S13 rear subframe, 5 lug, brakes, diff questions

[MELLO*SOS]

So my s13 rear subframe has been tweaked for months now, shit's gotta go. Someday in the near future, aka, my winter project is:

• Replace my rear subframe
• Go with solid subframe bushings
• Go 5 lug at the same time
• Upgrade the brakes to larger caliper.
• Keep cable e-brake if possible... Otherwise step up to hydraulic
• Add rear multilink
• Go to 4.4 final drive
• Goal: Keep/Re-use my 2way s13 non-vlsd/non-abs Kaaz
• Goal: Keep/Re-use my s13 coilovers
• Goal: Minimize labor & costs, do most of the work out of car and install as a unit.

I've just recently started researching this project, so help me out here! My ideas so far:

Option 1: Pick up a junkyard s13 subframe, some s14 hubs, Z32 brakes (ebrake hassle), bushings, rear multilink, 4.4 r&p. Install FD into and swap over my pumpkin/kaaz. Possibly the cheapest option and less Frankenstein than my other idea(s).. Rather not go hydraulic ebrake just yet, but am highly considering it if necessary .

Option 2: I think an R32 rear subframe bolts to s13, can anyone confirm this? If so, I could source a complete r32 rear: subframe+diff+axles+arms+hubs+rotors+calipers. Add bushings and multilink (s13 and r32 rear arms are identical??). afaik The GTS/GTS-T's (non GTR) came with 4.4 R&P and I believe it's also an r200 housing, but it has 5 bolt output shafts iirc. Can I swap my Kaaz into the new pumpkin? Would the driveshaft length still be correct? I believe I would probably also need rear HICAS eliminator.. This is the way I'm leaning, but it sounds cobbled together and frankensteinish... Also not sure about the diff or coilover re-use issue.

Option 3: Does the s14 rear subframe bolt into s13? If so I could probably find one complete with 5 lug+brakes+open diff, add bushings and multilink, source 4.4s and swap my pumpkin. Similar to option 2, but swap my kaaz across... Shelved for now I'm interested in a bolt on solution, not something requiring fabrication

I know a couple of you guys have done similar upgrades, so any help or input would be appreciated... I'm open to the other ideas as well as long as they meet most/all of my goals above. Thanks guys

[projectRDM]

S14 subframe is wider, you'll need to either make (or buy, someone had some) offset bushings to line up to the mounting studs.

[MELLO*SOS]

Thanks for the quick reply, wasn't aware of that fact. I'd rather not have to fabricate anything if possible so I'll shelve the s14 subframe option for now. Any input on the r32 subframe?

[projectRDM]

I've seen a lot of them but never measured. Someone else needs to get on that question.

[MELLO*SOS]

Alright... Just doing some more research on this and found a couple links I'll share since I don't see another r32 subframe->s13 thread here on zilvia (pls link me if u know of one).

FWIW, according to user Karay240 on Hybridz.org, the r32 is a direct swap for the s13 and is stronger.

Originally Posted by Karay240

Actually, the R32 subframe is not the same as the S14 & 15. The 32 subframes are a direct bolt-on for S13, but stronger (reenforced). The S14 & 15 subframes are not identical, but are interchangeable, as with the R33 (& I THINK the R34) subframe.

R32 rear subframe pic:



Here's another page (written by our own Slidin240Wayz/Carlos) that mentions R32 subframe onto S13.

It brings up but never addresses my 2 concerns, rear lower shock mount (need z32 coilover bottoms?) and ABS driveshaft/pumpkin differences. If anyone has input on these two issues I would like to hear.. Carlos?

[SILEIGHTY_DET]

you can see that it has the s14/15 style rear diff mount . as for the diff placement , you would have to measure .

[Slidin240Wayz]

I would try the R32 setup.

I don't have concrete information, but it is worth a try.

S14 and R33 are interchangable.

If you get the R32 rear subframe, make sure it's non-hicas.

Also, you can use S13 rear uprights on the R32 rear subframe, if the spindle hole matches the axle.

Carlos

[projectRDM]

Exactly. use S13 uprights or press the HICAS ball joint out and press a bushing in it's place.

[Bushido]

i believe you can add the s15 subframe to your list as well.

[Irukandji]

Yeah, s15 goes on s13.

[Dousan_PG]

dont do r32
i know some folks who did it. rear end is WAY too stiff
go the s15 route
its a great setup and its realtively easy
can make offset solid bushings or squeeze the stockers on

i used to have one
everything is bolt up
use s13 rucas
and everything else s14/15 (spindles dont matter nor hubs)

its sweet
good old days

[lflkajfj12123]

Excuse my noob question, but whats wrong with it being too stiff? What kind of problems would that cause?

[Dousan_PG]

easily over rotates
you find when u take ur car on the track
u dont want super over steer
its just stupid and annoying

GRIP is what u want
drifting road race you want GRIP

[MELLO*SOS]

Thanks for the replies!

Do you prefer 4.6 or 4.3 for the KA?

[racepar1]

Originally Posted by Dousan_PG

easily over rotates
you find when u take ur car on the track
u dont want super over steer
its just stupid and annoying

GRIP is what u want
drifting road race you want GRIP

I come from a road racing backround and I don't get it either. Stiffer chasis = better, period. If stiffening the rear causes it to over rotate then you need to dial in your suspension settings. A stiffer chasis is more responsive and more consistent once you dial it in. Right? It is all about development of the car. Anyone who thinks that you can just throw parts at a car without taking the time to set the car up to YOUR preference is sorely mistaken.

[Dousan_PG]

u know anyone who has run it 1st hand on a s13? i do.

stfu

get serious


for a KA? i like 4.3 all around on SR too
but i migth be picking up a 4.6 to give a try
now that i trailer the car i wont mind it. daily or going to track driving 4.6 is nutso.
but for the track..might give it a whirl.
my buddy runs it on his FD car now w/ stock trans (before an OS) and seems to really enjoy it. gotta see what he thinks of it lately.


anywyas
i really enjoyed having the s15 member
i would suggest that one for sure.

[racepar1]

I thought stiffening the chasis was serious. Also if a stiffer subframe isn't better then why would JUN make one? I think they know quite a bit more about how to set a car up properly for grip then you do. Your friend didn't have the right set up for the extra stiffness, PERIOD!

[Dousan_PG]

JUNs racing subframe reinforces the subframes and they dont make on for s-chassis.

the s-chassis subframes are for drag racing.

[racepar1]

Originally Posted by Dousan_PG

JUNs racing subframe reinforces the subframes and they dont make on for s-chassis.

the s-chassis subframes are for drag racing.

I saw one on RARE TRICK. I have been thinking about it though and there is on other possible difference that could cause excessive oversteer. It is possible that the skyline has slightly different geometry in the rear (most likely more anti-squat). That could cause such a problem, but I don't even know where to find the answer to that question and the silvia platforms already have a ton of anti-squat.

[fro20]

1st, why do you think you need to go hydralic ebrake? Z32 ebrake conversion is simple. Second, buy my s13 subframe with aluminum spacers already installed.

I could see the stiffer rear subframe being bad for a street car. It wouls also be bad if you did not equally or at least somewhat stiffen the rest of the chassis in relation to the rear.

If you have a stiff rear portion of the chassis and the rest is prone to torsional flex, then the whole balance of the car is out of whack. Decreasing torsional and lateral flex only in the rear and not the rest of the car would make it suck at handling theoritically.

If you dont get what I am saying, just think about it for a few minutes and it will make sense.

Stiff chassis offers great feedback and more precise handling and control when done properly.

Now throw in the r32 sub, do the cusco tension rod brace, Kansei service chassis brace that goes behind the motor under the car and a strut tower and you should be good, as well as tension rods. To make this even better do the Nagisa frame rail braces( to directly link torsional flex like a sway bar from the front of the car to the back applying force upon itself to counter act the flex) and shock tower braces, then damn. Torsional and lateral flex would be mad reduced, appropratly.

[racepar1]

Totally, 100% agreed ^^^^^!

[MELLO*SOS]

My car has a cage and fender braces, doing strut towers bars and stich weld in the future. Thanks for the ideas for added torsional rigidity.

At this point I'm leaning toward a cheap straight s13 subframe locally, they're like $50. What makes the s15 subframe superior, is it just newer and stronger or are there mechanical advantages? Also does the S15 subframe require much fabrication to install?

[hijack3d]

Not meaning to thread jack/step on toes but trying to help a fellow 240sx owner... I'm going to Vegas for Thanksgiving weekend, and am selling a rear subframe. If you like, I can bring it with me.

Also, IIRC.... if you want to go w/ the S14 hubs (for 5 lug?) and the Z32 e-brake conversion, you might consider using the Z32 rear hubs instead of the S14, since there's a bracket you'll need to modify if you're using the S14 hubs, whereas the Z32 wont require this.

[MELLO*SOS]

Thanks for the reply, sent you a PM hijack3d

[racepar1]

I'd just get an s-13 subframe and brace it, that's what I am going to do with my spare subframe. Sounds like you are on the right track to me. By the way, how did you manage to bend your subframe?

[fro20]

Originally Posted by mello88

My car has a cage and fender braces, doing strut towers bars and stich weld in the future. Thanks for the ideas for added torsional rigidity.

At this point I'm leaning toward a cheap straight s13 subframe locally, they're like $50. What makes the s15 subframe superior, is it just newer and stronger or are there mechanical advantages? Also does the S15 subframe require much fabrication to install?

Dont waste your time with a stitch weld. I just got into a big debate about this. The more I research the more I find this is a waste of time=money. The stitch welds make no real gain in rigidity, the only people that need to do it are works teams that strip all the seam sealer/weld to take out the extra 20lbs of crap and then need to stitch the panels backtogether since their is no more seem sealer. Spend your money on bars, making bars to connect your frame rails, get all the Nagisa braces they make, strut tower to firewall connectors, fender braces, tunnel braces, Kansei service bars,cusco tension rod connector, cusco rear triangulated strut bar, custom make a triangulated front strut, and a 4pt cage if it is a street car.

FOR A STREET CAR DO NOT HAVE THE FORWARD BARS IN THAT GO ABOVE YOUR HEAD FROM THE B-A PILLAR. tHE S CHASSIS PUTS YOUR HEAD AN INCH AWAY FORM IT AND IN A CRASH YOU ARE F'D. THATS IS WHY I PULLED THE FRONT BARS FROM MY SAFETY 21 CAGE FOR STREET USE AND PUT THEM IN FOR TRACK USE

[racepar1]

Originally Posted by fro20

Dont waste your time with a stitch weld. I just got into a big debate about this. The more I research the more I find this is a waste of time=money. The stitch welds make no real gain in rigidity, the only people that need to do it are works teams that strip all the seam sealer/weld to take out the extra 20lbs of crap and then need to stitch the panels backtogether since their is no more seem sealer. Spend your money on bars, making bars to connect your frame rails, get all the Nagisa braces they make, strut tower to firewall connectors, fender braces, tunnel braces, Kansei service bars,cusco tension rod connector, cusco rear triangulated strut bar, custom make a triangulated front strut, and a 4pt cage if it is a street car.

FOR A STREET CAR DO NOT HAVE THE FORWARD BARS IN THAT GO ABOVE YOUR HEAD FROM THE B-A PILLAR. tHE S CHASSIS PUTS YOUR HEAD AN INCH AWAY FORM IT AND IN A CRASH YOU ARE F'D. THATS IS WHY I PULLED THE FRONT BARS FROM MY SAFETY 21 CAGE FOR STREET USE AND PUT THEM IN FOR TRACK USE

I don't agree with your opinion on stitch welding. I stitch welded my whole front end and it made a huge difference. You definitely don't wanna do the whole chasis though. Do it strategically. Do the front end, rear strut towers & fenderwells, and the frame rails. The rest of the car you can basically ignore, especially if you have a cage and all the basic bolt-on braces. If you really wanna stiffen the fuck outta your chasis look into structural foam. It is messy and time consuming, but will net huge gains in overall stiffness.

[Rayne]

Originally Posted by mello88

My car has a cage and fender braces, doing strut towers bars and stitch weld in the future. Thanks for the ideas for added torsional rigidity.

At this point I'm leaning toward a cheap straight s13 sub-frame locally, they're like $50. What makes the s15 sub-frame superior, is it just newer and stronger or are there mechanical advantages? Also does the S15 sub-frame require much fabrication to install?

Here is some information I found while doing a web search:

"The geometry allows your car to have the correct roll center 2" below stock S13. The track is 10mm wider, the arms/sub-frame are reinforced, and is designed for less squat."

As for modifications...I believe all you need is some off center bushings.

[MELLO*SOS]

Thanks for the help everyone.

Ended up going S13 subframe, SPL solid bushings, Z32 ebrake/hubs/cables/calipers/rotors, ??? Mutlilink (not bought yet), SPL pineapples, SPL conversion lines, Hawk HPS pads. Keeping the stock R&P for now.

Anyway now my question is, where the hell can I find solid or poly diff bushings? SPL doesn't have them on their site and I forgot to call in before I placed my order with them.. Does Energy Suspension even make them? Their kits for s13 seem to be missing them....

[Dousan_PG]

because s13 diff is solid mounted to the subframe
no need for them.