just wonding what are the real advantages of going full 4/5 link over a 2/3 link setup like wat most 4X4s run, ie 2 lower control arms that had a bush and the front and back of the diff to eliminate the need for upper arms. and it would also have a panhard or watts link obviously

the reason i ask is that in the wagon there is no room for upper arms without cutting a chanel into where the back seat would go...which cant happen whilst keeping the seat as its fold up and has a metal bottom
and i wouldnt mind having coil rear end so that i can have it a bit softer without worrying about tramping

as it is the car will probably only have a coupe of inches of really usable travel so its not like the change in diff angle will really be that much

but yeah, just thought i'd throw it out there for discussion...so...discuss

I have no experience of it specifically in datsuns, but I can tell you that I've run a bunch of early (lc/j) toranas with 9 inch diffs and nothing more elaborate than boxed arms on the factory 4 link, and with similar power torque, without exception, they have all launched a lot more predictably/smoother/harder than any of the chargers I've had (I've only had 3 of them by contrast to more toranas than that octomum has had kids) over the years. They also tended to be more predictable out of corners (and that's a hard thing to quantify as obviously they are very different cars indeed, but what I mean to say was the better attached the diff, the more predictable it was out of a corner - i.e. the charger with leaves was far more likely to skit about when cornering near the lateral limit and power was fed in.

pure speculation to follow - I think that with an NA a series engine, you'd probably get away with just a watts link, or even a panhard rod if it fitted in a lot easier, but that it wouldn't be critical. For dragging, with a force fed 'whatever' in the engine bay, you'd probably do better with anti-tramp bars (and there's not too many I like - I have seen a triangualated bar on an escort that worked well, but would affect ground clearance. The ones that aim their force near the eye in the spring (to directly oppose the direction it wraps up into) should help reduce fatigue/damage to the main leaf, but I just don't have enough practical experience with them to make a decent comment.

thanks, got tramp rods on the sedan...but yeah they hang down a fair way so they arent the best thing. and i would have to remake the mounts for the wagon anyway

but yeah mainly wanting the know the difference between 2 link and 4 link with coils...leaves will be pissed off one way or another eventually

caltracs are the go
http://www.hotrodsandhemis.com/Traction.html

4 link and 2 link(ladder bars)
1) your upper shock mounts are not designed to take the weight of the car
2) you will need a crossmember for shocks
3) you will need a crossmember for lower front link ends
4) you will need a crossmember for upper front link ends (4 link only)
its a lot of work and re-engineering to do well. the caltracs are a huge improvement to a leaf rear end and dont require any cutting and are therefore still legal (and removable)
dazza

yeah but ive got a setup like that already....but it is really really low

strengthening isnt really that much of a worry

With a 4-link you can engineer into it "squat" and "anti-dive" geometry and so increase power transfer to the ground. 4-link is used by most modern sedans, including the Datsun B310. The better class of sedans use double wishbone geometry which is useful for improved lateral stability.

you said theres no room for upper arms?
go the ladder bars then
BUT the car may not be making enough power to need them and caltracs are cheap(ie:homemade)and removable if you decide to go ladders later
just to confuse you even more have a look under a gemini (2 link w/ a torque tube)
and ive seen heaps of hq's and toranas w/ boxed arms tear the mounts out of the floor pans. sometimes its good to have a weak link (fuse) so long as you keep a real close eye on them.
i know on my freinds race car (blown BBC full chassis car SC/O) moving the 4 link one hole radically changes the way the car launches. you really need to do some serious calcs to get a 4 link to work the way it should but when its right they are the best
dazza (keep in mind my area of expertise is drag racing only)

Sunny sedan has a 4-link suspension and a back seat. Depends on how you engineer the 4 links.

if i was to do it i'd be beafing up the mounts a fair bit obviously....and im doubting the CA will have the torque(or traction) to rip any mounts out

so the fact that the pinion angle wont change as much during the suspention travel is the only thing thats really different
coz adjustment of the pinion angle could still be done at the diff with 2 link

oh and yeah have had a look under a gemini once or twice...mmm yeah nah

and yeah lots of cars have 4 link and a back seat, but they also have alot more room under there to make that possible
whereas in a 1200 you have #OOPS# all room to fit anything

theoretically (i.e. a guess on my part) the gains from consistant pinion angle aren't massive, it's rather that the way the pinion angle 'goes bad' on a leaf sprung setup is because the leaves are twisting, and then it has a sort of ocillation (not to memntion axle tramp) that makes it hard to optimally plant weight from rearward weight transfer - so it stuffs up the maximum potential launch/acceleration as far as traction itself goes.

As much as I like the coil sprung 4 link setups on paper, I don't think that there would be quite enough advantage (over a leaf sprung with added anti tramp devices) on a setup like this to warrant the extra work/complexity of going to a 4 link. If it was something like a 2jz conversion in a drag only car, for sure you'd go beserk on the rear end. It's just probably not quite warranted with this (and to be fair, a ca18det will without question flog the pants off most streeters.).