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Old 04-08-2009, 09:04 AM   #1
Sil3nt_Ch4os
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Default AutoX suspension setup help

I've ran a few AutoX's now and I'm ready to try to get a little more serious and tune my suspension, problem is I don't really know what to do. I'm not going to be winning anything with my car but I do want to be able to perform as best as possible. I'm looking for a general tune that really just wakes up the car and makes it more responsive. Can anyone help with a nice standard setup (alignment/camber/caster/toe) for my car?

2007 Impreza 2.5i (STX prepared - at least I was told, let me know if that's wrong)

Mod list (at least the relavant ones)
Megan Racing 32-way adjustable coilovers
Rallitek 22mm front sway bar
Rallitek 22-24mm adjustable rear sway bar
Rear endlinks/Heavy duty mounting brackets/poly bushings
STi Front strut bar
STi rear strut bar
17x8 Enkei RPF-1's
Continental ContiSport Contact 3's (225/45/17)

I currently have the coilovers set at a 2in drop in the front and 1 3/4in drop in the rear.
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Old 04-08-2009, 09:19 AM   #2
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You have a nice setup. But since you are running 17x8, why don't you try 235/45/17 too?
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Old 04-08-2009, 09:28 AM   #3
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Quote:
Originally Posted by hklatte View Post
You have a nice setup. But since you are running 17x8, why don't you try 235/45/17 too?
I want to but I got a crazy good deal (basically just shipping price) on these tires so I'll use them until they're shot.
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Old 04-08-2009, 10:19 AM   #4
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Here's some crazyness about your classing.

5 speed? You should be in ST.
Automatic? STX is correct due to having something other than a) all open diffs and/or b)viscious limited slip.

What's your spring rate? People have had sucess from anywhere between 250lb springs to 500lb+ springs. Dependent on if your dampers can handle them.


What about alignment? I don't see any camberplates for the front, unless they're included with the Megans. I would get as much [edit] negative [/edit] camber as you can in the front. And then toe out the rear a hair and go from there.

--kC

Last edited by KC; 04-09-2009 at 08:31 AM.
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Old 04-08-2009, 10:34 AM   #5
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Quote:
Originally Posted by KC View Post
Here's some crazyness about your classing.

5 speed? You should be in ST.
Automatic? STX is correct due to having something other than a) all open diffs and/or b)viscious limited slip.

What's your spring rate? People have had sucess from anywhere between 250lb springs to 500lb+ springs. Dependent on if your dampers can handle them.


What about alignment? I don't see any camberplates for the front, unless they're included with the Megans. I would get as much camber as you can in the front. And then toe out the rear a hair and go from there.

--kC
It is Automatic

I'm not sure on my current spring rates, how can I get that number? I've been running the coilovers at their mid-range level (8 clicks I believe)

They have camber plates, so positive camber in the front?
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Old 04-08-2009, 11:56 AM   #6
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
It is Automatic

I'm not sure on my current spring rates, how can I get that number? I've been running the coilovers at their mid-range level (8 clicks I believe)

They have camber plates, so positive camber in the front?
Before each autoX you should jack up your front end, loosen off your canmber plates, and slam your camber to the maximum negative amount. All you need is an allen key. The extra camber really helps on a tight autox course, but make sure you re-set it to the original settings for the ride home or you'll have no tires left.

To be competative in STX you will also have to get a lot better tire.
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Old 04-08-2009, 12:13 PM   #7
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Originally Posted by wrxlad View Post
Before each autoX you should jack up your front end, loosen off your canmber plates, and slam your camber to the maximum negative amount. All you need is an allen key. The extra camber really helps on a tight autox course, but make sure you re-set it to the original settings for the ride home or you'll have no tires left.

To be competative in STX you will also have to get a lot better tire.
Thanks, will try...I'm not worried about being competitive though so no worries on the tires for now
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Old 04-08-2009, 12:19 PM   #8
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
Thanks, will try...I'm not worried about being competitive though so no worries on the tires for now
Your setup looks pretty sound, some STX WRX drivers go a lot bigger on the rear sway bar to force the car into oversteer but the secret is to find a good balance in handling between oversteer/understeer.
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Old 04-08-2009, 12:21 PM   #9
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With the drop you're running, some roll center adjusters to get camber under load back?
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Old 04-08-2009, 12:38 PM   #10
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^^^ where do I buy them?

I dont have the money right now but I'll put them on my list...unless someone else says it's a bad idea

OT question: Can you remove your rear seats and stuff for STX?
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Old 04-08-2009, 12:49 PM   #11
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Quote:
Originally Posted by vecdran View Post
With the drop you're running, some roll center adjusters to get camber under load back?
Roll center adjusters? What are those?
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Old 04-08-2009, 12:56 PM   #12
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
OT question: Can you remove your rear seats and stuff for STX?
No you cannot. You can buy lighter seats (minimum 25lbs) though.
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Old 04-08-2009, 02:25 PM   #13
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http://www.legacygt.com/forums/showthread.php?t=38837
http://forums.nasioc.com/forums/show....php?t=1055510

About all the info you need on roll center adjusters. Lower beyond 1", and you mess up the suspension geometry, which leads to bump steer and an even worse camber curve.
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Old 04-08-2009, 04:11 PM   #14
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Quote:
Originally Posted by vecdran View Post
http://www.legacygt.com/forums/showthread.php?t=38837
http://forums.nasioc.com/forums/show....php?t=1055510

About all the info you need on roll center adjusters. Lower beyond 1", and you mess up the suspension geometry, which leads to bump steer and an even worse camber curve.
Would it be better for me to raise the car back up a little?
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Old 04-08-2009, 04:35 PM   #15
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According to the links, this mod is illegal for STX

"Q. I Autocross. What class will the kit put me in?
A. For Autocross, installing our ball joint relocation kit will put you in Street Modified. Unfortunately neither Stock, Street Prepared or Street Touring classes allow modifications to suspension geometry. Unlike an ALK, which relocates suspension points and puts you straight
into Prepared class, our kit adjusts a part of the "moving suspension," which is legal in Street Modified."

OP..Dialling in a good amount of negative camber to your front tires will make a big difference for you, and Megan coilovers allow you to do this.

Question, how does the car feel now on the limt? Does it understeer?
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Old 04-08-2009, 05:03 PM   #16
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Originally Posted by wrxlad View Post
According to the links, this mod is illegal for STX

"Q. I Autocross. What class will the kit put me in?
A. For Autocross, installing our ball joint relocation kit will put you in Street Modified. Unfortunately neither Stock, Street Prepared or Street Touring classes allow modifications to suspension geometry. Unlike an ALK, which relocates suspension points and puts you straight
into Prepared class, our kit adjusts a part of the "moving suspension," which is legal in Street Modified."

OP..Dialling in a good amount of negative camber to your front tires will make a big difference for you, and Megan coilovers allow you to do this.

Question, how does the car feel now on the limt? Does it understeer?
That's why I asked if I should just put it back up some more, I do not want to leave STX, I'm already outclassed

Yes, the car understeers right now.
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Old 04-08-2009, 05:17 PM   #17
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Quote:
Originally Posted by KC View Post
Here's some crazyness about your classing.

5 speed? You should be in ST.
Automatic? STX is correct due to having something other than a) all open diffs and/or b)viscious limited slip.
He has 8" wide wheels. -> STX regardless
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Old 04-08-2009, 06:38 PM   #18
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
That's why I asked if I should just put it back up some more, I do not want to leave STX, I'm already outclassed

Yes, the car understeers right now.
My Experience (for what it's worth) is that with a WRX you want to be seeking a neutral balance...maybe even towards oversteer to get the car rotating in sharp turns. I achieved this with a 28mm rear sway bar and stock front sway bar, but you can do it by putting a bit more air pressure in your rears or by stiffening the coilovers in the rear. When my car started rotating nicely it put a big smile on my face and moved me towards the top of the class.

I know I've already said this, but you have megans which allow you to slam your camber to a huge negative amount for free! so do it. Invest in an allen key that fits your coilover screws on top of your camber plates, then jack up your car and slam the front camber before your run. That will dial out a lot of understeer right there.
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Old 04-08-2009, 06:49 PM   #19
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Quote:
Originally Posted by wrxlad View Post
My Experience (for what it's worth) is that with a WRX you want to be seeking a neutral balance...maybe even towards oversteer to get the car rotating in sharp turns. I achieved this with a 28mm rear sway bar and stock front sway bar, but you can do it by putting a bit more air pressure in your rears or by stiffening the coilovers in the rear. When my car started rotating nicely it put a big smile on my face and moved me towards the top of the class.

I know I've already said this, but you have megans which allow you to slam your camber to a huge negative amount for free! so do it. Invest in an allen key that fits your coilover screws on top of your camber plates, then jack up your car and slam the front camber before your run. That will dial out a lot of understeer right there.
Thank you!! I think I have enough knowledge to work from now.
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Old 04-08-2009, 07:42 PM   #20
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
Rallitek 22mm front sway bar

Continental ContiSport Contact 3's (225/45/17)

I currently have the coilovers set at a 2in drop in the front and 1 3/4in drop in the rear.
Depending on your spring rates you may want to switch sway bars. What's the spring rate F and R?

Your biggest issue is your tires. Get some wide/sticky.

You may be too low. I don't know though. Could you measure it a different way for us? The Nasioc Motorsport and Suspension forums generally measure suspension height from center of the wheel hub to the metal part of the fender directly above the hub. "Drop" means nothing to us because includes several things. Wheel diameter, tire profile and spring height. That is, I can install 2" drop springs, 19 inch wheels with 225/35R19 tires and ride higher than a stock WRX.
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Old 04-08-2009, 07:59 PM   #21
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Depending on your spring rates you may want to switch sway bars. What's the spring rate F and R?

Your biggest issue is your tires. Get some wide/sticky.

You may be too low. I don't know though. Could you measure it a different way for us? The Nasioc Motorsport and Suspension forums generally measure suspension height from center of the wheel hub to the metal part of the fender directly above the hub. "Drop" means nothing to us because includes several things. Wheel diameter, tire profile and spring height. That is, I can install 2" drop springs, 19 inch wheels with 225/35R19 tires and ride higher than a stock WRX.
by that my measurement ends up being 13 1/2" on all 4 corners

I still don't know how to tell what spring rate I'm at since it's adjustable (help?) but Megan's site says they're 8kg/front 6kg/rear.
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Old 04-08-2009, 10:54 PM   #22
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
That's why I asked if I should just put it back up some more, I do not want to leave STX, I'm already outclassed

Yes, the car understeers right now.
Sorry, I didn't think about it knocking your out of your class.
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Old 04-09-2009, 07:38 AM   #23
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Quote:
Originally Posted by Sil3nt_Ch4os View Post
by that my measurement ends up being 13 1/2" on all 4 corners

I still don't know how to tell what spring rate I'm at since it's adjustable (help?) but Megan's site says they're 8kg/front 6kg/rear.
The spring rate isn't adjustable - the dampener is. The spring rates you found are right, but usually spring rates are given in pounds for easier comparison to other springs. 8kg springs are about 440lbs and 6kg springs are about 350lbs, as I recall. I'm sure you can find the math somewhere to be sure, but that's accurate enough for your purposes.

And to clarify, because it's really really important. You do not want positive camber. KC meant you want as much negative camber as possible. Positive camber can even be dangerous.

After that, tires and seat time are going to be your best helpers.
-N
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Old 04-09-2009, 08:24 AM   #24
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And to clarify, because it's really really important. You do not want positive camber. KC meant you want as much negative camber as possible. Positive camber can even be dangerous.

-N
All 4 corners or just the front?
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Old 04-09-2009, 08:30 AM   #25
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Quote:
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All 4 corners or just the front?
Just the front. Thanks Niel. Yeah, I always think that I'm talking to someone who may have an idea... gotta work on clarifying a little more. I'll edit the post.

The rear? You want about -.8 to -1. The less the better for rotation.
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