M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: gtatbrissy on June 22, 2010, 02:36:10 AM
-
Hi all
just wanted to know if a e30 325 lsd center fits into the case of a 318is with an open center...
thanks
-
no, youre going from a smaller case to a bigger case. why not just swap the diffs?
-
no, youre going from a smaller case to a bigger case. why not just swap the diffs?
Yes it fits with no modifications, I am running a 3.73 from a 325, they hold more power and you can actually get parts for them. I think a Z3 diff will fit as well.
-
Good to know. 325 lsd common? I remember reading something about a z3 diff with a different (better?) kind of locker too...
-
You can install the entire differential into the 318is but you can not swap internals...The 318is came with a SMALL CASE diff...The 325 uses a MEDIUM CASE diff...
-
Yes it fits with no modifications, I am running a 3.73 from a 325, they hold more power and you can actually get parts for them. I think a Z3 diff will fit as well.
confirmed, i'm running a z3 torsen diff in my car. had to swap the cover over but it's a bolt-on deal.
-
You can install the entire differential into the 318is but you can not swap internals...The 318is came with a SMALL CASE diff...The 325 uses a MEDIUM CASE diff...
thanks, i knew i wasn't wrong...
-
confirmed, i'm running a z3 torsen diff in my car. had to swap the cover over but it's a bolt-on deal.
Awesome. Thank you.
-
I have a medium case LSD that i put in to replace my blown small case (harder to find) 4.10
-
I replaced my small case open 4.10 too when it started the coffee grinder routine. Bolt-in swap was pretty easy, just clumsy to lift that heavy medium diff while under the car. I like the 3.73 I put in, makes the car slower but more driveable in suburban stop-sign hell. LSD is overrated, but I might go for a Torsen if one comes up.
-
Are all the z3 diffs torsen?
-
no, you're gonna be looking for a specific 6cyl based on what ratio you want. the info is out there, but i don't have a link handy. i got mine from Jordan S. @ Lone Star in TX, and he got the ratio i asked for and beat every FS price i've seen on bfc by about $100.
you can either find him on e30tech (username "Stück"), or shoot me a PM and i'll pass along his email addy.
-
The most complete info I have found on quick search is this from E30tech:
Good diff. info. in this thread, thanks to the OP for posting his experience. I'll just add that a good source for Torsen diffs. is the non-M Z3s (MZ3s only had clutch packs). Here are the ratios:
Clutch Packs:
Z3 M52 2.8 Manual 3.15
Z3 M52 2.8 Auto 4.10
Torsen units:
Z3 M52tu 2.5 Manual 3.15
Z3 M52tu 2.5 Auto 4.27
Z3 M52tu 2.8 Manual 3.15
Z3 M52tu 2.8 Auto 4.10
Z3 M54 2.5 Manual 3.46
Z3 M54 2.5 Auto 3.64
Z3 M54 3.0 Manual 3.07
Z3 M54 3.0 Auto 3.46
Clutch Packs
Z3 S52 3.2 Manual 3.23
Z3 S54 3.2 Manual 3.15
Info. on the Z3 Torsen on this site: http://www.zvolution.com/documents/0...troduction.pdf
full thread here:http://www.e30tech.com/forum/showthread.php?t=83982
I've got the 4.27 ratio torsen in my 318. It is truly great in autocross competition. You need to force the rear end to stay on the ground by stiffening up the front sway bar as much as you can, that's what works for me.
-
Awesome info, thank you!
-
hi there mate i have a 325i motorsport 3.91 LSD in my 31.8is and i can say that it is quicker of the line than the standard 4.10 open diff that i had on there before also top end is reduced using the 3.91LSD you will get more top end out of a 4.10diff to a 3.91.
-
Actually, just the opposite. 4.1 turns on the input side = 1 output turn, vs 3.91 turns on input side. Top speed would theoretically be increased with the 3.91, but not by much, and only if the car has enough power to push into the wind at 150 ish... good to know it doesn't murder acceleration though.
-
I got to drive an all stock car with the 3.73 lsd and compared to my 4.10 lsd it just feels like I have a lighter flywheel with my taller gear. Not enough difference to matter in street condition. I felt a little less confidence in my rear end "sticktion" around a turn where the rear is all the way down on the outside. WOT throttle away from a safe public-speed turn feels less spirited. Just needs a for more ponies to go with it if you ask me.
-
I can tell you right now that if you had a real measuring device that you would be very intrigued. The 3.73 will be slower off the line and have more run out on top end. The 4.10 will be faster off the line and will not have the top speed of a 3.73 or a 3.91. The 4.27 will be even faster off the line but again slower at top speed. It all depends on your driving habits of city, highway or combined.
But if you change the gearing in the transmission then its another ball game.
I can hit 60 in 2nd gear with my 188 4.10LSD:D
Cheers,
~Ralph
-
I had to chip mine to get close to 60 in second with a 4.10.
-
I also have a chip..JC/Turner
~R
-
I can tell you right now that if you had a real measuring device that you would be very intrigued. The 3.73 will be slower off the line and have more run out on top end. The 4.10 will be faster off the line and will not have the top speed of a 3.73 or a 3.91. The 4.27 will be even faster off the line but again slower at top speed. It all depends on your driving habits of city, highway or combined.
But if you change the gearing in the transmission then its another ball game.
I can hit 60 in 2nd gear with my 188 4.10LSD:D
Cheers,
~Ralph
well put