suspension problems 02 wrx

[nabsie]

Hi, I own an 02 model Subaru WRX and I am currently experiencing some problems with my current suspension setup. I will leave out the brand names of what suspension mods I have so as to avoid any bias but here is a list of my mods

- coilover suspension, 2 way height adjustable, adjustable damper stiffness and adjustable camber tops on the front. (current setting is full soft front and rear on the stiffness adjustment)

- 22mm, 3 way adjustable rear sway bar (currently on 24mm setting)

- heavy duty rear sway bar mounts

- heavy duty rear sway bar droplinks

- front strut brace

The problem I am currently experiencing is when cornering hard in either direction the inside rear wheel lifts off the ground. I understand that this problem is partly to do with running the sway bar so stiff as it reduces the independant characteristics of the suspension system however I was wondering if there is any adjustment I could make so as to correct this problem. This problem did not occur when running the rear sway bar on the 22mm setting however when on the 22mm setting I still was experiencing understeer.

I would like to keep running on the 24mm setting as I intend to fit a front sway bar in the near future however the car feels extremely unstable when cornering due to its symptoms. I need to keep the inside rear wheel firmly planted on the black stuff because obviously we all know that 4 wheels grip better then 3.

Would adjustments to suspension droop benefit me? Any input or advice would be great.

Secondly, this is to do with ride heights. Following is a list of ride heights measured from centre of wheel to top of wheel arch:-

Stock: Front 385 - 390mm Rear 360 - 368mm

Recommendation 1: Front 347mm Rear 335mm

Recommendation 2: Front 355mm Rear 350mm

My current setting: Front 355mm Rear 335mm

As you can see I am running heights from both recommendations that I have been given. I do not seem to be able to go any lower in the front then my current setting of 355mm due to rubbing the inside edge of the tyre deep inside the top of the gaurd liners, even though I am running the recommended 18" x 7.5" +42 wheel size that is recommended the setup. Obviously having the car raked at the angle that it is sitting at is not helping my understeer problems. My question is, would i be better off in jacking up the rear to the recommendation 2's height to hopefully improve my handling?

Any advice in regards to this would be fantastic. Thank you.

[Wojtek]

Hi nabsie,

thanks for your question, let see how we can improve your car...
1. RIDE HEIGHTS
I recommend that you adjust the ride height to 360mm front and 350mm rear subject to the design of your coil-over kit as far as available suspension travel in both bump and droop.
This will result in more compliance and also considerable reduce understeer.
2. SWAY BARS
As I understand, your current set-up is;
front - OEM (20mm)
rear - 22mm set to its hard setting
If this is correct, and you have had to adjust your rear sway bar all the way to its herdest setting, while still using OEM front sway bar, in order to have a neutral car, then I suggest that there is an underlying problem with your suspension set-up such as spring and shock rates, wheel alignment settings, tyre etc...
We use 22mm front and rear adjustable sway bars in our suspension kits, for a well balanced car.
3. SHOCK ADJUSTMENT
Is there any reason why you have adjusted your shocks that way? (front full soft, rear full hard). This just seems wrong again, and could also be contributing to your problem. Too much reboud force is holding the wheel up.

In general, although it is always best to have all four wheel in contact with the road at all times, however as the WRX is predominantly a front wheel drive chassis with some rear torque bias, lifting inside rear wheel during hard cornering should not be a major issue.

Also, you mention that you cannot adjust your frnt ride height any lower then about 355mm. This "could" be due to the aftermarket adjustable camber tops.

Hope this helps. Let us know as you progress.

Regards,
Wojtek.

[nabsie]

Thanks for the reply however I am still not to sure as to what exactly I need to do.

Yes I am currently still running the standard OEM 20mm front sway bar. The spring and shock rates are just what the coilovers come equiped with as they are purchased (what the maker of the coilover feel is best for the car)

My wheel alignment is something that needs work as last time when I requested certain numbers to be dialed in the guy doing the allignment refused to set it to what I wanted due to the under lying tyre wear factor. (I wasnt happy about this, good thing i didnt pay for it)

Obviously a 22mm adjustbale front sway bar would be a wise investment for improved handling and a more neutral feel.

Also you must have miss read my original post as I actually said that both front and rear shocks are on there softest setting.

Could you please explain in further detail as to why you may think my adjustable strut tops could be leading to the rubbing of the tyre on the gaurd liner?

These camber tops came as standard fitment to the coilovers and recommend using a ride height of 347mm and a wheel and tyre recommendation of 18" x 7.5" +40 offset 225/40 R18 tyres. I am running 18" x 7.5" +42 offset 225/40 R18 tyres (close enough to the exact recommended) If I set my front suspension to 347mm ride height I would rub the tyre on the inside gaurd liner all day long even driving around a corner at a medium speed. My only explanation for this crazy low recommended ride height would be for track use only, as there is less bumps etc then experienced on the road. Could this be possible?

[EvanWRX]

When I read "current setting is full soft front and rear on the stiffness adjustment", I thought it said "current setting is full soft front and rear on the stiffest adjustment".

I wanted to reply to your first post. Lifting the inside rear wheel is no cause for concern. If you reduced the stiffness of your rear bar enough, that rear wheel would no longer lift and you would increase your REAR traction. If you increase rear traction, you are going to change the balance of the car (more understeer/less oversteer).

I run a 22mm Whiteline front bar (non-adjustable) and 22mm Whiteline rear bar (set on stiff like yours). I find the car pretty well balanced. The car will understeer or oversteer, depending on driving style.

Your setup would result in a pretty tail happy car, you should back that rear bar off to the medium or soft setting while you've got the stock front bar.

The first time I drove on a road course I felt that my car understeered a fair amount but in reality it was caused by taking a less than ideal line as well as jumping on the gas too hard.

Everything is a comprimise, trying to setup a car so that it NEVER understeers in any situation is going to get a car that is very tail happy and unforgiving.

[Wojtek]

Hi nabsie,

We're trying to help you, but it is difficult when you are holding back on information. As it is, I don't know anything about what your coil-overs are.
You haven't mentioned anything about tyre rubbing caused by your adjustable strut tops in your original post, but it difficult to say without any information of seeing the car. I suggest that you contact the manufacturer of your coil-over kit, especially since they came complete with the strut tops AND they recommended you to the wheel/tyre size and ride heights. Ask them for their comments and explanation for your problem.

As for suggestion, Evan's recommendations are correct. Also, see my first reply.

If you can give us some more information, we'll be more then happy to help.

Regards,
Wojtek.

[nabsie]

Ok here are the brands.

- Coilovers = Tein Type Flex

- Rear Sway Bar = Cusco 22mm

- Rear Sway Bar Heavy Duty Mounts = Whiteline

- Rear Sway Bar Heavy Duty Droplinks = Whiteline

- Front Strut Brace = Cusco Type OS

and i forgot to mention i also have an Anti Lift Kit which is also Whiteline.

Also i didnt mention anything about my adjustable camber tops causeing rubbing. Thats what you thought it may be. I just mentioned that i was experiencing rubbing i wasnt to sure what was causing it.

I do also understand that my car is never going to under steer in all situations as takeing the optimum line around a corner can have impact on this.

I think i am going to adjust my rear sway bar back to the medium setting until i invest in a 22mm front sway bar (preferably adjustable) and also alter my ride heights to what you have recommended to see what this results in.

Thanks heaps for the advice you have given me so far it has been of great help in giving me more points to think about and receiving knowledge from someone with greater experience then mine. Cheers.

[Wojtek]

thanks, but can you tell us the spring rates please?

Wojtek.

[nabsie]

Sure thing. They are as follows:-

Front = 10 kgf/mm

Rear = 8 kgf/mm

[Wojtek]

thanks.

These are very stiff springs.
Are you using your car for racing only?
Are you using slick or at least semi-slick 'R-compound tyres?

Wojtek.

[nabsie]

nope using the car for street use and also on street rubber. Dunlop Direzza DZ101 225/40 R18 to be preciese.

I thought the spring rates seemed very high. I got that from the american version of the type flex coilovers so i am not 100% sure if it is the same because i know of a few little differences from the JDM to USM do exist.

[Wojtek]

Hi,

Now it's starting to make some sense. In my opinion, the spring rates, and logically the shock valving as well, are significantly too stiff for a street car with street tyres. This is most likely what is causing the unpredictable handling. Your shocks may able be significantly shorter, so the the combination of short shocks together with stiff springs, shocks and sway bars, is the most likely reason why you are lifting inside rear wheel off the ground during cornering - although as we suggested this isn't a major problem on these cars.

In summary, it looks like you have fitted something that is more suited for a race car then a street car.
Just as a matter of interest, our Group'4 kit for your car uses 5kg/mm front and 4kg/mm rear springs.

Reards,
Wojtek.

[Arnie]

nabsie - in what situations are you finding that you are understeering? Just trying to get an idea of your driving style and how that may contribute to your understeering. You can set up a WRX to be completely neutral but still have it understeering like a pig if you don't drive it "properly".

Regarding you suspension setup, I agree with Wojtek's basic ride height suggestions. Definitely tone your swaybar down to the middle or even softest setting. It will be a better balance to the stock front bar. Once you get the larger bar up front i'd still suggest staying with the middle setting. Once you get your ride height sorted, you will need to start playing with your damping settings. These things are not there just to find you a comfortable ride. You will need to turn the damping up and find a setting that complements the track conditions and your driving style. In the US, people who autocross (low speed timed events around cones) tend to stiffen the rear damping more than the front to help promote rotation. This is usually combined with lots of front negative camber and very little negative camber in the rear. They also swap the front springs to the rear, giving the harder spring rate in the rear. This can be, however, a pretty unstable setup for a circuit. for circuit racing, keep your springs where they are. On the whole, setting the damping harder in the rears promotes rotation. However be judiciuous about how much rotation/oversteer you dial in as you will be having a nice look backwards if you are not careful!

Alignment angles will be pretty critical as well. Take a look at Whiteline's alignment suggestions for road and track for a starting point.

Basically, this is the double edged sword of having adjustable coilovers. There is just too much adjustment! There are more ways to f-up your suspension than to get it right, and its so easy to get it wrong with coilovers. Be methodical about your setup, get a notebook and note all changes and how they affect the driving experience. But once you get it right, the only thing that will slow you down will be your driving skills. Your particular coilovers are a very short stroke track biased suspension. Very hard spring rates to keep the car from bottoming in its short stroke and commensurate damping rates to control the springs. I'm afraid you will have to go harder in damping than full soft to reap the benefits of these struts/springs. I've driven on a few cars with this setup and it can be pretty harsh on the street. Plus, you more than likely will suffer from uncontrollable bounce due to the sidewall stiffness, respectively "softness" of a street tire. The spring rates on the Flex's are generally for much stiffer sidewalled tires, like slicks and semi-slicks.