corey_49 Posted March 26, 2012 Share Posted March 26, 2012 (edited) I have been researching what Subaru diff to use in an early 71 240z, and the internet is kind of fuzzy on this stuff so I want to post here to clarify. PLEASE TELL ME WHERE I AM WRONG. Subaru Impreza use r160 and r180 differential, the WRX and base model get the r160. While the STI gets the r180, I am unsure of the Impreza WRX STI as it is the highest trim level I would assume that it gets the same diff, ratio, and internals as the STI. 2004-05 has a CLSD with 3.90 ratios with the 27 spline side axels. 2006-08 has a Helix/Torsen LSD or a CLSD (depending on the year) with a 3.54 ratio. I am unsure of the spline count but I think it is the same 27. 2009 and up have Helix/Torsen LSD with 3.90 ratio unknown spline count (please fill me in as 2009 and up is what I would like to use). The exterior on the 240z r180 and the STI R180 are the exact same, so the stock 240z Diff mounting should work(however replacing 40 plus year old Diff mounts are a good idea, whole other conversation about diff mounts not going to get into it). All Diff mounts for 240Z R180 will work with STI r180. From there on out everything is different. With the help of www.betamotorsports.com they supply lovely differential side axles that allow the use of stock halfshafts. To replace the stock halfshafts www.wolfcreekracing.com has a very nice (kinda expensive) CV kit that swaps right in bolt for bolt. As for the Input flange where the drive shaft connects to the differential, there is little information. I assume that you can use part of the Subaru drive shaft and install it on the Z drive shaft. I do not have access to many s30 parts and STI parts are a lot easier to find. I will appreciate all the help on this issue. Edited March 26, 2012 by corey_49 Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted March 26, 2012 Share Posted March 26, 2012 Instead of mucking with driveshafts, perhaps the input flanges can be swapped, like on a turbo/LSD R200 swap into a 280Z. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted March 26, 2012 Share Posted March 26, 2012 (edited) Send a PM to johnc or jmortensen. Johnc sells the conversion parts to put a subi diff in a 240z and JMortensen has a driveline business. They know all the ins-and-outs of the subi diffs. I have one in my car and I love it - it is the R180 3.90 CLSD, but I can't seem to keep the WRx and STi straight in my head. I bought the diff off ebay, so I don't know for sure what it came out of. With my L24 I like the 3.90, but with the V8, I'd rather have the 3.54. Betamotorsport half-shaft adapters are worth the price-it is a bargain. They are first quality and make this a bolt-in affair. Switch over your input flange from your old diff and use your old driveshaft. I would go to an RT front diff mount - I've had stock and solid and the RT is by far the best and they are pretty cheap: quiet and solid feel, but all mounting systems allow a little bit of movement. I am more firm than stock, but not slamming the driveline on shifts like solid mount. Budget 300-500 for the diff, 500 for half-shaft adapters, 100 for RT mount and a day for the swap. It might be the best $1000 you can spend on your z-car. If you tear-down before the big day (this job takes more than a day for me): replace your u-joints in your axles and your driveshaft and you will be using and loving this driveline until you are an old man. If you do the Wolf Creek axles, they come ungreased and it is a chore to grease them up. They come with really good instructions on how to avoid dropping all the balls from the CVs. Make sure you buy the correct sized tap and chase all the threads in the aluminum adapters before you get under the car and have to do it. Several of my adapter bolts bound in the threads until I cleaned them up - I ruined a couple of the included bolts, but the kit comes with a few extras (either that or I forgot to install some). This is a really nice kit ($950) be prepared to have to modify your rear swaybar end links to clear the CVs and adapters. The Wolf Creek kit is really hardware intensive and you can still have trouble with your old 240z stub axle and half-shaft adapter bolts loosening up if you drive hard. I have one friend on the forum who dropped a Wolf Creek axle due to a fasteners loosening. There are 20 fasteners per axle! That is a lot of loosening and tightening, loc-titing, torquing and safety wiring (and in my mind-worrying). If you only have a 6-cylinder, this kit (CV axles) is probably not the best $1000 you will spend your car. The Wolf Creek kit does not include the Datsun bolts, and they are hard to find, so keep up with yours. It IS some major eye candy. I have a friend on the forum with a V8 and an automatic on drag radials. He has broken stock, Wolf Creek, and Z31 turbo axles. Don't know if he has tried Q45 axles, but he is either going to have to change tires, modify his driving technique or go to a solid axle. Edited March 26, 2012 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
BrandenZ Posted March 26, 2012 Share Posted March 26, 2012 I'm also running this swap using johnc's side axles and a 2005 STi 3.9 R180 diff. It's seen several autox events (granted just with an L28 setup right now), and it's wonderful for my purposes. FYI the input shafts are a direct swap. I was able to pull mine off of the my R180 240z diff, and press it back onto the subi diff, and directly bolt up my pre-existing driveshaft. Quote Link to comment Share on other sites More sharing options...
corey_49 Posted March 26, 2012 Author Share Posted March 26, 2012 Ok thank you for the clarification on the input shafts i was unsure of this. I Would like to use a Helix/Torsen LSD with 3.90 from a 2009 and up. Has any one put one of these in there car? If not does any one know if the input and output shafts are the same as a 2005. I think i will be sending a pm to Johnc very soon and as for the Wolf Creek CV i think that will be later after i get the diff installed and running. My car will be running a l24 with SU carbs and an aggressive cam so i am not to worried about braking any thing, as thing brake or get close i am upgrading/updating to better stuff. Thanks for the info Quote Link to comment Share on other sites More sharing options...
turbonat240 Posted June 1, 2012 Share Posted June 1, 2012 I just brought home a STI R180. It looks very recent and clean with no rust on the outer casing. I was told by the seller that it's a JDM 2007 3.54 so I was pretty sure from some reseach on the web that it should be a torsen type. I decided to open the rear cover just to be sure and this is what I saw Is this some clutch packs that I can see in the hole on the right? The stamping of 39:11 confirms that it's a 3.54 but I want a torsen and I'm not sure this is what I got. Can anyone confirm this is a clutch type center or even better post some pics of a torsen center from a STI R180 ? Thanks guys! Quote Link to comment Share on other sites More sharing options...
beermanpete Posted June 1, 2012 Share Posted June 1, 2012 It looks like the inside of ours which is a clutch type. If I remember correctly, the 3.54 units are the clutch type and the Torsen units have a 3:90 ratio. Quote Link to comment Share on other sites More sharing options...
turbonat240 Posted June 1, 2012 Share Posted June 1, 2012 thanks for the reply. after 2 hours of searching on mostly subaru sites here is the list that I have come up with: year / ratio / type / painted marking on case 2004 / 3.9 / clutch / HK? 2005 / 3.9 / clutch / ? 2006 / 3.54 / clutch / HX <---this is what I got 2007 / 3.54 / torsen / ? 2008 / unsure / torsen / H3 (different than older years rear cover shape for temp sensor) 2009 / 3.9 / torsen / ? Quote Link to comment Share on other sites More sharing options...
Ejkej Posted June 4, 2012 Share Posted June 4, 2012 (edited) Hi, I swapped a subaru outback diff into my 280Z, becuase of the short ratio I was looking for - I had 3,90 and now have 4,44 ratio installed. I use original 280Z half-shafts - the 4 bolt flange was welded to each subi inner side axle. What I found very useful when searching for subi specs was this site: carfolio where You can choose exact model and check final gear ratio. I also found this info on subi diffs: subaru_ratios.pdf Edited June 4, 2012 by Ejkej Quote Link to comment Share on other sites More sharing options...
mrcheeze36 Posted June 5, 2012 Share Posted June 5, 2012 (edited) ...The stamping of 39:11 confirms that it's a 3.54 but I want a torsen and I'm not sure this is what I got. Can anyone confirm this is a clutch type center or even better post some pics of a torsen center from a STI R180 ? Thanks guys! Here you go...pic of my 07' STI 3.54 R180 with Torsen LSD. You're right, you have a 2006 STI diff. 2004 and 2005 Subaru STI R180 - 3.90 mechanical LSD 2006 Subaru STI R180 - 3.54 mechanical LSD 2007 Subaru STI R180 - 3.54 with Torsen LSD 2008 Subaru STI R180 - 3.90 with Torsen LSD Edited June 5, 2012 by mrcheeze36 Quote Link to comment Share on other sites More sharing options...
turbonat240 Posted June 5, 2012 Share Posted June 5, 2012 Great ! Thanks for the picture. I guess when I 'll go exchange mine I could check for the type of diff with the color of the oil? Red for the clutch type and regular oil for the torsen ? Quote Link to comment Share on other sites More sharing options...
Gritz Posted August 11, 2013 Share Posted August 11, 2013 Great ! Thanks for the picture. I guess when I 'll go exchange mine I could check for the type of diff with the color of the oil? Red for the clutch type and regular oil for the torsen ? Which diff is better to use? Clutch or Torsen. I thought clutch was best Quote Link to comment Share on other sites More sharing options...
beermanpete Posted August 12, 2013 Share Posted August 12, 2013 Which diff is better to use? Clutch or Torsen. I thought clutch was best No "best" allowed on HybridZ. How you use the car will determine which is likely to yield a result you are happy with. Quote Link to comment Share on other sites More sharing options...
rick240zed Posted April 23, 2014 Share Posted April 23, 2014 (edited) So I just got my Subi r180. Haven't had a chance to verify all is good - but seems OK. I assume i just remove the funky sensor and replace with a standard 240z r180 fill plug, right. Also, what is the RT mount referred to above? Thanks. OK, I found one answer, RT = Ron Tyler. So, is the TechnoVersions the preferred way to go RT these days? Edited April 23, 2014 by rick240zed Quote Link to comment Share on other sites More sharing options...
beermanpete Posted April 25, 2014 Share Posted April 25, 2014 Yes, use the fill plug from the old differential. It works fine for me. Quote Link to comment Share on other sites More sharing options...
rick240zed Posted April 28, 2014 Share Posted April 28, 2014 (edited) This weekend while working cleaning parts at a friend's house he mentioned that changing the input flange requires a certain amount of precision to ensure that things don't bind in the diff which can result in bad noise. Are there any tricks people employ when swapping the flanges? I'm jusr surprised that no-one has built a Subaru r180 input flange to Datsun driveshaft u-joint adapter. Edited April 28, 2014 by rick240zed Quote Link to comment Share on other sites More sharing options...
johnc Posted April 29, 2014 Share Posted April 29, 2014 You don't need an adapter. Just swap the flange. Your friend does not understand the R180. Quote Link to comment Share on other sites More sharing options...
z240 Posted April 29, 2014 Share Posted April 29, 2014 (edited) Allow me (the friend) to clarify. Rick didn't quite translate the discussion we had about this accurately. I never intended to indicate any binding might occur, just the lash tweak that might produce more whine. I believe the issue is with the reports posted here and on other forums of having "different" than original torque on the input flange bolt after the flange switch, that results in a change in lash, which in turn results in additional or a change in the preceived diff noise. This what I recall from these prior posts, it may not reflect the actual problem, if there is one at all. Generally changing the flange is reasonably safe if you use the recommended FSM torque when putting it back together I would think. One method mentioned mentioned in prior posts to 'duplicate' the original torque is to mark the nut and end of the shaft before removing them, then put the nut back where you found it using the witness marks as reference. There are many frictional variables in this that make even this method a bit suspect. My direct experience with this is null, I am mearly parroting what I believe I have read. The Subie diff swap thing is suddenly becoming popular in my neck of the woods, and I want to understand the best way to accomplish it. Let's use this chance to summarize and get solid experience based input from the experts about if this really is a problem, and the best way to ensure that the least degradation of diff performance (even if its just a sound change) post flange swap. Edited April 29, 2014 by z240 Quote Link to comment Share on other sites More sharing options...
Zealous Posted December 29, 2014 Share Posted December 29, 2014 (edited) Sorry to revive an old thread but after spending hours researching rear Subaru LSD ratios. There is a lot of conflicting information primarily from people confusing the front and rear final drive ratios. This thread comes up on search a lot and has a ton of views. I wanted to share what I found: Subaru WRX STI rear differentials: 2004 3.90 ratio mechanical LSD 2005 3.90 ratio mechanical LSD 2006 3.545 ratio mechanical LSD 2007 3.545 ratio Torsen LSD 2008 3.545 ratio Torsen LSD 2009 3.545 ratio Torsen LSD 2010 3.545 ratio Torsen LSD 2011 3.545 ratio Torsen LSD 2012 3.545 ratio Torsen LSD 2013 3.545 ratio Torsen LSD 2014 3.545 ratio Torsen LSD 2015 ???? Edited December 29, 2014 by Zealous Quote Link to comment Share on other sites More sharing options...
Gritz Posted March 29, 2015 Share Posted March 29, 2015 This summer I plan on swapping in my '07 sti r180 .. And of course I'm researching axles, I'm fine with going with the side adapters; if its possible i would like try something a little stronger.. Question is do you guys know if the 280zx CV axles 27 spline will plug in the 27 spline sti r180 diff? I have a 260z with single turbo 1jz under the hood that will have around 420whp when tunned.. I'm just not sure the stock half shafts can hold up to light drag racing, or track days... Quote Link to comment Share on other sites More sharing options...
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