Black91n/a

Hey All, It’s a little long, so bear with me.

I was doing some looking around on the net and I came across some springs for FC’s that I'd never seen before. They are the following:

Make Model Spring Rates F/R Lowering F/R
Tanabe GF210 168/140 1.5/1.5
RS-R Race 335/224 1.2/2.0
RS-R Down 201/123 1.4/0.8

Firstly, how low can you go before you have to start buying adjustable suspension pieces?

I like the RS-R Race springs as I think that the spring rates are good (very close to the Ground Control standard rates for FC, and I think the stock rates are too low). The only problem is the drop in the rear which seems excessive to me. Does anyone know if they actually drop the car that far? I’m not looking for a pavement pounding show car, I want a setup that I can drive every day and kick *** with at the track (road course). With those spring rates (F/R bias) will it tend to oversteer or understeer, and how stable will it be at high speed (i.e. is it good for auto-x, or road race)? I remember seeing someone post about spring spacers (bolt in metal pieces that go between the upper mount and the spring), but searching turned up nothing. Does anyone know if there’s a place where I could buy some spring spacers to bring the car up to a level that would not compromise the alignment, or would I have to get some custom made($$)? Oh, and are they safe?

Can anyone who has any of these springs on an FC please post your experiences. The RS-R race ones are the current favorites, but I like the specs on all of them. I don’t really want to go for coilovers yet as I’m a student and there’s no way I could afford it (GC aren’t as cheap as they seem, camber plates are $299, and shocks are extra too). If it turns out too be much more expensive to make it work than I think then I’ll just save up for Tein Flex’s.

The current plan would be to get (eventually, I’ll have to do it in stages) the RS-R Race springs (with spring spacers to bring the height up), some Koni Yellows or Tokiko Illuminas, RB anti-swaybars, some Energy Suspension poly bushings, front and rear strut tower bars, and a lower arm bar and maybe a couple other goodies. I have 17x8 Mustang GT wheels (32 offset) with 225/45/17 Falken FK-451’s and my suspension is bone stock now.

Thanks!

locketine

wow no response to this yet? I was just perusing rx7store.net's website and happened upon these and noticed they were the cheapest and most powerfull springs. I like the drop of the 'down' set a lot better, seeing as how my car feels like it wants to fly above 90mph and i think lowering the front more than the rear will fix that.

I want to know if that spring rate is at the point where it will handle worse on regular roads, which I hear happens. I'm planning on mixing these with some KYB AGX's unless someone convinces me otherwise.

damnit, just noticed these are for the turbo model only. damn my SE.

snub disphenoid

I originally had ST springs. When I switched to JIC coilovers, I lowered the car another inch, so I believe the car was actually dropped 2 inches all around. I found this to be perfect. The car had very minimal body roll, so rubbing was never an issue (even if I autocrossed). Now that I don't have a set of coilovers in, I think the car sits way too high and looks kinda funny.

Here's what it looked like with the coilovers and two inch drop:

snub disphenoid

I imagine that those spring rates are acceptable. I think maybe when you approach 10kg/mm you're getting into "too stiff" territory.

Snrub

iTrader: (1)

The spread between F/R spring rate will cause the car to understeer less and I *think* even have a bias towards oversteer. I researched all this stuff a while back, but I've forgotten some of it. I believe spring rates in the range of 335/224 will be awfully rough on the street. (that's the impression people who have those sorts of rates have led me to believe)

Black91n/a

I don't mind stiff springs, and like I said, I think the car's way too soft now. I am concerned with how the rates will affect the characteristics of oversteer/understeer, how they will affect grip on wet, snowy or uneven surfaces, how the drop affects alignment, and the quality of the springs (ie do they sag). I don't dive it in winter now, but I might have to in a few years.

My main concern with the RS-R race springs is whether or not I'll need to buy additional components to cancel out the negative camber that the drop will induce. If this is the case then it may just be better to go with coilovers.

snub disphenoid

Well yeah, when i lowered the car two inches in the rear I bought a rear camber adjustment rod, so you'd need one of those if you wanted to run the RSR springs. Costs about $100, either from Ground Control or Racing Beat.

Rotary_7

are u changing tha shocks too or leaving them stock???

Black91n/a

I'm not doing any of this right now, just asking for future reference, but I'd plan on doing shock and springs at the same time.

End3r

Bump. Good thread and I'm in the exact same research situation, though it's mainly between the RSR Down springs and the Tanabe Sustec GF210's. They will be going on Tokico Illumina's on a daily driven FC.

Are both linear rate springs?
Which is better suited for my application and why?

Thanks

sub9lulu

iTrader: (7)

i think u have to roll the fender if u drop it like 2 inches at the back

Black91n/a

After reading Caroll Smith's Engineer to Win I've come to the conclusion that the RS*R springs probably aren't that good. They brag on their site that they are the only company that hot rolls their springs, but according to Smith that is a BAD thing. For good quality you should cold roll the springs. I'd think that with all the hassle and potential problems of making spacers you might as well get GC coilovers and just run them at near stock height to avoid having to buy expensive alignment correction parts. GC coilovers will also let you chose your spring rates to suit your needs, from super stiff to soft.

drft_180sx

^ Thanks a lot, i really appreciate the update...

End3r

Are Ground Control coilovers overkill for the street (i.e. daily driver)?

So let's get this straight: GC coilovers include springs, but you still need to buy struts. So it's roughly $400 for the coilovers (correct me if I'm wrong) and another $400 or so for either AGX or Illuminas. Good springs seem to be around $200, so I'd be paying another $200 exta for the ability to adjust my ride height? Any other benefits?

snub disphenoid

With GC coilovers you can select your springrates, so you can have your springrates suited to your application. That means you can run a bit stiffer than with plain old springs which means less body roll.

End3r

Excuse the potential stupditity of this question, but you mean that buyers can choose their spring rates upon purchasing the coilovers or adjust them on the fly?

What I really want to know is which is better for a daily driver that probably won't ever see a track:

1.) Adjustable struts and performance lowering springs

OR

2.) Ground Control coilovers with adjustable struts

I'm sure GC's are better, but is it a waste? I'd rather save that money for a different upgrade on my car if it's total overkill.

Black91n/a

What's better all depends on the application. For a daily driver I'd think something like the eibach's are best, seeing as it'll be nice and soft for normal conditions, but it stiffens under greater loads. For a a full coilover setup on a more track biased car I'd think that the GC's aren't the best as they're $400, plus shocks $400 (and up), plus camber plates $300. That's $1100! You can get Tein Flex's for about $1300, and they have more adjustability and the shocks are designed for those spring rates.

I'd say that the GC's are a good mid range option, if you can't afford the complete coilover setups, but want stiffer springs or different drop heights than the stock replacement springs offer.

rs_1101

what if i just want a pimped out 2" drop that rides well and eliminates understeer?

sub9lulu

iTrader: (7)

rs-r

Black91n/a

Most would say that 1" is about the largest drop you can go without severe alignment issues, but the Intrax springs give a 1.75" drop, but i don't know about ride or hadling, but know this, they are for looks, not performance. For a 2" drop you need coilovers, and to make up for the drop you need to raise the spring rates to compensate, or you'll scrape and bottom the suspension all the time. It's not cheap to go that low, either you'll spend alot for alignment products, or for tires that wear out prematurely.