How I fixed my Knocking inverted Sti Type struts!
 

Hi all, thought some people might be interested to know a "third Way" to sort out the inverted struts failures.

As we all know, inverted struts on New Age Imprezas like to fail. these were fitted on STi's form around 2001 and to WRX's from MY 2005 (so note that 54 plate and on WRX's may be on inverted struts!).

The failure mode is that the struts run out of grease, and the damer itself doesn't fail, but the strut starts to knock and bang at low speeds, and you may hear graunching as you manouver at low speed. Ride quality will be affected. You may notice the car "settle" when coming off the handbrake, or after coming to rest usually with a nasty graunching noise. Like it or not handling will be affected because the damper is unable to damp properly because of the "sticktion" in the strut (primary friction that must be overcome before the strut starts to move and the damper can damp)

This picture shows the thickness of the "damper tube (actualy the damper body) on an inverted strut Attachment 56584
Normal struts are much thinner in the damper rod:
Attachment 56585

Up until now, it seems like there are 2 ways to "properly" fix this problem,

1) Fit Coilovers and replace the suspension wholesale. Fine if your car is a weekend driver/special stage warrior, or you want to alter ride height drastically. HOwever, without spending £1000 or more I'm still not convinced that you can get real ride quality out of coilovers. The adjustability available goes without saying though and it is undoubtably the best route for some.

2) Disassemble the existing inverted shocks, regrease them, and if you're doing a proper job, fit grease nipples so you can stay on top of the problem and periodically re grease them. No doubt this would work well, particularly if you did it before the shocks actually failed. However, I'm not a fan of having to re-grease my suspension, even just with a grease gun every 3 months or so. My struts had also been failed for a while, so the damper bodies looked scored and no doubt the seals were properly knackered too so any fix wouldn't last long.

Subaru wanted £550 A STRUT for replacements! :freak3:

So I decided to go my own route: I wanted a nice riding car with good handling, suitable for daily and fast road use. I did not want inverted struts as KYB have been making them for 10 years and they've been failing for 10 years! This doesn't fill me with faith for the aftermarket solutions like KYB Ultra-SR's
I did a lot of work looking up and finding out Damping rates and spring rates, and I also ended up getting into lots of bother because KYB if you ask them state that their Excel G shocks do not fit cars 2004-2006. There is good reason for this - they have to say that to avoid annoying Subaru because they are OEM suppliers and have a deal that they will not release after market parts until 5 years after the model build run has finished, to protect Subaru dealer revenue.
The standard KYB Excel-G shocks, and Ultra SR's (shown 2003 >on) WILL fit 2005/2006 model year cars despite what KYB say if you phone them direct!
The other issue is some confusion re Top mount fitting. This appears to be a non issue amongst WRX's. All top mounts appear to be the same 2003-2006 and most likelt 2001-2006 FOR WRX's. STis may be different. If you're fitting STi Struts onto a WRX car, make sure you have Sti top mounts too.

Anyway, My Solution: (Fora MY05 WRX PPP Wagon)
I got KYB Excel G Shock absorbers From Camskill. (nb These are Wagon, chsssis code GG specific!)
I got Eibach Pro-Kit Springs because their srping rate was only 20% up on standard, and they lowered a modest 20mm and I don't want to ruin my geometry or handling for the sake of looks, but I do think a slight lowering actually helps in twisties and looks a little better for a performance car. They also make Wagoon, GG chassis code specific springs - the wagon is only 20Kg heavier, but it's all over the rear axle and these springs have a higher progression rate for the wagon to cope with loads).
I got 2 sets of Eibach Camber bolts.
I took the car to rich at FB Tuning for Fitting and 4 way alignment.

HEre's all the stuff - About £580 all in
Attachment 56586

Here is how the car sat before:
Attachment 56587

Attachment 56588

Here is how the car sits now:
Attachment 56589

Attachment 56590

It's also been aligned, about -1.2 deg neg camber at the rear, -1.5 at the front, 5 mins toe in at the front and 2 at the rear. This was what Rich @ FB tuning recommended for me given my requirements.

I picked the car up this morning. It was raining hard and I haven't got time for a "proper" drive now but first impressions:

1) Instantly, primary ride comfort is there. Previously, the car was "Jiggly"... no primary ride/harshness reduction at all, and I guess this was because the shock struts were efefctively stuck in their tubes and took quite a big amplitude bump to knock them into motion. Now, the car feels like a magic carpet ride (Comparitively). It glides along very, very nicely.

2) Ride height looks good. I wouldn't want to go any lower personally, but the wheels sit well in the arches and the 4x4 front arch gap has gone.

3) Jurys still out on geometry. I impressed upon Rich at FB tuning that this is an everyday family car that needs to handle when a twisty road presents itself, not a tarmac special stage warrior. In the wet it's hard to tell to be honest. I had a couple of good hoons in the car as it was before, so I'll have to find time to compare when conditions are right. Nothing feels wrong, anyway.

Rich (in his own words: "I do nothing but drive these things") was impressed - he's driven it 30 miles for a shakedown and general condition check. He's asked me to get back to him with an update once I've had a chance to get used to the car and find any problems, but if all is dandy he said he'd be recommending this damper/spring combo to customers who want a comfy fast road set up because he was impressed with the Eibach springs.

So, first impressions are I'm happy. Time will tell exactly how happy. :D


Sumamry: Important points that I've learned:

• KYB aftermarket shocks, either Excel-G's or Ultra SR's WILL FIT WRX's from 2003-2006 no problems. you do NOT need new top mounts front and rear.
• Many springs are either too short or to ostiff or both. Eibach Pro R'#s seem good.
• If you want a cheap all round solution, a pair of rear shocks are £160 form Camskill, or the whole set ar £330 for Excel-G's or £370 for Ultra SR's and these will work fine with Standard springs.
• Camber bolts are needed if yo ulower the car - £20 a pair for Eibachs.

So what are your options:

• If you want a really aggressive set up with loads of adjustability, go for coilovers.
• If you want an STi spec set up, then KYB Ultra SR shocks have slightly more damping force than Sti shocks, and are inverted design. Combine with your chosen springs for lowering - again Eiabch Pro-Kit/Pro-R springs will work well and not drop the car too far.
• If you want to refresh your WRX suspension, Excel-G Shocks will fit fine and ride nicely, and can be combined with a MILD drop if you choose but I would not drop the car any more than I have (20mm) on them as they will not control a much shorter stiffer spring adequately! This wil lstop the inverted shock failure mode as you now have right way up shocks!
• If you are happy to keep your standard inverted shocks alive, rebuild them with grease nipples and stay on top of lubrication.

i changed my sti shocks to coilovers and i have to say when set on soft setting (bcs) it is the same ride quality as the original shocks and no knocking issues.
also have the added ability to adjust ride height,stifness etc when required. makes no sense to me to replace with originals really especially as the price is similar.

At the end of the day if your happy with your set up Dave good for you as your clearly not bothered about all the adjustments that come with coilovers:thumb:

I will be going down the same route at TT here.:thumb::D

Spot on bar the....

• Camber bolts are needed if you lower the car - £20 a pair for Eibachs

Not really needed for the road IMHO, but recommended given the lack of rear camber adjustment. I have them, but not because they were needed :)

Rich is a top man ;)

I got the camber bolts on Richs recommendation, basically to get a bit more of a "fast road" setting on them, particularly the rears, and of course doubling up the camber bolts on the front gives you more adjustment.
Makes life easier for him aligning it. Better to have and not need than need and not have!

Nice write up mate. Made for some interesting reading. And fair play with the route you went down. :thumb:

Dan

Good stuff.

The drop looks fine to me (not a fan of over-lowering). Eibach say you get a 25-30mm drop which I would have guessed make the car lower than what you have. You couldn't measure your wheel centres to wheel arch distances for us could you?

Be interesting to see what you think of the damper & spring combo with a bit more cycling of the dampers to settle them in :)

The STi red coloured inverted monotubed strut was introduced on the late classics (V5/6 P1 etc). They are known to sometimes feel a little 'nuggety' on small bump especially before getting warmed up (I haven't found this personally, and think they are firm, and comfortable)

hi mate, interesting write up-just a question if you dont mind, my 03 wrx seems to be doing the same and i was considering doing the grease nipple treatment next weekend but you say wrx are from 05? also worst case if my rear shocks have had it can i get them from camskill for £160? thanks spencer

First things first is to find out if you have 'inverted' shocks or not - you could do but if it's a standard '03 WRX I think it's unlikely. Top mounts can also fail and knock, as well as dampers themselves although the normal struts are less prone to this.

If you jack the car up and lift the dust boot behind the spring, if the shiny rod is only a tiny bit thinner than the strut leg itself then you have inverted dampers. If it's about half the diameter of the strut leg or less it's a sandard shock. I'll get comparison photos when I get a moment, I have my inverted shock and a 2003 standard shock for comparison in the shed.

But either way, if you narrow it down to failed dampers, the KYB's from camskill will fit your car fine for £160 ish a pair.

ok thanks mate, ive just had a nosey and the legs are thinner so i guess different than the ones shown? the rattle/knock isnt very loud but driving me mad, i had new drop links not so long ago, just had new clutch and still needing 4 tyres but ive got to get rid of the rattle....its getting to me....lol...and the stereo isnt very loud so cant drown it out...:lol1:

Here's the two together.

That's a silver painted Bilstein btw, almost indentical looking to the red STi

Edit: note the spacer adapter ring on the Bilstein

https://lh3.googleusercontent.com/-h...0/P1010775.JPG

Great write up. In laymans terms, whats the differences between the Excel G and the Ultra SR? I am running Prodrive springs and have a knocking n/s/r shock.

thanks mate, pritty sure mine are the same as the one on the left...i will have to get it on the ramps and have a good look and hope it doesnt need 2 shocks...cheers

The Excel-G are basically KYBS aftermarket "OEM" replacements and match the damping rates the car came with. They should feel better waht with being new (and mine certianly do).
The Ultra SR's are (as far as I've seen for the Subaru WRX) inverted designs (although 03' spec ones may not be! Confusing!) but their damping rate is 180% compared to "normal", ie. nearly double the damping force. This put me off them a bit, because I wanted something compliant and I wasn't going for a big drop. Apparently they're comparable to Sti shocks, but I've not driven any suabrus bar mine so I'm not placed to comment. The real reason I didn't go for them is they're inverted, and because KYB make the shocksfor Suabru, I felt that they were every bit at risk of failing as the Standard ones.

I think the Ultra SR's would combine really well with the Pro-R springs for a fast road car - think Sti Spec really. I wanted something a tad more compliant.

I've driven the car quite a bit more now, and I'm happy with the results. It should be said this is NOT an agressive set up, I'd describe it as "OEM+". It rides really nicely, absorbs small bumps well and even horrible pot holes don't jar the suspension or bottom it out.
I had 4 lads in the car tonight plus a full tank of fuel, it sat fine, no problems whatsoever with speedbumps and handling was fine too even loaded.

Handling is really nice with the geometry I have. It still understeers a smidge on turn in (Rear ARB coming up I feel!) body roll is controlled and feel no different to before and the stance is very neutral mid bend when on part throttle, cornering grip is high and the nice central "yaw axis" remains.

So far, it's exactly what I wanted.

Only thing that remains is an extended drive out on fun road to check its manners when pressing on are still good, I see no reason why they shouldn't be.

Have got simillar setup on my classic , exactly what i needed for a fast road car.. Had 2 sets of coilovers and i think its not nescesary needed on the road and ocasional track use... The car is much more predictable now and with a little body roll is the joy to drive. If the rear end grip is about to lose, you will have enough of time to ne ready for correction to make. To much of stiffness makes rear end to snap.

i now have coilovers fitted ,but after booting it around roundabout *to test coilovers* that was my excuse to the misses lol now when i drive slow there a clunking noise coming from the back left what could it be.?

cheers rob

Hi dave glad u got to the bottom of the problem seen ur earlier posts on this.
I have the problem with the shoulder on the shocks are diffrent so won't sit correctly (02 shocks on 55 plate Waggon) still not got round to getting some 05 shocks so they sit right.
I also have the same eibach springs fitted and they are spot on for me.
So just to confirm the kybs that say they are not for 05 models actually work if I buy 03on ones and keep my wrx top mounts. Do they all go together fine.
I might get the kybs now and fit my springs to them as they are still newish.
And the camber bolts, do I need for front and rear is that for £20 a pair or for all four corners.
Gonna ring camskill and get them ordered , do they supply the camber bolts aswell .
Also which ones should I go for (ultra sr,exel gs etc) as I want them for the best handling not bothered about it being too stiff, but don't want coilovers .
Regards busta

P.s is that my car(identical) lol has it got leather and sunroof

Just done a check and I belive it's only excel gs that are for the estates only is this right check link

http://www.camskill.co.uk/m10b0s2713...03_on_Excl_STi

Camber bolts
http://www.camskill.co.uk/products.php?show=64140

Yes, if you buy: 03 on KYB Excel G's they fit 03 Top mounts and bolt up to an 05-06 car fine. I'm convinced having looked at the top of '05 and '03 shocks that '03 Shocks will fit '05 Topmounts fine too, despite the change from normal to inverted shocks. I haven'tgot calipers to measure anything up sadly, but it all looks exactly the same.

I dunno, ask Camskill. The front has one set of cabmber bolts as standard, but adding a second set gives a bigger range of camber adjustment (using both upper and lower camber bolts). THe Rears have no camber adjustment as standard, so a set of camber bolts gives you a bit of adjustment. One pair is £20 and does one axle, so you can not fit them at all, or fit just one pair, or 2 pairs for as much adjustment as possible. I got Eibach camberbolts from ebay from the same supplier as my springs, as it worked out cheapest that way.

That's entirely up to you! I can only confirm that KYB Excel - G's fit the car, I haven't tried the Ultra SR's but I'd put good money on them fitting absolutely fine. Ultra SR's will be "stiffer" but may control the drop of the Pro-R Springs a bit better. I'm perfectly happy with my set up, but if I lived in South Wales or spent all my time hooning I might want things a bit firmer.
Yup, mine is an SL Spec so heated leather and sunroof. And it has the Prodrive kit too.

Probably, but to be honest I don't think damping rates are going to make much difference between Estate and Saloon - the Estate is only 20Kg heavier. Most important is to get the right springs as the Eibach springs for estates have a higher progressive spring rate to stop the car bottoming out if you load it up. Damping rates won't make any difference to that, and only an extra 20Kg against 600Kg or so over the back axle is nothing really. There obvioulsy is some small diffrence (or perhaps they just have 2 parts numebrs for the same part) but I don't think anyone would be able to notice.

dave.. i now have coilovers fitted ,but after booting it around roundabout *to test coilovers* that was my excuse to the misses lol now when i drive slow there a clunking noise coming from the back left what could it be.?

cheers rob

I dunno! I'm no expert and haven't heard your car!

Clunks can be notoriously difficult to find, even finding out where they're coming from as the body shell transmits noise in odd ways.

As a rule of thumb, try and isolate:
Knocking topmounts.
Spring seats/spring knocking onto damper body under load
Rear ARB links/bushes.
Some other suspension bush (i've heard these aren't bad on subarus though)
damper fault?
Something rolling around in the boot?

Lifting the car and moving things with a long bar can help find whats clunking, but be careful the car is stable. failing that bouncing the car (mate in the boot?) or take it to a specialist.

Cheers dave.
Plus 1 for the sl crew same here
So the ultra srs will fit as that's what I want, I'd go for the agxs but they don't do em for newages.
I have jdm bug shocks at mo with ebaichs on and they are excellent with rear arb, it's just that diffrent shoulder issue that's a bit annoying.
Don't want the excel gs as that might be a bit too soft for me as I do hard driving on road/tracks

Just a quick epilogue. I got around to dismantling my 2005 spec inverted shocks that came off the car, so I could compare them directly to the 2003 spec non inverted shocks. The only issue is whether or not the shape of the top of the shock damper is the same where it fits into the top mount:
Attachment 56594
Attachment 56595

It's not an issue. They're exactly the same shape. If anything when offered up the 2003 spec strut felt like it fittted the 2005 top mount better!

So, there we go.

And an epi-epilogue:
I've been out for an hours hoon on A roads, B-roads and unclassified roads, no mrs in the car so I was able to push it as hard as I dare.
I'm very, very happy with the chassis set up as it is. It has real composure and compliance over broken and uneven roads, even taking big bumps or dips under braking in its stride. It never feels like it's bottoming out or fidgety. Traction is complete with all four wheels on the road at all times.
It also has superb balance and mid bend composure. I really can't see why people characterise Imprezas as understeering!
I'm chuffed to bits, it's an awesome daily drivers car and has fulfilled my aims wholeheartedly for this car!
:)e car so i was able to push it as hard as I dare!
I'm really ,really happy with the chassis set up as it is. It's

I personally was amazed to read this. Perhaps you fitted the more expensive RM series.
When I fitted BC's BR Series to my old WRX, on the softest setting the car bounced down the road like a mad thing - and as such was totally undriveable, felt ridiculous.

About 6-7 from soft was more sensible, but even that made little difference on a badly surfaced or potholed road.
I ended up running around 15 from soft as I found it offered the best damping rates vs comfort; apparently you couldn't have both on the BR's. The missus hated it on bumpy roads; said it made her feel like she needed a sports bra!

Having gone back to standard STI shocks and Tein springs, WOW what a difference; the car is SO much more civilised and easy to live with, yet there's still very little body roll and it absorbs bumps without complaint and without rattling my fillings in the process. Given the choice again I'd buy replacement shocks or have mine rebuilt.

Just in my eyes. Everyone's different and everyone's tolerances are the same, but if you don't drive everywhere on A roads and motorways I'd stay away from coilovers (unless perhaps we're talking KW 3's or clubsports lol)


And back on topic - to the OP - thank you for an informative and helpful post.
I may well end up going for a full set of KYB ultras based on this information, cheers bud.

I've got this exact problem on my 05 WRX. It's annoying to say the least. The car is totally standard and used daily.

What setup do you recommend for me? Links to all the gear would be great.

Save yourself an absolute fortune:thumb:

https://www.scoobynet.com/suspension...uspension.html

Think i might. Do you know how much it would cost for a garage to do this?

Would of thought 25-50 quid a corner
Or you could get some kybs (not that expensive) oe shocks

OE KYB's are dealer only. The online ones are different