Upgrades: differentials and limited slips!

[Green Dragon]

Just checked the specs on my wife's '04 e83 x3 6-speed manual. 3.64 final drives are used. Interesting. The ratios in the gear box are massaged as well. That would account for her X having a more "friendly" car-like driving attributes when it came to shifting. Her X also weighs about 500 lbs lighter at just over 4000 lbs. 1st gear is better and easier to live with, but still some what tall. Not sure how many e83 owners tow but it does have that option.

My guess, BMW is addressing the M54's lack of low end torque and 'rev' happy nature to move the weight around. Once you get 'er moving, the I6 power delivery is silky smooth with more urgency as the revs build. That is truly when the m54 is in its element and accounts for, at least in my mind, why they choose the gearing.

Sedc, I love the idea of an S54 powered e53. I know its been done, but I don't know much about it. The S54 would defiantly be a screamer, and would naturally have to be, to tap into its upper power reserves where that engine just thrives. If you go that far, you might tune it for a little more torque delivery down low. My guess is that you wouldn't give up anything that the M54 offered. Good Luck which ever direction you take, S/C'ed or whatever. Keep me posted.

[sedc]

Originally Posted by Green Dragon

Sedc, I love the idea of an S54 powered e53. I know its been done, but I don't know much about it.

It's a lot of work. We did an S54 into an E39 wagon, many many headaches.

Originally Posted by Skyline

The cost of that would be much, much higher than selling your 6 cyl and buying a V8.

Sure, but three reasons why this isn't an option for me: 1) I haven't yet driven a V8 BMW, of any variety, that felt balanced, 2) I spent a couple years wrenching BMWs professionally, and I know V8 E53s are less reliable than I6s, and most importantly, 3) No manual trans for V8 E53, and no easy remedy for swapping one.

[Nick P]

Hi!

Since there are Quaife and Drexler LSDs for E53, it seems to be much easier way to get the axles locked. But I saw, the older front Diff is adaptable quite easily for E53.

I'm considering though, to lock both axles and not just the front, even I'll get more understeer, the winter and off-road capabilities would be much better, which I appreciate more.

[sedc]

An update on this...


We had our first snow storm since I put the LS in the front and did the gearing change.

Naturally I turned OFF DSC and did some parking lot tests, the truck is a freakin' beast even with ~20k mile michelin energies! It's unstoppable!!

I've also driven it about 12k miles since install, the 3.64 gearing has been fantastic all around. I am getting 21/21.5mpg on the OBC in mixed driving, around 530 miles a tank in pure highway driving at 80-90mph which I think is excellent for a 4500lb truck.


Highly recommend this upgrade, if you can make it happen!!

Originally Posted by Nick P

Hi!

Since there are Quaife and Drexler LSDs for E53, it seems to be much easier way to get the axles locked. But I saw, the older front Diff is adaptable quite easily for E53.

I'm considering though, to lock both axles and not just the front, even I'll get more understeer, the winter and off-road capabilities would be much better, which I appreciate more.

Right, the limitation with the Quaife is that if one wheel completely loses traction, it reverts to acting like an open diff....not an option in this case.

We have a '01 3.0 5 speed with both front and rear LS, and driving them both/if you like to drive fast in the snow, having to pull the park brake to get the rear to swing out around a corner is tedious.

[Nick P]

Originally Posted by sedc

Right, the limitation with the Quaife is that if one wheel completely loses traction, it reverts to acting like an open diff....not an option in this case.

We have a '01 3.0 5 speed with both front and rear LS, and driving them both/if you like to drive fast in the snow, having to pull the park brake to get the rear to swing out around a corner is tedious.

I'm glad to hear it works so good, congrats!

Every type of LS has its advatages and disadvantages, but I think for snowy roads the quaife would be as good as clutch-type lsd. After all, the benefits over unlocked stock diffs would be present in any case.

Just wanted to know, how you figured out, it will understeer with both locked axles? On tarmac it would be irrelevant, due to the very high initial grip, and on snow everything I need is traction, so I wouldn't mind the understeer at all.

[Ricky Bobby]

ok so if you just want to get the better gearing and not add the limited slip, do you still have to do the machining for the axles and the transfer case?

Basically Im asking is there any way to just drop the 4.10s out and pop in 3.64s?

[Nick P]

Originally Posted by Ricky Bobby

ok so if you just want to get the better gearing and not add the limited slip, do you still have to do the machining for the axles and the transfer case?

Basically Im asking is there any way to just drop the 4.10s out and pop in 3.64s?

They're interchangeable, same housing.

[Ricky Bobby]

wow, nice to know.

I could forego the limited slip, just to get the better ratios (and gas mileage) on my 3.0i with sport pack.


looks like I may want to start scouring for good condition diffs.

[Nick P]

Yes, I also wanted to say -obviously it's better to get a complete diff, rather than just the gears. 3.64 is the most common one and therefore the cheapest. You'll get a much better milage for sure!

[deepblonde]

Originally Posted by Nick P

They're interchangeable, same housing.

I have 3.91 gears in my 2006 3.0d, and would like to swap them for 3.64 gears, but I think the differentials are different on X5's from 2004 to 2006? What options would I have?