison)
posted image
posted image

8SixS12Aug 18, 2010, 9:55 pm · #27

Damn I just saw this after doing another search.  It seems that the s13 strut is alot shorter in stock trim hence the reason for the extention. Thanks Eighty Six.

So EightySix, I know Sterling shortened the tube on the left. Did you just add the washer perch to the stock tube on the right in the second pic with no cutting?

EightySix200SXAug 18, 2010, 10:15 pm · #28

the one in the second pic; the right one was before cutting. the left one was after.

sam31183Aug 19, 2010, 12:57 am · #29

yah...like...i dont think my ride height is too high with the spacer....i mean, i can barely fit a jack underneath my car now as it is...you must need ramps to get the front of your car up now right?

8SixS12Aug 19, 2010, 4:04 am · #30

What's the spring rate on the Canucks anyway?

vegasS12Aug 19, 2010, 9:52 pm · #31

so for the rear z31 5 lug conv. we can only use solid rotors rite?
or can we use vented rotors?

EightySix200SXAug 19, 2010, 10:35 pm · #32
8SixS12What's the spring rate on the Canucks anyway?

325lb/in front
275lb/in rear.

if you go the section/sleeve method run 350's or use that as a baseline all around you wont regret it. i may do 425's depending we'll see imma try adjusting the dampening some more and see what its like but its the perfect medium between weekend track and daily. they perform well. a friend of mine is running 430lb fronts with 350lb rear but its a vg swapped notchback it dosent even feel like there is a vg30e under the hood.

pm me if u need any help with the setup im running if thats the route u decide to go.

vegasS12so for the rear z31 5 lug conv. we can only use solid rotors rite?
or can we use vented rotors?

see mod_mastaz master suspension thread for that info. he is running vented rotors but you will need the z31 arms also if im not mistaken
8SixS12Aug 20, 2010, 2:38 pm · #33

Thanks, I will hit you up when I get started EightySix.

s-chassis_onlySep 23, 2010, 2:20 am · #34

if you wanna compete in formula d pro am dont swap ur subframe because if you do swap it you wont be able to compete for safety reasons unless you were already in formula d before the rule change

RB25sx - SLPRSep 23, 2010, 3:37 am · #35

I have done this mod, it is not worth the time and the chances of screwing it up are quite high. x2 on formula d regulations, you cannot modify suspension mounting points.

celestialsilviaSep 23, 2010, 5:06 pm · #36
IggyEGuana on 11:26:20 AM / 12-Aug-102010 Formula Drift Rulebook (excerpt)

3.2.1.4 All cars must be equipped with an on-board starter and power supply

as opposed to an off-board starter? hows that work?
RB25sx - SLPRSep 23, 2010, 6:13 pm · #37

Some people tend to get extreme with their modifications - things like alternator removals (lots of drag cars do this) and starter 'delete's - but this would just be a horrible inconvenience with all the push starts and dying batteries.

ericclopeinNov 10, 2010, 3:05 am · #38

okay so i dont know a huge deal about suspension.

i'm going to buy the Canuck lowering springs for my s12. should i replace the shocks too? i would think it would be a good idea especially since the back dives down when you take off. i'm sure i could replace the backs but i dont know how to do the fronts. is it easy? and what kind should i get. i'm on a budget so keep that in mind.

RedneckNov 10, 2010, 3:28 am · #39

You can't really go cheap on suspension with the s12 if you want decent results. The canuck springs are at least twice as stiff as the stock rates and are 2ish inches shorter. For any kind of aggressive driving, especially on rougher road surfaces, the OEM replacement shocks will blow fairly quickly. Currently the s12 only has OEM replacement shocks specifically available for it so we have to retrofit shocks from different cars that fit our cars as well. If you search the suspension threads there is a ton of info on both coilovers and traditional shock/spring combos.

ericclopeinNov 10, 2010, 3:32 am · #40

okay, thanks. im found some stuff since i posted that

ArroNov 10, 2010, 4:55 am · #41

Next time just make sure your title is more to the point of your question, makes it easier for others to search for it later.

ericclopeinNov 10, 2010, 5:13 am · #42

okay thanks.

ArroNov 10, 2010, 5:32 am · #43

ALso, you can always EDIT your thread's title by editing your original post in "Full Edit" and changing the title there. Try it here if you like Wink

lexlaxluxNov 12, 2010, 3:01 am · #44

Tanner Foust has a converted Scion to rear wheel and supra suspension instead of stock. Also modified firewall
check it out they still let him drift.
http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1678/a-look-inside-tanner-fousts-rockstar-scion-formula-d-drift-machine.aspx
So maybe it might be possible to go to FD with swapped subframe?

tommyNov 12, 2010, 3:49 am · #45

They modified the existing rear subframe.... so it's allowed in order to fit the diff... other than that, I guess you have to modify the control arms to bolt different hub, but that is totally within the rules... going from trailing arms to multilink in a S-12 require to use a different subframe (no way around it) so it will always be illegal.... the TC had the stock rear subframe at the right place... the S-12 as it in the wrong plce to use multilink, it's the way the it has been designed, end of story....

sweet16vNov 12, 2010, 6:14 am · #46

Formula D is changing the rules for 2011. Getting rid of some of the grey areas in the rule book. So Tanner Foust's car, Vaughn Gittin's Carbon Fiber Mustang, and a couple others will no longer be allowed to compete. I think if you are looking to compete professionally you will have to design something that uses the s-12s subframe.

lexlaxluxNov 12, 2010, 6:19 am · #47

Thats good that the rules will change. I think its not fair for them to be special while everyone else cant do anything. As for the s12 i think its rear end is pretty good how it is.

s-chassis_onlyNov 16, 2010, 12:56 am · #48

ya im sure you could design a multi link setup for a s12 but would be alot of fab work and such

s-chassis_onlyNov 19, 2010, 7:22 pm · #49

hey eighty six how did you cut the s12 strut and do you have part numbers for the setup ur running and do you have to modify the mounts in the back to mont the top

MaxpowNov 19, 2010, 7:45 pm · #50

Edit the title already jeeze.

Much <3 I just wish mods could like help a mother fucker out. I hates me some spelling errors for searchin'

Moderator Edit
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-J