• BoKu
  • BoKu
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  • From: Douglas Flat, CA
  • Registered: 2010-01-08
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Topic: Subaru AWD rear diff in RWD car?

I'm thinking ahead of putting together a Spitfire for the '12 season. Up where I live, Spits are kinda rare, but there's a thrashed Subaru AWD wagon on every street corner.

Here's the questions: Has anybody ever used a Subaru rear differential in a RWD car? And if so, how did it work out?

The reason I'm asking is that I've heard tell that the Subaru rear end is specifically designed to deliver a relatively low percentage of the total power to the ground, and that it probably wouldn't last long if you tried to run all the horsepower through it. However, that could easily be third-hand scarelore from folks who have never tried it.

Yeah, I know: What could possibly go wrong?

Thanks, Bob K.

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Re: Subaru AWD rear diff in RWD car?

I always had it in the back of my head to do something like that so I have this bookmarked you know just in case

http://www.clubwrx.net/forums/powertrai … -pics.html

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  • jrbe
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Re: Subaru AWD rear diff in RWD car?

You can check out an audi quattro rear diff.  They come in 3.89 and 4.11 flavors.  They are WAY overbuilt and most will handle any Lemons amount of power.

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  • FJ40Jim
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Re: Subaru AWD rear diff in RWD car?

Many Subies have a Fuji R160 IRS in the back, same as Datsun 240Z and 510.

So yes, somebody has used the Subie rear diff in a RWD application: Nissan.

Jim C.
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Re: Subaru AWD rear diff in RWD car?

Didn't nissan own part of Subaru back in the day.  I thought they were the ones who sold their shares to gm.

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  • From: Mentor, OH
  • Registered: 2010-02-22
  • Posts: 207

Re: Subaru AWD rear diff in RWD car?

Bottom line is the subaru rear diff is exactly that...just a rear open diff.  All the amazing awd-ness happens in the tranny/transfer case at the viscous coupler.

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Re: Subaru AWD rear diff in RWD car?

Actually the Subaru awd system mechanical and is pretty simple as especially when compared to most of the other ones.  Of course this is what makes it better than most of the ones that are used by the other companies and while it often gets commented on how old their system is and how much more high tech the other ones and then they beat them in testing basically because their system works while sensors and computers tend to not always work.

If you were looking to drop a whole subaru drivetrain in, the first link shows how to disable the center diff which is where amazing awd-ness that porkchops mentioned happens.  Doing that should turn it into a straight rwd car.  There were some older subarus that could go into fwd mode you had to remove a fuse if I rember right.  those were probably the ones back in the 80's and you probaly won't want one of those.

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8 Reply by Spinnetti (edited by Spinnetti 2011-01-20 02:32 PM)

  • From: Frisco, Texas
  • Registered: 2009-05-02
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Re: Subaru AWD rear diff in RWD car?

jrbe wrote:

You can check out an audi quattro rear diff.  They come in 3.89 and 4.11 flavors.  They are WAY overbuilt and most will handle any Lemons amount of power.

+1... I've put around 350ft/lb through mine for the last 60k miles (aggressively) without a whimper smile (stock is 166ft/lb)

Also, if you don't tell the diff its not in a Soob, it won't know! Sure, it will work just fine. Go for it!

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  • From: Boulder, CO
  • Registered: 2010-11-12
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Re: Subaru AWD rear diff in RWD car?

What about converting AWD to FWD? For example to use the transmission as a rear transaxle for a midengine car.  What do you have to do to convert it to this?

-Victor
  • From: Frisco, Texas
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Re: Subaru AWD rear diff in RWD car?

sublimate wrote:

What about converting AWD to FWD? For example to use the transmission as a rear transaxle for a midengine car.  What do you have to do to convert it to this?

Well, in that case, save yourself some hassle, and just use the FWD transaxle - e.g. a soob FWD transaxle mounted mid-ship, and RWD... By your asking the questions, not sure you want to attempt that level of hoonery at this stage of your mad-max experience?

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  • From: Boulder, CO
  • Registered: 2010-11-12
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Re: Subaru AWD rear diff in RWD car?

Spinnetti wrote:

By your asking the questions, not sure you want to attempt that level of hoonery at this stage of your mad-max experience?

Just casting around for options for my R5 Turbo Le Lemon.  Beat-up & rusty AWD subies are common as dirt out here, but haven't run across any FWD ones.

I'll probably end up going with a transverse FWD set up for ease.  But the possibility of making it longitudinal (as the R5 Turbo was) and getting a turbo engine in the package as well is intriguing.

-Victor
  • From: Frisco, Texas
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Re: Subaru AWD rear diff in RWD car?

sublimate wrote:
Spinnetti wrote:

By your asking the questions, not sure you want to attempt that level of hoonery at this stage of your mad-max experience?

Just casting around for options for my R5 Turbo Le Lemon.  Beat-up & rusty AWD subies are common as dirt out here, but haven't run across any FWD ones.

I'll probably end up going with a transverse FWD set up for ease.  But the possibility of making it longitudinal (as the R5 Turbo was) and getting a turbo engine in the package as well is intriguing.

Cool.. go find a soob FWD and you are golden!

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  • From: Brookfield, WI
  • Registered: 2009-12-15
  • Posts: 222

Re: Subaru AWD rear diff in RWD car?

96-01 Fwd Audi A4's and VW Passat's have longitudinal 4 cylinder turbo engines mounted to transaxles.  Usually cheap too since the audi community treats fwd cars like redheaded step children. 
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  • From: Columbus, OH
  • Registered: 2009-05-26
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Re: Subaru AWD rear diff in RWD car?

The Acura Vigor had a longitudinal mounted FWD 5-cylinder engine.  You get bonus points for 5-cylinder weirdness.  176 hp is pretty decent, too.  Manual transmission available.

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  • From: Mentor, Ohio
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Re: Subaru AWD rear diff in RWD car?

BoB wrote:

There were some older subarus that could go into fwd mode you had to remove a fuse if I rember right.  those were probably the ones back in the 80's and you probaly won't want one of those.

Acutally the newer models with automatic transmissions had this feature for towing purposes.  The automatics were an electronically controlled diff versus the standard shifts were manual.

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  • Serj
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Re: Subaru AWD rear diff in RWD car?

go for the 3.5L chrysler in the LH cars. those were all longitudinally-mounted FWD; plus 230-250HP can only help the potential awesome factor (I should probably stop sharing this idea as I want to do it myself)

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Re: Subaru AWD rear diff in RWD car?

Serj wrote:

go for the 3.5L chrysler in the LH cars. those were all longitudinally-mounted FWD; plus 230-250HP can only help the potential awesome factor (I should probably stop sharing this idea as I want to do it myself)

And quite possibly the single most unreliable automatic transmission in the modern era.  Even the guy I know that owns a transmission shop gave up on his Intrepid when it stranded his family out of state with a blown transmission.

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18 Reply by BoB

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Re: Subaru AWD rear diff in RWD car?

rpone605 wrote:
BoB wrote:

There were some older subarus that could go into fwd mode you had to remove a fuse if I rember right.  those were probably the ones back in the 80's and you probaly won't want one of those.

Acutally the newer models with automatic transmissions had this feature for towing purposes.  The automatics were an electronically controlled diff versus the standard shifts were manual.

I know 2000 and above didn't have this on the legacies.  so maybe it was in the 90s.  The only cars I remember seeing people do this was on the cars that were also offered as fwd only also.  Although I remember a lot of questions about doing this both on if it really worked and if it would make a difference on fuel mileage which was the reason people would do it.

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  • Serj
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Re: Subaru AWD rear diff in RWD car?

dculberson wrote:
Serj wrote:

go for the 3.5L chrysler in the LH cars. those were all longitudinally-mounted FWD; plus 230-250HP can only help the potential awesome factor (I should probably stop sharing this idea as I want to do it myself)

And quite possibly the single most unreliable automatic transmission in the modern era.  Even the guy I know that owns a transmission shop gave up on his Intrepid when it stranded his family out of state with a blown transmission.

so you're saying it's Lemons perfection incarnate? big_smile