progressive springs bad?

[yudalicious]

I have a s14 and have a set of RSR race springs sitting in the room downstairs. When I bought these I was under the impression they are linear, but turns out they're progressive. Right now I'm havng 2nd thoughts because I have heard progressive springs can be unpredictable (can some explain to me more why?)

My options right now are to:
1. keep the RSR, they appear to be high quality and have good reviews
2. sell the KYBs and RSR and go for coilovers (FLTA1us from JIC is being sold for around $900 on group buys)
3. ground controls - although this really isn't that good of an option since for $400, it puts me in the coilover cost range.
4. another brand of linear springs, know any?

So far the only linear springs I know of besides custom and KG/MMs are tanabe's GF, but Tanabe themselvesev said the springs were designed for the SR motor, and plus the spring rate is a bit low for my taste.

[misnomer]

As I've read, progressive springs are essentially a compromise between performance and comfort. They start soft, but will stiffen as they compress at an ever increasing rate (the spring constant. . . isn't really constant :P). Linear springs will still stiffen as the spring is compressed, but. . . linearly. The ramifications of this on suspension could be better explained by one of our gurus.

As far as what springs to get, we need to know what your goal is for the car. Some folks may read about coilovers with some insane spring rate and want them when they'd really be happier with pro kits or H&Rs.

This link will prove very useful to you:
http://www.zilvia.net/f/showthread.php?s=&threadid=7590

Lastly, don't discount ground control, they are a pretty good way to go for coilovers.

[yudalicious]

I know what I want, a spring rate like the RSR of 5/4.2 is just right, not too stiff for the street yet still good enough for weekend track days. I mainly already discounted GCs because they are $400, and with the cost of shocks/struts, I'm almost at coilover price.

I udnerstand the difference about progressive vs. linear, but I want to know more about why ppl consider progressive bad on the track/performance, something about less predictable. Lastly, any personal opinions would be great on what I should do.

[misnomer]

hehe, wow, I personally don't consider 5 kg/mm very comfortable for the street :P I suppose that's where personal opinion comes into play. Maybe I'm just too old for this shit. . .

My main point on the GCs is that with a decent shock, they aren't bad as far as coilovers go. You had mentioned they would price you "near coilovers" when they. . . are coilovers :P But hey, you don't want GCs, that's fine. I don't either.

I'm afraid that's the limit of what I can tell you, since you already know what spring rate you want. . . take a gander at the archives and wait for somebody more awesome to post.

[Var]

It's cause the racetrack has smooth pavement. When you're going at maximum speed you want the linear springs on a smooth road so you can weight trasfer more predictably. If you go left to right with progressive springs there is a mushy spot but you probably wont even notice the goddamn difference cause all track shit is over-rated by average drivers.

[yudalicious]

hehe well put pimp,

anyway there's been talk RSR springs are linear...
http://www.nissaninfiniticlub.net/forums/showthread.php?s=&threadid=48557


I;m just trying to get to the bottom of this. If they are in fact, linear, then great.

[Var]

This may sound retarded but in the pictures they look linear..meaning that every single progressive spring i've seen has a variation in the coil separation. Usually the top(or bottom) of a progressive spring has more distance between coils. Look at tein S-tech's. Then look at RSR Down Springs. Then look at RSR race springs. They Race ones look different right?

http://www.store.yahoo.com/phase2motorsports/losp.html

[yudalicious]

that picture isn't really the s14 spring. They look a whole lot diff. in person. But I think I may have found the answer:

from FA (fresh alloy)

the front is definitley progressive, the rear is linear, although it looks progressive because the spring gets thinner.

But I've taken a look at it, and it sure doesn't look like it gets thinner.