Some Suspension Advice Please.....

[StageaTypeS]

I have a 1999 Stagea Type S. (Manual with GTR rear end)

A few months ago I upgraded the suspension to a set of Greddy Type S coilovers. They fit perfectly just had to have the rear billet strut tops machined slightly to fit.

Driving feels pretty good to me not to rough and quite a nicely damped ride e.g. no bouncing down the road. But I get the feeling that maybe the rear end is a little soft. I am thinking that this is probably due to the R33 GTR rear springs. The spring rates are 8kg Front and 6kg rear.

Is this a bad thing? Is it going to affect the performance of my car much? and can I do something about to solve it e.g. keep the shocks and buy another set of springs with a higher rear spring rate to make the car handle better.

Any comments are most appreciated.

Cheers

J

[Sydneykid]

I have a 1999 Stagea Type S. (Manual with GTR rear end)

A few months ago I upgraded the suspension to a set of Greddy Type S coilovers. They fit perfectly just had to have the rear billet strut tops machined slightly to fit.

Driving feels pretty good to me not to rough and quite a nicely damped ride e.g. no bouncing down the road. But I get the feeling that maybe the rear end is a little soft. I am thinking that this is probably due to the R33 GTR rear springs. The spring rates are 8kg Front and 6kg rear.

Is this a bad thing? Is it going to affect the performance of my car much? and can I do something about to solve it e.g. keep the shocks and buy another set of springs with a higher rear spring rate to make the car handle better.

Any comments are most appreciated.

Cheers

J

The springs rates (both front and rear) are higher than I would recommend, so I doubt it's a rear spring rate issue.

What height do you have it set at (centre of wheel to guard)?

Rear bump stop contact could be the issue if you have it too low.

Cheers

Gary

[StageaTypeS]

The springs rates (both front and rear) are higher than I would recommend, so I doubt it's a rear spring rate issue.

What height do you have it set at (centre of wheel to guard)?

Rear bump stop contact could be the issue if you have it too low.

Cheers

Gary

Thanks for the super fast response Sydney Kid. I believe the measurement from the centre of the wheel to where the guard starts is 33cm. Does this sound correct. The shock still looks like it has some travel left so I don't think it is hitting the bumpstops. If I adjust the rear shocks e.g. turn the hardness adjuster to make the rear harder it does harden up the rear but i still feel as if the rear is sagging a bit of that makes sense.

I have never had a station wagon before so could it be my imagination as I am unfamiliar with driving a car with so much weight in the rear.

I have included a couple of pics that show how it has been lowered.

[ssshonky]

does the car tend to lean over in corners? maybe you need an upgraded swaybar..

SK is teh mastaah when it comes to suspension on stags on this forum - so I am sure you will glean some good bits of info from him

I found the stagea quite wallowy around corners.. we are in the middle of installing bigger swaybars but have not got it quite as flat as I would like - yet.

so just putting that idea out there

[Sydneykid]

Thanks for the super fast response Sydney Kid. I believe the measurement from the centre of the wheel to where the guard starts is 33cm. Does this sound correct. The shock still looks like it has some travel left so I don't think it is hitting the bumpstops. If I adjust the rear shocks e.g. turn the hardness adjuster to make the rear harder it does harden up the rear but i still feel as if the rear is sagging a bit of that makes sense.

I have never had a station wagon before so could it be my imagination as I am unfamiliar with driving a car with so much weight in the rear.

I have included a couple of pics that show how it has been lowered.

The pictures look like around 330 to 340 mm front and 320 to 330 mm rear. Which is too low, 355 mm front and 345 mm rear is as low as I would go if you want decent handling ansd some ride comfort. The geometry of ther Stagea suspension is set up for the standard height, which is around 395 mm front and 385 mm rear. What you may be feeling is the excessive geometry effect, the rear wheels in particular with both camber and toe changes angles being exacerbated by the low ride height.

Try raising in it up see what difference you feel.

At that height it would have been necessary for you to trim the bumps stops, by at least 10 mm. If you haven't done that, then what you may be feeling is rebound back off from the bump stops when the suspension travel required (to absorb the impact) is greater than the available travel. The bump stop rate is typically 10 to 20 times that of the spring rate and the shocks simply can't dampen that sort of change in rate. This feels like inadequate damping.

Try raising in it up see what difference you feel.

As for the roll problem mentioned by ssshonky, by reducing the ride height so much you have lowered the roll centres (CoR), particularly the rear, to below ground level ie; around 150 mm from standard. But you have lowered the centre of gravity (CoG) by only 60 mm. Hence you have increased the Roll Couple (RC) by 90 mm or so. A larger RC means more roll, so what you may be feeling is more body roll in corners caused once again by the excessive lowering.

Try raising in it up see what difference you feel.

Cheers

Gary

[Tangles]

350mm front and rear is a nice setting

coupled with adj.swaybars and its a very pleasant ride.

[StageaTypeS]

Thanks for the advice, I think I will get my car raised to 350mm (Centre of wheel to guard) and a new alignment and see how it drives then.

Also I am interested in the whiteline swaybars. Will they fit my car being that it has a gtr rear end? Also I have had a look under my car and I can't see any sway bars there at the moment should there be some?

Sorry if these are dumb questions, I don't know much about suspension.

[wolverine]

you already have a hollow 24mm rear sway bar on a RS4S so the whiteline upgrade isn't as large as the auto guys are getting (??19mm solid??).

the whiteline bar is 24mm solid so SK may be able to give you the difference in rate from hollow to solid. just from memory it is about 20% but don't rely on this number.

the amount of roll in the RS4S is much much less than the autos. the ride height seems to be the issue.

i have just changed the ride heights again. i now have 352mm front and 358 ish rear. we don't have enough rear camber adjustment at that height.