Suspension Setup?

[Pzary3233]

So I've had my car setup for Auto X for the last couple seasons and I want to get my WRX dirty!!!

So far my suspension is totally geared towards the Tarmac.

This is my setup currently
Brakes:
FHI 4/2 Brakes
Front DBA 4000 Rotors
Rear DBA Sport Rotors
Hawk HPS pads

Suspension
Front:
Koni inserts in wagon struts
Whiteline Camber Plates
GC 450# Springs
Whiteline 22mm front sway bar and endlinks

Rear:
Koni Inserts in wagon struts
Group N Top hats
GC 450# Springs
Whiteline Adjustable 22mm rear sway bar and endlinks

Wheels:
Stock WRX with 5mm spacer in front
Stock RS 2.5 wheels
My Solo wheels 17x8 RPF-01

What do you guys think needs to be improved? I for one am pretty sure that the springs are gonna have to go! I have some 320/300# springs but I am looking for other opinions. Swaybars?

What about a decent tire to fit on the stock RS 2.5 wheels?

Thanks!

[UP2MTNS]

go much lower on the spring rates, see this thread:
http://www.dirtyimpreza.com/forums/showthread.php?t=1867

[I Like It Sideways]

As for a decent tire, any M+S tire will get the job done. Gravel tires are difficult and expensive in 16", so snow tires are the next best step.

The 22m FSb might be too much for the dirt, but give it a try and see how your car does. I would set the RSB on the softest setting (you'll still be able to get the car to rotate)

BTW I love RPF01's.

[Pzary3233]

Thanks guys for the pointers.

As far as spring rates, 3-3.5k translates into ###lb springs?

Also, what have you guys found to be the week points in the WRX when playing in the dirt?

EDIT: anwsered my own question:
180lb/in (3.2K)
225lb/in (4K)

So pretty much multiply ()K x 56.25 = (____)#

[sebhockey]

Also, what have you guys found to be the week points in the WRX when playing in the dirt?


The weakest point really isn't in the car itself, but the wheels/tires. I and many others tend to debead a lot. A solution to that is to use rally tires/wheels, have spares or air tank. Of course the real solution is to avoid the hazards that cause debeads all together, but that can be difficult sometimes.

Beyond that if you really want to beef up the car, then underbody protection along with mud flaps. Beefy struts and springs help, but choose a spring rate that you like. If the spring rate is too stiff then you can break stuff, or make cds skip.

You will find stuff to be weak spots on your car for your style of driving, or just things you want to change. It's just something that comes with time, experience and severly beating your car in the dirt.

My person favorite mod though is the driver mod. No matter how good a car you have, it doesn't do you any good if you aren't a good driver. The cost of a good rally school is by far the best money spent for those of us still learning.

[UP2MTNS]

Thanks guys for the pointers.

As far as spring rates, 3-3.5k translates into ###lb springs?

Also, what have you guys found to be the week points in the WRX when playing in the dirt?

EDIT: anwsered my own question:
180lb/in (3.2K)
225lb/in (4K)

So pretty much multiply ()K x 56.25 = (____)#

correct, my spring rates are 5Kfront/4krear

[Draco-REX]

I have a 2003 WRX that I plan to start Rally-Xing (for fun, not competitively.) I also have/will have a bunch of '07 STI take-offs. Right now I have F+R sways and in a little while I'll have struts/springs/tophats. I know the struts won't work, but I think I read that the springs will.

So if I'm reading correctly, I'd want to swap in the STI springs and just the front sway. Correct?

Thanks. :)

[BlackParis]

whoa.. can some one tell me what K stands for?

Mathematically please...

Cause you went from (Lb/in)/56.25 = K ............ So is K a rate?

1lb/1inch = .45kg/25.4mm and that doesnt equal 56.25...

[sebhockey]

k is the spring constant, it varies for each spring. It comes from Hooke's law.

F = -kx

Where F is force, k is the spring constant and x is the amount of compression or extension from the standing length.

[BlackParis]

ahh I C ;)

[Team Illuminata]

All the above advice is great with two over-riding exceptions: you didn't tell us what your goals are in rallcross; fun, win nationals, somewhere in between and you need to take into account the conditions the events will take place in. You don't need a rally car for rallycross.

For instance, we run 80% of our events on dirt oval horse racing tracks. This may sound a bit dull but believe me it's not. These are board flat, smooth and fast. I ussually run my autocross setup on these consisting of KYB AGX struts on full hard with 10% stiffer springs on coilover kits lowered as much as possible. Whiteline rear bar set in the middle, stock front bar. I run Primitive skid plates front and rear just to be safe, and mudflaps to stop the abraision down the sides over time. This setup often wins it's class (M4) if someone else is driving it as I am ****e, but apparantly, I can build a fast car.

Now, if you just want to have fun and get your feet wet. I would start with protection so you can find out what else you need with confidence and not have to replace an engine finding out. Next you will probably need to get some stock-ish springs and dampers unless you want to win nationals this year where you might benefit from proper rally dampers. If your really need to do well you will have to go to 15" rims and rally tires but you can have fun on all seasons or snows and still be competitive. I am not sure how big your brakes are but if they are any larger than stock WRX only our Team Dynamics or very few other 15" rims will fit over them. Used rally tires are also perfect for rallycross and a lot cheaper than new ones.

If you don't want to spend money and your courses are slow and tight just disconnect the front bar to get the car to turn in. Saw it at snow drift this past weekend. Otherwise I think you'll soon want to go to a smaller front.

The main element in Rallycross is the driver so work on that first once your car is safe from abuse that is.

Hope this helps.

[Pzary3233]

So I am digging this thread up from the dead.

Some things came up and I was not able to get any springs and tires for the last rally X that the Mid South Region put on... I guess that is what happens when you're Solo Chair... :roll:

From the first post in this thread you'll see where the car is in it's current state. I even ran the event on Khumo MX track day tires... I know stupid!

So I was 4 seconds behind FTD except for my slopy driving on the first 3 runs hitting too many cones. DOH!

Basically with the 450# springs the car was beating it's self to death. The tires while not rally tires, didn't do TOOOOO bad. There were slower people with rally tires. But I feel that with the right suspension and tires it could have been a much faster car. Though I did win PA... but I was the only driver. lol!

So I am going to order a couple sets of springs from Hyperco this week.
This is what I am thinking:
250# 8" long
300# 8" long
225# 8" long

I am thinking that I may not even need the 300# springs, but it sure would be nice on the street!