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1999 RBP 2.5RS
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210 Posts
Discussion Starter · #1 ·
As I am fairly unhappy with the amount of body roll on my car after installing prodrive p1 springs, I was looking into a bc racing coilover setup for my car.

Sitting in my friend's rsx with 10kg/14kg springs felt fairly ideal for me. I'm wondering what spring rate I should be looking for as an equivalent to that. The BC racing coilovers come on 8kg/6kg springs but I was looking for something stiffer.

I realize that suspension customization is largely dependent on how I drive but can someone ballpark a spring rate for me?
 

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1999 RBP 2.5RS
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210 Posts
Discussion Starter · #4 ·
22-24mm rear bar. No bracing as I'm thinking on grabbing that later. I'm looking into getting a 27mm+ front bar and setting the rear to 24mm.
 

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Meany Head
2000 RSC
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10,236 Posts
I'd say your on the right track.. but.. I think to say that braces are what really prevent body roll is not really true. Struts/Springs and Sway Bars are really where you want to start. Braces are for that "extra little bit" of rigidity.
 

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1999 RBP 2.5RS
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Discussion Starter · #7 ·
I'm thinking that the bracing increases chassis rigidity and instead of the force going chassis, it'll go somewhere else. But that's not what I'm looking for.

I'm looking for a spring rates to use on my car for a high end setup that I won't need to replace due to it being inadequate. I'll worry about the bracing later after I get my coilovers. In addition, I daily drive this car so don't tell me to get 20kg springs >___>
 

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93 Imperza L Ameythst
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I'd say your on the right track.. but.. I think to say that braces are what really prevent body roll is not really true. Struts/Springs and Sway Bars are really where you want to start. Braces are for that "extra little bit" of rigidity.
I see your point and i know your not busting my chops, i just thought instead of spending 800+ he could pick up some ods and ends for a whole lot cheaper before he makes the switch to see how it helps.
 

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2000 Impreza 2.5RS BRP
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too bad your not in socal i have coilovers with 12k/12k springs on it right now. im actually selling them since thye are a little too much for a GC. i think ideally 10k/9k is good.

if you dont drive your car a lot on the streets its perfect for the track imo. but to compromise for the street nothing more than 10k.

i'll report back and see what the car feels like with R-comps and 12k/12k.

when i had 8k/6k megans and 8k/6k stance, it was okay, but still soft imo.

if u dont have sway bars yet, get those first, 27mm front and a 24mm rear
 

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1999 RBP 2.5RS
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Discussion Starter · #10 ·
I don't mind a few visits to the chiropractor if I'm going to corner well:lol:

But really, is 12k really unbearable? Maybe 11k/10k would be okay for the street? I wanted a comparable setup to my friend's RSX 10k/14k suspension, which is actually bearable, albeit still uncomfortable, on the street.

I'm going to grab a front sway after I grab coilovers, as the prodrive setup isn't cutting it. Where do I go about grabbing a 27mm+ front sway for an N/A gc8 anyways? Also, do I need heavy duty mounts for the front sway as well?
 

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2000 Impreza 2.5RS BRP
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I don't mind a few visits to the chiropractor if I'm going to corner well:lol:

But really, is 12k really unbearable? Maybe 11k/10k would be okay for the street? I wanted a comparable setup to my friend's RSX 10k/14k suspension, which is actually bearable, albeit still uncomfortable, on the street.

I'm going to grab a front sway after I grab coilovers, as the prodrive setup isn't cutting it. Where do I go about grabbing a 27mm+ front sway for an N/A gc8 anyways? Also, do I need heavy duty mounts for the front sway as well?
its not unbearable for me. as a driver it feels fine. i think some of my passengers dont like it that much.

my friend 16/16k on his s2000 is very streetable. i think its comfortable, but its cuz we have macpherson struts that make the ride much harsher.

forgot about n/a stuff. no idea where u would get a 27mm front. gotta get a turbo xmember.

you can buy my stance coilovers from me, i'll even deliver them to you in cupertino. LOL. (im just playing about the delivery, gas is too expensive)
 

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1999 RBP 2.5RS
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210 Posts
Discussion Starter · #12 ·
So how stiff can I make my car before bumps and road irregularities start to compromise my traction? I could really care less about my passengers :D
 

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2000 Impreza 2.5RS BRP
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So how stiff can I make my car before bumps and road irregularities start to compromise my traction? I could really care less about my passengers :D
12k/12k on our cars arent meant to handle great on rough roads. my friend with a stock wrx can almost hang with me on bumpy corners cuz the traction isnt there mid corner. but on the track where its a okay to smooth surface, it is awesome.

i think on the street, 8k/6k probably felt the best even on rough roads.

but i got a significant amount of body roll on the track with just RE01R with the 8k/6k setup. 12k makes the car really flat thru the corners. not a lot of body roll even with 255 neovas.

it really depends on where u plan on taking your car. if its mainly going to be a "canyon cruiser" 12k/12k is an overkill. but if u plan on tracking or autox, the higher spring rates is nice.

i need to make my car more civilized, that's why im moving to softer springs 10/9.

you need to ride in a GC with high spring rates to find out if u can take the high spring rates.

the exact same coilover in a GD body feels really nice. its comfortable but then again their car weighs a few hundred more and the chassis stiffness might have something to do with it too.
 

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MY99 GF4 EJ227 JDM 6spd
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I have the BC Racing coilovers 8k/8k setup on my wagon.
With street tires they are fine. When you run SLICK tires, they are a bit soft. I'd say with SLICKs you'd want to run 10-12k springs. I like the equal rate setup. It's really nice for track. Reason for stiff is because the slick tires are STICKY and the there'll be more roll. You don't see that with street tires because they're less grippy.

I run 20mm sways front and rear. I don't really use the sway cars to control body roll when I have stiff springs. I just use them to control the roll coupling. The SPRINGs control the body roll. I have fender braces front and a rear strut brace in the rear.
 

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2001 2.5RS-T BRP
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You shouldn't compare spring rates from the RSX since the motion ratios are most likely not the same. Just to back up what others have said. Your spring rate has to be matched to the level of grip offered by your tires and the pavement. If you are too stiff you will lose grip. Remember when tuning your suspension you are looking for grip not 0 body roll.
Another thing to consider is whether or not the BC's can control the spring rate you want to run. A shock generally can only run a certain range of spring before needing to be revalved. If you are going to run a spring that is much stiffer than the shock came with it might be best to buy different shocks.
 

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1999 RBP 2.5RS
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Discussion Starter · #16 ·
So if my plan were to go with a set of falken rt615's, is there a ballpark spring rate that will get me maximum grip? Does anyone here have experience with a coilover setup and azenis?

If I had the time and money I'd sure as hell experiment with all sorts of spring rates and swaybars. However, I'm a mere college student and hopefully you guys can save me both time and money. Thanks for all your help so far guys.
 

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Premium Member
2001 2.5RS-T BRP
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575 Posts
Maximum grip for where? I've run 215 Azenises on my T2 setup with 7/6K springs and it's pretty good for the street. There are few times I've wished for softer springs. For autocross I'd prefer the rear stiffer. I've never done a track day in a car so I can't say how it will work there.
I think maybe a good place to start for you would be 8/7K. that way if you wanted to go a little stiffer you could get some 9K springs for the front and move the 8's to the back. Conversely if you wanted to go softer you could move the 7's to the front and get some 6's for the back.
If you are into autocross go a bit stiffer and use the same rates front and rear.
 

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Discussion Starter · #18 ·
I'm really looking for an autox/track car that works as a daily driver. Not a daily driver that works as an autox/track car. The roads on the streets and mountains are reasonably smooth so I'm not worried about losing traction to bumps. I just don't want my shocks to blow out on a pothole or have a completely unbearable ride.
 

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overdeveloped beater
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8,335 Posts
I don't think you want to go any higher than 12k at either end. Your roads must be glass smooth and the rest of the car will suffer from too stiff of spring. I have a Kg/mm to Lbs/in conversion table at home, but 12kg/mm is around 600lb/in....there really isn't much need to go any higher. The Street tires (azenis and the like) aren't going to like the uber stiff rates. Even DOT racing slicks work well with rates in the 600lb range.

Lord help you if you happen to get stuck in wet weather with anything over 12k on the car. There's no way to soften it up when you have to crank the damping up to control the springs to keep from pogo'ing around like a ricer.....
 
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