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LSD Front and Rear!?!?


Gravityman
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Whats up Subaru Freaks... A Question.

 

I just scored a full rear diff clutch type LSD with half shafts from a 1992 SVX. I have been searching whether or not it is an R-160 or R-180, mixed info all over the web! Is there an official way to check? The foil on the back of the case was removed, so I was not completely sure that it was an LSD until I jacked it up and spun the axles.

 

I also have a viscous LSD R160.

 

Since i am going to be building a frankinstein of a car, would it be possible to throw the R-160 VLSD in as the front diff and the R-160 or R-180 Clutch LSD on the rear with all the SVX rear end suspension?

 

If it turns out that the Clutch LSD is an R-160 could I put that into the front diff?

 

Where would they provide the best traction based off of the type of LSD?

 

Mind you I am running these with the ER27TT and the XT6 5spd trans with center locking diff. I am not too fimliar with the front diff on the 5spd, are the front and rear diffs even close to matching?

 

Thank you for your information!!!

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AFAIK, the SVX should be a VLSD r160. (definitely an r160 though...if you've got both, put 'em up next to each other, the 180 is substantially bigger).

 

 

front and rear diffs are very different. you can put a front LSD designed for an EJ-series 5MT into an EA-series 5MT. but you can't put a rear diff in the front.

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The front and rear diffs have to match, or you would have some serious binding issues. The SVX rear diff is a 3.54 ratio, but its close enough to a 3.7 its not a problem. Pretty sure its a R160. The basic difference of the 160 and the 180 is the 160 have stubs for the axles and the 180 dont.

Not sure if you can use the guts of a rear diff in the front. But if your using a XT6 tranny with locking diff, you shouldnt need it. And the XT6 5spd has a ratio of 3.9, but you can swap out the 3.5 guts into the 3.9 case. Theres a write up in the USRM for the swap.

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The numbers actually mean the ring gear diameter..so pretty easy to measure the ring gear and find out what is r160 and what is r180. 20 mm is a smidge over 3/4" in difference so it is quite onbvious as 'chux has stated. You'll also notice that r180 diffs are actually made by hitachi while most r160s are made by FHI under license from hitachi so the r180 diffs actually have the hitachi logo on the diff housing.

 

Numbchux has stated the facts on front LSD options..Subaru hasn't altered the design of the front diff since '84-'85, only exception being the STi 6 speed, which internally shares no major parts with the 5 speed.

HTH,

 

Kaz

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So this is what I got! From what you see R-160 or R-180? You said that the R-160 has stubs, this one does not... R-180?

 

If it is an R-180, where can I find an R-180 3.9 R/P?

 

With the R-160 up front and the R-180 in the rear with the Gear ratios the same but different diameters will I be ok or do the gear ratio AND diameter have to be the same to prevent damage?

 

On the other hand, I have about 10 2.2L legacys sitting in the junkyard U-pull-it yard. Would there be a better gear ratio that I can pull from one of those that might work, or from a nissan for the rear R-180 and a subaru front R-160.

 

Also, can I take the D.O.J. from the svx axle and swap it with the D.O.J. from a EJ22? Just curious. I might just go back and pull the entire rear end from the SVX and fit it under the BRAT. Yep, either crazy or retarded!

 

Sorry about the questions, I know the basics about diffs but I really want to learn more. Thanks for your help guys!

 

DSC02292.JPG

 

DSC02296.JPG

 

DSC02293.JPG

 

DSC02294.JPG

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So this is what I got! From what you see R-160 or R-180? You said that the R-160 has stubs, this one does not... R-180?

 

If it is an R-180, where can I find an R-180 3.9 R/P?

 

With the R-160 up front and the R-180 in the rear with the Gear ratios the same but different diameters will I be ok or do the gear ratio AND diameter have to be the same to prevent damage?

 

On the other hand, I have about 10 2.2L legacys sitting in the junkyard U-pull-it yard. Would there be a better gear ratio that I can pull from one of those that might work, or from a nissan for the rear R-180 and a subaru front R-160.

 

Also, can I take the D.O.J. from the svx axle and swap it with the D.O.J. from a EJ22? Just curious. I might just go back and pull the entire rear end from the SVX and fit it under the BRAT. Yep, either crazy or retarded!

 

Sorry about the questions, I know the basics about diffs but I really want to learn more. Thanks for your help guys!

 

DSC02292.JPG

 

DSC02296.JPG

 

DSC02293.JPG

 

DSC02294.JPG

 

That looks like a vlsd r160 with a 3.54:1 ratio...the stub issue is actually a year thing not an r160 vs r180 thing.. Early diffs have stubs later diffs don't, I believe the official change over was '94 or at least between '90 and '94..

 

Again as Numbchux and I have said NO subaru front diff is in anyway compatible with the rear diff. The front diff is MUCH bigger than the back diff,

HTH

 

Kaz

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