So here is my little review of the MFactory D Series (40mm) LSD.
This is the prototype unit that I inspected and am currently running in my 96 hatchback. Trans is a EX D16Z6 trans I rebuilt a couple months ago as a backup and decided to use for the testing.
Appearance of the diff is great, no visual defects.
Bearing hubs measured out at 40.00mm each. On an OBX I have (new) they measured 40.01mm and 40.02mm.
Runout on the MFactory LSD is .0005". On the OBX it is .005" (ok, but more than I like, and disappointing as OBX checked it before shipping it to me as it is a replacement for the OBX I had with .023" runout).
Ring gear bolts go in fine with no clearance issues, and no issues with a strandard 6 point deep socket clearing the housing.
Internals are clean of burrs and amazingly close in weight (1g). Everything was installed correctly and the case bolts were torqued correctly. Clearances are tight as is per usual with MFactory.
Some steps were taken to remove unneeded weight. Awaiting arrival of a new scale so I can weigh the OBX and Quaife without disassembling them. Total weight of the MFactory LSD is 4,766g, or 10.507 pounds. I'm having MFactory look into taking another step on the production units to save even more weight.
Install was uneventful. Speedo gear slid on fine, bearings pressed on fine, diff shim clearance was in spec. Axles even slid in and out just like stock.
Driving the car now is totally different. Noise free operation, and it works as an LSD should. I can turn in earlier and not understeer as with an open diff. Late turn ins, the car goes where I want it to. Just point and gas and the car remains neutral versus having to lift to get it to oversteer to overcome the understeer. I beat the crap out of it. Pounding it over "gators" as you would on track, putting one wheel off, 7,200 RPM clutch dumps, wheel hopping, everything.
To sum it up, this is as good as it gets for a D Series helical LSD IMO.
No 35mm D15 Quaife in these pics, still haven't even opened the box the replacement came in.
MFactory vs OBX
MFactory vs OBX 2
MFactory case removed