After doing some research, the S13 suspension, front and rear are a better design than the
S30, s130, and z31.........for performance.
All are more than adequate for street driving but one needs to make the S130 and Z31 rear suspension overly stiff or limit it's movement to combat excessive toe and camber change.
It's been done and the cars do respond........in a racing type situation but you sacrifice the comfort that made the cars popular to begin with.
The S13 front suspension is better in that it enjoys a near zero scrub and again.......it is plentiful in the junkyards of america.
The S13 rear suspension has better articulation and enjoys more adjustability in stock form than the S30, S130, and Z31 but it's not always a gain but fitting this suspension to other nissan models could net one a lot of cutting and welding.
Now the Z32?
It's suspension has superior articulation in both front and rear but I spent many years replacing the upper control arms after on cars that had relatively low mileage because the control arms get hoggeed out from driving in most any conditions that feature bumps and potholes....or dirt roads.
It's also ten times the work to fit that front suspension to another car because of those upper control arms.
Even though the s30, s130 and Z31 dont' have a zero scrub in the front, the Z31 has less than the s30 and s130 mostly because it enjoys a different wheel offset with the S13 being near zero scrub.
One reason to consider newer rear suspension such as the S13, S14, or Z32 is the available differntials.
There are a higher percentage of R200s out there with any sort of LSD in the short nose form than there are in the r200 long nose.
Of course, there is also the R230 found in Z32 turbos and some V8 infiniti cars but the R200 in 4 pinion form has proven strong enough for any but the craziest drag car.
For me, my current project is a M30 which uses S130 style rear suspension with a R200 that is a rare "extra long nose" in that it has a sensor for the abs in the nose which makes it near an inch longer.
If I go through all the hassle of making a one-piece driveshaft for that car and the diff fails, I may not find another easily meaning fitting a long nose and getting the driveshaft shortened.
Fitting the S13 rear setup would get me differential dimensions that are more common and the mentioned availability of LSD is more common.........plus you get a bit more adjustability and toe/camber control in stock form meaning softer springs can be used while still getting good performance.
Even though I took offense to racepar's quip about the Z31, this thread did prompt some research that will help me in the end so I am cool with Racepar and thank him for getting me moving on this.
Back to discussing RB engines in the Z31.......
The Z31 and any left hand drive nissan were never intended to use that engine so no consideration was made for fitment so...........you usually find steering shaft or the rack itself in the way when fitting different engines as well as needing crossmember mods to make everything fit.......and usually a custom elbow/downpipe or downpipes in a turbo application.
The N/A crossmember of the Z31 seems to be a better starting point because it's pads are not skewed like the turbo crossmember but maybe you could use the clearance afforded by the skewed mount pads on the turbo crossmember.
The RB setup is best fit as a engine/transmission unit together because the Z31 stock setup has the tranny bellhousing between 6 and 7.5 inches hanging into the engine bay while an inline engine like the RB cannot sit that far forward because it just won't fit that way.
For some reason nissan also had hung the VG30DE and DETT way out front about the same amount even though they don't have the intrusive crossover pipe.
Racinjitter's setup is a good template to follow and he did a good write-up which is more than adequate to help someone else do the same.
One thing when considering these swaps is shifter location. The availibility of RB versions of the FS5R30 tranmissions is low in the US and there are at least 3 different shifter locations in that tranny found in US market cars.
Pathfinder v6 two wheel drive is the shortest at 27 inches from bellhousing to center of shifter shaft but you can find them for 150 bucks at a u-pull junkyard.
The Z31 version of the FS5R30 tranny, if I'm not mistaken, has a bit more distance from bellhousing to shifter shaft while the Z32 is far and away a lot longer in that it has the shifter actually hanging behind the tranny on a sub assembly.
Which is best for you, is up to the engine choice but I don't know the measurement of the RB tranny from bellhousing to shifter..........it might be the same as the pathfinder somewhere between the Z31 implementation and the pathfinder........which would make it 4 different lengths for the same tranny......I just don't have that measurement.
For my application, 29 or 30 inches distance would be ideal and I'll guess the RB application of that tranny would fit better.
If you make over 400hp, the FS5R30 is almost a must.
The bellhousings can be swapped from application from application but it's a bit involved and that tranny was never intended for any L series engine.
You can see what's involved in Austin Hoke's Z32 to L engine adapter thread or the thread for the mazworks adapter at hybridz because his adapter for the L series requires the bellhousing to be removed for machining.
http://forums.hybridz.org/showthread.php?t=113143
Then you have tailshaft length differences with the pathfinder being the shortest but that dimension only impacts driveshaft length and you would already be having one made a custom length anyway.
There you go hypertek.