Learn Me - Spring rates for 2006 Outback 2.5i

So, I'm considering swapping in a set of Silvers Neomax single adjustable coilovers into my 2006 Outback 2.5i as seen here.

I use this car as a daily driver, but it's also the TSD/Road Rally weapon for the Finger Lakes Region Winter Challenge Series.  These are still public roads, but the rallymasters do a good job finding the gnarliest dirt/seasonal roads they can, and it would be nice to have some compliance versus crashing through on the worn, stock stuff.  I'd also like to be able to adjust spring rates to prevent blowing through travel, and keep ride height at OEM or 0.5"+.

Factory spring rates (if the InterWebz are to be believed) are about 196 # / 308 #.  Standard rates for the Neomax coilovers are 8kg / 10kg which are waaaaaay too stiff.  I was considering 4kg / 6kg (224 # / 336 #), although that's about a 14% increase in the front and only a 9% increase in the rear.  I could go to 7kg (392 #) in the rear, but not sure if we're getting to the edge of compliant.  The car understeers enough as is, so not sure I want to stiffen the front up if that might exacerbate the issue.  I am just learning to speak Subaru again, so am assuming that a higher rate/stiffer rear could get the tail a bit happier, but not certain.  For what it's worth, Rallitek higher rate springs are 205 # / 355 #.

Yes, I know, I'm overthinking this to the nth degree, and probably anything will be better than the current setup...but I'm open to S.W.A.G.'s, friends of friends experiences, band camp stories, and/or open ridicule.  :)

Thanks!

I think you are going to sacrifice a lot of suspension travel with those coilovers (and the outback already has less travel then the legacy it is based on to fit the larger diameter tires). Less travel is not what you want if you plan on having fun on those crappy roads, you'll be into the bump stops constantly.

My 07 Legacy has a bit of unique setup that is great on crappy roads, I'm running a set of JDM bilsteins out of a previous generation legacy (BH, 99-04). In the front I gained over 1" of travel and ground clearance and the rear was the same as stock so I fitted some slightly cut down Outback springs to bring it up a bit to match the front. My car sits higher then a stock legacy by about 1-1.5" which still puts it a bit lower then an outback. My crude at home spring rate measurement shows that my rear springs are around 400 lbs/in and the car is pretty nuetral when I rallycross it. 

So what would I do if I was in your shoes? I'd start looking at various Subaru models KYB shocks and struts on Rockauto, not because those are necessarily what you want but because in the info tab it shows you the travel and extended lengths of those components so you can compare. I'd want to put together a package that gives me the most travel possible out of the shocks and struts (you'll likely find that the 99-04 legacy gives you the most in the front, rear you will need to stick to legacys 99-09) and then build my own set of coilovers using the cheap amazon adjustable spring perches and QA1 high travel springs, maybe 400-450 lbs/in rear and 250 lbs/in front.

Adam

As a follow up, to give yourself tire clearance in the front you might have to cut the stock legacy spring perches off just leaving enough to support the adjustable perch for the 2.5" spring. The older struts will bolt right into the newer generation car but you will need to use the top hats for your car as those did change. If you want more camber upfront then what the stock adjustable bolts offer you can replace the other strut to knuckle bolts with crash bolts (I have done this on my car).

Adam

Hey Adam, thanks so much for the info!  I hadn't considered shock travel on the Silvers coilovers and certainly don't want to give up any...I've sent a note to them asking for measurements front and rear.

I wish Bilstein would build a set of HDs as a direct fit for the 05-09 Outbacks as I think they'd sell like hotcakes, but if they haven't done so yet, odds are good it's not going to happen.  I liked the idea of the JDM Bilsteins, but would really like to keep stock ride height if possible - we've had cars lose oil pans before in TSDs, and I haven't bolted up a skidplate yet.    

Great call on checking out RA for KYB info, and I have heard good things about the 00-04 front struts with the 05-09 rear combo.  The other option (assuming I don't want to fart around with coilovers) would be KYBs in the aforementioned combo, with Rallitek springs front and rear (0" lift front, 0.4" lift/overload rear).  I do like this idea as it would be plug in and go, although if I replace the upper mounts, bump stops, etc, it actually works out to be a couple hundred dollars more expensive than coilovers.  That said, I've got a dedicated car for RX/stage rally, so this really is going to spend it's life on public and seasonal roads...I need to make sure scope creep doesn't grab hold of me (again).

Any other insight is always appreciated...

Thanks!

Jason

Forgot to add (and for my own reference when I lose the paper I wrote this on)....

2005-2009 Outback - KYB GR2 Struts -

• Front - 20.05" extended, 15.15" compressed, 4.9" of stroke
• Rear - 18.01" extended, 12.75" compressed, 5.26" of stroke

2000-2004 Outback - KYB GR2 Struts -

• Front - 20.98" extended, 16.1" compressed, 4.88" of stroke
• Rear - 17.75" extended, 12.51" compressed, 5.24" of stroke

As far as comfort goes, as long as the shock valving is well matched to the springs, you have enough travel and the bumpstops are progressive enough when you do hit them, it'll ride at least pretty decently.  Running out of travel in a too-soft suspension will often feel worse than having something stiffer.  

Being that you're local, I'm happy to take you out for a ride in the Jeep as an example of ride quality on much stiffer than stock suspension (it's +47% spring rate in the front over stock, +118% in the rear at ride height and more as it compresses due to progressive rear springs).  

As another data point

2005-2009 Outback - KYB GR2 Struts -

• Front - 20.05" extended, 15.15" compressed, 4.9" of stroke
• Rear - 18.01" extended, 12.75" compressed, 5.26" of stroke

2000-2004 Legacy - KYB GR2 Struts -

• Front - 20.71" extended, 14.09" compressed, 6.62" of stroke
• Rear - 17.75" extended, 12.51" compressed, 5.24" of stroke

If you have a U-pull yard close by they can be a great place to go take measurements and get cheap parts to try out before spending a bunch, for example the Legacy struts give you a lot more travel but you don't know if your tires will clear so this could be a way to confirm that (besides more internet research to see if others have squeezed Outback wheels and tires under their Legacy's).

rslifkin is right though, high spring rates matched to the shocks do ride surprisingly well. I just wouldn't want to give up any travel (droop or bump travel) over stock in this application (or any daily driver with our roads in Ontario).

Adam

rslifkin said:

As far as comfort goes, as long as the shock valving is well matched to the springs, you have enough travel and the bumpstops are progressive enough when you do hit them, it'll ride at least pretty decently.  Running out of travel in a too-soft suspension will often feel worse than having something stiffer.  

Being that you're local, I'm happy to take you out for a ride in the Jeep as an example of ride quality on much stiffer than stock suspension (it's +47% spring rate in the front over stock, +118% in the rear at ride height and more as it compresses due to progressive rear springs).  

Thanks rslifkin!  I don't know what Jeep spec'd originally, but those seem like some pretty healthy increases, and good to hear it's still daily drivable.  I think I've actually seen your Jeep in Webster before...you should come out to play next winter in the FLR road rallies, as it looks like you're all set up for it!

adam525i said:

As another data point

2005-2009 Outback - KYB GR2 Struts -

• Front - 20.05" extended, 15.15" compressed, 4.9" of stroke
• Rear - 18.01" extended, 12.75" compressed, 5.26" of stroke

2000-2004 Legacy - KYB GR2 Struts -

• Front - 20.71" extended, 14.09" compressed, 6.62" of stroke
• Rear - 17.75" extended, 12.51" compressed, 5.24" of stroke

If you have a U-pull yard close by they can be a great place to go take measurements and get cheap parts to try out before spending a bunch, for example the Legacy struts give you a lot more travel but you don't know if your tires will clear so this could be a way to confirm that (besides more internet research to see if others have squeezed Outback wheels and tires under their Legacy's).

rslifkin is right though, high spring rates matched to the shocks do ride surprisingly well. I just wouldn't want to give up any travel (droop or bump travel) over stock in this application (or any daily driver with our roads in Ontario).

Adam

Thanks Adam - much appreciated.  I did a bit more research and it seems like Legacy struts can cause contact at full lock when installed on an Outback with Outback-sized wheels.  It's a little unclear if there was also lowering involved, but for mainly rough road based stuff, I'm expecting standard travel should be okay.

As I'm already way too deep in other projects, I took the simpler (and cheaper) way out.  Rock Auto had good prices on KYB struts (including a half-price "wholesaler closeout" on the front right), so I picked up 00-04 Outback KYB GR2 front struts, 05-09 Outback KYB GR2 rear struts, and a set of Rallitek springs (0" lift front, 0.4" lift rear) for the 05-09 Outback.  Also threw new strut mounts, boots, and bump stops in so that I can just assemble off the car, remove the old, bolt in the new.  After the cheaper price on the one strut, GRM discount from RockAuto, $40 rebate from KYB for a set of 4, and a $84 discount on the Rallitek springs, it ended up being a bunch cheaper than the Neomax coilovers, and I can bolt it in and forget about it.  I have too many projects going on already...I probably don't need to add my DD into the mix.  

Thanks again!

Jason 

In reply to Rotaryracer :

I've been thinking about doing the road rallies for a while, just haven't gotten to one yet (I've mostly stuck to rallycross with CNY).  Jeep needs a bunch of work at the moment though, so I've put a whopping 50 miles on it in the last 5 months.  Hopefully I'll have time to get through most of the issues over the next few months.  And I'll have to tweak the lighting setup a little to comply with the FLR road rally rules (only 4 forward facing lights allowed at a time, currently the high beams can be switched to either just high beams or high beams + the 4 on the front which gives 6 total).  

As far as spring rates, it was originally 190 lb/in front, 160 rear.  I'm now at 280 in the front (and went from a 26mm sway bar to a 29mm) and the rear springs are progressive, around 360 lb/in at ride height, close to 600 at full squish (and deleted the stock 16mm rear sway bar).  I've got a set of 400lb linear springs on the shelf to go into the rear at some point.