R100 Posted July 11, 2013 Share Posted July 11, 2013 OK so i need some help, ideas, input from people in regards to my Gemini coupe. Build thread here > //oldschool.co.nz/index.php?/topic/27942-r100s-gemini-coupe/ The vehicle has been sold to a friend who is continuing the build. Looking at replacement diff options. Important things are it must be an LSD and correct ratio. Haven't decided on tire size as yet but rim will be no bigger than a 15" So maybe a 195-50-15 Obviously nothing will bolt straight in and we are not worried about that, we are just after a good diff that will be strong and allow the car to cruise comfortably at 100kmh with engine revs no more than 2500-3000rpm Could possibly look at fitting an entire IRS rear but don't really want to play around with getting axles shortened. I don't trust them. Have looked at hilux, hiace, mazda ute diffs etc but i dont think the ratios would work... would they ? Give us your ideas etc. Usually im ok with figuring this sorta stuff out but im hitting my head against the wall. Cheers. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted July 11, 2013 Share Posted July 11, 2013 Hasn't Flying Brick got something like this already made for a Gemini and for sale? Quote Link to comment Share on other sites More sharing options...
R100 Posted July 12, 2013 Author Share Posted July 12, 2013 Just had a bit of a search on here but couldn't find anything. Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 12, 2013 Share Posted July 12, 2013 shortened borgwarner diff out of a commodore/falcon with ladder bar thing to replace the torque tube? if you're lucky you could find a piazza lsd. Iduno how strong they are tho edit: or if you're really lucky you could get an lsd diff out of a zz/t gemini /australians know all about geminis: http://www.ozgemini.com/forums/non-tech/index.php?sid=3d3defb5186cc733c4ef2246f9146d1f 1 Quote Link to comment Share on other sites More sharing options...
R100 Posted July 12, 2013 Author Share Posted July 12, 2013 I used to be a member on there, forgot my password, tryed to get my password resent but it says email addy not found. Si tryed to register under a new name but it says email submitted already in use. Fuck i hate forums sometimes. Sure its full of good info but im not going to open a new hotmail account just to get a blah blaaahh. fuck it. Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 12, 2013 Share Posted July 12, 2013 they all seem to use commodore diffs anyway edit: what about some kind of nissan diff? Quote Link to comment Share on other sites More sharing options...
R100 Posted July 12, 2013 Author Share Posted July 12, 2013 Ive heard of borg warners but know jack shit about them. I have heard or read previously that borg warner diffs are a good replacement for the geminis. What do they look like ? i have a 1995 ecotech berlina wagon thats just come into my yard this morning. Will it be a borg warner ? its a soild axel not independant. Where the lsd heads a factory option ? are they any good ? Are they easy to come by ? Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 12, 2013 Share Posted July 12, 2013 yes to factory option. I think they come in stuff like v8 failanes etc(i have driven a couple of EB spec falcon/fairlane/fairmont with lsd). There was a guy up north who would shorten and add ladder bar etc to a commodore borgwarner for like $500. on the gm-t forum but that was years ago. I think he made zeps diff the same except zep used a hilux diff? Quote Link to comment Share on other sites More sharing options...
R100 Posted July 12, 2013 Author Share Posted July 12, 2013 Just curuios, i have a brand new mazda boundy LSD diff. Its a 4.1 ratio. What sort of revs would my car being doing at 100kmh in top gear assuming the engine was spinning at the same speed as the driveshaft ? Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 12, 2013 Share Posted July 12, 2013 basically add shit like this to any live axle and it 'bolts in' http://www.mcdonaldbrosracing.com.au/geminicontrol.html otherwise 4 link it. theres a PDF on the internet somewhere which tells you how to do it to chevettes. Or that guy tony from lynch built or whatever will know how to do it/he does it for $$. The guy with the 1UZ hsr chevette. Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 12, 2013 Share Posted July 12, 2013 Just curuios, i have a brand new mazda boundy LSD diff. Its a 4.1 ratio. What sort of revs would my car being doing at 100kmh in top gear assuming the engine was spinning at the same speed as the driveshaft ? like 3700 ish? disclaimer: i suck at maths Quote Link to comment Share on other sites More sharing options...
ryanfels Posted July 12, 2013 Share Posted July 12, 2013 Just curuios, i have a brand new mazda boundy LSD diff. Its a 4.1 ratio. What sort of revs would my car being doing at 100kmh in top gear assuming the engine was spinning at the same speed as the driveshaft ? G52 right? in 5th, they are almost the same as a w58. A 4.1 would be ok but a 3.9 will put you at about 3500rpm in 5th at 100kmh (thats what my grande did and it had 205/50/15s) Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted July 12, 2013 Share Posted July 12, 2013 Gem diffs are reasonably strong. I'm pretty sure a stock diff with an LSD center from a zz would be the cheapest and by far the easiest. (they come up every now and again on yahoo auctions japan) There are quite a few gems in Aus running stock diffs with beefy turbo engines, V8s etc. My zz/r diff seems to love the old 3rd gear skid on 195s - ratio IIRC is 3.9 so would rev even higher with a bounty 4.1 2jz autos have a pretty long 4th gear ratio of like 0.71, so match that with a 3.9 would be much better I think If you plan on doing massive limiter dumps or using drag slicks then I'd use something else, but from what I've experienced first hand and read on ozgemini, stock diffs take quite a beating Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted July 12, 2013 Share Posted July 12, 2013 a340 i think Ryan? Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted July 12, 2013 Share Posted July 12, 2013 Sorry, just read your thread, thought you were keeping it auto. Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted July 12, 2013 Share Posted July 12, 2013 Quick google tells me g52 and stock gemini box both have a .85 5th gear, so around 33-3400rpm @ 100k with stock 3.9 ratio diff and 195/50/15 Quote Link to comment Share on other sites More sharing options...
KKtrips Posted July 12, 2013 Share Posted July 12, 2013 Just had a bit of a search on here but couldn't find anything. I may have been recalling this thread - //oldschool.co.nz/index.php?/topic/37936-gemini-tq-tube-shaft-upgrade/ But perhaps PM FB to find out if he is selling his diff anyhow as he is going LS1 now and not sure if a stock Gem diff will tackle the challenge of an LS1 all that well. Quote Link to comment Share on other sites More sharing options...
R100 Posted July 12, 2013 Author Share Posted July 12, 2013 Is this a borg warner diff ? Quote Link to comment Share on other sites More sharing options...
projectr30 Posted July 12, 2013 Share Posted July 12, 2013 you can use a r31 borg warner diff ,get the long side cut to the same lenght as the short then get a second short axel to put in (saves get one made),i heard they fit perfect but wrong stud pattern. just what ive heard. Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 12, 2013 Share Posted July 12, 2013 i think thats a borgwarner bw78?(in the VS) it has rubber bung insted of bolt to fill oil? http://forums.justcommodores.com.au/v6-development-modification/71234-diff-all-you-need-know.html according to that theres heaps of diff ratios you can get and you can find lsd in commodores and falcons and the ausi r31 skyline edit: Diff ratio'sFor those interested in other diff ratios for the BW78, the Nissan R31 Skyline and Pintara also used the BW78, these were fitted with 3.73 (manual and very rare) and 3.89 and 4.11:1 other ratio's also available are 3.27 (VP GTS). Ford also used the BW78, i'm certain that the XD and XF falcons had the BW78 but not certain what ratio's were used. i've heard 3.23:1Latest info I have is that Ford used the BW78 diff centres from XF to FG model Falconsedit:I've since discovered that the Ford Falcons have used various ratio's. XR6/8 models seems to have been fitted with 3.45 ratio LSD units. XD/XF Falcon utes have 25 spline centres with 3.23 ratio where the sedan models have a 2.77 ratio (this would explain why they seem to be slower on the road when they tended to have a lot more power then the equivalent Commodore model). if that is a bw78 then it sounds ideal cos you'll be able to get an lsd with ratio to hit that 100kph rpm you want Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.