DeLorean Posted March 9, 2011 Share Posted March 9, 2011 I am working on an RB25DET swap for my '73 Z. I can't decide what diff to run, I have a 3.90 R200 open diff which more and more seems like a faster way to new tires every month haha. I want to match the final drive of the rb25, which is 4.11 or is that essential? I'm doing a lot of research on R230 swaps, it's a more expensive but much stronger option. If I have read it correctly, the R230s have 3.54 or 3.69? What diffs are you guys running? Any advice or experience you have would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
zgeezer Posted March 9, 2011 Share Posted March 9, 2011 (edited) I am working on an RB25DET swap for my '73 Z. I can't decide what diff to run, I have a 3.90 R200 open diff which more and more seems like a faster way to new tires every month haha. I want to match the final drive of the rb25, which is 4.11 or is that essential? I'm doing a lot of research on R230 swaps, it's a more expensive but much stronger option. If I have read it correctly, the R230s have 3.54 or 3.69? What diffs are you guys running? Any advice or experience you have would be greatly appreciated. There are a number of threads that address this issue. The search function will give you hours of pleasant and useful reading. "Most" on this forum are running a long nose R180 or R200. "Most" who have built or swapped in horsepower are running the long nose R200 with or without limited slip of some sort: welding rod, clutch, or viscuous. Long nose R200's are somewhat limited in gear sets: 3:90, 3:54 or 3:36 (maybe 4:11) are about the range available out of the junk yards. Short nose R200 and R230 have higher (longer) ratios. They require some fabrication skills to put them into an S30. The R230 is the import functional equivalent of the Ford 9 inch: available and strong. The long nose R200 is a proven and tough differential. I doubt that your RB25DET swap will develop more torque than any number of Turbo'd CSB, LSx, builds that are pulling 10-12 second 1/4 mile times on the R200. What you run in the backside should correlate to what is in the front side and the purpose for which you use your vehicle. My build is a cammed LM7 with A/T. I've installed a long nose R200 with 3:36 and CLSD with full set of clutches. I'll use this as a daily driver for short and very long hauls. I want to keep my rpm down; therefore, the 3:36 (I would have gone with 3:15 if I could have found them) It is not worth the $ to install an R230 with the higher (longer) ratios. An S30 built for 1/4 mile drags and wearing really wide shoes and traction us the waazoo, might opt for more torque muliplication and an R230. Now, grasshopper, start with the first question: for what do you wish to use your S30? The second question is: how much money do you have? The third questions is: Why not use the search function? Regards, G Edited March 9, 2011 by zgeezer Quote Link to comment Share on other sites More sharing options...
DeLorean Posted March 9, 2011 Author Share Posted March 9, 2011 You've heard this before, but I really did search. I really appreciate the info, to answer the three questions: my Z will be a fun cruiser, not racing it quite yet, I have almost no money left haha, and I respect the search, just didn't see anything RB specific. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted March 9, 2011 Share Posted March 9, 2011 I'm using a RB25det 5 spd with a 3:7 VLSD long nose diff. I could easily move up to a 3:9 or 4:11 and still be a cruiser on the freeway. My 3:7 is almost to low of a rear gear. At 70 mph in 5th gear, I'm at 2200 rpm or so... I'd go at least 3:9. Quote Link to comment Share on other sites More sharing options...
jakeoster Posted March 9, 2011 Share Posted March 9, 2011 Running an open long nose R200, not sure what the final gear is. Looking to put in a Quaife when I actually have money to spend on such niceties. Quote Link to comment Share on other sites More sharing options...
Wedge Posted March 10, 2011 Share Posted March 10, 2011 What gearing does the quaife has 3:90 ? Quote Link to comment Share on other sites More sharing options...
jakeoster Posted March 10, 2011 Share Posted March 10, 2011 (edited) What gearing does the quaife has 3:90 ? Quiafe is just a limited slip unit to replace the open carrier in your differential housing. It doesn't include the gear, you bolt it on yourself. Edited March 10, 2011 by jakeoster Quote Link to comment Share on other sites More sharing options...
DeLorean Posted March 11, 2011 Author Share Posted March 11, 2011 (edited) Thanks everyone, I am going to stick with the 3.90, I'm going to stay as close as I can to the original ratio, a quaife setup would be pretty sweet too... Edited March 11, 2011 by DeLorean Quote Link to comment Share on other sites More sharing options...
ZT-R Posted March 11, 2011 Share Posted March 11, 2011 i have a r230 which is out of a 300zx twin turbo. its 3:69. havent been able to drive it yet. very similar to joels. is there a gear kit for the r230 btw? Quote Link to comment Share on other sites More sharing options...
synthtk Posted March 15, 2011 Share Posted March 15, 2011 Whatever you do make sure you convert to CV joints of some sort... the half shafts are very week and after breaking and changing them a few times you will just wish you went with a good CV setup the first time. I started with a long nose 3.9 R200 w/ Clutch LSD that still used the half shafts and now run a Q45 R200 VLSD to get the big strong CV shafts. Quote Link to comment Share on other sites More sharing options...
DeLorean Posted March 15, 2011 Author Share Posted March 15, 2011 I definitely plan on doing a CV swap, probably with the MM kit. That or the wolf creek one, which is a lot more expensive... Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted March 15, 2011 Share Posted March 15, 2011 I definitely plan on doing a CV swap, probably with the MM kit. That or the wolf creek one, which is a lot more expensive... I have a new pair of heavy duty stub axles, made by Mosier, that have more spline count and also matching companion flanges made specially for the WolfCreek 1/2 shaft kit. http://forums.hybrid...post__p__620755 I bought them from ezzzzzzz Here is the thread he made while they were being produced>> http://forums.hybrid...with-34-offset/ Let me know if interested. I bought another set for 4 lug wheels, so these 5 lug with 3/4 + offset do me no good now... Quote Link to comment Share on other sites More sharing options...
Wedge Posted March 19, 2011 Share Posted March 19, 2011 Quiafe is just a limited slip unit to replace the open carrier in your differential housing. It doesn't include the gear, you bolt it on yourself. Thanks I thought id get flamed for asking but im happy i didnt. Quote Link to comment Share on other sites More sharing options...
240zdan Posted April 15, 2011 Share Posted April 15, 2011 r32 GTR LSD! Best diff by far you can put in a Z car 4.11, clutch lsd, usually low milage too... Quote Link to comment Share on other sites More sharing options...
DeLorean Posted April 15, 2011 Author Share Posted April 15, 2011 The R32 R200 would be ideal, do the kits out there work for mounting it though? I'll have to research what flange it uses, 5 or 6 bolt. 4.11 is what the RB25s were designed to work with out of the factory (as far as I am aware). Thanks for the info. Quote Link to comment Share on other sites More sharing options...
240zdan Posted April 16, 2011 Share Posted April 16, 2011 (edited) You want the r32 GTR diff. It uses 6 bolt cvs and has clutch lsd. The Q45 kit shoudl work great! Although I just redrilled my moustache bar and made my own front mount. You have to cut two brackets off the top of the diff too for clearence but thats no big deal. The only thing is the input flange... I used a s13 input flange that I had to machine to fit the seal. Im sure a q45 inout flange would work though. (r32 uses 6 bolt cv axle instead of standard u jointed driveshaft) for axles I u sed 6 GTR CVS and machined my own 4140 axles but the modern motorsport q45 units shoudl work here. same goes for stub adaptors. The clutch LSD hooks very nice and the 4.11 is perfect this is the diff u want Edited April 16, 2011 by 240zdan Quote Link to comment Share on other sites More sharing options...
240zdan Posted April 16, 2011 Share Posted April 16, 2011 It would also be sweet to utilize a traction control device using the oem abs brake sensors hahaha Quote Link to comment Share on other sites More sharing options...
ZT-R Posted April 16, 2011 Share Posted April 16, 2011 can you put that ratio in a r230? Quote Link to comment Share on other sites More sharing options...
240zdan Posted April 16, 2011 Share Posted April 16, 2011 (edited) the r230 uses a 230mm ring gear so id have to say no imho a r230 is overkill Edited April 16, 2011 by 240zdan Quote Link to comment Share on other sites More sharing options...
jakeoster Posted April 16, 2011 Share Posted April 16, 2011 It would also be sweet to utilize a traction control device using the oem abs brake sensors hahaha How difficult do you think it would be to implement traction control in a 240z like that? That would be really neat haha. Quote Link to comment Share on other sites More sharing options...
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