» Site Navigation | | » Recent Threads | | | | | | 09-15-2005, 12:51 AM | #1 | Member Join Date: Sep 2005 Location: New Mexico Posts: 66 | What diff do I use? O.k. guys as most of you know I have a 98 M3 motor going into my 97 Ti. I was told that the M-roadster rear was the best, but know I'm having doubts. I was told by Azevedo Motorsports that a 1987 323 diff would be better than an M-roadster diff?? They said I would feel more power out of the 87 323! I will be using this car as a daily driver and occasionally some roadtrips, but I want that power there when I need it. What other diffs would work and why would you choose them? Any help would be appreciated. | | | 09-15-2005, 01:28 AM | #2 | Senior Member Join Date: Aug 2004 Location: state college, pa Posts: 3,431 | there was no e30 323. i would edit your posts' subject to read something about doing a swap. you'd get more feedback from people who have actually done it, and what they used. __________________ I scream, you scream, we all scream for ZOMBIES. | | | 09-15-2005, 02:42 AM | #3 | Member Join Date: Sep 2005 Location: New Mexico Posts: 66 | I don't know why he told me a 323? I guess I'll have to call back and talk to Diego! The swap was easy! I just need to know more about the different diffs. This was my first BMW swap (not bad). Well anyone who actually knows about the diffs please post! Thank You! | | | 09-15-2005, 04:36 AM | #4 | Senior Member Join Date: Aug 2004 Location: state college, pa Posts: 3,431 | i mean editing "what diff do i use" to "conversion help: what diff do i use" or something. that way, people who have completed the motor transplant (and subsequently also upgraded the rear end) will be able to tell you specifically, their experiences and what they have done. clear? __________________ I scream, you scream, we all scream for ZOMBIES. | | | 09-15-2005, 07:03 PM | #5 | Senior Member Join Date: Jun 2003 Location: Saint Paul, MN Posts: 3,244 | What was the stock M3 diff ratio- 3.73? Seems like more power with a little taller gearing would be a good compromise for local vs. highway. __________________ My Former Rides 1999 318ti Alpine White, Cali Roof, Dinan goodies 1996 318ti Hellrot California Edition | | | 09-15-2005, 09:32 PM | #6 | Member Join Date: Sep 2005 Location: New Mexico Posts: 66 | Thanks guys! I found out that the E30 m3 diff works wonderful for this swap, the problem is I plan on putting the turbo on after I get back from SEMA, and I don't know if the E30 gearing is substancial for that. I have'nt really seen anyone with a Ti M3 turbo. I'm gonna slap the M roadster diff on and try that, and I'll also try the E30 M3, I will have to see which one feels right for me. Thanks for the help! I agree with you 96cali about the taller gearing, but if I do the turbo I will have to go with a lower ratio. Thanks again aceyx and 96cali. | | | 09-15-2005, 09:40 PM | #7 | aka Stabby Join Date: Nov 2004 Location: Mead, CO Posts: 5,336 | i forget, but isn't the e30 m3 diff ratio something like 4.10? if so, that's going to be way too high. again, if memory serves, i believe the mz3 and m coupe ratios are 3.23. talk to maurolin if you can (try PMing him). he was going to supercharge or turbo his swap. not sure what state he's at with it right now. __________________ 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 | | | 09-15-2005, 09:47 PM | #8 | Member Join Date: Sep 2005 Location: New Mexico Posts: 66 | I will run the e30 m3 diff all motor and probably the mz3 for the turbo, unless there is a lower one possibly a 325? We'll see! | | | 09-16-2005, 07:55 PM | #9 | Senior Member Join Date: Jun 2003 Location: Toronto Posts: 148 | If you are planning to turbocharge your M3 motor, I would recommend against going higher than 2.93. e30 M3 diff is definitely NOT the way to go. With 4.10 gearing your engine will not have time to build enough boost unless you are in 4th or 5th gears. SL Quote: Originally Posted by Clemente I will run the e30 m3 diff all motor and probably the mz3 for the turbo, unless there is a lower one possibly a 325? We'll see! | __________________ 1996 318ti Active Garrett aspirated... 1996 318ti Sport | | | 09-18-2005, 09:57 PM | #10 | Senior Member Join Date: Mar 2005 Location: Springfield, Va Posts: 164 | Yeah, I would have to say go with a taller gearing (lower number). I'm not sure what cars have what gearing, but a low, near 3.00 diff should be substantially better, especially with that kind of power in your car. | | | 09-26-2005, 10:58 PM | #11 | Senior Member Join Date: Jun 2003 Location: San Jose, CA, USA Posts: 253 | I think the Euro-only 87 323 had either a 3.64 or 3.73 rear end -- you will definitely feel a difference having a lower ratio rear end, turbo spooling notwithstanding. __________________ Andy Chittum - Mad Man Motorsports | | | | Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | | Posting Rules | You may not post new threads You may not post replies You may not post attachments You may not edit your posts HTML code is Off | | | |