Complete Dereliction of Sense

[unenthuzed]

Hey guys, 

This may be an odd request for support, but I'll be asking questions about the 2000-2007 Imprezas as they are the likely candidates to donate some of the Subaru love into my next off road project.  The goal is to dump the AWD system and suspension from the Impreza & Forester, along with either an EZ30D/R or EZ36D w/ Megasquirt into the car.  I'll post up a list of questions that I have based on threads that have the information that I'm looking for.

Thanks in advance for the support.  This will be an undertaking of sorts.  

[montana tom]

Somebody has been playing in the mud!   Looks like fun!  Good luck with your project.

[gbhrps]

unenthuzed

,It would appear that the sheep approves as well.

[unenthuzed]

Thanks guys.

It should be no surprise that as a Saturn owner, the cheapness is strong with me.  It's also no surprise that a rusted out WRX with 280K on it, blown HGs, and is in need of an exocism would still go for 3k on craigslist.  

The main reason to grab the WRX is to get the VLSD R160 with matching ratio to the front diff as well as the rear subframe/cradle that is similar in function to the Saturn [Lateral links w/Trailing Arms].  However I do realize its going to be difficult to nab one for the right price which is why I may need to settle for the right priced Legacy/Forester/Outback.  I've tried to look on rock auto to look at axles to understand differences between models and trims and transmission type [AT/MT] and am not too much closer to figuring things out than before since RockAuto doesnt have all of the variations labeled. 

Can you guys confirm the following details:
1. Are WRX rear Diffs incompatible with all generations of the Forester/Legacy/Outback axles and driveshaft?  
   - I understand driveshaft lengths are different [Not important to me right now].
   - I also understand that I'd need to find an R160 to match the front diff ratio since Foresters/Legacys have different diff ratios.
   - Rockauto is showing 2002 axles are Male/Male for the Forester/Legacy but Female/Male for the Imprezas.  Im wondering if this is true for all years.

2. Are axles different between the Auto and manual transmission vehicles?

Edited November 5, 2018 by unenthuzed

[matt167]

WRX isn't what you want. All Subaru's except the STI have R160 differentials. Many of them also had the VLSD ( outback's and Forester S/XS 2000+ ). The VLSD is probably not functional in any car you find. It wouldn't do what you think it would if you found a working example.   WRX uses a center differential that is 1.1:1, so the front and rear differential ratios are actually split ratio's. All other Subaru's use a 1:1 center diff and the front and rear gear ratio's are the same. Either 4.11:1 for manual or 4.44:1 for automatic ( JDM turbo and Forester XT manual is 4.44, in general )

Axles changed by the years and models, but you can generally make anything work. Automatic/ manual axles are different lengths but interchange, basically.. All in all, a 2000-2004 Outback LL Bean or other with the H6 EZ30 will be a good donor. A 1992-1997 Subaru SVX with it's EG33 H6 also had 5x4.5" bolt wheels and would allow you to run truck rims if you wanted .

Edited November 5, 2018 by matt167

[unenthuzed]

As far as the VLSD not functioning, can you elaborate?  Are they a wear item that turn into an "open" diff over time? 
I'd love to rock a mechanical LSD in the back.  I have a Quaife in the Saturn and the stupid car does things that it rightfully shouldn't be able to do.  However STI diffs and transmissions are pricey.  Aftermarket diffs are more readily available, but arent the cheapest.

Rallitek has both front and rear diffs for a WRX:
https://www.rallitek.com/534-differentials

Edited November 5, 2018 by unenthuzed

[unenthuzed]

Maybe Ill poke around other forums.  500 for a rear diff isnt bad at all over on NASIOC:

https://forums.nasioc.com/forums/showthread.php?t=2888337

[matt167]

Nothing special about a WRX diff other than the ratio being 3.54:1. Those LSD's will fit any R160 Subaru if you get the right one ( get ahold of Cusco ). True friction based LSD's were available in the 80's in the USA and some special cars JDM market only got them 90's-2000's. You can find them from importers.

The Viscous coupling in the differentials that makes the VLSD work stops coupling and then it becomes an open diff. It's not a great solution in working condition but Subaru didn't have anything serious in mind.

Going STI/ R180 differential is a whole different ballgame. You would need STI hubs, and everything outbound to make it work. STI anything is spendy

[unenthuzed]

I'm reading that the knuckles and hubs are different between the WRX and STI.
Anyone know if its possible to press in the STI bearing/hub assembly into a base Impreza knuckle to adopt the STI axle without having to use the STI knuckles/brakes/Struts?  I'll see if I can find the bearing specs on RockAuto, but am not confident they will have that info.

 

***Edit

So the front bearings are the same between the STI and other trims, so it would be possible to press in the STI hubs if the axle splines were different.  However the rear bearings are different for the STI and cannot be pressed into the rear knuckles of the lower trims.  Womp womp.

-----------------------------------------
2004 Impreza (2.5)  Front Bearing
National Taper Bearing (517008)
Bore = 1.6535"
Outer = 2.8346
Width = 1.4961

Rear Bearing (513248)
National Taper bearing
Bore - 1.4961"
Outer Diameter - 2.5591"
Width - 2.0472
-------------------------------------------
2004 WRX (2.0T)  Front Bearing
National Taper Bearing (517008)
Bore = 1.6535"
Outer = 2.8346
Width = 1.4961

Rear Bearing
National Taper Bearing (513248)
Bore = 1.4961
Outer = 2.5591
Width = 2.0472
----------------------------------------
2004 STI (2.5T) Front bearing
National Taper Bearing (517008)
Bore - 1.6535
Outer - 2.8346
Width - 1.4961

Rear Bearing
National Taper Bearing (516003)
Bore - 1.6535
Outer - 2.8346
Width - 2.0472
------------------------------------------

 

Edited November 5, 2018 by unenthuzed

[carfreak85]

Why not just buy a Subaru instead of spending the time/money to install all this into a Saturn?

[unenthuzed]

The Saturns are dirt cheap, lighter, more plentiful, and they're not prone to body rust or denting (Plastic panels).  Since I can take a razor blade to cut the fenders to make room for large tires, I should be able to make it look cleaner than if I took a clapped out, rusted Subaru and sawzalled the fenders.  In the end I'll be modifying the entire suspension anyway [Mounting points, control arm location, etc] and extending the wheel base, so which platform I choose doesn't really matter, but I work with Saturns so I have a better idea of what I'll need to do.

I've also got a boosted Saturn as well, but it's currently going through a rebuild.  

Edited November 5, 2018 by unenthuzed

[nvu]

4 hours ago, unenthuzed said:

I'm reading that the knuckles and hubs are different between the WRX and STI.

it's a bit misleading, they are and aren't depending on the years.

05+ sti's changed to 115x5 hubs and cartridge style bearings.  They are no longer press in bearings.

08+ wrxs changed to cartridge like sti's.

so, 04 sti,  07 and earlier wrx are exact same knuckle/hubs as base impreza.  no differences there, only beefier axles or different brakes on the better models.

[unenthuzed]

So riddle me this.  Is the STI R180 diff ratio common with other models?  Or is it only meant to be used with the STI Trans/Center Diff ratios?

 

***Edit

Found this handy Chart: http://www.gearhack.com/myink/ViewPage.php?file=docs/Subaru Transmission Chart.
Im assuming if the center diff is not 1.1:1, that the rear diff ratio matches the front diff ratio.  With the 3.900 ratio for the R180, I would just need to find a car with that front ratio.  But I'm probably gonna have an easier time if I narrow my search for an impreza from '05-'07 since it'll have the hubs and trans that I want [unless the driveshaft splines are different for the R180...]

Edited November 5, 2018 by unenthuzed

[nvu]

R180 only found in sti, and mated to the 6spd.  Will need bigger axles and the bigger hub knuckles from an sti of that era.  To drop in and replace an r160 you'd have to frankenstein some axles and possibly slot out the driveshaft flange.  I'm only familiar with the gc/gd era up till 2007.  Maybe later models have something what would drop in. 

[unenthuzed]

Right, so in a base model vehicle from '05-'07, I would need to bolt in the STI hubs/bearings into the base knuckles, find STI rear axles, an  R180 diff, and then Figure out how to get the correct length driveshaft mated to the R180 Diff flange...or weld an adapter plate onto it and hope it doesnt completely fail or cause an imbalance making the whole thing vibrate to death.  lol

Edited November 5, 2018 by unenthuzed

[matt167]

But why do you really need the R180?  The R160 will hold some HP and if H6/ 230hp is what your after then it's well within your limitations.. If it's the 5x4.5" bolt pattern you like then you could adapt it with a spacer

[unenthuzed]

I really only want a mechanical LSD in the back that doesn't break the bank.  R160/180/200, whichever diff I can find/use with a decent LSD.  It's not so much for power capacity, but for traction through nasty terrain.

[1 Lucky Texan]

I have no experience with this stuff but, don't some Mazda MX5s (miatas) have a Japanese Torsen-clone rear diff? Or there's a LSD available for Miatas?

Maybe it could be adapted into a rig?

if your rig was always on dirt/gravel - never dry pavement - you could weld the gears inside.

Edited November 6, 2018 by 1 Lucky Texan

[unenthuzed]

I wish I could simply weld it all up and be done with it, but this is something that will be on the road to drive out to offroad events with my buddies.
Thanks for the suggestion on the Miata parts, I haven't looked that up.  I did some reading on the R200s for the nissans and didn't dig up anything promising. 

Thus far, I think the easiest route for me will probably have me rocking the R180 and STI axles in the back, and keep the base trans and add STI axles up front.

Edited November 6, 2018 by unenthuzed

[1 Lucky Texan]

one other quick thought , you might want to at least know about Heri heavy duty axles, particularly if you are going for an extreme lift.

 

[unenthuzed]

Thanks!  I'll look into those as well.  Im figuring with the wheels on the ground, I was going to limit the axle drop to 1.5 - 2", especially with 30-32" wheels on the end of them.  I'd rather not be grenading axles left and right due to extreme angles since reliability is a nice thing to have.
One interesting thing is that subaru tribeca axles are pretty long compared to impreza axles32" vs 27"].  If I could move the hubs further out, at the same axle drop height [1.5-2"] the joint angles would be reduced.

[1 Lucky Texan]

Perrin also makes some rear bushings for the LCA;

 

[unenthuzed]

I'm liking this direction:  

 

 

If this is possible to do for the longer tribeca axles, and if those axle splines will fit the Impreza hubs, that would be excellent

[1 Lucky Texan]

at about 8:30, he doesn't seem to be concerned about 'clocking'/'timing' the inner race - does it not matter? I have read that you get the greatest deflection angle if the bearings on one end are aligned with the inbetween -bearings portion of the race at the other end.

I have seen 3 marks on the inner end of my outback's axle where the tripod joint goes.

 

[unenthuzed]

That I am not sure of.  I've never intentionally taken CV axles apart.  Are the marks you are referring to from machining or abnormal wear?

Also, are the transmission mounts, driveshaft bearing support mount, and differential mounts the same between the manual and automatic cars?  Due to the lack of cheap manual cars on FB and SearchTempest/CL, I'm thinking that there's a greater likelihood that I'll  find an Automatic car priced right and just deal with locating a manual trans & related parts elsewhere.