E9X Future of Xdrive Drivetrain

Cheezy

Lieutenant
Nov 7, 2016
588
Toledo Ohio
I often look to @[email protected]! 's build for information, as well as seeking information found in @Twisted Tuning 's posts. As i explore the options of strengthening the driveline of my car to handle more power, sometimes im left with questions from ideas i know im not the only one asking. Ive purchased justins tcase mount insert, and i plan to purchase his front diff brace followed by a rear. Now im thinking i want to put sticky tires all the way around my car, and with that comes the fear of broken axles. My question today is if anyone knows if mfactory axles would be direct drop in for the rears, and if there are any options for upgraded fronts? Also around what power levels would you think this is necessary? I know dave flirted with 600hp 600wtq and was snapping the front axles and more importantly exploding front diffs. And justin has a 750hp car but the torque curve (as i understand it) is set more for roll racing and 1/2mile. Does anyone know of any upgrades coming down the road for the xi guys that could allow us to launch the piss out of these cars and have traction for quicker 1/4mile passes?
 
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Twisted Tuning

Lieutenant
Platinum Vendor
Oct 25, 2016
852
New York
Busy at the moment. But will make a post soon here in reference to:

-front diff bracing
-possible tcase iinternals
-full time awd conversion

And some other things.
 
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Twisted Tuning

Lieutenant
Platinum Vendor
Oct 25, 2016
852
New York
Sorry, completely forgot about this thread.

So, about the front diff brace. I've been pondering and pondering this to decide whether or not anything can be stiffened/locked down with the front differential for a while now.

This issue, well I won't count that as an issue is that the front diff is bolted directly to the oil pan. So short of engine movement on stock engine mounts there's not much there that moves. So I've been researching front diff failures and honestly only found a few. So locking the front differential down could be helped with upgraded engine mounts.

As you don't really want to brace it to the chassis or subframe as it may cause stress to the oil pan casting. So I may look into an lsd front diff if nothing else.



Full time awd.........

I'm looking into that and have a design in my h head for it. Being that most failures of the tcase that I've seen is the work great that engages the front driveaxle. It strips and when that happens there is no more awd. So my thought process was to simply remove the switching function and keep the tcase locked into awd so the worm gear isn't the issue anymore.
 
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Cheezy

Lieutenant
Nov 7, 2016
588
Toledo Ohio
So locking the front differential down could be helped with upgraded engine mounts.

Full time awd.........

I'm looking into that and have a design in my h head for it. Being that most failures of the tcase that I've seen is the work great that engages the front driveaxle. It strips and when that happens there is no more awd. So my thought process was to simply remove the switching function and keep the tcase locked into awd so the worm gear isn't the issue anymore.
Im glad you saw that the diff is mounted to the oil pan because that never even crossed my mind. With that now in mind i suppose the best way to reduce slop would be a solid motor mount like ADEs.

I know i had looked up some worm gear options and found a guy making cnc aluminum ones iirc or some soft steel, but he said they wouldnt hold up to repeated drag use. If you do end up making something to block the switching function (assuming its an elecrical component) could it be possible to design it as a switch for rwd, then stop and lock the car into awd. Im thinking for the sake of burnouts, idk when the worm gear sees the most stress but assuming if the vehicle was completely stopped it wouldnt see that stress as it foregoes the switch. If that doesnt make sense ill try to reword it.
 

Twisted Tuning

Lieutenant
Platinum Vendor
Oct 25, 2016
852
New York
Im glad you saw that the diff is mounted to the oil pan because that never even crossed my mind. With that now in mind i suppose the best way to reduce slop would be a solid motor mount like ADEs.

I know i had looked up some worm gear options and found a guy making cnc aluminum ones iirc or some soft steel, but he said they wouldnt hold up to repeated drag use. If you do end up making something to block the switching function (assuming its an elecrical component) could it be possible to design it as a switch for rwd, then stop and lock the car into awd. Im thinking for the sake of burnouts, idk when the worm gear sees the most stress but assuming if the vehicle was completely stopped it wouldnt see that stress as it foregoes the switch. If that doesnt make sense ill try to reword it.

I knew the whole time it was attached to the oil pan. Ive just been looking at it over and over thinking of possibilities of locking it down more. But with it being attached to the oil pan. Not much can be be done in that area.

There was only one thing I thought about doing. Because I had thoughts of the actual bolts loosening up and causing issues, sincewell, aluminum.

but I haven't found any posts or mentions about that ever occurring.

For the full time awd, I was not planning on making it switchable. Because in order to keep it switchable, the failure point still remains. And that's the worm gear. I was planning on bypassing that completely. With a physical upgrade.
 
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savageN54

Lurker
Feb 2, 2018
14
Question, so if my tcase gears got chewed up which means no AWD, do you necessarily even need to fix that? Wouldn't the car just operate as rwd. I understand you'll still have the drivetrain loss since power is still trying to be applied to the front wheels. But in theory, would it even absolutely NEED to be fixed?
 

Twisted Tuning

Lieutenant
Platinum Vendor
Oct 25, 2016
852
New York
Question, so if my tcase gears got chewed up which means no AWD, do you necessarily even need to fix that? Wouldn't the car just operate as rwd. I understand you'll still have the drivetrain loss since power is still trying to be applied to the front wheels. But in theory, would it even absolutely NEED to be fixed?
Should be fixed or removed. The stripped gears metalbis now inside the tcase. Some of the gears in there still rotate since its physically attached to the transmission.

So what can happen is the pieces of metal chew up other parts of the tcase
 

savageN54

Lurker
Feb 2, 2018
14
But on an xdrive can just the tcase he removed without hurting other components, such as electrical, the transmission, etc?
 

Cheezy

Lieutenant
Nov 7, 2016
588
Toledo Ohio
And lastly, what happens to the front diff if the t case is removed?
Ideally you would want to remove tcase, front diff, front driveshaft, and replace the front axles, oil pan and rear driveshaft. Or you could just remove the front driveshaft and leave it at that.
 

savageN54

Lurker
Feb 2, 2018
14
Ideally you would want to remove tcase, front diff, front driveshaft, and replace the front axles, oil pan and rear driveshaft. Or you could just remove the front driveshaft and leave it at that.
Well I suppose now I have options if I blow the piss out of my front diff. I'm flirting with 600 wtq
 

savageN54

Lurker
Feb 2, 2018
14
I've always been a big believer in if you're going to remove a part, replace it with an upgrade, not another stock piece lol. Of course has limitations but thanks
 

The Banshee

Corporal
Nov 18, 2017
121
Lehigh Valley PA
I am putting big power down on my XI and want to replace a few things. I already have the twisted tuning inserts and have just replaced my traction strut arms with upgraded bushings. I see axles like from aftermarket companies for $76 and then the BMW re-manufactured for $700+ That's quite a price difference. Is there a difference in part quality? If yes is it a $600 difference? Anyone tried either of them?
 

Jeffman

Captain
Jan 7, 2017
1,049
I am putting big power down on my XI and want to replace a few things. I already have the twisted tuning inserts and have just replaced my traction strut arms with upgraded bushings. I see axles like from aftermarket companies for $76 and then the BMW re-manufactured for $700+ That's quite a price difference. Is there a difference in part quality? If yes is it a $600 difference? Anyone tried either of them?
Which upgraded bushings did you get and how did you install them?
 
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