ABLS or LSD

[kmfernandez]

Originally Posted by bestatchess

O.K., a wench that knows how to put tire chains on, and then perhaps a bit of mud wrestling aftewards.

... - Ok; now Im confused: Winches, wenches, LSD, ABLS, mudwrestling -and- tire chains?

[Quad T]

Originally Posted by Austin

Enter ABLS.
ABLS clamps the RR brake caliper shut (it'll never actually go this far - I'm just giving an extreme example). The RR wheel now has effectively infinite traction - allowing infinite torque to be generated and distributed equally to both sides. This allows the torque necessary to move the truck to be delivered to the LR wheel. Truck not stuck.

I don't have a Titan yet, and I don't have time this weekend to go deal with a pesky salesperson, but all I want to know is this:

VERSION ONE- if you stop the truck in 2WD on dirt, leave the VDC active and stand on the gas, what do you get?
- do you get only 1 tire spinning and turning over the dirt
- do you get 1 tire spinning and then the other tire spinning and then back to the first tire spinning and turning over the dirt
- do you get both tires spinning at the same time turning over the dirt

VERSION TWO- if you stop the truck in 2WD on dirt, turn the VDC off and stand on the gas, what do you get?
- do you get only 1 tire spinning and turning over the dirt
- do you get 1 tire spinning and then the other tire spinning and then back to the first tire spinning and turning over the dirt
- do you get both tires spinning at the same time turning over the dirt

[ChuhBaca]

I think the only way to get this settled is for someone to get a video camera, turn off the VDC on the truck (if so equipped). Park the truck in some reeeally loose dirt or mud and take video of what the rear wheels do when you floor the gas. Will they spin or will they try to control the wheel spin. Personally, I'd prefer the spinning. In deep mud, you need your tires to spin for two reasons: They need to create a paddle effect and; they need to clean themselves out.

[keane]

Originally Posted by Quad T

I don't have a Titan yet, and I don't have time this weekend to go deal with a pesky salesperson, but all I want to know is this:

VERSION ONE- if you stop the truck in 2WD on dirt, leave the VDC active and stand on the gas, what do you get?
- do you get only 1 tire spinning and turning over the dirt
- do you get 1 tire spinning and then the other tire spinning and then back to the first tire spinning and turning over the dirt
- do you get both tires spinning at the same time turning over the dirt

VERSION TWO- if you stop the truck in 2WD on dirt, turn the VDC off and stand on the gas, what do you get?
- do you get only 1 tire spinning and turning over the dirt
- do you get 1 tire spinning and then the other tire spinning and then back to the first tire spinning and turning over the dirt
- do you get both tires spinning at the same time turning over the dirt

Answer for one is the VDC slows the engine so I didn't get much spin, if any. I didn't try it with VDC off so I can't help you with that yet. Someday I will try it and see what happens.

[kmfernandez]

Originally Posted by Quad T

I don't have a Titan yet, and I don't have time this weekend to go deal with a pesky salesperson, but all I want to know is this:
...

This is a response trom BigHawaii to PigPen in the 'Brake Active Limited Slip' thread over in the Technical Discussion Area.

Quote:
Originally Posted by PigPen
While I dont recommend it, I got underneath the rear end
and disconnected the ABS/ABLS whoziwhazit. While I was
able to lay a sick patch, the dashboard lit up like a xmas tree. Reconnected things and everything went back to normal. This is the only thing nissan muffed, the VDC should be fulltime and the ABLS should be on demand(button). (end quote)

i dont think you want VDC to be full time since the VDC cuts your engine power rendering you helpless when both tires are slipping, if you turn it off with the VDC switch you can bring your engine up to any rpm you want, even with ABLS on. ive done it myself many times on minor trails, abls isnt "powerful" enough to stop your engine if you really juice it. when on minor trails ive found out that you have to feed it a bit and the abls will wither kick in or after a certain point wont do a thing, 1 wheel may spin or both.
__________________

Now my turn: I've got a 2wd, and I want a limited slip or on demand locker. Anybody know where I can find such a thing for a Titan?

[bestatchess]

"The brakes will definitely not lose. They are specifically designed to clamp, which, due to their mounting location, means they're specifically designed to stop rotation of the tire/wheel. Without ABS, you'd be able to lock up the wheels anytime you wanted to. Brakes that size have the clamping force necessary."

Ahhhh, someone else gets it, too!! Here is a nice explanation:

http://www.teamscr.com/grmbrakes.htm

[Quad T]

Originally Posted by ChuhBaca

I think the only way to get this settled is for someone to get a video camera, turn off the VDC on the truck (if so equipped). Park the truck in some reeeally loose dirt or mud and take video of what the rear wheels do when you floor the gas. Will they spin or will they try to control the wheel spin. Personally, I'd prefer the spinning. In deep mud, you need your tires to spin for two reasons: They need to create a paddle effect and; they need to clean themselves out.

I'll fax you over a cold beer right now!

I totally agree with you, and I would only add in your reply above, as far as I'm concerned, you can also add SNOW where you mentioned MUD. In deep mud and snow I believe I have a better chance to get on through if I can keep the momentum of the vehicle up, get the tires spinning, chewing and cleaning themselves out, as I keep up with the steering inputs.

[CI338]

I want both! Plus a locker in 2Hi! Plus 2Lo! Should I have voted for other? Or bought a Rubicon and put in a twin stick transfer case?
I've never had it transfer wheelspin from right to left or vice-versa. It just cuts the wheelspin on the inside (spinning) tire slightly and flashes the dash light at you.
I did notice that there is a spot on the gauges for the locker light on the lower righthand corner.
Anyone know if the axle uses a gasket or just sealant to seal the cover to the rearend? I may just pull the cover to see what's in there around 6K miles plus just to put fresh lube in it.

[Austin]

Originally Posted by CI338

Anyone know if the axle uses a gasket or just sealant to seal the cover to the rearend? I may just pull the cover to see what's in there around 6K miles plus just to put fresh lube in it.

From the manual:

CARRIER COVER

Removal and Installation

REMOVAL
1. Drain gear oil.
2. Remove carrier cover.
Disconnect the parking brake cable from the carrier cover.
Disconnect the hydraulic brake tube from the carrier cover.

INSTALLATION
1. Install new carrier. Apply liquid sealant to carrier cover side and install axle housing.
2. Tighten carrier cover bolts. (31 Ft-lbs)
3. Fill final drive with recommended gear oil.

[ChuhBaca]

Originally Posted by Quad T

I'll fax you over a cold beer right now!

I totally agree with you, and I would only add in your reply above, as far as I'm concerned, you can also add SNOW where you mentioned MUD. In deep mud and snow I believe I have a better chance to get on through if I can keep the momentum of the vehicle up, get the tires spinning, chewing and cleaning themselves out, as I keep up with the steering inputs.

Thanks for the faxed beer Quad! It was a little flat, though

I think I'll try to find the Trucks! TV website. Maybe we can get Stacey David to clear up this issue on national TV once and for all! That would be cool!

[bighawaii]

Originally Posted by bestatchess

"The brakes will definitely not lose. They are specifically designed to clamp, which, due to their mounting location, means they're specifically designed to stop rotation of the tire/wheel. Without ABS, you'd be able to lock up the wheels anytime you wanted to. Brakes that size have the clamping force necessary."

Ahhhh, someone else gets it, too!! Here is a nice explanation:

http://www.teamscr.com/grmbrakes.htm

sorry if i was to blunt and general. in my driving experiences ive concluded that the ABLS isnt programmed to completely stop all wheel spin on all 4 tires under heavy loads rendering you a sitting duck. im sure theres other drivers out there who turned off thier VDC and had 1 or more tires spinning. at certain times when the ABLS kicks in depending how hard you feed it and the surface you are on it may slow the spinning wheel or wheels down causing the other/others to grab traction propelling you foward, on unstable surfaces it may apply braking to hard or suddenly causing both wheels to spin . i cant be the only one getting my titan dirty.

[JS02]

I don't have the problem as bad with an empty truck. When I pull a heavy trailer in the mud the ABLS doesn't seem to do as well as an LSD. I think having both is the best way to do it. I just want to use 4WD HI and have the LSD work. They should be able to disable the rear ABLS when the electronic LSD is engaged. I still would like to know if the ABLS would have to be shut off if you only used the LSD in extreme conditions.

[Bluto]

Originally Posted by bestatchess

"The brakes will definitely not lose. They are specifically designed to clamp, which, due to their mounting location, means they're specifically designed to stop rotation of the tire/wheel. Without ABS, you'd be able to lock up the wheels anytime you wanted to. Brakes that size have the clamping force necessary."

Ahhhh, someone else gets it, too!! Here is a nice explanation:

http://www.teamscr.com/grmbrakes.htm

A nice explanation of why the system won't work.


558 psi?

The master cylinder is very large, and requires 360 lbs of force to generate 558 psi. Where in the ABLS system is something that can generate and modulate from 0-558 psi???


For ABLS to work, it will need an impressive range of pressure to provide to the "wheel some resistance to turning - allowing torque to be generated - and that allows the open differential to deliver torque to the other side."

The resistance will not always be the same in all situations. Example, driving through the mud would only require a small amount or resistance. However driving slowly up a rocky trail or pulling a boat up a ramp will require a lot more. Different levels of traction require different levels of brake force.

Does anyone have a shop manual? Where is the pump for ABLS that can provide 0-558 psi, incrementally? One or two levels won’t cut it. I willing to bet the ABLS can not provide enough psi to overpower the engine and resistance from the wheel with traction, the brake will lose, the wheel will spin.


In my experience with VDC in low traction, it has one level of brake force it can pulsate. It does not sustain or increase force. The caliper merely hums away. Unless ABLS is a totally different system from VDC, it is not going to work like an LSD.

[Bluto]

Originally Posted by bestatchess

380 Ft-lbs is peanuts for a braking torque for a vehicle with power brakes and big rotors (like the Titan).

Where is the brake pressure to stop 380 ft-lbs coming from???

[Austin]

Originally Posted by Bluto

Unless ABLS is a totally different system from VDC, it is not going to work like an LSD.

Lucky for you, ABLS *is* a totally different system from VDC.