S13/S14 subframe vs T3

[260DET]

TechnoToy and Arizona Z both make great rear end stock improved setups, both specialise in race orientated parts for older cars. Either would be a far better option than messing around with a S chassis rear end, they bolt in simple as. As a foreigner it makes me wonder how come these specialist American suppliers probably sell more to people like me than Murricans, they never get mentioned on this forum.

[260DET]

To elaborate, you won't be able to get the S chassis subframe high enough without extensive and expensive body modifications. Of course it can be bolted in easy as but what about being able to use the new suspension at it's correct OE alignments? Unless you want a high arsed car the suspension will have to be lowered way past it's preferred alignments which means the performance advantage of the S chassis is lost.

 

The lesson is, if you are serious, improve what you already have.

Edited April 14, 2017 by 260DET

[jthom5147]

Attached are some drawings of the s30 undercarriage and 240sx subframe hard points overlaid at 240sx factory ride height and my Z's current ride height with axle position overlapping as reference. My brother did most of the drawings for an iterative project feasibility study I hired him for.

 

You can tell the front RLCA mount is directly in the S30 frame and the upper traction rod is deep within the z tool compartments.

[TUME]

Those drawings seems to be right. Here is pic how much it takes to modify chassis to take S13 subframe. I had to modify little bit of those frame rails, also, to make room for control arm attachments.

 

It´s pretty easy to found right height. Just mount rear mounts to level with rear frame rails and keep upper arm (camber and traction) attachment points to level.

[jthom5147]

We're looking into significantly narrowing the track to bring the s13 hubs closer to the Z hubs and see where the mounts fall inside the body.

 

the OE subframe would get ditched and replace for a two-piece weld in rear tube frame integrating the mount points. The main lower hoop would be welded in first to reinforce the chassis, cutting out the tool compartments, and then welding the upper hoop. Finish with sheet metal repair and a full cage which will tie the chassis, cage, and new subframe together.

[jthom5147]

I should add that on our models, it looks like that a 3"-ish per side narrowing will allow the RLCA to clear the existing Z frame U-channel which you cut out and rebuild.

[260DET]

There are dropped spindles available for a S chassis transplant which will help to overcome the height disadvantage but, as I keep saying, for the S30 there are better options. 280ZX and Z31, yes, the S transplant works well if done properly. For a bit of a reality check the video, S30 standard type suspension.