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Old 12-14-2005, 07:17 PM   #1
tctwnd
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Default 325ti Differential Help

Hello all. I currently have a ti with a 92 325i engine swap. This was done a while ago by someone else. The car runs gfreat, and I have a 3.91 (i believe) diff in the car. The diff is not limited slip, and revs a bit too high for my taste. I want to throw in a 3.25 or similar ratio LSD. I still have the ti subframe, any idea which diffs will fit my car without more mods? Would a 3.25 LSD form an e28 5 series fit? I have a line on one from an 84 533i. Another line on a 3.45 LSD made for an e30 4cyl that. any input would be really appreciated.

Thanks,
Ben
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Old 12-14-2005, 08:14 PM   #2
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large case diffs are going to be a tight fit (need to mod the diff mounts on the car and hammer the trunk floor subframe a bit), but they do work. the 3.73 from an e30 is a common swap. you'll need an e30, z3 6-cyl or m-coupe diff cover that has the single diff mount. the e30 4-cyl diff is most likely a small case diff and would fit, just a question of the power handling capabilities.
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-14-2005, 08:30 PM   #3
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Quote:
Originally Posted by tctwnd
Thanks for replying about the diffs. I have a non-stock diff in there now, 3.91. I did not do that swap, but how can i tell what car that diff came from and if my half-shafts or flanges were modded? I am sorry for all the quesitons, just branching into the e36 world.
the question is, what size is your current diff? believe the stock ti diffs were 3.45 (manual, open and limited slip) and 4.44 (automatic), so it must be from something else, just not sure what. forget if the e30 had a 3.91 diff. do you have any pics of the install? might be easier to tell from that. i'm guessing it's a large case diff, but it should be much easier to tell from pics
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-14-2005, 08:38 PM   #4
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Quote:
Originally Posted by cali-ti
do you have any pics of the install? might be easier to tell from that. i'm guessing it's a large case diff, but it should be much easier to tell from pics
I will take pics tonight when I have the car jacked up. time to put on the snow tires. perhaps even a little late...
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Old 12-14-2005, 08:49 PM   #5
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hehe ... my car hasn't moved in more than a month and i chucked my 3 year old snow tires in the trash (recycled them actually) before i moved to denver this summer. i could take pics of anything though, it's up on 4 jack stands
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-14-2005, 08:53 PM   #6
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here are the best i could do in my work parking lot with my camera phone. prob will need better, let me know if you can tell anything.

Quote:
Originally Posted by cali-ti
hehe ... my car hasn't moved in more than a month and i chucked my 3 year old snow tires in the trash (recycled them actually) before i moved to denver this summer. i could take pics of anything though, it's up on 4 jack stands
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Old 12-14-2005, 08:55 PM   #7
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gotta be a small case diff, it looks so tiny!

here's mine (large case with m-coupe cover): http://www.318ti.org/gallery/showpho...me=999&way=asc
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-14-2005, 08:58 PM   #8
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this means i need a 4cyl diff, either e30 or e36, correct? A 6 cyll. e30 will not fit without mods. Will a 320is diff fit?
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Old 12-14-2005, 09:05 PM   #9
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there are a few mods, but it's not too bad. there has been a large discussion around whether or not you need to change the halfshafts, but i'm willing to say you don't now (whether you WANT to is something else). you'd need to move the ti diff flanges into the large case diff. you might get away with only having to grind the diff mounts coming down from the floor pan on the ti to get the large case diff to fit. it's tight. you might need to hammer the points where the top diff cover bolts would hit the beam in the floor of the ti (i ground mine away and wish i'd hammered at it instead - if/when i learn to weld, i'll fix it up somehow). otherwise, as you said, a small-case diff would work. the e30 diff should bolt right up with no changes. so should a z3 4-cyl diff or a ti 3.45 LSD.

EDIT: see the pic i posted a link to above. those are the areas i had to mod to get the large case diff to fit. the mount on the left has a counterpart on the other side of the diff cover.
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-14-2005, 09:09 PM   #10
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Quote:
Originally Posted by cali-ti
the e30 diff should bolt right up with no changes. so should a z3 4-cyl diff or a ti 3.45 LSD.
this is only the 4 cyll. e30 diffs? or also the 325is? I am just unsure which cars came with large diffs and which came with small ones.

Ben
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Old 12-14-2005, 09:11 PM   #11
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the 325 has a 6-cyl and has the diff that i now have in my car (3.73 LSD large case diff).
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-15-2005, 03:17 AM   #12
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There are small, medium, and large diffs. The 318ti came with a small 3.45 (manual) or small 4.44 (auto). I put a medium 3.25 from an m coupe (6 cyl) into my ti last winter. I had to pound the floorpan of the trunk up about an inch in one spot and grind away a little on the diff mount "ears", plus put in half shafts from an e30 6 cyl car. I did not want to mess with putting 4 cyl half shafts into a 6 cyl diff, although some have done it, it is weaker that way.
So that's what you're up against.
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Old 12-15-2005, 03:26 AM   #13
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Quote:
Originally Posted by ClubSport
plus put in half shafts from an e30 6 cyl car.
did you try the m-coupe halfshafts and they wouldn't fit or did you not have those to try?
__________________
1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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Old 12-15-2005, 03:39 AM   #14
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Didn't have those to try, and got the e30 ones cheap.
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Old 12-15-2005, 03:43 AM   #15
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Quote:
Originally Posted by ClubSport
Didn't have those to try, and got the e30 ones cheap.
damn. i was hoping you'd have positive or negative info on whether those work or not. i'd like to get a set of reman'd halfshafts and would like the biggest ones possible. i might go with z3 3.0 coupe shafts as it appears the e30 flanges i bought new are the same size as the inner (diff side) mounts of those. i'm hoping the ABS rings are the same size as the ti so i can remove my ABS sensor shims i had to make.
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1996 318ti, California package, 267k miles
current mods: bilstein sports, bavauto springs, e30 m3 LCABs, solid metal ball joints, bavauto RSMs w/reinforcements, e30 3.73 LSD & halfshafts, supersprint cat-back exhaust, turner rear sway bar reinforcements, IE poly subframe & RTABs + camber/toe kits, powdercoated e36 32x front calipers, sport mirrors, H&R 28mmF/19mmR sway bars, x-brace, auto solutions SSK w/poly bushing upgrade, BMW CD43 head unit, DICE HD Radio w/iPod integration and "stealth" HD antenna, staggered style 68s, orange electronic TPMS, leather arm rest, JT Designs metal undertray

acquired and awaiting install: heated seat kit, cali top switch relo, lumbar support kit, park distance control kit, heated washer nozzle kit, m-coupe rear subframe, trailing arms, differential, and halfshafts, m-coupe front/rear brakes with master cylinder, under hood light kit, mud flaps, rear sun blind, auto-dimming rear view mirror, tilt steering wheel retrofit, apexcone 5000K HIDs with 55W ballasts




2002 X5 4.4 Sport Package, 53.5k miles
Current Mods: e46 m3 steering wheel
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