E30 m50b25 lsd question
Moderator: martauto
Hi i have a e30 with a m50b25 engine manual gearbox it has a open diff i want to put a lsd in it but wanted to know what would be the best ratio for it? also i have a lsd from a 2002 z3 3.38 ratio will it fit and will it be a torsion type or clutch type?diff wats the difference between the two and whats would be better? Thanks
Gearing might be a bit long in that case, but probably not undriveable. Ideal ratio would be between 3.64 & 3.91. But you won't find a Z3 diff in that ratio.
The Z3 will be a Torsen if it's from a 2.8 or 3.0 Z3. Should be able to tell quite easily what kind of diff it is if you take the back plate off.
If you have access to the expertise, you could get the diff ratio changed by rebuilding using the crownwheel and pinion gears from an open diff with the appropriate ratio.
The Z3 will be a Torsen if it's from a 2.8 or 3.0 Z3. Should be able to tell quite easily what kind of diff it is if you take the back plate off.
If you have access to the expertise, you could get the diff ratio changed by rebuilding using the crownwheel and pinion gears from an open diff with the appropriate ratio.
Depends in what sense 'better'. A Torsen has no clutch plates to wear out and doesn't need special oil or friction modifiers to work properly. Fit, change oil at the requisite intervals and jobs a good 'un. Arguably a clutch pack diff is better in motorsport applications. Lighter, more predictable, can be rebuilt with different ramp angles, no. of clutch plates and preload to suit. Downside - special oil required, clutch plates wear out and require periodic replacement. Under hard use this can be as often as every season.
Doubt I'd notice any difference though driving the two back to back
Doubt I'd notice any difference though driving the two back to back
Better as in lock wise with the e30 lsd diff i had previously it would lock both wheels some times not everytime it would spin one wheel only probly becuase it was worn out after so many years of use the guy with the z3 diffs has two lsd he is saying one is from a1.9 sport and other is from a 2.2 sport both have same 3.38 ratio he wants £350 they are from a 02 plate car what would you recomend go for a e30 diff 3.64 or 3.91 or get this z3 one thanks
Somebody feel free to correct me if I'm wrong - but the 1.9/2.2 Z3s were only fitted with small case (Type 168) differentials. I also wasn't aware they were available with LSDs.
Ideally you want a large case (Type 188) differential for an M50 E30 swap. There have been a few cases of spectacular small case diff failures with M5x/S5x E30s pulling fast starts
Ideally you want a large case (Type 188) differential for an M50 E30 swap. There have been a few cases of spectacular small case diff failures with M5x/S5x E30s pulling fast starts
A medium case E30 (type 188) diff is your best bet with regards to ratios for the E30 gearbox. Any E30 LSD is going to have to be rebuilt with new clutch plates at the very least to work as intended though. Budget for that and you're good to go!