discopotato03

I've just measured up a beat up XT4 backplate and is approximately like this . Overall diameter ~ 30cm . The gap between the plates large middle hole and the half round section between the calipers mounting bolt holes 31.4mm . The direct as in shortest distance between the caliper mount holes and the plates large middle hole - 48.8mm . I expect the XT6 plates to be something like 20+mm larger overall and the other measurements approx 10+mm greater . Cheers Adrian .

Yes that would be fantastic if they are . I reckon the way to tell would be to measure the inside of the dust cover section as XT6 disc rotors are supposed to measure 256mm diameter where L series and XT4 are 226mm . If the overall diameter of the XT6 plate is known I suppose that would be a good reference as well . Fingers crossed , cheers Adrian .

BTW you CAN use EJ ratios in an AWD L or XT4 box because the hollow shaft with the countershaft gears is dimensionally the same for both types of AWD transmission . The center diff in the L AWD type is longest of all these Subaru front pinions . So the matching set would be L type AWD front pinion/center diff/short extention with diff lock selector mechanism . The other matching set is the EJ type AWD system with the Ej pinion/viscous coupling center diff/separate transfer driven gear shaft and the longer extention . Here in Australia some mobs grind (with coolant) the crownwheel for clearance when 4.44's are used with the shorter LR gears . Ways and means , cheers A .

Thank you anyway , am looking to buy some over there and have them sent to me in Australia . Cheers Adrian .

Thanks for that , you wouldn't have a pic of the other side would you ? Cheers A .

So is the XT6 one a modified L/XT4 one or completly different - larger . Does anyone have pics of the XT6 one ? Cheers A .

Hi Numbchux , the thing I really really need to know is what if any significant differences exist between the XT6 and 92 Liberty/Legacy caliper mounting bracket - the bit the pads slide in . The manuals pretty much show the exact same floating caliper section , piston and pad dimensions , so if the early Legacy caliper bracket is functionally the same as the XT6 one then I can make to all intents and purposes an XT6 front caliper . The Liberty/Legacy front disc rotor is similar enough I think particularly if the wider disc is used in its native caliper mounting bracket . An interesting experiment would be to see if the XT6 calipers floating section and slide bolt pins can be fitted to the 90-92Legacy caliper mounting bracket - and the whole lot assembled over the Legacy knuckle and disc rotor . This would prove once and for all that they are dimensionally the same - L/XT6 and Legacy floating sections and L/XT6 slide pin bolts . I tried this over here with L floating sections and Liberty caliper brackets but the thread pitch is different where the slide bolt fittings screw into the caliper bracket . Funnily enough the RS turbo Liberty caliper mounting brackets use the same coarser pitch thread as the L series slide bolt fittings but have longer legs to place the floating twin piston section further out for the larger diameter disc rotor . I may have to resort to begging someone over there to sell/ship me a pair of XT6 back plates and disc rotors if all else fails . Cheers A .

Hi all , I need some information on the differences (dimensionally) between L/XT4 and XT6 rear disc backing plates . From the manuals the disc rotor diameters are 226 , 256 , 266mm diameter for L/XT4 , XT6 , 1st Gen Legacy . As I said in the above thread I am exploring the possibilities to see if XT6 type brakes can be made up without their unique components . BTW I have the Aus reproduced rear hubs . Cheers A .

Hi all , I've been looking at trying to see if its possible to re create what Subaru did with XT6 front brake calipers because we didn't get XT6's in Australia though we did get L/XT4/and Liberty's (Legacy's) . From reading FSM's for the XT6 , L series and 1st Gen Legacy its looks like dimensionally the slide bolt centres are the same for the three different calipers . I am wondering if the basic early Legacy caliper mounting bracket could be used with the common L/XT4/XT6 E brake type bridge or floating section to end up with the same deal as the XT6 - with the Legacy disc . So the bottom line is that if the XT6 and Legacy mounting bracket sections are the same it should work . The XT6 disc itself is 262 x 22 and the 1G Legacy 260 x 24 . Actually the Leg' bracket is possibly 2mm wider to suit the 24mm disc rotor but the 1mm extra on the radius really stuff all . Want to keep the E brake on the front of my RX Sedan , cheers A .

Yes my Aus spec 86 RX has those all orange indicator lights . Cheers A .

Hi all , does anyone know if the last of the L or Vortex full time 4WD gearboxes were viscous center types ? Also its been brought to my attention that second gen Liberty (Legacy over there) have 3.7 ratio in their dual range gearboxes so could in theory make up a box with EA casings and the longer type EJ extention a viscous center . Cheers A .

Hi , this has been an interesting read . One possible solution (depending on room) may be a side draught carburettor adapted to fit where the std throttle body did . I wouldn't be the greatest fan of SU carbs but at least they are available in reasonably large sizes . Just then a case of stuffing around with the needle and dashpot springs . Thoughts ? Cheers A .

I'd like to kinow whats available aftermarket for EA82T engines over there . Cheers A .

Firstly I bought one of Gareth's Crossbred performance 5 stud conversion kits . They do exchange front control arms so you get the correct ball joint fitting like XT6 arms have . We will use the 3 ring RX turbo front drive shafts but with the 1st gen Liberty (Legacy in US) N/A FWD CV joints . The upright and hub are also 1st gen Liberty . Early Liberty RS Turbo front caliper mount brackets allow you to mount the L handbrake caliper on the uprights and fit over RS disc rotors . The strut tops will be Noltec or Nolathane adjustable ones intended for a WRX GC8 because these fit in L strut towers . The spherical joint is suspended in urethane to save back teeth . We will be using 66mm ID springs on small diameter perches which allow more movement of the struts in the top of the towers . The dampers are an aftermarket thing that are threaded for their body's whole length . Both the lower spring perch and upright mount are threaded so they can screw up or down as required . In the US all you need is the XT6 control arm/Legacy hub/upright/RS caliper mounts/discs and CV joints . WRX struts (93-00) are generally a little shorter than Legacy so probably better in an L Series . They also have springs smaller in diameter at the top so they and their upper perches fit in L Series towers . We didn't get Vortex XT6's in Australia so we have to improvise with the control arms and rear hubs . The Crossbred rear back plates/adapters are a real piece of work and the pics at their site don't do them justice . These and the splined billet hubs were the reason why the kit cost a bit . Cheers A .

Hi all , we are building an 87 Spider turbo Vortex engine up and mulling over which cams to run . Mods are raised static CR to ~ 8.55:1 and ported heads . We are also going to make an exhaust header that's beter than the std horror . The piston crowns and exhaust valves are ceramic coated . Do you think I should stick to the turbo cams or fit the later MPFI NA ones ? To fill in the gaps the gearbox will be a dual range converted Vortex AWD box and if we can get a set the closer 1st gen Legacy DR NA gearset with the std L RX 3.7 diffs . Cams is the last question and we are very limited to what we can get here in Australia . Cheers A .

Well going off the rotor's diameter the XT6's backplate/caliper mount must also be larger to get the commom L/XT6 rear caliper over the larger 255 by 10mm disc rotor . MY 87 FSM shows L rear disc roters as 226 by 10mm . Cheers A .

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 .

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 .

Just found out we never had XT6's in Australia , apparently JDM USDM only . If someone has the overall dimensions ie diameter/thickness/hat section height in relation to the back face of the disc we may be able to modify something else . Thanks for your time cheers A . BTW already have CrossBred rear hubs which are dimensionally XT6 .

The easy way to raise any std CR is to deck the block cases and adjust the cam timing with slotted cam pulleys . This is how my not finished EA82T MPFI has risen to 8.6:1 with std EA82turbo pistons . Pulleys , slot the three bolt holes and dowel pin hole , set up and time correctly . Mark pulley then weld dowel hole and redrill . Fixed , cheers A .

I'm not sure which set of ratios XT6's get but there are two basic 5 spd spreads The first is the L Turbo AWD which is ~3.45 1st to ~ 0.76 5th . The 2nd is a closer set from ~3.45 1st to ~ 0.83 5th . Now provided the ER27 could pull it if you used the close set with 3.9 final drive that should feel fast . Cheers A .

Hi all , it's been suggested that 93-00 Impreza WRX racks may fit L series front cross members . The thing I need to know is if they do does the rack pinion shaft point in the same direction (angle) as the L series power rack ? If it's a bolt up I believe the rack ratio falls from ~ 3.5:1 to 2.7:1 so quick rack ? Cheers A .

Skip we will be making a mark on the conventional pulley and most likely with the engine on the stand before the heads go on - dial indicator on one of the piston crowns . I just wanted to get to the bottom of what Subaru did on the Vortex pulley mark wise . Cheers A .

Yes I realize that but there must be some mark on the pulley that lines up with those on the pointer plate and we can't see any . BTW this engine has the Spider Turbo Voltex manifold on it because thats what the engine is - 9/87 Australian spec AWD Turbo Vortex . Cheers A .

The people who made the bars have some pics as it's their guinea pig RX-Turbo . They have the Rex struts as well . Cheers A .