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'06 WRX Suspension Upgrade Review

40K views 31 replies 14 participants last post by  Feelsonumb 
#1 ·
Determining your objectives when doing suspension upgrades is the first and most important step of the process. Some will want to maximize handling for competition, others may do suspension mods entirely for aesthetic reasons (lowering). My goal has been to improve handling as much as possible with little or no effect on ride quality. I realized from the outset that this would take some planning, and that I would not get the same results as someone who is not concerned about ride quality. With that out of the way, here are the parts and pieces that I used.

My first additon was new tires - P225/45ZR-17 Kumho SPT summer performance tires. Looking at the the user feedback on Tirerack.com, the tire was generally praised for its excellent grip on both dry and wet surfaces, while some complained that the sidewall is not stiff enough for competiton use. This was exactly what I was looking for - a tire with good grip, but without an excessively stiff sidewall that hurts ride comfort. I mounted the tires on a set of Rota 17 X 7.5 (48mm offset) Subzero wheels. This wheel/tire combo weighs the same as the factory wheels with the 215/45-17 RE92 tires. The tires performed as expected, and are quieter than the stock RE92s as well.

Next up was a set of springs. After a short stint with Prodrives, I installed the Subaru SPT Pink springs. As opposed to the Prodrives, these springs have enough ride height to maintain front control arm geometry (an important consideration for handling) and suspension travel, and have a higher spring rate to reduce body roll. Out of all of the suspension mods I have done, these had the most noticeable effect on ride quality, but are not nearly as much as springs with less suspension travel (lower ride height). The addition of the springs in combo with the wheels/tires made a big difference in the handling ability of the car, with only a very minor hit on ride comfort.

Immediately following the spring install, I had a performance alingment done on the car at a Local Sunoco station that has a Hunter machine. We maxed out front camber, ending up with minus 1 degree on each side. In the rear, one side was minus 1.4 degrees, the other minus 1 degree. We installed one camber bolt - on the minus 1.4 side - to even out the rear, ending up with minus 1 degree camber on all four corners. I had hoped for more in the front, but was pleased we were able to get the rear to 1 degree. Toe was set at minus .02 degrees (toe in) as per my request to help with straight line stability on the highway. The alignment made a big difference - more than I expected. I suspect even a stock WRX would really benefit from a "performance alignment."

Last month, I replaced the OEM 17mm RSM with a Subaru 20mm bar. I reused the stock links to help keep NVH in check. The heavier RSB made a difference, but not as much as the springs. With the heavier RSB, slight oversteer became evident for the first time, but it felt as though the front end was still trying to roll too much. At this point, the car handled immensely better than stock - no comparison. But I knew I was going to have to do something in the front.

I picked up a 22mm Whiteline FSB a few weeks ago and finally had the chance to do the install. Once I removed the subframe and jacking plate, the bar was very easy to swap out. I reused the OEM links, cleaned up the subframe and jacking plate and put it all back together.

I have to say, the FSB made a huge difference - perhaps as much as the springs. On the cloverleafs, the car feels glued to the road. Around and 'round the cloverleafs I went, pushing the car faster and faster. Squealing tires (front and rear) finally gave way to just a touch understeer, but at a much higher speed than I have been able to do before. The car feels extremely well balanced and poised, as if all of the parts are "singing in harmony." I am very pleased with how well this combination of mods has fulfilled my original objective.

Are there better handling WRXs out there? No doubt about it, but I bet few if any of them ride as comfortably as mine, especially on less-than-smooth roads.

Here is a break down of the costs to get to this point (includes shipping costs where applicable);

Wheels, tires and lug nuts - $1050
SPT Pink springs - $260
Alignment - $95
Camber bolt set - $35
RSB - $95
FSB - $110

Total cost of parts = $1645, or $595 for just the suspension components.

If your objectives are the same as mine (improved handling with little decrease in ride comfort), I can recommend this combination of parts.
 
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#3 ·
9d2TSi said:
Nice review, stuck. !Thumbs Up
Thanks!

I should also mention that I'm still running on the stock struts, and plan to do so until they give up the ghost. They seem reasonably well matched to the SPT springs and I believe have played a big role in maintaining the smooth ride a 52 year old car enthusiast (me) likes. It's pretty cool hanging those bumpy curves without the dashboard rattling!
 
#9 ·
bigbadbuddha said:
Good job CANNONSHOOTER... That was all center mass(HAHA)... ie bullseye

The Kumhos are a good tire but are very susceptible to shifting belts, and thus as they get older tend to become increasingly difficult to properly balance.
Had good luck with my first set up to 10k miles, no detectable problems. Then again, I'm a fairly conservative driver. I have a few thousand on my second set and am so far happy. The stock wheels/Blizzak LM-25s will be going on around Thanksgiving.

 
#19 ·
Are there better handling WRXs out there? No doubt about it, but I bet few if any of them ride as comfortably as mine, especially on less-than-smooth roads.


Total cost of parts = $1645, or $595 for just the suspension components.

If your objectives are the same as mine (improved handling with little decrease in ride comfort), I can recommend this combination of parts.
:rocks:
 
#21 ·
this may seem like a stupid question but how do you guys know whether or not your car is under steering or over steering? i know what both are and understand the physics with each but i really have a hard time telling when im just taking turns at a moderate speed on the street. are you guys going to the track and pushing your car harder and harder around turns intil the back kicks out or you have to correct steering to keep the front end on the line?
 
#22 ·
Take it to a roadcourse or autocross event... You will see what everyone is talking about. Learn to learn your car there and you will notice every little improvement as they come. Mine is bone stock and does great on the mtn roads (Mt Evans was fun yesterday), but I get it to the track and its a whole different story.
 
#23 ·
Here`s my example. I would run the car a little hard on the clover leafs and notice that the steering wheel would turn more than the direction of the car and the faster I would go the more the front tires would squeal. Once I changed the swaybars (22mm F/ 22mm adj. R) this understeer was less obvious , almost evened out. I decided to try the hardest setting (coming from the middle setting) and at higher speed the rear just felt a little more loose. Like Chevarian said I am am sure the track time would speak clearer to you and you would get a better feel of this subtle changes.
 
#24 ·
per GO4IT Racing schools training a couple of weeks ago, If the car gets squirly as a reaction of something (too much acceleration, braking, steering) do the exact opposite and give it less of that action. Or figure out how to get traction in otherways (suspension modification) If you feel it understeer, it is because you are not getting enough traction with the front wheels for them to turn. Let off the gas and the body weight goes down on the front more. Or stiffen up the suspension so that the body does not buck/roll when turning. That is what causes the understeer. The oversteer can be cause by too stiff in the rear without matching the front up.

Please feel free to correct me if I am wrong.
 
#25 ·
We maxed out front camber, ending up with minus 1 degree on each side. In the rear, one side was minus 1.4 degrees, the other minus 1 degree. We installed one camber bolt - on the minus 1.4 side - to even out the rear, ending up with minus 1 degree camber on all four corners. I had hoped for more in the front, but was pleased we were able to get the rear to 1 degree.


I am confused.
You put a camber bolt in the -1.4 side to give you "more" camber and ended up with -1?
Would`nt it be the other way around. You put the bolt in to get more negative camber from -1.0 to -1.4 ( if you were looking at the passenger rear tire from the rear then this \ would be more negative camber, this / would be more positive camber (i.e. -1.4 to -1.0) and this | would be zero camber

Thanks!:D
 
#31 ·
Update: Installed WL ALK, front camber bolts, rear outrigger and subframe bushes, IXIZ pitchstop and another alignment. (not sure if I posted the new BFG g-force a/s 235/45-17 I have ). All is good no rubbing no issues a little extra road noise from the stiffer bushes, but well worth it.
Next up is botox bolts and lateral link/ trailing link bushings and fender stays!
 
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