RSready Posted November 30, 2010 Share Posted November 30, 2010 Hey guys, I've tried searching but haven't found too much info on this. I have a 77 280z with a 83 280zx 5 spd tranny and a stock diff. I found this 4.11 720 R180 front diff for sale locally and I want to know how hard of a swap it would be into my Z. I won't be driving on the highway or doing much high speed racing, just looking for a little more quickness off the line. Would this be a straight swap or would I have to remove the guts from this and transplant it into my stock housing? Thanks for your help. Sorry if this has been covered before, I haven't been able to find out much! Here are some pics off the diff: Quote Link to comment Share on other sites More sharing options...
neotech84 Posted November 30, 2010 Share Posted November 30, 2010 Why go from a R200 to 180?? Unless its LSD yours is going out or you just can't pass it up hold off. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 1, 2010 Share Posted December 1, 2010 Why go from a R200 to 180?? Unless its LSD yours is going out or you just can't pass it up hold off. I dunno... gearing that he wants, saves 35 lbs, and gets better halfshaft angles for a lowered car. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 1, 2010 Share Posted December 1, 2010 Hey guys, I've tried searching but haven't found too much info on this. I have a 77 280z with a 83 280zx 5 spd tranny and a stock diff. I found this 4.11 720 R180 front diff for sale locally and I want to know how hard of a swap it would be into my Z. I won't be driving on the highway or doing much high speed racing, just looking for a little more quickness off the line. Would this be a straight swap or would I have to remove the guts from this and transplant it into my stock housing? Thanks for your help. Sorry if this has been covered before, I haven't been able to find out much! The unit will essentially bolt right in but you'll have a problem with the side axles. The K series R180s use a snap in side axles while the side axles for the 240Z are bolt in. The side axles from your R200 won't work due to the different spline count (29 vs. 25). Quote Link to comment Share on other sites More sharing options...
neotech84 Posted December 1, 2010 Share Posted December 1, 2010 I dunno... gearing that he wants, saves 35 lbs, and gets better halfshaft angles for a lowered car. Very true. There was none of that info in the OP so I guess it should have been phrased as a question. What are your reasons for wanting the R180? The taller gear? Reasons stated above? ect. (Thanks John) Quote Link to comment Share on other sites More sharing options...
RSready Posted December 1, 2010 Author Share Posted December 1, 2010 Basically I would want it for the taller gear. I just recently bought the car and have only driven it a few miles before parking it. I bought the car from a guy who didn't know anything about it, but I found out an experienced Z mechanic/race team owner used to own it. I got in touch with him and he told me it has an '83zx 5spd tranny, which I was previously unaware of. He said it had different gear ratios than the original Z tranny, but I don't know what they are... But he said 4.11 gears would help the acceleration quite a bit. Thanks for all the help guys. I'm new to this car and it has quite a few mods that this guy did a long time ago (15+ years ago). Unfortunately he just doesn't remember everything that he did to the car. I actually was told by another guy the 280z's had an R180, I didn't realize it was an R200. Maybe I'll look into an S13 LSD as those are quite readily available around here. Quote Link to comment Share on other sites More sharing options...
Moltar Posted December 1, 2010 Share Posted December 1, 2010 The unit will essentially bolt right in but you'll have a problem with the side axles. The K series R180s use a snap in side axles while the side axles for the 240Z are bolt in. The side axles from your R200 won't work due to the different spline count (29 vs. 25). The later K series had snap in side axles. The 720 was equipped with bolt in side axles - as seen in the picture. I just finished swapping in a 720 4.11 diff into my 71 240z. All you have to do is swap the side axles (straight bolt in swap), and change out the flange the drive shaft mounts to. I can't speak to any effect of how much of this is true for a 280z, but for my 240z it was a very hassle free swap. How much is it selling for? Quote Link to comment Share on other sites More sharing options...
RSready Posted December 1, 2010 Author Share Posted December 1, 2010 The later K series had snap in side axles. The 720 was equipped with bolt in side axles - as seen in the picture. I just finished swapping in a 720 4.11 diff into my 71 240z. All you have to do is swap the side axles (straight bolt in swap), and change out the flange the drive shaft mounts to. I can't speak to any effect of how much of this is true for a 280z, but for my 240z it was a very hassle free swap. How much is it selling for? So assuming it is the same as the 240z - I would need the 720 side axles as well? Pretty sure he doesn't have them. Then what? And I can pick it up for $75. Quote Link to comment Share on other sites More sharing options...
Moltar Posted December 2, 2010 Share Posted December 2, 2010 So assuming it is the same as the 240z - I would need the 720 side axles as well? Pretty sure he doesn't have them. Then what? And I can pick it up for $75. All I had was exactly what is pictured. I just swapped the side axle flanges (the portion that bolts into the differential) and in it went. $75 is a good price for that - I paid about $100 for mine. Quote Link to comment Share on other sites More sharing options...
Leon Posted December 2, 2010 Share Posted December 2, 2010 (edited) ***Admin edit*** ...it is very unlikely that his R200 came with LSD since most of them were open differentials. The LSD came much later, and then only in the 300ZXT. Unless it's some rare comp piece, it's unlikely to be LSD. It would be much easier to install the 4.11 R180 than putting 4.11 gears into an R200. All you have to deal with are those pesky drive-shafts. Edited December 3, 2010 by BRAAP Quote Link to comment Share on other sites More sharing options...
RSready Posted December 2, 2010 Author Share Posted December 2, 2010 ***Admin edit*** I'm also not sure if its an R180 or R200, I have been told both and haven't found definitive info on what would be in the car. Like I said though, it is stock. I know what an LSD is and there were no LSDs in S30s, so I'm not sure we're you're getting that idea from. And thanks, I never thought about changing the oil. Quote Link to comment Share on other sites More sharing options...
Leon Posted December 2, 2010 Share Posted December 2, 2010 If your Z was originally an auto then it came with an R180. If manual, then R200. Here's a good reference: http://atlanticz.ca/zclub/techtips/differential/index.htm Quote Link to comment Share on other sites More sharing options...
RSready Posted December 3, 2010 Author Share Posted December 3, 2010 If your Z was originally an auto then it came with an R180. If manual, then R200. Here's a good reference: http://atlanticz.ca/zclub/techtips/differential/index.htm Thanks for that. The car is in Canada now, but I've been told it's originally a Colorado car, and that since it was a US car, it came with a 4-speed manual. That was swapped out for the S130 tranny by the guy who owned the car several years before me. I guess it's an R200 then. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted December 3, 2010 Administrators Share Posted December 3, 2010 Having an R180 in hand, you'll know right away after taking a peak under the car if the diff in your car is R-200 or R180. The R200 is physically larger and the mustache bar for the R200 is thicker, taller in height and routes behind the vertical uprights, vs the thinner R180 mustache bar that routes forward of the vertical uprights. If you have the R200, you’ll need the R180 Mustache bar to get your R-180 in the car. Might be able to find someone local to trade your R200 m-bar for their R180? Stickies in the drivetrain section cover the differences more indepth. Quote Link to comment Share on other sites More sharing options...
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