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Forester struts on an Impreza GC8

143K views 238 replies 40 participants last post by  Jack_Stalk  
#1 · (Edited)
Notable Forester Strut Links and Info, updated 3/11/11:

http://www.dirtyimpreza.com/forums/showthread.php?t=16330
http://www.rs25.com/forums/f105/t141028-outback-lift.html

There is a TON of good information in here about Forester Suspension swaps, notably pages 6-15.


So I put Forester struts on my GC. I'm sure other people are interested about doing this because the lift looks AWESOME! It's about a 2-3 inch lift in the front, and a bit higher in the back. I acquired these Forester struts with 75k on them from a friend who lowered his Fozzy. I figured it would be a nice and easy swap, but after doing a bit of research I realized the rears wouldn't be a direct bolt-in. The fronts bolted in fine with the sway bar disconnected, and I had to do some "custom work" to the rear strut towers to get this to work. This was not an easy swap, but can be done by a skilled "mechanic".
There's two options to fit the rear struts onto a GC impreza:
1. Swap your original tophats with Forester tophats
2. Keep the forester tophats, and drill new holes in your strut tower

I went with the latter, and it was pretty time consuming because I made sure I drilled the holes in the correct spot. To start, one must know how to change a strut. You can check out the strut replacement in the DIY section http://www.rs25.com/forums/f105/t70898-diy-strut-spring-install-pics.html
I'll give you a quick shot explanation. There are 5 bolts that need to be removed to take out the strut. Jack up the car and put it on jack stands, then remove the wheel.
You should see the first two bolts bolting the strut to the wheel/disc brake/drum brake etc.
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These are 19mm and are best removed with an impact gun or a large breaker bar. I went through four 3/8" breaker bars doing this install over the weekend. You need a wrench on one side to hold the nut, and the breaker on the other side. I used a ton of PB Blaster and quick jolts of force(thanks jakeachy) to get these suckers loose. After getting these two bolts loose, the rear seat must be removed to get to the strut tower. There are 3 12mm nuts here, and are pretty easy to take off.
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After taking off these 3 nuts and the two bolts, the strut should come loose. For my car ('95 coupe) the drum brake line is connected to the strut with a small clip and a mount. The easiest way to free the brake line is to pry the clip out and hacksaw the mount open, then pry it apart with plyers to get the brake line out. Be careful and don't damage the brake line, or you'll have a big mess.
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After disconnecting the brake line from the strut and taking out the nuts/bolts, the strut should come free (may require a little convincing or kicking). At this point, I realized the rear forester strut doesn't line up with the holes correctly. It took me about 6-12 hours of research and careful planning to do this next part correctly. I looked everywhere for the easiest way to put these rear struts in, and IMO it's simplest to leave the Forester hats on and just drill a new hole. The first two need to be widened a bit, but the outermost hole needs to be re-drilled. So I got to work with my drill, widening the first two holes and redrilling the third. Make a template of the forester top hat, and carefully mark the holes in the strut tower for drilling. The first side took me a ton of time because I messed up my measurements and had to re-drill two of the holes.
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This next step you can do yourself, but it's best to have a buddy. Disconnect the rear sway bar, which is the tiny 13mm "bar" connected to the rubber bushing at the rear of the axle(if youre stock), and let it hang freely. The axle should come down a lot farther now, and you're now able to wiggle the Forester strut into it's new home, the Impreza tower.
I used my friend inside the car to line up the bolts with the holes, while I wiggled the strut from the bottom to get it in. Once you get it in(may take awhile) you can put the 3 nuts back on and tighten them.
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After this you're going to have to muscle the bottom of the strut to line up with the holes on top of the axle. We used a scissor jack for this, to compress the strut a bit and line up the holes. Be careful, take your time, and get those two bolts back in.
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At this point, the strut should be in it's final resting place, and you can torque down the two bolts on the bottom of the strut. I personally didn't reconnect the rear sway bar, I'm sure you'll need new endlinks to get it to line up properly. I put the brake line back into the mount on the strut, then proceeded to put the wheel back on and lower the car. This could be used as a DIY, but it involved a bit of custom work that other users might not agree on as safe. I drove the car offroad all day today until we broke the driver's side front axle after going off a jump. These forester struts put a lot of strain on the other parts of the car, so use them with care. Luckily I've got another couple axles laying around, so I could afford to experiment a bit. The suspension is a lot softer especially with the sway bars disconnected. The newly drilled rear strut towers have held up AWESOME during the test. As you can see in the video, I drove the car fairly hard to make sure everything was working properly.

The lift looks great, here's the difference over my parts car on 13s:
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Here it is next to my stockish height 2.5RS:
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By itself:
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Attempt this mod at your own risk, there's a lot involved and I wouldn't do it if youre afraid of severely messing up your car. I did it to my daily, because the older GCs are a lot easier to work with. If you have any questions at all about putting forester struts into a gc coupe or sedan, feel free to PM me anytime about it. I'll try to answer them as best as I can.

Here's the test video. We broke the axle shortly after the first clip, and proceeded to film the rest with the shotty front axle. I've got a whole parts car, so I'm not worried about the center diff. I suck at embedding, heres the link.

YouTube - Lifted '95 Subaru Impreza coupe on Forester Struts


OTHER MISC LIFTING INFORMATION (courtesy of kostamojen)

Struts:

The basic principle behind Impreza lifting is that as it turns out, Forester struts are aprox. 2" longer between the spring perch and hub mount, providing an instant 2" ride-height lift. These struts ALSO allow for taller tires by providing more clearance between the hub and spring perch. Late 90's Outback struts may also provide lift in this manner (need more information).

Forester struts come in various varieties, and there are aftermarket options too.

XT struts are stiffer than the non-turbo varieties.

KYB offers GR-2 Forester struts, which are also stiffer.

There are also JDM "STI" struts which offer more stiffness, although will cost more.


Strut Top Spacers:

Several companies currently offer strut top spacers (Paranoid Fabrications, Subtle Solutions, Jackson Rally). Anything over 3/8" WILL require new strut top bolts in order for enough thread to fit through the spacer.

This is also a way of performing a strut-lift without changing struts... HOWEVER, taller tires will still not clear the spring perch on Impreza's due to clearance issues.


Strut Top Mounts:

Front top mounts are the same on all model year Imprezas and Foresters, so front suspensions can be installed without changing tophats. Group-N tophats are available of course for extra stiffness if so desired.

Rear top hats are an issue for 93-01 Imprezas (02-07 Imprezas match up with 03-08 Foresters)

There are two options:

1) Install your stock 93-01 Impreza rear top hats onto the Forester struts. This MAY require some sort of washer/spacer between the top hat and strut (more information required)
2) Keep the Forester top hats, drill a new 3rd hole into your chassis to fit those mounts. This has a couple of issues, including the fact the center of the top hat runs into the strut top hole as they don't match up, and the Forester top hats DO increase the ride height in the rear some more. (I corrected this with a 1/4" spacer in the rear, and a 3/8" spacer up front)


Springs:

Forester springs provide MORE lift over just using Forester shocks, because if you use WRX/STI/etc. springs on a stock Forester, it lowers it quite a bit. Various Foresters have different spring rates (more info required).

If you want even MORE lift, King Springs makes lift springs for various Subaru models including Foresters.

If you don't wish to do more than 2-3" of lift and wish to maintain good handling, use WRX or STI springs in order to reduce the amount of lift (Aftermarket springs are also an option).


tires:

Taller tires can also provide more lift to your vehicle.

Forester-height tires (IE 215/60/16) can work with a lifted Impreza, but for more radical tire sizes with off-road tread patterns there are other options such as Grabber AT2's (215/75/15 or 215/65/16) and Superswampers.

NOTE: Larger tires can and probably will cause issues with fender clearance. Major modification of fender liners, rolling of fenders, and even trimming of bumpers MAY be required depending on the tires you select, so be warned.


Trailing Arm Brackets - When performing a lift, the rear trailing arms start to pull the rear tires closer towards the front of the rear fender wells, as well as causing issues with suspension geometry. To fix this, trailing arm brackets that "move" the pivot point are required.

97-99 Outback trailing arm brackets have a pivot mount that is over 1" lower than an Impreza bracket, which will correct the geometry and keep the tire farther away from the fender.

Forester brackets have pivot points that are farther rearward, and move the tire away from the fender, but don't provide as much geometry correction.

Adjustable length trailing arms can also partially solve the trailing arm issue (See: Cusco and OBX trailing arms) but should probably also be used with Outback brackets.

"Spacers" for the trailing arm bracket. Some people have made custom spacers that lower the trailing arm down, which can be especially useful for cars with quite a bit of suspension lift and need more than the stock brackets can provide.

Note: I can't confirm this yet, but apparently some trailing arm brackets from various Impreza and Forester model years have DIFFERENT bolt patterns, I need more information on this.


Swaybars:

When performing a lift, Swaybars become an issue because you are increasing the distance between the swaybar and where the suspension rests at. The EASY solution is to remove the swaybars all together, but at the expense of on-road and higher speed handling.

Rear Swaybar - 97-99 Outbacks have rear swaybar brackets that sit about 2" lower than stock Impreza brackets, which in turn lowers the swaybar to correct for added lift. Forester brackets may also be compatible (need more information).

Front Swaybar - The front swaybar is enclosed by the subframe, so there is no easy way of lowering the swaybar. HOWEVER, longer endlinks will also solve the problem. I recommend running Kartboy STI rear endlinks on the front, since they are longer than stock front endlinks (contact Kartboy for more information, if you have a stock non-sti front control arms, the endlinks may require a different bushing).


Other "required" parts:

Rear Camber bolts - These are important because without them, you can't properly align the rear suspension when lifted.


Body Lift, IE body spacers: (possibly required depending on the amount of lift you are doing)

Outbacks and Foresters over the years have used spacers between their subframes and chassis in order to lower the drivetrain to correct for CV angles.

IF you are doing a lift of several inches, this may be required to prevent your CV's from constantly dying.

There are several items required: Front subframe spacers, Rear subframe spacers, Rear differential support spacers and brackets and bolts, corresponding transmission cross members (MT or AT depending on your application), pitch rod, and longer steering joint.

This can also be accomplished via custom work of course, which some people have done.


Optional parts:

Adjustable rear lateral links - These can help with the rear alignment, along with lock bolts, for off-roading purposes. They can also increase the rear track width if so desired.

WRX sedan/STI front control arms - These can increase the track width, which can help with fitting taller tires.

Adjustable rear trailing arms - Can help move the rear tire toward the center of the wheel well when lifted.

Aftermarket subframes - These are starting to show up, and may provide lower mounting points to help with lifts, and perhaps lower drivetrain components as well like a body lift.
 
#10 ·
Be sure to loosen/re-tighten your front control arm bushings so that they are unloaded at this new ride height.

-- Dave
 
#12 ·
It shouldn't have caused the axle to blow, it will just tear up the bushing and put unnecessary preload on the LCA. I have a feeling the axles for a Fozzy are a tiny bit longer than Impreza axles because of the extra ride height, that's just a guess though.
 
#13 ·
Here's what I call a 'blown axle', I used a general term.

The driver's side front axle constantly clicks now, and it clunks when I try to turn. If I put the car in park it will still roll (90/10 diff). The car is 100% driveable this way, but I haven't had time to really check under the car and figure out what's wrong. I'm thinking the CV joint is all f'd up.
 
#17 ·
The video through the woods looks like a good time!

i can totally understand the need for clearance after seeing your woods footage just be careful with tight turns on that set-up. We had a buddy with forester rears who rolled his impreza over in a tight turn on dirt. He had a cage so it wasn't a big deal...but he did have to spend the time and cash to repair, paint, fix glass, etc. He went back to stock struts after that one.
 
#20 ·
UPDATE: The front/rear swaybars fit with some modification, and the car handles infinitely better offroad with a rear swaybar connected. It's really easy to kick the back end out with a rear sway. The forester struts do make the car tip more, but installing strut tower bars and upgrading the sway bars eliminates a lot of that. I love this setup for offroading, no more bottoming out ever!