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View Full Version : How much of a difference will I notice with a 3:15?


98323IS
07-25-2003, 01:59 PM
Okay I just bought a 3:15 rear end and it should be here in a few days, and I want to know what kind of performance gains I will notice with it because I know a few people here have done this to their cars. I have the stock 2:93 in there now...............thanks all,

Brad

djcontra
07-25-2003, 02:18 PM
it should give you a little more bottom end torque. Usually the preferred swap is 3.91 or 4.10 LSD. The downside to going with either of those however, is your top speed drops I believe.

WASABI
07-25-2003, 02:46 PM
Here's some info, there's a chart there somewhere for a 3.15 diff.

http://www.maxbimmer.com/forums/showthread.php?threadid=7179&highlight=differential

MP328
07-25-2003, 04:06 PM
Originally posted by WASABI
Here's some info, there's a chart there somewhere for a 3.15 diff.

http://www.maxbimmer.com/forums/showthread.php?threadid=7179&highlight=differential

those old charts i did, dont work anymore *sad*. when i moved rogers deleted all my files on my website :(

but to give u an idea with the 328's

starting side by side in 2nd gear a 328 with the 3.15 diff will be a car length ahead by the end of the 2nd gear against the stock 2.93 diff. proven by mkgino and thinair

98323IS
07-25-2003, 04:17 PM
Ya I've heard of that race before. Fron what people have been telling me it is a pretty sweet mod. I really wanted something a little bit higher like a 3:23 or something, but 3:91 is just way too high.......top speed is like 205 I think, and without going into TOO much detail, my car sees that quite a bit........oh the joys of going to school and living in hicktown Barrie.......lol.

SickFinga
07-25-2003, 06:19 PM
contra, no way 3.91 is a prefered, if you never see a highway go with 3.91. 4.10 is just nuts.
the most desireble diff is 3.38 for NA 6cyl 3series.

mp328 i do not believe that diff was the only factor in that race, there is no way he could pull a car lenght with just a 3.15 diff.

djcontra
07-25-2003, 06:26 PM
Originally posted by SickFinga
contra, no way 3.91 is a prefered, if you never see a highway go with 3.91. 4.10 is just nuts.
the most desireble diff is 3.38 for NA 6cyl 3series.

I could be wrong, but I always see posts about people wanting to swap to a 3.91 or 4.10 LSD, so I assumed those were the most sought after diffs.
I know what you mean about the highway though, hence how I mentioned that the car's top speed would be limited.

MP328
07-25-2003, 08:33 PM
Originally posted by SickFinga


mp328 i do not believe that diff was the only factor in that race, there is no way he could pull a car lenght with just a 3.15 diff.

that's also true thinair has a few more mods done to the car then Mk's stock 328

98323IS
07-25-2003, 08:59 PM
Well guys I'll post my thoughts once I get it installed next week sometime................

Peter1998
07-26-2003, 04:31 AM
3.91 is great.. only problem is on highway max can go is 210 at 7000rpm...