Author Topic: Where to find 3.91LSD? (Read 3316 times)

jfdublyu · « **on:** April 21, 2006, 12:10:12 AM »

next week i'm doing the 9lb LTW BMP flywheel. my next change i think might be to look into swapping the old 4.10 for a 3.91. I hear that the 0-60 is improved and a higher top speed can be reached. Can anyone attest to this? who has the 3.91? pros/cons? where can i find a good cheap one and exactly how easy is a diff swap? thanks guys (and ladies if there are any, and if there are any, let us know who you are!)

StreetSpec_iS · « **Reply #1 on:** April 21, 2006, 12:37:52 AM »

diff swap is heaps easy mate. just a bit of fiddling, but nothing too complex.

i put my 3.9 in like last week. in all honestly, i can't notice much of a difference to the 4.1. Apart from the LSD ... obviously, but in terms of acceleration, you wont really miss the 4.1s.

Go for it man.

i got my m40 flywheel last week too. just need to get a lil more shaved off it, then il be slapping it in.

1991318is · « **Reply #2 on:** April 21, 2006, 01:01:53 AM »

Quote from: jfdublyu

my next change i think might be to look into swapping the old 4.10 for a 3.91. I hear that the 0-60 is improved and a higher top speed can be reached. Can anyone attest to this?

Yes, w/ the lower the number the higher the ratio and the less bottom end you'll have nad the better top end you will be able to achieve. That's the turnoff of swapping for higher gears, but it all just depends on waht you want out of your bmw and which you prefer.

jfdublyu · « **Reply #3 on:** April 21, 2006, 08:36:26 PM »

well i think that i will have plenty acceleration after the flywheel swap so i wanted to drop diff gears for easier highway cruisin. where is the cheapest place to find one?

2002maniac · « **Reply #4 on:** April 22, 2006, 10:40:53 PM »

Where are you guys finding these 3.91 LSDs? From an early m10 318i? I wouldnt think that many 318i'scame with LSD.