Part identification and LSD options

[Zor]

Hey, I picked up an E30 with 5 lug, big brakes, has coilovers/rear shocks and an m50 5 speed manual box. I'm not sure exactly what parts were used to do the 5 lug, my last E30 was 4 lug so I'm in New territory.

The car goes great and is fairly clean but previous owner didn't know much about the setup as he didn't build it. This leaves me with some guess work so I can refresh everything with the right replacements parts as required.

The main thing I'm trying to get sorted first is diff and fuel system overhaul, new lines and fuel tank. I already got most parts from BMW for overhauling the fuel system and I'm going to add a standard in tank pump, up to a swirl pot with a 044 pump and a fresh fuel pressure regulator and guage to make sure I have 5 bar and in preparation for turbo charging later on.

For the diff I'm not sure what will fit because I'm not sure which rear end I have, from researching I would guess it's off one of the Z3 models. I want to run a quaife LSD because it won't require much servicing and will work great without being overkill or noisy.

I need to figure out what diff I can use, I think any 188 medium will work but not sure? Could I just get any Z3 standard diff in the desired ratio and rebuild it to make it an LSD by swapping the internals with the new quaife part? I'll attach some picks of my rear end and current diff for identifying what parts would bolt in. Thanks for any help in this

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[Zor]

Few more picks , does anyone recognise parts or methods used on this 5 lug swap?

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[Zor]

Few more pics
I wait on a tool to be able to get the wheels off so I can have a proper look. I want to refresh all the steering components some of the rubber is looking a little old. But I need to figure out what I've got before I can order or upgrade things, the diff that they've swapping out what I'm assuming used to be an LSD is so rusty I can't make out any markings on it.

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[DanThe]

That has E36 front hubs/struts, the rear will be either Z3 or compact trailing arms, the arms and beam are the same as E30 just the hub ends are different on the trailing arms, I would estimate those rear coilovers are for an E36 too and in which case there is a good chance they will be bottoming out as the E36 rear strut is longer than E30.
The diff is a small case so unlikely to be an LSD, to check jack one rear wheel off the floor and try to turn it, if it turns easily you have an open diff, if there is considerable resistance its an LSD, there is also the possibility it could have been welded

[Zor]

That has E36 front hubs/struts, the rear will be either Z3 or compact trailing arms, the arms and beam are the same as E30 just the hub ends are different on the trailing arms, I would estimate those rear coilovers are for an E36 too and in which case there is a good chance they will be bottoming out as the E36 rear strut is longer than E30.
The diff is a small case so unlikely to be an LSD, to check jack one rear wheel off the floor and try to turn it, if it turns easily you have an open diff, if there is considerable resistance its an LSD, there is also the possibility it could have been welded

Yeh I know it's an open diff as it doesn't skid proper, I think the previous owner sold the diff off before selling the car and just put a cheap thing in. The question about the diff was, what will fit and and which case/diff is a good starting point to have refurbished with a proper aftermarket LSD. The rear shocks don't bottom out the car actually drives incredibly well considering the mix of parts, I've put it through the paces on some really and I mean really! rough roads as well, it doesn't seem like the rear ever bottoms out as far as I can tell and fronts don't rub or bottom out either.

Thanks for the input, this I kind of a rolling project, I'm looking to go over what's been done and improve it / refresh it where possible so looking at the wiki's and trying to figure out the parts. The end goal is going to be a 6 speed turbo m50 but first I'm going to overhaul everything else so it's well sorted for the extra power.

[DanThe]

You want a 188 medium case diff, small case is too fragile for more than 200hp

Good to hear the rear dampers work properly

[Zor]

You want a 188 medium case diff, small case is too fragile for more than 200hp

Good to hear the rear dampers work properly

It looks like I have Z3 trailing arms like you mentioned, which means it should be possible to bolt any Z3 diff on and use z3 drive shafts, then just move the speed sensor over, then I can just rebuild the Z3 diff with an aftermarket LSD, I'm wondering if my assumptions are correct lol and also now looking for a z3 diff medium case type 188 with a good ratio to start from, does such a thing exist?