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Ultimate EA81 BRAT suspension!


Gravityman
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Whats up Subaru Freaks!

 

Down to the point: ER27 engine and entire suspension swapped into an EA81 Brat with any upgrades possible.

 

Question: With no worry about metal fabrication seperate of cast materials (ie. stock xt6 knuckle), What do you think would be the ultimate suspension setup under an super fast EA81?

 

Elaboration: As you all know I am building a ER27TT. My plans are to remove the entire stock suspension system from the Brat, this includes; Control arms, sway bars, stabilizer/bracket, transverse link, torsion bar..yada yada. What I want to keep for the base to build up from will be the ER27s fulltime 4wd trans, halfshafts for the 5 lug and the knuckles. On the rear I have a VLSD R160.

 

 

Goal: I want to modify whatever I can on the stock xt6 suspension in order to upgrade it. I would love to build a custom transverse link that would look more like one out of an Impreza (lower A arm) to help increase strength and stability. As far as the struts go, anything that I could wrap around an ER27 steering knuckle, I dont care if I have to spread the lower strut mount or grind down the xt knuckle (minor modifications here are acceptable). Modifing the upper strut mounts (front and back, within plausable means) is totally acceptable as well. I want a fully adjustable suspension front and back, adjustable height and dampening. I want upgraded bushings all around. I want to keep the price of the Struts as low as possible. I know I can get cought up with $2000 struts but something like KYB AGX with adjustable coilovers would work just as well.

 

Nitty-Gritty: When all is done I want a suspension under the Brat with an XT6 foundation with its increased wheel base, 5 lug and 5 speed full time 4WD that is fully adjustable and extreamly durable! I want to flog it and have no problems at the end of a rough day.

 

Your input: What do you think would work for this setup? Examples. Also, what do you think? Shoot links if you have seen anything similar on a soob.

 

Thank you for your input!:headbang:

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Easy Peasy for EA82 but should work for brat aswell.

 

 

Megan Coilovers for a 05+ Legacy GT.

 

See pics here: http://cgi.ebay.com/ebaymotors/Megan-Coilover-Damper-Kit-Subaru-Legacy-05-06-2005_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQcategoryZ33582QQihZ022QQitemZ350026683801QQrdZ1QQsspagenameZWD1V

 

Can be found for as low as $850 around the net.

 

Adjustable so you can have it stiff, or floppy, high or low.

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Those are nice! a little pricey but nice and they have everything I want. Do the 05 legacy's have the same knuckle style as the XT6? Also, I am curious as to the differences between the Brat, XT6 and Legacy's stock spring rates. I see that the ones for megan are 6 kg front and 8 kg rear. I wonder how that would feel on the brat which would be tons lighter then the legacy. I bet it would be like driving on rails. What about KYB?

 

What about the A arm Idea? I thought I saw someone fab up one out of tube steel but cant remember where I saw that. Would that be better then going with the control arm and tension rod?

 

I was also thinking that using the stock XT6 sway bar with the larger diameter would be sufficiant.

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You might want to see about getting an EJ rear subframe and modify the body to accept it if you're not worried about fabrication. Look into a '03 and up WRX rear subframe since the diff bushings are much better designed. Then you can make custom lower control arms for the rear to make the stance any size you want. It would be a lot of work and probably require the bed getting chopped up and a custom "subframe" made welded to the unibody that the EJ subframe can bolt up to. If you need alignment specs, let me know, I have access to them all, plus any sort of aftermarket alignment pieces you might be interested in:banana:

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ej suspension is far superior than the xt6... however, if i were to do it without doing TONS of fabbing, i would probably opt for getting koni yellow inserts and ground control coilover kit. very tunable with this setup and relatively cheap.

 

assuming the inserts fit in your old strut bodies, there will be no need to modify your knuckles with this setup. :)

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I would highly recommend using EJ front knuckles/axles. then you can use EJ suspension options more easily, and brakes too! but the EJ front struts can be modified to bolt to XT6 knuckles.

 

 

personally, I'd run ground-control coilover springs in the 250-300 lb/in range. with some KYB AGX struts/shocks (will need to use Miata application rears and EJ fronts). a bit less spendythan the megan racing coilovers, but much higher quality (the megan's are pretty cheap!), and just as adjustable.

 

EJ rear suspension would be awesome, but would be a fabricating nightmare. as they're a true McPherson setup, so the location of the strut tops in relation to everything else would have to be exact, you'd definitely be cutting up the bed to make it happen.

 

don't forget some SuperPro Poly bushings.

 

 

 

for brakes, I love my RS 2-piston fronts with XT6 rear rotors and 200SX calipers. lots of braking power, and 15" wheels still clear (cheaper tires than with larger wheels!).

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You might want to see about getting an EJ rear subframe and modify the body to accept it if you're not worried about fabrication. Look into a '03 and up WRX rear subframe since the diff bushings are much better designed. Then you can make custom lower control arms for the rear to make the stance any size you want. It would be a lot of work and probably require the bed getting chopped up and a custom "subframe" made welded to the unibody that the EJ subframe can bolt up to. If you need alignment specs, let me know, I have access to them all, plus any sort of aftermarket alignment pieces you might be interested in:banana:

 

look up mixthetoo's thread about his OBS swap into a BRAT. from what I remember he is having a bear to a time getting all of the suspension to work. He said that he had to redo his rear subframe b/c it was not centered or lined up or something like that. If you are looking for custom rear suspension, it might be easier to use the torsion bar to mount a trailing arm made out of tubing. Not sure if the benefits outweight the fabrication time.

 

BW

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Actually just going through all this with an 86 RX Sedan here in Kangaroo country . Also these are our opinions ATM in a development phase .

 

Front : Keep your std control arms and radius rods because you can do more with them than fixed "A" arms . Need urethane radius rod bushes .

I'd use Legacy knuckles as you call them because they fit between the "ears" of Legacy/Impreza front struts .

I'm told L front calipers and 1G Legacy RS brackets go over the RS sized disc rotors - will get back on this one .

 

Rear: Impreza GC8 rear geometry is not all its cracked up to be (roll centers) , they are effectively Chapman struts .

 

You can do a fair bit with the stdish semi trailing arm IRS and simple mods .

The first is to beef up the std anti roll bar mounts so that they can handle much higher rate bars . I had custom 24 and 22mm bars made for my RX L sedan and honestly the rear could easily be 24mm especially on a heavier car like an XT6 . The std bar mounts failed dismally with the up from 16mm 22mm rear bar , the tinny hoops open up because of the cheap nasty tag and one bolt design . What you need to do is remove the captive nut and slide in a piece of flat bar with two captive nuts fitted so that you can use easily available two bolt hoops . May need to strengthen the gussets under the arms in this area as well . Use urethane bushes as well .

 

We are having made up a Koni rear damper (gas/hydraulic) here in Aus that's a std thing and even its rate looks suitable for 200-240 in/lb springs . The only mod it should need is a circlip groove down low to mount the lower spring seats threaded tube .

Springs are easy peasy , 66mm ID motor-sport springs are common and cheap - hell even L 4WD wagon rears are 196 in/lb so very cheap starting point .

If you can take most of the body roll out of the equation camber/caster problems are much reduced .

Must do something about very soft rear diff and cross member body mount bushes otherwise the whole rear end tries to "rear steer" under high cornering loads . If you cant get urethane ones we found the next best thing was filling the air gaps in the bushes with "Stikaflex" which is a silastic like flexible gunge with rubber like consistency when set . On an R30 Skyline we used lots so remove the X member and fill in the gaps on one side and let set for a day . Turn over and repeat the same the following day . Works surprisingly well and cheap !

 

I would try spring rates more like 220-240 front and 200-220 rear . The increased anti roll bar thickness increases the roll stiffness both ends so the spring rates don't need to be mega high .

To keep the wheels on the ground (tyres can't steer/stop/drive if bouncing off the road) you really need to use the lowest rate spring that gets the job done - by low I mean adequate not the lowest you can find !

 

Geometry wise we will start with ~ 0.5 neg camber and as much positive caster as we can get . BTW adjustable front Impreza tops are available in Aus that have the spherical joint suspended in urethane so less agro for your back teeth . We spaced the std radius rods as far forward as we could which is ~ 10-12mm . This and pulling the top of the strut back with adjustable tops should get us maybe 6 deg pos caster , running 66mm ID front springs gives more room to move in the front towers .

 

If this car is for tarmac only you could think seriously about flicking the EA/ER FT box for the 1 gen Legacy type with the viscous drag on the center diff . The trouble with the EA/ER type with its open centre diff is that it WILL feed ALL the power out through the least loaded wheel . Typically the front inner is the first to go "lite" when going hard so the center diff sends all the power to the front diff and its open centre feeds all that to the spinning wheel .

With the viscous type there are 3 variations of the viscous "drag" , they are rated in Kg and don't quote my numbers but they are something like from memory 4/8/15 ? for Legacy/WRX and STi .

A fellow Australian has the Legacy viscous type in a Brumby (Brat) with the STi center and front and rear LSD's . VERY adequate I'm told ...

 

Lastly we are thinking of using an Impreza coil over strut where the lower section (with the 4 mount holes) is hollow and threaded as well as the lower spring seat . This way can screw the seat and foot up and down to make the stroke of the damper match the suspension travel - damper wont bottom out .

 

The suspension specialist I go through may one day be interested in doing kits for MY/L/XT's if there is enough interest , anti roll bars (sway bars) wouldn't be a problem as they have a master for L front and my old RX Sedans rear is their new master so can make in any size up to I think 32mm !

 

Thoughts ? Cheers Adrian .

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BTW guys could someone please give me the dimensions of the XT6 rear disc rotor , we never had XT6's here so I need the diameter and thickness sizes in mm (should be same as RX L) but mainly the hat section height as measured with the rotor sitting on its back . I have the Crossbred 5 stud hubs and only missing rotors to fit them .

 

Presently waiting on rear Koni dampers and A arm bar mount mods .

 

Cheers A .

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BTW guys could someone please give me the dimensions of the XT6 rear disc rotor , we never had XT6's here so I need the diameter and thickness sizes in mm (should be same as RX L) but mainly the hat section height as measured with the rotor sitting on its back . I have the Crossbred 5 stud hubs and only missing rotors to fit them .

 

Presently waiting on rear Koni dampers and A arm bar mount mods .

 

Cheers A .

 

check your thread in the old gen thread. I responded with all the measurements you'd need.

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  • 2 months later...

Ok I am raising this from the dead to get some more info to piece this puzzle together fruther.

 

I just found a 92 SVX with an LSD in my local junkyard, NO ENGINE OR TRANSMISSION:mad: :mad: !!!. I plan on pulling the suspension from it. I know everyone has said to go with the EJ22 suspension but what additional could I gain from the SVX suspension.

 

I know it has LSD but do they use the R160 180 or 200? I plan on running the r160 with 3.900 Gear ratio that is stock on the XT6 manual trans. Will I be able to make the SVX rear end and the XT6 trans work together? I cant get underneath the car to see the rear axle specs.

 

Also I noted that the SVX has dual piston calipers up front. I will have to pick up the pass rear rotor.. actually all of them would be great! Drilled and slotted.

 

Are the suspension mounting points on the EJ22 the same as the EG33?

 

GIVE ME INFO!!!!:popcorn: I am stoked!!!

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the SVX is to the legacy as the XT6 is to the EA82. similar.....but quite different.

 

biggest difference, is they have a different lug pattern, 5x114.3 instead of the XT6/legacy 5x100. so if you use SVX knuckles etc. in the front, and XT6 stuff in the back, your lug pattern won't match :eek:

 

also, the front brakes are comparable in size to WRX stuff, but the rotor has a different offset than any other subaru, making it entirely not swappable.

 

the SVX does, however have an r160 rear diff. I'm not sure how the axle stubs work, but it could probably be used in an EA car. I don't remember them having rear LSDs though....

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I think the biggest thing I feared was whether or not the axle splines would mount to the XT6 transmission. I was reading on cars101.com that the SVX came standard with a rear LSD.

 

So is there any way that anyone can see how I can make any of this work? The rotor size and brake calipers would be ideal and all the joints would be able to handle any extra power I could throw at them compaired to the XT6.:-\

 

Maybe I should just snag the rear end... I hate bad news, but thank you Numbchux!

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I think the biggest thing I feared was whether or not the axle splines would mount to the XT6 transmission. I was reading on cars101.com that the SVX came standard with a rear LSD.

 

So is there any way that anyone can see how I can make any of this work? The rotor size and brake calipers would be ideal and all the joints would be able to handle any extra power I could throw at them compaired to the XT6.:-\

 

Maybe I should just snag the rear end... I hate bad news, but thank you Numbchux!

 

just stick with legacy parts. many other brake options (IMHO RS stuff will be plenty, but you can always upgrade to WRX, STi Brembo, or bigger aftermarket...), and if those joints aren't strong enough....you're going to be breaking other stuff first.

 

 

I just hopped on RockAuto.com. SVXs have a 25 female splines. and since I know that other EJ series 4EATs are a direct drop-in into SVXs....I would assume the axles will work just as easily as EJ stuff.

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In my parts pile...

 

Ksport '05 GT Coilovers

Superpro radius rod and control arm bushings

Reamed control arms to accept Impreza ball joints

Addco Front swaybar w/ poly bushings

JDM STI GC knuckles

 

I'll post a new thread once I get pics, and get all the stuff on.

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In my parts pile...

 

Ksport '05 GT Coilovers

Superpro radius rod and control arm bushings

Reamed control arms to accept Impreza ball joints

Addco Front swaybar w/ poly bushings

JDM STI GC knuckles

 

I'll post a new thread once I get pics, and get all the stuff on.

 

Cool! that sounds fun!

 

I am definetally getting the rear diff!

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