Peter

Guys,
I have a question for u guys. What is a welded diff?
How does it work? Is it kinda like a LSD? Do you get drive through both wheels with a welded diff? Just wondering because looking around for a 3.9 R200 out of a 280ZX for some more acceleration, and was considering an LSD, but real pricey, and then you have to make em fit. I thought I might be able to compromise with a welded diff if it is cheap to do and is like an LSD (in that it drives both wheels). If any of you guys could explain to me how it works, and if it is cheap to have done, reliable etc that would be much appreciated.

Thanks
Peter.

Adelaide
260Z

rogersz

Hello Peter
A welded diff will drive both wheels all the time , no good for street driving particularly going into a corner. Ihave only heard of it being done on low budjet dirt only speedway sedans and off road racing vehicles. I think a LSD only locks up in a throttle on situation and depends upon the amount of power you are feeding into it. Some one else may be able to explain it better, hope this helps.

Cheers Roger

Adelaide 260Z

Zpeed

a welded diff will make ur tyres jump around on corners, but will be like a LS diff on the straght line...

i've driving a car with a locked diff, and its not that good for street, but plenty of people do it, but i wouldn't do it unless u got the diff for basically free, and u had a spare diff incase u didn't like it,

roger is right about the trottle on situation...


btw: are you sure 280zx's came with 3.9 r200, i'm wanting a 3.9 R200 not exactly sure that they came in 280zxs, pretty sure it supposed to be a 280zx manual car 82-83 model

<font color=blue>76 260z</font color=blue>
The NiteRider

AlansZ

Yeah, I welded diff is just like a locked diff, both wheels rotate at the same speeds. This is not good for corners, as when a car goes around a corner the inner and outer wheels travel differnet arcs of different length, and we all know speed=distance/time, and time is constant, therefore they travel at different speeds. this is not possible in a locked diff, so you are going to scrub your tires and wear them out pretty quickly

Alan, Australia

Ben

Hi Peter,
Who is the seller, how much do they want for it & what ratio is the LSD? (I'm not in the market for another, but have dealt with most of the importers in Adelaide - reply in private if you like).

I've just spent $600 on a 4.375 R200 for my 240Z, but there is additional cost if you want to make sure that everything is ok. R200 clutches are $120-160 each (depending on which part you need). I spent $350 on a rebuild for my other R200 LSD (a 3.90:1 in my DR30) as it was so worn that it was completely open.

You should check the diff before you buy it (remove the back cover, check the ratio & condition of the internals) and also make sure that you cannot turn the output-shafts opposite directions.

Welded diffs suck, but they do seem to fit in with the 13BT RX3 scene....[img]/w3timages/icons/smile.gif[/img]

Ben
Adelaide
Sth Australia
IZCC#1902
240Z L31ETT
L28ET MR30 Skyline
FJ20ET DR30 Skyline RS-X

Peter

Ben,
I actually havent got any quotes. I have a 260Z 2 seater, and as you probably know they come with an open R200. Now What I was concerned about was whether I needed a viscous one or a clutch one, and which came out of which cars, with which ratios.
The other thing is what mods need to be done (more importantly where and how much can I get them done for) to make it fit and drive. I've heard of a place in melb that will convert my diff to a LSD. But don't know details or cost.
So if you could tell me where you think they are cheapest (and how much roughtly), and where someone has the expertise to make it fit and drive (and how much roughly), and it would be much appreciated. Sounds like you've been around a bit to the wreckers and done the research.
Thanks,
Peter.
And by the way, for those of you who were wondering, the 82-3 ZX had 3.9 for the 5sp manual.

Ben

Hi Peter,
Providing your 260Z DOES have an R200 (the delivery of R200 vs R180 was not consistent in the 260Z's here), then all you need is a long R200. You can fit your 1/2 shaft stubs & front flange from your existing diff to it & you're away.

You're after a clutch unit, and if anyone says that they've got one from a Silvia, or R32 & it'll fit, they're wrong. The later Nissans use a short diff, which is not suitable.

The problem is getting hold of one.... I've been looking on & off for a couple of years in various importers. Most of them get snapped up by people putting SR's or whatnot into 1600's. (Craig Williams from MadDat is a VERY guilty party for buying up all the LSD's that arrive here). Craig's a good mate of mine & he's running a business, but it'd be nice for him to leave some stock for us privateers!! [img]/w3timages/icons/smile.gif[/img]

I managed to get in 1st at Jap Parts (on South Road) & nabbed the 4.375 they had there (possibly from a 200ZX, 300ZR, but who cares), the other place to try is Jaustech @ Holden Hill. It's even worth giving City Dismantlers a visit - they have been known to suprise regarding what's in stock.

You can buy a Nissan Motorsports centre from the US (look at http://www.courtesyparts.com). Cost is ~$900USD.

The other option will cost you ~$3500AUD (landed) and that is the Quaife ATB centre. This was my ultimate aim, but I just can't justify the $$$. The factory unit from Jap Parts was only $600 (this was a discounted mates-rate, list was $750). It's currently being checked out, and looks like there's almost no wear. My 3.90 from my DR30 required new clutches & shimming (the breakaway torque is now 90ft/lbs) which cost a little.

Ben
Adelaide
Sth Australia
IZCC#1902
240Z L31ETT
L28ET MR30 Skyline
FJ20ET DR30 Skyline RS-X

Peter

Ben,
Thats roughly what I thought, the clutch type is the go.
It must be difficult to get the viscous LSD to fit. Anyhow I'll look around, and if I fail, then I'll just go with the open 3.9.
Thanks,
Peter.