[chilledn52]

So its been about a week of running 3.91 diffs in my 328xi manual. From the 3.38 to the 3.91 gave a jump of 14% more torque to the wheels. Straight across swap, didn't need different flanges.

Impressions:
DAYMN so much more acceleration in every gear. You notice it pretty much at any rev range. Gears are shorter so 1st is 50kph, 2nd is now 80kph. Highway speeds have me pretty much at 3k rpm in 6th.
Also its been harder to launch as I seem to get just wheel hop in first gear if I drop the clutch (xdelete rwd), still haven't felt the torque with AWD enabled.

100% Worth the $400 of used diffs. Would recommend to anyone wanting more power out of their N52 to do a diff swap from the automatic if you're a manual transmission.

[Biginboca]

I’ve been saying this for years. The single best mod I ever did was a $200 off eBay final drive swap (rwd so only needed one).

[chilledn52]

Originally Posted by Biginboca

I’ve been saying this for years. The single best mod I ever did was a $200 off eBay final drive swap (rwd so only needed one).

You are one of the main reason I ended up doing this job so appreciate your work here Biginboca!

[houbmw]

I need to do this asap on my E60

[Runnin'Rich]

I have the 328i xdrive 6MT and feel like the OE gearing is on the limit of being too short

Maybe I just drive like a grandad? I rarely rev my engine past 4K when daily driving. Starting from a stop you have to change to 2nd real quick. When I first got the car it took a while to adjust to being able to use first gear smoothly without jerking or shunting. The blind clutch feel doesn’t help!

I can totally see why a RWD 6MT owner would swap the diffs as the gearing is a little taller than the xdrive.

I feel like using first gear would just become annoying if my gearing was any shorter!! Maybe it would be fun for a week, but for a daily would be overkill?

Or maybe that’s just how cars are geared these days… I’m coming from a 1998 e36 328i Sport 5MT where the gears were loooog.

[AdrianE36]

I've had a 3.91 on my car for 3 1/2 years and I love it!

[chilledn52]

Originally Posted by Runnin'Rich

I have the 328i xdrive 6MT and feel like the OE gearing is on the limit of being too short

Maybe I just drive like a grandad? I rarely rev my engine past 4K when daily driving. Starting from a stop you have to change to 2nd real quick. When I first got the car it took a while to adjust to being able to use first gear smoothly without jerking or shunting. The blind clutch feel doesn’t help!

I can totally see why a RWD 6MT owner would swap the diffs as the gearing is a little taller than the xdrive.

I feel like using first gear would just become annoying if my gearing was any shorter!! Maybe it would be fun for a week, but for a daily would be overkill?

Or maybe that’s just how cars are geared these days… I’m coming from a 1998 e36 328i Sport 5MT where the gears were loooog.

With first gear yea its a quick change, doesn't need to be if you do rev it out to 5-6k before you shift. Its honestly a difference of like 300rpm from stock and not too far off. Most of my adjustment in driving has been first and second.

[E30M CW]

Did you complete the swap yourself, or did you take it to a shop?

[chilledn52]

Originally Posted by E30M CW

Did you complete the swap yourself, or did you take it to a shop?

I did this myself with a coworker as I needed to do oil pan gasket at the same time.

[cooperolson]

I did a manual swap on my auto 328xi, in doing so I kept the 3.91 gearing. Other than the manual swap the shorter gearing is amazing, makes the car feel so much less sluggish. I honestly just start in 2nd all the time because first is almost too short to use imo.

[E91Swagger]

Originally Posted by chilledn52

I did this myself with a coworker as I needed to do oil pan gasket at the same time.

Did you replace the front diff with the 3.91 ratio as well? How do you like the xdelete with the car?

[chilledn52]

Originally Posted by E91Swagger

Did you replace the front diff with the 3.91 ratio as well? How do you like the xdelete with the car?

Yes I replaced front and rear differentials with 3.91.

Xdelete is fun to change on driving dynamics, save a little on fuel economy, and getting a little more power to wheels. It’s usually on RWD for summer time and a mix of fully AWD and snow mode during the winter time.