a98pmalcolm Posted October 18, 2016 Share Posted October 18, 2016 Hey all, never really considered before until now. What kind of upgraded diffs are there for the Supra JZA-80 TT. I'm running around 750bhp and a better/stronger diff maybe a good idea. I have read in the past people selling "Big case diff" What is that in comparison to a stock OEM or is that the term for an OEM? Mine is a pre face lift 1993 Thanks Paul Quote Link to comment Share on other sites More sharing options...
JackyBoi Posted October 18, 2016 Share Posted October 18, 2016 http://www.supraforums.com/forum/showthread.php?608545-JZA80-Differential-Info!#/topics/608545?_k=iecwln That's all the OEM diff options. I believe the big case diff is far superior and rarer than the small case diff, not sure why (I can only assume it performs much better.) Aftermarket everyone seems to go for TRD LSD or Os Giken, both are expensive upgrades and have very positive reviews regarding how the out-perform an OEM diff, I believe you need a big case diff to fit the internals, but again I may be mistaken. For upgrading from an OEM diff, I believe going straight to a TRD LSD or an Os Giken is probably the best route, albeit the most expensive one - but it's what I plan to do! Can someone add, do you need a big case diff to fit the TRD/Os Giken internals? Or can this be done on a small case? Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted October 18, 2016 Share Posted October 18, 2016 The big case diff is oem. Diffs came in either a small or larger diff case depending on the model. Most TT6 prefacelift jspec supra's came with the larger casing diff. You can check if yours has it on the engine bay vin plac, your differential code should start with B if you have a large case, or A if you have a small case, for example B02B or A01B etc. The issue with all the supra factory LSD's are that they are torsen diffs, which means they generally last a long time and require less maintenance but due to their operation, they are far less aggressive/efficient then proper clutch type LSD's. Generally speaking a large case oem diff will be stronger than the oem small case diff and can handle more abuse. If you already have a big case diff then you could upgrade to a TRD clutch type (if you can find them) or Kaaz, OS Giken etc etc. The type of LSD you choose should also reflect the type of driving you expect to put the car through. If you only plan on driving the car on the road, I wouldn't really bother with a diff upgrade if you already have a big case, but if you expect to take it to the track then it could be worthwhile. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted October 18, 2016 Share Posted October 18, 2016 http://www.supraforums.com/forum/showthread.php?608545-JZA80-Differential-Info!#/topics/608545?_k=iecwln That's all the OEM diff options. I believe the big case diff is far superior and rarer than the small case diff, not sure why (I can only assume it performs much better.) Aftermarket everyone seems to go for TRD LSD or Os Giken, both are expensive upgrades and have very positive reviews regarding how the out-perform an OEM diff, I believe you need a big case diff to fit the internals, but again I may be mistaken. For upgrading from an OEM diff, I believe going straight to a TRD LSD or an Os Giken is probably the best route, albeit the most expensive one - but it's what I plan to do! Can someone add, do you need a big case diff to fit the TRD/Os Giken internals? Or can this be done on a small case? All depends. TRD back in the day made internal replacements for both big and small case diffs, the small ones being rocking horse poo to find these days. Not sure on the other, but I'd be surprised if they didn't include said information on their information pages. Quote Link to comment Share on other sites More sharing options...
el_bandido Posted October 18, 2016 Share Posted October 18, 2016 I'm about to have a cusco 1.5 way fitted to my NA 5, you're welcome to take it for a spin once it's ready. Quote Link to comment Share on other sites More sharing options...
ashloys Posted October 18, 2016 Share Posted October 18, 2016 I thought you would still be able to get aftermarket diffs for small case diffs, am I wrong then? I've always planned to upgrade to a Cusco 2 way or something along those lines, I had one in my old JZX100 and really liked it. Can I not get one for my A02B casing then? Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted October 18, 2016 Share Posted October 18, 2016 I thought you would still be able to get aftermarket diffs for small case diffs, am I wrong then? I've always planned to upgrade to a Cusco 2 way or something along those lines, I had one in my old JZX100 and really liked it. Can I not get one for my A02B casing then? Cusco RS diff should fit the small case, I think the MZ version is for the large case diff Quote Link to comment Share on other sites More sharing options...
David P Posted October 18, 2016 Share Posted October 18, 2016 I thought you would still be able to get aftermarket diffs for small case diffs, am I wrong then? I've always planned to upgrade to a Cusco 2 way or something along those lines, I had one in my old JZX100 and really liked it. Can I not get one for my A02B casing then? If you go that route, use an open diff case it's just the same and a lot cheaper and avoids destroying a perfectly good Torsen. Quote Link to comment Share on other sites More sharing options...
Lee P Posted October 18, 2016 Share Posted October 18, 2016 OS giken would be my choice, they do small and large case internals Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted October 18, 2016 Share Posted October 18, 2016 (edited) Look at OS Giken, Jellybean has one fitted and Chris Wilson has highly recommended them for years. He supplies them too I believe Edited October 18, 2016 by Frank Bullitt Spelling. (see edit history) Quote Link to comment Share on other sites More sharing options...
JackyBoi Posted October 18, 2016 Share Posted October 18, 2016 OS giken would be my choice, they do small and large case internals Would it be significantly more beneficial to go for a big case diff with big OS Giken internals? Or will a small case diff with small internals perform just as well? Quote Link to comment Share on other sites More sharing options...
el_bandido Posted October 18, 2016 Share Posted October 18, 2016 Cusco RS diff should fit the small case, I think the MZ version is for the large case diff This is what I have fitted into a spare small case diff. Quote Link to comment Share on other sites More sharing options...
ashloys Posted October 18, 2016 Share Posted October 18, 2016 Cusco RS diff should fit the small case, I think the MZ version is for the large case diff Ah that's good news then If you go that route, use an open diff case it's just the same and a lot cheaper and avoids destroying a perfectly good Torsen. Probably a good idea. Could make some of the money back selling the OEM LSD then! Quote Link to comment Share on other sites More sharing options...
jcbt Posted October 18, 2016 Share Posted October 18, 2016 I thought you would still be able to get aftermarket diffs for small case diffs, am I wrong then? I've always planned to upgrade to a Cusco 2 way or something along those lines, I had one in my old JZX100 and really liked it. Can I not get one for my A02B casing then? I have a small case TRD diff on mine and it has handled the power upgrades well Quote Link to comment Share on other sites More sharing options...
Nic Posted October 18, 2016 Share Posted October 18, 2016 I have read in the past people selling "Big case diff" What is that in comparison to a stock OEM or is that the term for an OEM? The larger diff was factory fitted to the pre-facelift 6spd TT and UK Supras. All other models had the smaller diff fitted. At the power you are running the larger diff would be the stronger option. I'd also recommend the OS Giken LSD. http://www.mkivsupra.net/vbb/showthread.php?336525-Kaaz-DAT3020-LSD&p=4170539&viewfull=1#post4170539 Quote Link to comment Share on other sites More sharing options...
a98pmalcolm Posted October 18, 2016 Author Share Posted October 18, 2016 Thanks for all the feedback fellas, how would I know if its big or small case? Thanks Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted October 18, 2016 Share Posted October 18, 2016 The diff code or if it has cooling wings as per Nic's link Quote Link to comment Share on other sites More sharing options...
ashloys Posted October 18, 2016 Share Posted October 18, 2016 Thanks for all the feedback fellas, how would I know if its big or small case? Thanks If it's the factory diff it'll say on your chassis code plaque thingy in your engine bay. Large case diff would begin with B i.e. B02A and a small case would begin with an A i.e. A02B Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted October 18, 2016 Share Posted October 18, 2016 I'm going the BMW M5 diff route purely because is was free and the installation is also going to be free and it's a Plate LSD to start with. I can pay to have it upgraded with extra plates and modified ramp angles by Dave Mac should it not cut it as is. It's very similar to a Big Case Supra diff with the rear cooler wings on the back plate. But that's just me and I'm a cheap skate bastard Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted October 18, 2016 Share Posted October 18, 2016 I'm going the BMW M5 diff route purely because is was free and the installation is also going to be free and it's a Plate LSD to start with. I can pay to have it upgraded with extra plates and modified ramp angles by Dave Mac should it not cut it as is. It's very similar to a Big Case Supra diff with the rear cooler wings on the back plate. But that's just me and I'm a cheap skate bastard The BMW M cars have the LSD that Supra should of come with imo Quote Link to comment Share on other sites More sharing options...
Nic Posted October 18, 2016 Share Posted October 18, 2016 (edited) Thanks for all the feedback fellas, how would I know if its big or small case? Thanks If yours is a factory 93 6spd TT it should have the large diff fitted and the axle code will start with a B. If you stick your head under the car you should be able to confirm this from the photos in the link I posted. Edited October 18, 2016 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
a98pmalcolm Posted October 18, 2016 Author Share Posted October 18, 2016 (edited) The larger diff was factory fitted to the pre-facelift 6spd TT and UK Supras. All other models had the smaller diff fitted. At the power you are running the larger diff would be the stronger option. I'd also recommend the OS Giken LSD. http://www.mkivsupra.net/vbb/showthread.php?336525-Kaaz-DAT3020-LSD&p=4170539&viewfull=1#post4170539 Thanks Nic, well mine is pre face lift so thats a good start Will have a look under the car in a min Edited October 18, 2016 by a98pmalcolm (see edit history) Quote Link to comment Share on other sites More sharing options...
a98pmalcolm Posted October 18, 2016 Author Share Posted October 18, 2016 (edited) Hey guys pics of my diff and chassis info pannel Judging off nicks link to the pics of the diffs he uploaded a while back it looks like the big case diff as it looks like the large plate which is apart of the diff that bolts to the rear sub frame Edited October 18, 2016 by a98pmalcolm (see edit history) Quote Link to comment Share on other sites More sharing options...
Jellybean Posted October 18, 2016 Share Posted October 18, 2016 Thats the big case diff 220mm ring gear 12 bolt My Review of the OsGiken http://www.mkivsupra.net/vbb/showthread.php?332305-Review-OsGiken-Super-Lock-LSD&highlight=OsGiken Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted October 18, 2016 Share Posted October 18, 2016 Take the picture of your plate down Malcolm Quote Link to comment Share on other sites More sharing options...
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