[Volasko]

This thread goes out to any members who have completed the above rear diff swap from their MT 330i. I am really interested in doing this but I am hesitant about the nearly 15% increase in RPM's from a daily driver perspective. How much do the added revs affect the day-to-day livability of the car. I do a lot of hwy driving and fear the higher cruise rpm will cause exhaust drone (just a PE). Also did anyone notice a big drop in fuel economy especially at highway speeds? So for those who did it how much am I over thinking this. Are there any dif swaps that are plug and play (ie. no modifications to the input and output shafts)

Edit: See video on 2nd page of acceleration with new diff!

[dragonsi]

I have a 2006 330i MT with the automatic 2006 330i differential, coupled with an M factory LSD. The automatic 2006 330i differential is a direct swap.

As far as MPG, before I would get about 22 mpg on average, now I get roughly 21.5-21.8 mpg. It is the lowest its been at right now which I would attribute to the winter gas.

I was afraid of the highway cruising speed as well since I like to cruise around 75-80 mph,in Mexico. It's hard to describe the difference, yes you do feel the car operating at a higher rpm, but it's really the nature of the car that has changed. Now the car feels like it's begging you to go faster.

I highly recommend this to anyone looking to add more "sport" to their car, it is certainly worth it for how much it costs. If you can afford it, definitely get an M factory LSD to go with it. Like others have said, the car should of came from the factory like this.

[Volasko]

Originally Posted by dragonsi

I have a 2006 330i MT with the automatic 2006 330i differential, coupled with an M factory LSD. The automatic 2006 330i differential is a direct swap.

As far as MPG, before I would get about 22 mpg on average, now I get roughly 21.5-21.8 mpg. It is the lowest its been at right now which I would attribute to the winter gas.

I was afraid of the highway cruising speed as well since I like to cruise around 75-80 mph,in Mexico. It's hard to describe the difference, yes you do feel the car operating at a higher rpm, but it's really the nature of the car that has changed. Now the car feels like it's begging you to go faster.

I highly recommend this to anyone looking to add more "sport" to their car, it is certainly worth it for how much it costs. If you can afford it, definitely get an M factory LSD to go with it. Like others have said, the car should of came from the factory like this.

Thanks for the reply. I'm glad your sentiment about the swap follows what others have said with respect to how much you like it. I'm not interested in the LSD at this point (too much $) as aside from the diff swap I am planning on refreshing all diff, tranny and engine bushing/mounts at the time of the swap. Probably need to do a clutch refresh while I am at it.

[mbanks21]

I've been researching this for a while as well and have sourced a few auto diffs around my area for $250-300 so even if I don't like it it's not a huge loss. Everyone I've seen that's done it is happy. I also don't do a LOT of highway driving so I'm not too concerned about higher RPMs.

[F30RiK]

Worth every penny, do it

[Volasko]

I have yet to see ANY video of a N52 stock or modified running the through the first 3 gears with this modification! Please someone make an easy video with your phone and youtube that!

[F30RiK]

Ill do it soon

[driverman]

I've been considering doing this for my 2008 328i MT. It is easy to swap the auto diff (3.73) for my MT diff (3.23) on the 2007-2008 models like it is for the 2006 models? Can i use the diff from an auto 335i (3.46)?

The thought of having 15% more torque applied to the rear wheels is very appealing but I too am concerned about the increased revs on the highway. To get a feel for what it would be like, I downshifted from 6th to 5th gear while going 70 mph. There's about a 15% difference between those gears. I don't think I want the higher revs because I spend a lot of time on the highway.

[hassmaschine]

You could use the 3.64 from a 330i automatic.

[Volasko]

Just bought 330i AT rear diff from a wreckers yard for $240 after tax! Car is winter stored now, anyone attempt to DIY this swap? Doesn't look too hard and I am in no rush?

Edit: I have the loose diff in the my basement and when I turn one of the output flanges', while holding the input flange, it to makes a clicking noise. When just turning the input shaft it is smooth as butter. See this quick vid for a reference, is this normal??

Update: It is normal. I removed my original diff and it also made the same noise.

[Volasko]

troubleshooting help bump!

[mbanks21]

No idea if that's normal but I just swapped my 3.15 for a 3.64 and couldn't be happier. Rpm is only 3-500 higher than normal but every gear feels like a turbo kicks in. Found one with 51k miles.

[PureE92]

I wonder if you could swap a 3.64 from a 330i into a 328i? Or a 3.91/3.73 from an auto 328i to a manual 328i? And if it would be a direct fit.

[approximate]

Originally Posted by PureE92

I wonder if you could swap a 3.64 from a 330i into a 328i? Or a 3.91/3.73 from an auto 328i to a manual 328i? And if it would be a direct fit.

does fit directly!

[DRiiFTAHOLiiK_e90]

Originally Posted by dragonsi

I have a 2006 330i MT with the automatic 2006 330i differential, coupled with an M factory LSD. The automatic 2006 330i differential is a direct swap.

As far as MPG, before I would get about 22 mpg on average, now I get roughly 21.5-21.8 mpg. It is the lowest its been at right now which I would attribute to the winter gas.

I was afraid of the highway cruising speed as well since I like to cruise around 75-80 mph,in Mexico. It's hard to describe the difference, yes you do feel the car operating at a higher rpm, but it's really the nature of the car that has changed. Now the car feels like it's begging you to go faster.

I highly recommend this to anyone looking to add more "sport" to their car, it is certainly worth it for how much it costs. If you can afford it, definitely get an M factory LSD to go with it. Like others have said, the car should of came from the factory like this.

when you had the lsd put in did you have the bearings inside the diff replaced? currently right now i have my 3.64 diff in hand and a after market lsd and im trying to find bearing specs so i can replace them with new ones

[chris82]

Can one of you guys put a video up of the acceleration?

[dragonsi]

Originally Posted by DRiiFTAHOLiiK_e90

when you had the lsd put in did you have the bearings inside the diff replaced? currently right now i have my 3.64 diff in hand and a after market lsd and im trying to find bearing specs so i can replace them with new ones

I had M factory do the install for me and I think that they did replace the bearings inside as well. Try asking them, they're a board sponsor.

[neoduffer]

Originally Posted by DRiiFTAHOLiiK_e90

when you had the lsd put in did you have the bearings inside the diff replaced? currently right now i have my 3.64 diff in hand and a after market lsd and im trying to find bearing specs so i can replace them with new ones

MFactory has bearings and other parts available for the rebuild.

http://www.e90post.com/forums/showthread.php?t=1097995

[GTKrockeTT]

i went with a 3.38 out of a 328xi MT. had to get the input flange swapped out though. my 07 328i MT was a four bolt, whereas the sourced 07 328xi MT assembly had a 3 bolt.

[Volasko]

I finally got my car back on the road after my winter rear suspension rebuild. I just gotta say how happy I am with the new final drive ratio. I haven't had enough time on the road to properly comment about the fuel economy, but the new found acceleration is making me fall in love with the car all over again. This really is the final drive ratio BMW should have put in the car to begin with. I am super happy with this mod and recommend it to anyone with a 330i.

[mbanks21]

I have a 3.73 auto diff from an 09 328i if someone with a manual wants to upgrade. PM me!

[Jashley73]

So obviously, this will require some software tuning, to correct the speedometer, correct? Any idea what this would cost to have done? Not interested in a performance tune, so I'm guessing this would need to be done at a dealer or Indy shop?

I'm getting slightly more interested in this diff swap...