[aoisubaru]

Okay, when it comes to suspesnsion, I have absolutely no knowledge. So I need some help. I want to improve the handling of the car. I am planning to do swaybars, endlinks. Also I want to change springs and I have read teh prodrive springs are very popular and I have read alot of reviews about it and it seems to please many STi owners. I just thought spings can be installed and bam! its done.

But this one guy started to talk about "roll ceters being below ground" with the approximate 20mm drop claimed by prodrive with its springs. Now I am really confused. I am not sure what I am supposed to do. Can't I just put springs on? Do I need to do heck of alot more stuff to it for it to be done "right"?

Can someone give me the simplist answer or advice on this? MY goal is to lower the car a little so I can emilinate some body roll. Thanks for any help.

[Draco-REX]

"That Guy" was probably me or Stretch.

If you have no intention of driving the car at 9/10ths, then a lot of the technical stuff doesn't really matter. The Roll Center heights and Camber Curves really only apply when the car is going all-out. If you don't plan to Auto-X or run at a Track day, then you can ignore minor changes in Roll Center height.

Start with a 24mm Adj rear sway.

If you want more, get a 24mm front sway (27mm if you want a flater car and don't mind mild understeer). That should make you happy.

If you want a lower car that won't scrape over speedbumps, I recommend the RCE Black springs.

If you want more even wheel gaps, then get the RCE lowering camber plates as well.

[aoisubaru]

Originally Posted by Draco-REX

"That Guy" was probably me or Stretch.

If you have no intention of driving the car at 9/10ths, then a lot of the technical stuff doesn't really matter. The Roll Center heights and Camber Curves really only apply when the car is going all-out. If you don't plan to Auto-X or run at a Track day, then you can ignore minor changes in Roll Center height.

Start with a 24mm Adj rear sway.

If you want more, get a 24mm front sway (27mm if you want a flater car and don't mind mild understeer). That should make you happy.

If you want a lower car that won't scrape over speedbumps, I recommend the RCE Black springs.

If you want more even wheel gaps, then get the RCE lowering camber plates as well.

Now I feel like an idiot.

I just don't have knowledge at all and I notice you and the other guy's knowledge was way beyond my capacity in suspension.

I hope you didn;t take this in the wrong way. But This is hte kind of answer I was really looking. I have been reading your stuff and many other stuff on suspension,but it is taking alot of time for me to understand.

So Prodrive is not good? Also, if I just put on springs (like RCE) and not do anything else a the time, will I be hurting the car in any way? Do I eventually "need" to do other stuff? Let me know.

Thanks Draco!

[05_GD7]

You can't go wrong with the Prodrive springs.
RCE blacks are very very close to Prodrive springs in terms of drop, but I think they are a little stiffer, by just a bit.

For someone who isn't going to the track, your plan sounds just fine.

[evilSTi7]

If you would just like to eliminate some body roll, sway bars should be your first modification. A lot of people agree that the stock springs are well suited for the stock struts, so when you want to make the next big step you might want to think about coilovers.

[BlueGold]

The COBB sway bars with Kartboy endlinks works very well in a stock setup. I've been running that setup with JDM Pinks and RCE camber plates for some time now.

What part of Ohio are you in? I can help you install these items.

[aoisubaru]

Originally Posted by BlueGold

The COBB sway bars with Kartboy endlinks works very well in a stock setup. I've been running that setup with JDM Pinks and RCE camber plates for some time now.

What part of Ohio are you in? I can help you install these items.

Thanks guys for the advice and recommendations. I plan NOT to take my car to AutoX or RallyX. How does RCS work with stock struts compared to Prodrive? Also, What about JDM Pinks? I guess I will read some reviews on each springs and make my final decision. I know what camber plates are, but I don;t know the functionality of it well. I gatta read on that, too.

The only things is, I want to lower the car to reduce some of the body roll and also yes, for appearance. I want it to even out the gap for better looks.

I know I want to do this, but I just want to minimize the pressure/burden on the car by doing suspension mod....

[Draco-REX]

Prodrive springs are fine, so are pinks. Bu I liked the pairing of the rates with the Blacks. I have a friend who rides on Prodrive springs and he loves them, and is very fast with them.

Originally Posted by aoisubaru

Thanks guys for the advice and recommendations. I plan NOT to take my car to AutoX or RallyX. How does RCS work with stock struts compared to Prodrive? Also, What about JDM Pinks? I guess I will read some reviews on each springs and make my final decision. I know what camber plates are, but I don;t know the functionality of it well. I gatta read on that, too.

Camber plates let you tilt the tops of the struts inwards to get more negative camber in the front (something our cars love.) The RCE lowering camber plates also drop the front by 3/8" (about 10mm).

The only things is, I want to lower the car to reduce some of the body roll and also yes, for appearance. I want it to even out the gap for better looks.

Sway bars (also called anti-roll bars) are what you want to tame the cars roll in a turn. You can do it with springs, but it would take exceedingly high spring rates. Start with sways.

I know I want to do this, but I just want to minimize the pressure/burden on the car by doing suspension mod....

Honestly, just start with a rear sway. Get a Whiteline 24mm Adj sway and use the softest setting first (the hole at the ends of the arms, you'll know what I men when you see it.) A rear sway bar is the BEST bang for the buck with the STI suspension.

As above, whereabouts in OH are you? If you don't want to post it, feel free to PM. There are some great groups in OH.

[aoisubaru]

Originally Posted by Draco-REX

Prodrive springs are fine, so are pinks. Bu I liked the pairing of the rates with the Blacks. I have a friend who rides on Prodrive springs and he loves them, and is very fast with them.


Camber plates let you tilt the tops of the struts inwards to get more negative camber in the front (something our cars love.) The RCE lowering camber plates also drop the front by 3/8" (about 10mm).


Sway bars (also called anti-roll bars) are what you want to tame the cars roll in a turn. You can do it with springs, but it would take exceedingly high spring rates. Start with sways.


Honestly, just start with a rear sway. Get a Whiteline 24mm Adj sway and use the softest setting first (the hole at the ends of the arms, you'll know what I men when you see it.) A rear sway bar is the BEST bang for the buck with the STI suspension.

As above, whereabouts in OH are you? If you don't want to post it, feel free to PM. There are some great groups in OH.

Draco, so now you know who I am, don't get your flame suits on.
I always try to get second opinion and conclude my research. You just happen to give me a hand here also.

Anyway, now I pretty much know what I want, but one last question. As long as I do not take my car to Auto-X or something it will be fine. How about if I would take it to Mid-Ohio for driving classes and stuff? Would that be same as going to Auto-X?

Edit: Oh, I Guess you did mention it on your first response. NO Auto-X or track day..... hmm.... I do want to try the tracks at Mid-Ohio... Then, I will need a whole new setup.... , right?

[Draco-REX]

Originally Posted by aoisubaru

Draco, so now you know who I am, don't get your flame suits on.
I always try to get second opinion and conclude my research. You just happen to give me a hand here also.

Anyway, now I pretty much know what I want, but one last question. As long as I do not take my car to Auto-X or something it will be fine. How about if I would take it to Mid-Ohio for driving classes and stuff? Would that be same as going to Auto-X?

Edit: Oh, I Guess you did mention it on your first response. NO Auto-X or track day..... hmm.... I do want to try the tracks at Mid-Ohio... Then, I will need a whole new setup.... , right?

Again, the bad habits of a low roll center are not catastrophic. At worse, the car's handling just won't be as improved over stock as it could be. And with the adjustable sways, if you go 24/24, you can tune some of the understeer out by stiffening the rear sway.

It's not something to worry about. Think of it as having your sundae without the cherry. It's still a good sundae regardless.

As for seeking out a second opinion, that's fine. In my write-up (which I know I have yet to finish... bad me!) I recommend two books to read which cover much the same material. I recommend them both because the two separate viewpoints on the same subjects helped me understand some of these things better than I would have with only one point of view. Stretch, Myles at RaceComp Engineering and TurnInConcepts are all great sources for this info. You'd do well to contact any of them with questions, they won't steer you wrong.

[aoisubaru]

Originally Posted by Draco-REX

Again, the bad habits of a low roll center are not catastrophic. At worse, the car's handling just won't be as improved over stock as it could be. And with the adjustable sways, if you go 24/24, you can tune some of the understeer out by stiffening the rear sway.

It's not something to worry about. Think of it as having your sundae without the cherry. It's still a good sundae regardless.

As for seeking out a second opinion, that's fine. In my write-up (which I know I have yet to finish... bad me!) I recommend two books to read which cover much the same material. I recommend them both because the two separate viewpoints on the same subjects helped me understand some of these things better than I would have with only one point of view. Stretch, Myles at RaceComp Engineering and TurnInConcepts are all great sources for this info. You'd do well to contact any of them with questions, they won't steer you wrong.

Draco, thanks for all the info. I appreciate it very much. Now I not as confused as I was before. I say not as much becuase I have yet to "understand" how suspension works in general. But I will try to look for those books of your this weekend. I saw the titles in your Ultimate Suspension topic.

Anyway, I will let you know when I get my stuff and I will probably ask for your help on installing them! Thanks!

[stretch]

Here's a little bit I wrote on roll centers, though it just barely scrapes the surface:
Roll Centers | Build A Faster Car

Strut suspensions aren't very friendly to roll centers even at the stock height. (They're better for high cars, like a Forrester, though Porsche seems to use them well.) For aggressive cars, you'd want double-wishbones- but, you're stuck with struts.

That being the case, you just need to be aware of the problems a low roll center creates. If you lower your car, the car will want to have more body roll. You MUST use firmer springs just to keep body roll constant. Likewise, roll center migration will accelerate, which means your roll center height will change more in turns. This means the amount of body roll your car is trying to settle at is constantly changing, and this means the car won't feel as settled in turns.

You can cope with this by reducing body roll, which will alleviate roll center migration problems. You can also install a Whiteline roll center adjuster (also called a ball joint extender). The Whiteline part compensates for just 10mm of ride height change.

So, I'd only recommend lots of lowering (half inch or more) on really stiff suspensions (coilovers). Even stiff coilovers can't lower the car over an inch without feeling sloppy. You can run the Whiteline kit to compensate for 10mm of height up front.

Actually, a silver lining to this car's bump-travel issue is that the lack of bump travel limits how far the roll center can migrate in a turn (at the expense of jacking forces, which is every bit as bad).

If your goal is reduced body roll, do not do springs. Sway bars are for reducing body roll and do so very well. Springs are for ride quality (not necessarily improved) and looks with a relatively minor change to body roll.

[06STImulus]

another quick noobie question... can i run prodrive or RCE springs with the stock sti struts??

[Draco-REX]

Originally Posted by 06STImulus

another quick noobie question... can i run prodrive or RCE springs with the stock sti struts??

Yes. They don'e have a huge drop so there won't be a big issue. However, if you do, you'll want to replace or cut the front bumpstops. I know the RCE Blacks come with shorter bumpstops, and that Prodrive makes shorter ones (don't know if they come with the springs though.)

[06STImulus]

sweet thanks! I'm going to assume since i'm not lowering it that much, a camber kit won't be necessary either?