Jump to content
HybridZ
grayson260z

S13 Rear Subframe upgrade for 260z

Recommended Posts

grayson260z    0

So I came across a hell of a deal on an s13 rear sub frame and ended up picking it up for $10 :icon14: ! I've seen a few threads on this topic so don't think I haven't done my research it's just that they were all older threads and I didn't feel like resurrecting it from its hibernation. Now a few of my buddies told me that it should bolt in with little to no modification/fabricating. I know also then you could run more recent brakes (Z32 all day baby) and also have an easier platform to a 5 lug swap and better differentials. Some insight on if this will work and if it will the steps it would take. Thanks guys! - Grayson

Share this post


Link to post
Share on other sites
AkRev    0

Well, its not a bolt in modification, you will need to fabricate all four subframe brackets. I have a S14 subframe on the back of my 78 280z 2+2. Due to the fact mine was a 2+2 the forward mounts for the subframe worked out under the back seat. The trailing two mounting points are about two inches back and three inches to the center from the mustache bar mounting points. The main got ya with this swap was getting the diff to line up and getting the traction rods mounted (they are in interference with the rear frame support)

 

That is a great deal to get it for 10 bucks.

 

I have had a chance to drive mine a bit, the main difference I can report on is that the S13/14 subframes have bump steer. Car feels very modern with respect of going around a corner. Mind you, it was a lot of work and the only reason I did it is because the previous owner started the process, hit some roadblocks and ran out of time to finish it. 

 

If you are set on doing this swap send me a pm and I will give you things that will help you out.

 

 

Good luck

Share this post


Link to post
Share on other sites
AkRev    0

I took a stock 280z for a drive shortly after I posted that. There was a huge difference between the two with regards to comfort and ease of cornering. I was very pleased with how it turned out. Before, I would have said not worth it, but I think a fresh reminder from the stock 280z was quite enlightening. As I said before, the bump steer in the s14 subframe is a tremendous benefit and defiantly makes the back end of my Z feel more stable over bumps in the road.  

Share this post


Link to post
Share on other sites
johnc    724

Without knowing condition of the stock 280z rear suspension and the condition of the 240sx rear suspension that you installed, the comparison is not valid. Yes, a multi link is inherently better at locating the rear wheels and maintaining proper alignment over the range of suspension travel. But the rear suspension of the S30 is pretty good and can be made a lot better for under $1,000.

Share this post


Link to post
Share on other sites
AkRev    0

Very true. To further add to John's point the stock 280z did need some work, and it was not a 2+2 like my car is. Also keep in mind my style for comfort and feel is not like most on here (My other car is a 56 Ford Fairlane, and I love driving it and I think it is one of the most comfortable cars for joy riding around town.) 

 

I don't have track times or any numbers to back my feelings. I am just building my car to my tastes and feel. I am tall and have little room between my head an the roof of my 280. I like when I hit a pothole, with the way my car is set up, my head stays relatively still. Sadly, I do remember always hitting my head on the side of the roof back when it had stiff springs on the stock suspension.

 

To further drive home the point. I would not recommend anyone subject themselves to the pain of doing this for the thought or hope of a faster car. The amount of hours of math, cussing, welding, cutting, grinding, and measuring took its toll on me to the point I didn't touch the car for a year because I lost my motivation.  

 

That said, Thank you for pointing out my previous post John. Hopefully I am not encouraging some to hastily go out and buy a 240sx subframe with the hope of achieving something not advertised.

Share this post


Link to post
Share on other sites
grayson260z    0

My only true desires to do this is the want to JZ swap it this summer. I admit I haven't really researched alot on the rigidity of the 260z rear end but it seems like problems would become known very fast if one were to put a fair amount of power to the rear wheels. It wouldn't hurt my feelings one bit to sell the thing but i feel like it can and will work excellently. I'd really like to see some pictures of the subframe installed in cars. (Coupes if possible)

Share this post


Link to post
Share on other sites
Daz    0

The s13 subframe was fairly easy to install. I did it on my 260z. *also running a 2jz gte vvti with a z32 trans. I will post some pictures later so you can see.

I'm getting ready to do this swap too ! Thanks for the pics, if you have more please send them to me or post them.

Share this post


Link to post
Share on other sites
G-E    3

I make a couple of kits for the Z31 people that may be relevant:

 

A subframe swap kit, with hardened pins pre-welded to some brackets, they get bolted into the subframe, raised into place while you cut away everything on the car to make things fit. The work is not really hard, just extensive and expensive after all the arms, driveshaft, diff etc are totaled up. Most swaps run well over $2k in my experience, usually close to $3k

 

http://responsetype.com/shop/gazelle-s12/subframe-swap-kit-2/

 

And a Z32 upright to S13 style coilover adapter, which will let you re-orient the strut axis for better placement

 

http://responsetype.com/shop/silvia-s14/aluminum-upright-strut-adapter/

 

The toughest part of the swap is always notching and patching the body, there's numerous places where things almost fit, then you clearance for the subframe, only to realize you can't reach a nut.

 

Same goes for re-inforcing the subframe itself, you do that AFTER everything else fits so you know where you can add braces. Don't modify and powdercoat it off the car...

Edited by G-E

Share this post


Link to post
Share on other sites
tube80z    17

Here is some pics about my swap. I wouldn´t say it was easy, but there is many ways to do this. As we can see....

 

It looks like if you modified the stock 240SX cradle this would be easier to do.  I'm guessing there's an opportunity for an enterprising individual.

 

Cary

Share this post


Link to post
Share on other sites
TUME    10

It looks like if you modified the stock 240SX cradle this would be easier to do.  I'm guessing there's an opportunity for an enterprising individual.

 

Cary

I thought that too, unfortunately it came in my mind too late. 

I did little modification on my subframe afterwards, lowered LCA front pick-up point to reduce anti-squat. After that i noticed there is unnecessary notch in my chassis because of that... :wacko:

 

When I was saying there is many ways to do this modification, I meant mainly suspension geometry. If you want decent roll-center and low car you must install subframe deep in your car. It means lots of metal working...

Edited by TUME

Share this post


Link to post
Share on other sites
grayson260z    0

the rear most mounting points for the subframe look easily done with just that bar across where the spare tire well was. Correct me if I'm wrong of course though. the front if im seeing it right goes into the lower mounting "hole" for the bottom part of the seat belt. That area on ours was pretty rusty though. I'll try to get back to the shop here soon and reevaluate the subframe. Thanks for the replies!

Share this post


Link to post
Share on other sites
TUME    10

the rear most mounting points for the subframe look easily done with just that bar across where the spare tire well was. Correct me if I'm wrong of course though. the front if im seeing it right goes into the lower mounting "hole" for the bottom part of the seat belt. That area on ours was pretty rusty though. I'll try to get back to the shop here soon and reevaluate the subframe. Thanks for the replies!

U got that right, sir. Here is a poor pic inside car. As you can see, seat belt rollers can´t be there anymore.

post-3341-0-59081700-1429047730_thumb.jpg

Share this post


Link to post
Share on other sites
RPS30.Drvr    0

 

the rear most mounting points for the subframe look easily done with just that bar across where the spare tire well was. Correct me if I'm wrong of course though. the front if im seeing it right goes into the lower mounting "hole" for the bottom part of the seat belt. That area on ours was pretty rusty though. I'll try to get back to the shop here soon and reevaluate the subframe. Thanks for the replies!

Yes the rear part on a bar near where the spare tire was pretty easy.

Rear suspension, Rear mount

rear mount location

 
Yes right in the seat belt retractor pocket. I cut mine out.

Rear suspension front mount

 

 

Edited by RPS30.Drvr

Share this post


Link to post
Share on other sites
grayson260z    0

Not to kick a dead horse or anything but what are you guys running in the coilover department? I swear until now I had never looked at a coilover for a 240sx and just assumed they shared the same top hat bolt pattern as our cars. I'm kinda iffy on saying the s13 and 14 are the same but I know the s14's use 2 bolts on the rear top hat whereas the Z takes 3. Is this solved by using a Z top hat on the 240sx coilover? Also on the topic of length. I have figured out that the s13 rear is much taller than a 14 so without having some to test fit I really have no idea which model I'm going to need to go with. I do know however that I'll be using s14 coils in the front to go with the s14 spindles so I don't have to widen the holes. Thanks guys for all of this information so far and hopefully some of you are still around almost a year later.

Share this post


Link to post
Share on other sites
TUME    10

Agreed, go with S14´s. MIne is S13´s and I had to cut down strut tower. Also made new hat on it, so i get those S13´s upper mounts to suite. 

 

It´s worth to ask, if they (BC) swap upper mount´s. I get mine with Z32 bottom mount by just asking.

Share this post


Link to post
Share on other sites
Star08    0

I need more information about this. I've seen rolling280z car on a mini clip on YouTube. Car looks awesome. I'm trying to see what people are doing for shocks in the rear when using the S13 IRS. Also what's the smallest wheels size you can use, when using Z32 30mm calipers. What about fuel tank /cell.... Anyone here on IG? Getting ready to do this soon on my 76

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×