Transfer Case - Open or Limited Slip?

Originally Posted by karatechop5000

If I jack up my front end, put on the ebrake, and put the car in drive; will that be a definative test? If the fronts spin, we have an open transfer case. Does anybody see a problem with that test?

Edit. DSC off.

Well I think you just proved it. Case closed then!

Originally Posted by karatechop5000

Does anybody see a problem with that test?

1) Did you give it some gas?
2) What happens when you floor it without the e-brake on?
3) With 4 wheels on the ground, can you put it in D, set the handbrake, and not move anywhere?
4) What happens when you do the same thing with the rear off the ground?

In a simple planetary gear set, there is one input, one output, and one fixed component. On our TC, there's one input (planetary carrier) and two outputs (sun to the front; ring to the rear). By lifting the front, you are in effect making the ring gear fixed, and turning it into a simple torque reducing planetary gear set. This move toward a simple planetary gear set is the 'slip' and is the reason the drivetrain doesn't bind up around corners. Even in a simple planetary gear set, a fixed ring gear is under load.

That video proves the TC isn't a 4x4 locker, and that your car won't drive itself up a hill at idle with the e-brake on.

Originally Posted by SamDoe1

Well I think you just proved it. Case closed then!

+1

Originally Posted by Kubica

1) Did you give it some gas?

A little bit. Before I got out of the car to shoot the video.

Originally Posted by Kubica

2) What happens when you floor it without the e-brake on?

Did not do that.

Originally Posted by Kubica

3) With 4 wheels on the ground, can you put it in D, set the handbrake, and not move anywhere?

Yes. As with all automatics. Engine revs to stall limit.

Originally Posted by Kubica

4) What happens when you do the same thing with the rear off the ground?

Same thing? I don't have a front ebrake; so I couldn't easily test.

Originally Posted by Kubica

In a simple planetary gear set, there is one input, one output, and one fixed component. On our TC, there's one input (planetary carrier) and two outputs (sun to the front; ring to the rear). By lifting the front, you are in effect making the ring gear fixed, and turning it into a simple torque reducing planetary gear set. This move toward a simple planetary gear set is the 'slip' and is the reason the drivetrain doesn't bind up around corners. Even in a simple planetary gear set, a fixed ring gear is under load.

Agreed (except for the last sentence). 'Hold' is not either off or on. It's on with traction; and its variable during slip. I view it as 'feedback torque'. The ring is easily held until the fronts grab ahold of something.

Originally Posted by Kubica

That video proves the TC isn't a 4x4 locker, and that your car won't drive itself up a hill at idle with the e-brake on.

Could you agree "Its open; but specific torque ratio is enforced by wheel traction, 1/1 speed ratio is dependent on planetary gearset's 'mode', and it is permanantly engaged." ?

Originally Posted by karatechop5000

Could you agree "Its open; but specific torque ratio is enforced by wheel traction, 1/1 speed ratio is dependent on planetary gearset's 'mode', and it is permanantly engaged." ?

I would agree with this sentence except for adding in the statement of up to a maximum of the ideal torque split. Even with the ring gear held fixed with traction, you are still gearing the front wheels down through the planetary gears and therefore reducing the percentage of engine torque heading to the front.

I can answer all of this bullshit if you want I've had an xi in my garage with the front half shaft off. Only reverse works, The car won't move, vise versus. If you disconnect the rear half shaft it won't move unless in reverse. Nothing needs to be reflashed for the car to work, etc. No check engine lights provided you rewired your wheel speed sensors for your dsc/abs system. Bottom line is this has already been covered. forget about your tq split you guys are missing how this system works. wtf EDIT: you don't have a limited slip or an open TC Another EDIT: if you don;t have your abs unplugged, your DSC is still on so this thread has been a fail the whole time.

Originally Posted by xixixi

I can answer all of this bullshit if you want I've had an xi in my garage with the front half shaft off. Only reverse works, The car won't move, vise versus. If you disconnect the rear half shaft it won't move unless in reverse. Nothing needs to be reflashed for the car to work, etc. No check engine lights provided you rewired your wheel speed sensors for your dsc/abs system. Bottom line is this has already been covered. forget about your tq split you guys are missing how this system works. wtf EDIT: you don't have a limited slip or an open TC Another EDIT: if you don;t have your abs unplugged, your DSC is still on so this thread has been a fail the whole time.

I'd ask a few questons; but you seem kinda edgy.

Originally Posted by karatechop5000

I'd ask a few questons; but you seem kinda edgy.

Shitty day my friend, ask away! I'm sure I could help ya out I refuse to read this entire thread!

Some of the threads I read seemed to give conflicting information. I'd like to see a link to the one you are referring to. I think I read it and came away confused. Also the issue came up in another good thread about putting in a rear wavetrak LSD. I have seen the issue indirectly come up in staggared tire size threads.

I was trying to 'keep the ball on the court' by staying focused on the transfer case. (I fear a lot of smart people here have a misunderstanding). I know it's a boring read, but my nerd antenna is fully extended.

First question: What's the thread title you are referring to?
Second question: What does the DSC do when 'off' different than when 'on'?
Third question: If the transfer case is not 'fixed', 'open', or 'limited slip'; what is the other choice?

Originally Posted by karatechop5000

Some of the threads I read seemed to give conflicting information. I'd like to see a link to the one you are referring to. I think I read it and came away confused. Also the issue came up in another good thread about putting in a rear wavetrak LSD. I have seen the issue indirectly come up in staggared tire size threads.

I was trying to 'keep the ball on the court' by staying focused on the transfer case. (I fear a lot of smart people here have a misunderstanding). I know it's a boring read, but my nerd antenna is fully extended.

First question: What's the tread title you are referring to?
Second question: What does the DSC do when 'off' different than when 'on'?
Third question: If the transfer case is not 'fixed', 'open', or 'limited slip'; what is the other choice?

http://forum.e46fanatics.com/showthr...ghlight=xi+rwd

I gave up on the thread, but I got it done.

Originally Posted by xixixi

http://forum.e46fanatics.com/showthr...ghlight=xi+rwd

I gave up on the thread, but I got it done.

Did you ever finish the conversion?

OK yes. Your thread was right about the TC. Other threads... not so much. It's 'open'. That's why you were spinning the fronts after removing the front axle. The reverse is a puzzle to me. I think either something in the front was jammed up, or it was rolling backwards down your driveway.

Originally Posted by TiAgXi

Did you ever finish the conversion?

yes.

Just the front output on the T case was spinning yes. Idk about the reverse. However a few people drove it before i swapped the diff and they said in reverse it "felt" like an lsd? IDK

Originally Posted by Kubica

Damn. Good point. But we don't have a torsen. Got me thinking though.

I saw Steve Dinan last night and asked him if he knew how the E46 transfer case worked. He smiled and said his "head was filled with pistons and boost right now" and that he didn't know.

Also asked him if he planned on making any more xi springs, since they've been out of stock for a couple years. He had no idea and punted on that question too.