STi version 7 struts and springs into 91 Legacy Turbo SS

[ultrasonic]

I recently installed STi ver. 7 suspension from a 2002 JDM STi sedan into my SS. Special thanks to Gabe (ac30treb) for the assistance on the install. Details follow:

Part numbers:
Front struts RH 20310FE300, LH 20310FE310, with pink/orange/blue color code paint on the black springs.
Rear struts RH 20360FE300, LH 20360FE310, yellow/orange/orange paint code on springs. The set I have is well used, but appear to be in alright condition.

These came assembled with their stock springs and top mounts, which required changing to GC style top mounts in the rear to fit the BC chassis. Also GC rear upper spring perches are necessary as the GC mounts use separate perches. Part number 20373AA200, around $20 each from an online source like subaruparts.com.

To match GC rear top mounts to the version 7 struts, a couple washers are required to allow the strut top nut to tighten down on the mount. I used some washers from Lowes, they are Hillman brand which is carried by most hardware store chains, so the part number may be helpful to you: Hillman 9/16” SAE Flat Washers, Hardened, H# 880260. You will need two for each side and they come in packages of three. You will pay around $2.25 total.

A convenient tool to have when assembling struts is a pass through ratchet. The top nut is 17mm and you need a 6mm allen key to keep the strut shaft from turning. I found a pass through socket set at Harbor Freight for about $25 that works reasonably well.

Because the geometry is slightly different, the rear struts will induce some amount of positive camber. I used camber bolts in the upper rear strut to hub position to correct for this, and set them to full negative (eccentric lobe pointing inboard). I used Specialty Products Company 81260, +/- 1.75 degrees of adjustment, for replacement of 14mm bolts.

I set the front camber bolts to full negative.

Installation was uneventful. Search and read some of the step by step instructions here at legacycentral or on NASIOC. It is very useful to have another person to hold a wrench or lift a strut into position.

My stock ride height before the install, with what I assume are the original suspension parts with over 109,000 miles on them:
(Measurements taken between center of wheel to bottom of fender lip)
Front: 14.5"
Rear: 12.5"

After the install I measured:
Front: 14.25"
Rear: 13"

We'll see if this settles in after some amount of driving. I don't expect it to change much.

Without using any fancy tools to measure things, it appears that I have very slightly negative camber on the left rear, but slightly positive camber on the right rear. I'll look into this more later.

You'll need several hours, a jack, jackstands, a long breaker bar, some penetrating oil like PB Blaster, and about a six pack of beer to complete the job. We used Heineken. Also, we broke the job up into two nights to ease family schedules. We did the rears the first night, fronts on the second. The front goes faster.

Driving Impressions:
While this is an obvious improvement over the worn out stock set up, it is not nearly as stiff and harsh as I feared that it might be. It's reasonably comfortable around town, much flatter in the corners, and more composed when dealing with mid-corner bumps. It seems to display some slight amount of the infamous STi "bounciness," especially evident at cruising speeds on the highway.

For comparison, here is a list of other modifications that may impact how this set up feels:
- 16" x 7" 2000 2.5RS wheels
- Falken Ziex 205/50/16 high performance all season tires
- Whiteline BSF18 20mm front sway bar
- high performance solid front sway bar links
- STi Group N transmission mount
- WRX front brakes

I'll provide more detailed driving impressions after I get an alignment and have an opportunity to try different driving conditions.

[ac30treb]

I don't know who this guy is or what he's talking about!

Just kidding.

I thought I'd chime in and thank the guys here on the board for posting tons of useful info. "Ultrasonic" and I have done both our cars' suspension systems after researching here.

I'll let Steve give everyone the update on his rear camber issue. I think it had something to do with reading the instructions on the box of camber bolts.

[ultrasonic]

I'll let Steve give everyone the update on his rear camber issue. I think it had something to do with reading the instructions on the box of camber bolts.

Yes, exactly that... after following the directions my camber issue has been resolved. Time to book an alignment.

I had a chance to get out on some twisty back roads for a few minutes tonight, and I can say that I really like the way this car feels now. I have not had the opportunity to push really hard, but it feels so much better now.

I'll be out driving, looking for the limit...

[vrg3]

Yeah, you have to make sure you get the little tab on the washer in on the correct side. And make sure it doesn't get smushed flat!

And even though you're not supposed to do it this way, I usually get away with using an impact wrench instead of a pass-through socket.

[wiscon_mark]

pictures?

Its interesting to see someone trying STi stuff on the Legacy

[ultrasonic]

pictures? ;-)

Its interesting to see someone trying STi stuff on the Legacy :)

There's not really much to see. Struts are red instead of black. Most people have seen the hardware before. It's an inverted strut, so the upper part of the shaft is of larger diameter than the stock, non-inverted design. Ride height is nearly identical, so there's nothing to look at there.

I believe that vrg is running ver. 7 struts and springs, and I seem to recall that kelly has had both ver. 7 and ver. 8 STi suspension on his car. I know there are more but can't recall the names right now.

So far this set up is working out really well. Once I figured out the camber bolts, that is. I'm really looking forward to an alignment, and then I can really dig in and see what it will do. So far, so good. Certainly not too harsh for a daily driver, much more overall grip, more responsive and precise. Tighter overall feel. And the price is reasonable.

[vrg3]

Yeah, I'm running v7 stuff just like you. Brat4by4 is running v8 stuff I think.

But, yup, it just looks like red struts.

I found my ride height went up a lot, especially in the rear, but that may have had to do with my stock springs being really saggy.

In my car it balanced the suspension out a lot... I used to get a lot of understeer that I hated, and now I can actually make the car rotate pretty easily. The way it is now I'm almost considering a bigger front sway bar.

[ultrasonic]

In my car it balanced the suspension out a lot... I used to get a lot of understeer that I hated, and now I can actually make the car rotate pretty easily. The way it is now I'm almost considering a bigger front sway bar.

vrg-- I installed a Whiteline 20mm front sway bar several weeks before doing the strut and spring swap. I think it was a good mod even on the old suspension. I know the long standing rules say that stiffer front sway bar will increase understeer, and I'm sure this is true at the limit of adhesion. But below that limit, where most people spend most of their driving time, the stiffer front bar works to increase overall grip up front. My guess would be that it does this largely by providing a more consistent contact patch on both front tires. Also, as it keeps the front of the car flatter and more stable. It just feels better.

I was encouraged to try the stiffer front bar (without stiffening the rear bar) by a local auto crosser who runs only an upgraded front bar to stay within certain class rules. He stated that most understeer situations are "driver induced," so I figured I should learn some techniques to avoid it. In practice I only experienced an increase in understeer when I would get sloppy and not manage the weight transfer smoothly enough at the entrance to a corner, and also not come in too fast. Beyond that, there was no downside to having upgraded only the front bar.

It works even better with the ver. 7 struts and springs. There must be additional stiffness in the rear of the ver. 7 set up that results in more oversteer. What are your alignment specs with ver. 7?

Still, I'd like to try the Whiteline adjustable rear bar.

[vrg3]

Hm. I don't really understand suspensions all that well, but I understand what you're saying... So I guess a Whiteline 20mm front bar is something I should indeed pursue.

[ultrasonic]

Just picked up the SS from the alignment shop. I asked for:

a. In the front, maximum negative camber using stock eccentric bolts. Zero cross camber. I suggested that it would be between -1.0 and -1.5.

b. Rear negative camber slightly less than the final front camber, i.e. if the front ends up being -1.5, then make the rear -1.0 -or- as negative as possible approaching this.

c. Zero toe, front and rear.

Final results:
Front Camber (L) -1.1 degrees (R) -1.3 degrees, Toe (L) 0.02 degrees, (R) -0.03 degrees
Rear Camber (L) -0.8 degrees (R) -0.9 degrees, Toe (L) -0.00 degrees, (R) -0.02 degrees

Although not adjustable, the caster is (L) 3.1 degrees, (R) 2.4 degrees.

And the steering wheel is straighter than it was before.

In theory, I'm fairly pleased with the results. I'm least happy with the front cross camber, but that may be nit picking. I'm excited to hit the road and see how it feels.

[Busdriver]

Has anyone had any luck with STI takeoffs for a early wagon? Rear sag...?
I would like to stiffen up the ride considerably without lowering too much...
I have thought about just starting with bushings, but the shocks are really wavy, gets an after bounce and lots of body roll....

[ultrasonic]

I've been rolling on the STi suspension for over 1500 miles now, so I'd like to share my driving impressions.

The short story is... I really like the car set up this way. It is much tighter and far more solid feeling, but remains totally comfortable for a daily driver. I even put my GF and our son in for a three hour trip to visit my parents. At the same time, the overall increase in grip, stability, and composure is nothing short of amazing. Granted, this is a direct comparison to 110k mile worn out running gear, but it's still obviously a transformed car. I don't have much else to compare to, but I'm quite satisfied with the v. 7 STi suspension.

I really spent a lot of time (thanks legacycentral and NASIOC Suspension forums) researching this suspension overhaul, and I think I pretty much achieved my goals:
a. sportier, higher performance handling
b. minimal change in ride height
c. low cost
d. OEM fit

Since installing the STi struts and springs I have also installed a Whiteline RSB17XZ adjustable rear sway bar, which has really added to the overall package. It is currently set at the middle setting (20mm equivalent).

I'm looking forward to some fun in the snow this winter, and I'll probably try my hand at some autocross next year.

Next up... intercooler and more boost.

[ultrasonic]

At over 5,000 miles on the STi struts, the inevitable has happened... the ubiquitous "clunk" noises have appeared.

The symptom: dull clunk or thunk noises from the rear suspension while driving over surface irregularities at low speed. The noise can also be replicated when the car is sitting still by bouncing on the bumper. At speeds over 20mph or so there is no noise. There does not seem to be any problem with the way the struts work otherwise.

The theory: Common theories about this issue blame this problem partially on the inverted design of the STi struts. It seems to happen across the board to pretty much any model year / version of the STi struts.

The solution: Some users find that jacking the car up so that the weight of the wheels extend the strut, letting it hang for a few minutes, then setting the car back down will make the clunking go away-- for a while. Others claim that lubricating the shaft of the strut (while the car is jacked up and the strut is extended) makes the symptoms go away, too. Many owners of new STi's have had struts replaced by SOA under warranty. Some have had many rounds of warranty replaced struts, one owner claiming that he is on his fifth set. Recently, a guy from after market suspension maker DMS has stated that removing the damper cartridge from the strut body, lubricating and reassembling it is the best and longest lasting cure. It appears that while it is not guaranteed to happen to every strut, the problem is common to all the current versions of STi inverted struts. It seems to happen mostly on the rears, but there are reports of the noise on the front struts, too.

I have had slight reduction in noise by jacking up the car, but the noise was back within a hundred miles. I may try the DMS grease repacking technique if I have some other reason to take the rear suspension apart.

Now, all that being said, if it weren't for the clunk, I would never know there is a problem. The car generally feels great, and seems to react well to being pushed hard in cornering. Now that the threat of snow and ice is pretty much over I now have the rear sway bar set to the highest setting (22mm equivalent) and the feel is nicely flat in corners, stable over mid corner bumps, and very solid. I can really tell if my tire pressures are not set correctly, especially in the front. I had a slow leak due to a drywall screw that was embedded in my right rear, and I discovered it when I rotated the tire to the front. After a couple days it would be down 5 or 6 lbs. and would call attention to itself. Keep the tires inflated correctly after having the puncture repaired, and everything is cool again.

Spring projects: STi engine mounts, intercooler, and chassis/suspension bushings. Oh yeah... and more boost.

[BAC5.2]

That has to be the worst alignment shop I've ever heard of.

On the front, L&R camber should be the same. Toe should be .01" L&R.

Front camber should be greater than rear if off-throttle oversteer is what your game is.

Rear camber should be the same L&R (though factory rear bolts are noneccentric), and rear toe should again be around .01" L&R.

[ultrasonic]

That has to be the worst alignment shop I've ever heard of.

On the front, L&R camber should be the same. Toe should be .01" L&R.

Yeah, not the best alignment those guys have given me. Like I said in the original post, the cross camber is annoying. Moreso on paper than on the road. It actually feels pretty good as it is. There are probably more suspension mods on the way, so they'll have a crack at getting the alignment more spot on before it's all said and done.

Front camber should be greater than rear if off-throttle oversteer is what your game is.

Rear camber should be the same L&R (though factory rear bolts are noneccentric), and rear toe should again be around .01" L&R.

Well, front camber IS greater than rear camber. Slightly. Not as much of a difference as some guys like. I like it a bit closer to neutral. Between the adjustability of the rear bar, and the stiffness of the STi springs and struts, it works out nicely. Oh, and I do have eccentric bolts in the rear, too.

I just installed the Whiteline KSB751 Rear Differential Bushings today. I picked them up from a local guy who took them off his WRX prior to selling the car. I love getting cool stuff on the cheap. The good news: quickly removing my foot from the accelerator does not cause dramatic surging anymore. That sloshing effect must have been the rear diff rocking back and forth. It is also easier and smoother shifting from 2nd. to 3rd. gear in many circumstances. The bad news: significant increase in NVH. Nothing I can't live with, but certainly noticeable.

[Busdriver]

The symptom: dull clunk or thunk noises from the rear suspension while driving over surface irregularities at low speed. The noise can also be replicated when the car is sitting still by bouncing on the bumper. At speeds over 20mph or so there is no noise.

I have the same symptom on my 91 wagon. By the feel of the suspension, I believe it is the original stock stuff with just over 180k miles on it. I need new suspension. Any recomendations?
I would love sti stuff, but am not sure they will benefit the rear of a wagon.
Does anyone else have that thunk noise?
What is NVH?

[ultrasonic]

I have the same symptom on my 91 wagon. By the feel of the suspension, I believe it is the original stock stuff with just over 180k miles on it. I need new suspension. Any recomendations?
I would love sti stuff, but am not sure they will benefit the rear of a wagon.
Does anyone else have that thunk noise?
What is NVH?

You have a completely different issue, separate from the clunking on STi inverted struts.

You probably have worn out struts, and possibly worn or broken strut mounts. Search around this forum for replacement options.

[wiscon_mark]

NVH is the amount of noise something creates.