Suspension Questions

[Astaroth]

Hey guys,

I'm in the market for an R33 gtst and have one in particular in mind.. problem is it's had no suspension work done other than lowered springs so the first thing I would want to do to it is get riding nicely. It's worth noting I'm not interested in an adjustable setup as it's going to to be a road car with maybe some occasional track work, but nothing serious.

I've seen SydneyKid's group buy thread and a couple of other threads here and there but I'm having trouble finding a comprehensive suspension guide.. I'm basically looking for an idea of everything I'd need if I were to do a complete suspension overhaul and (if possible) ball park prices. I'm basically looking for an idea of what I might spend on a suspension package

I'm guessing the list would start out something like this:

Swaybars

Struts/spring combo or coilovers

Control arm bushes

Subframe bushes

Steering rack bushes

Strut brace(s)

but being new to the world of skylines (coming from the cordia the above list covers it all ) I don't know what else is needed. Are there other bushes and bits that you'd do if completely overhauling the suspension?

Ok... some questions for my info.... sorry if these are a bit n00b but they'll help me get a hang of the skyline..

1) Is the rear suspension a strut design like the fronts or independent spring/struts like a trailing arm? I ask because I wonder whether there are strut braces available for the rear and whether they're worthwhile.

2) What's the difference between a coil/shock strut design and a 'coilover'? I've always purchased separate spring/strut combos for my cars but I keep seeing coilovers for skylines at fairly massive prices, so what's the difference?

3) Are nolathane products common and in a skyline what is the compromise between comfort and handling like? Some cars get a really sharp and ultimately uncomfortable ride with nolathane while others just seem to tighten up and still feel nice. And are nolathane bits made for most of the car?

4) Re strut braces: reading SK's Shockabsorber 101 thread I found the following information:

The extra rigidity is necessary because the strut has to not only act as a damper, it also has to stop lateral movement of the suspension. Since R32/33/34 and Stagea have double wishbone suspension, they upper wishbone does that job. All the shock has to do is dampen the spring and chassis movements.

Since the purpose of a strut brace is to try and stop the tower from moving when the strut takes (mainly) lateral force, if the double wishbone setup takes care of this is there any point to strut braces? Or is there still significant force in the direction of the strut that a brace is valuable?

Mmmm that's about it for the moment, sorry for the long post!!

[salad]

Almost everything in SKs groupbuy serves a good purpose, you definitely need to add radius/castor rod bushes to that list. Only thing that doesn't do much is rear strut brace.

1) Rear suspension is a multilink system, lower L arm and 2 upper control arms, with a coil over damper strut. Rera strut braces dont do much as all the suspension arms are connected to the rear subframe and not the strut towers, so flex here does not really affect much.

2) A "coilover" these days is usually a shock and spring combo that is height adjustable and sometimes damper adjustable. It's a bit hard to say, in reality any spring over a damper is a coilover.

3) Nolathane products are fairly common. I'm not sure what the compromise between handling and comfort is as I've never used them, but other people have said that they are faily good for this. Nolathane make a replacement for pretty much every bush in the car.

4) SK is talking about lateral movement down the length of the car, this is controlled with the upper control arm and radius/tension/castor rod. strut braces stop movement of the strut towers towards/away from each other. They are quite valueable and keep camber how it's set as you are cornering hard.

Edited January 17, 2007 by salad

[djr81]

I'm guessing the list would start out something like this:

Swaybars

Struts/spring combo or coilovers

Control arm bushes

Subframe bushes

Steering rack bushes

Strut brace(s)

but being new to the world of skylines (coming from the cordia the above list covers it all ) I don't know what else is needed. Are there other bushes and bits that you'd do if completely overhauling the suspension?

If you inspect the bushes then you only need replace what is stuffed. Your list is comprehensive.

1) Is the rear suspension a strut design like the fronts or independent spring/struts like a trailing arm? I ask because I wonder whether there are strut braces available for the rear and whether they're worthwhile.

The rear suspension is a double wishbone like the front. (ie not a semi trailing arm). On the rear, strut braces aren't needed.

2) What's the difference between a coil/shock strut design and a 'coilover'? I've always purchased separate spring/strut combos for my cars but I keep seeing coilovers for skylines at fairly massive prices, so what's the difference?

A 'coilover' has a threaded shock case & the coil is closely wound around the shock body.

On ordinary shock wont have the height adjustability that a coil over has. In terms of function there is no real difference.

There is a third type eg the bilsteins whereby an ordinary spring is used but the shock body has clips to allow height adjustment in increments.

3) Are nolathane products common and in a skyline what is the compromise between comfort and handling like? Some cars get a really sharp and ultimately uncomfortable ride with nolathane while others just seem to tighten up and still feel nice. And are nolathane bits made for most of the car?

The Whiteline gear is not Nolathane, nor is the Noltec stuff. To be honest it is probably not worth bothering with on a Skyline.

4) Re strut braces: reading SK's Shockabsorber 101 thread I found the following information:

Since the purpose of a strut brace is to try and stop the tower from moving when the strut takes (mainly) lateral force, if the double wishbone setup takes care of this is there any point to strut braces? Or is there still significant force in the direction of the strut that a brace is valuable?

Strut braces work much better on MacPherson strut suspended cars than on Wishbone suspended cars. I would defy anyone to notice the difference in a back to back drive, but they don't hurt & if you want some bling then go buy one.

[Astaroth]

Thanks guys, comments:

2) A "coilover" these days is usually a shock and spring combo that is height adjustable and sometimes damper adjustable. It's a bit hard to say, in reality any spring over a damper is a coilover.

A 'coilover' has a threaded shock case & the coil is closely wound around the shock body.

On ordinary shock wont have the height adjustability that a coil over has. In terms of function there is no real difference.

There is a third type eg the bilsteins whereby an ordinary spring is used but the shock body has clips to allow height adjustment in increments.

That's what I thought - a 'coilover' to me has always described simply a strut setup where the spring is around the shock. Maybe that comes from my old school r/c car racing days I don't really have much use for adjustability and don't really want to spend what I don't need to so I imagine I'll just go with a spring/shock combo rather than single units.

1) Rear suspension is a multilink system, lower L arm and 2 upper control arms, with a coil over damper strut. Rera strut braces dont do much as all the suspension arms are connected to the rear subframe and not the strut towers, so flex here does not really affect much.

The rear suspension is a double wishbone like the front. (ie not a semi trailing arm). On the rear, strut braces aren't needed.

Strut braces work much better on MacPherson strut suspended cars than on Wishbone suspended cars. I would defy anyone to notice the difference in a back to back drive, but they don't hurt & if you want some bling then go buy one.

4) SK is talking about lateral movement down the length of the car, this is controlled with the upper control arm and radius/tension/castor rod. strut braces stop movement of the strut towers towards/away from each other. They are quite valueable and keep camber how it's set as you are cornering hard.

Ok... there seems to be a little conflicting information here. Firstly there's talk of the rear being identical to the front but that strut braces are useful on the front but not the back. If the mechanics of the front/back are the same then loadings would be similar, albeit the rear wheels dont turn as much as the fronts and I'll probably remove hicas anyway... but if this is the case wouldn't strut braces be equally useful or pointless between the front and the back?

Re: the nolathane - I'm particularly interested in nolathane steering rack bushes, I'm a big fan of tight steering (ex go-karter) and am not *quite* so concerned about control arm bushes etc as I doubt they'd serve much purpose... Might consider it though if the price difference is minimal.

[salad]

The front is a double wishbone setup and has 1 upper arm. This upper arm is connected to the strut towers and when the strut towers flex, it affects camber. Adding a strut brace removes most of this flex.

The rear has 2 upper control arms shaped sort of like an A-arm in a double wishbone setup, but they are seperate arms, hence multilink. I think what djr81 is getting at is it is very similar to a double wishbone setup. The rear suspension arms are all connected to the rear subframe which is then bolted to the chassis. Nothing is connected to the strut tower (except the strut) so flex here has no effect on camber.

[djr81]

Yeah, sorry I get lazy & tend to refer to rear suspension as double wishbones when there are inevitably different layouts of the links involved. Probably it's because of the rear wheel steering, but may just be a lack of application on my behalf.

They are fundamentally different to struts & semi trailing arms & in a way the arrangement of the links doesn't make a whole heap of difference. Here is one prepared earlier.

What Salad said with regard to the transference of load to the chassis via the suspension arms to bang on.

Edited January 17, 2007 by djr81

[Astaroth]

ahhh I see now, that all makes sense. If the front upper arm is connected to the tower then the tower would be pretty loaded up, similar to the single arm setup on the cordia where the strut *is* the upper arm, they benefit quite a bit from strut bracing. We'll see how I go - a strut brace is only $200 in SK's group buy so I might go with it. That's not much in three odd grand