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Willie Joubert (Willie)
| | Posted on Tuesday, April 02, 2002 - 04:28 pm: | 
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Any one know if the ABS on a D1 pulse all wheels when working or just the wheel that locks?
I suspect it pulses all at the same time....? |
p m
| | Posted on Tuesday, April 02, 2002 - 04:36 pm: |
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it is supposed to deal with the wheels individually.
peter |
Brad Russell (Bradnc)
| | Posted on Tuesday, April 02, 2002 - 07:56 pm: |
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If it truly does, then couldn't this be used as a sort of ETC? now, if i am correct, there is not sort of traction control on a D1. So, when you are off road and find yourself in a tough spot, could you not use simultanious breaking and gas using the left and right feet to simulate ETC? If you applied the break in a small to moderate amount, it would try to stop the wheels that are spinning more so than those which aren't. Then apply more gas until you get going. It all seems theoretically possible to me. Anyone with something to prove otherwise let me know, but i don't see why it wouldn't work... Virtually the same system, just human operated... ABS may be worth more than previously thought...
Brad |
Milan
| | Posted on Tuesday, April 02, 2002 - 08:36 pm: |
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The problem with that theory is that by pushing the pedal you're supplying brake pressure to all wheels not just the one spinning like ETC does. So using the brake, works but it works best with limited slip. It works but not very well with open diffs and in both cases, you're sort of slowing yourself down in forward momentum when you really just want to keep going. Oh, and ABS does not really come into play in this case.
I love my dual TTs on my Jeep but I'm getting tired of having to use my brake and have the rotors screech when all I want is to either lock up the spinning wheel, or have the diff locked so I can just keep going. On the Disco I may do the dual TTs only because it should not see as much trail duty but who knows what I'll put in. On the Jeep I may go for the Elockers once they come out.
I think the best non-locker setup on a Disco would be a CDL, TT f&r and ETC. That should work handsomely. Anybody have that setup? |
Brad Russell (Bradnc)
| | Posted on Tuesday, April 02, 2002 - 08:39 pm: |
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but say you are stuck on a few rocks with one front wheel and one rear wheel spinning w/ the CDL locked, if you applied the break it would break the spinning wheels, and then apply the gas to overpower the breaks and it should get your previously stoic wheels spinning thus providing traction. It would probably require a lot of brake and a lot of throttle, and would be inefficient as far as gas, but could it not get you unstuck from a tight spot? |
p m
| | Posted on Tuesday, April 02, 2002 - 09:54 pm: |
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Brad,
here's an example of ABS' operation in a all too frequent situation off road:
you're stuck, and the wheels are spinnin'. If you have been wheeling for a while, you may think of rocking the truck back and forth to gain some momentum and get yourself out of the hole dug by the wheels. BUT - you've got an automatic transmission, so no quick flips from the 1st to reverse. You can still rock the truck, but a bit differently - go as high and forward as you can, hit the brakes, hold the truck there, switch to reverse, hit the gas, go as far high and back as you can, stop the wheels, etc. Sounds good?
The damn ABS won't let you stop the wheels. And as a result, every time you try doing it, you will be sliding back into the very same hole. I can hardly relay how pissed I felt when I discovered it. Since then, every off-road trip I pull the damn fuse out.
I can only guess how ETC works in this situation, and it is not very comforting.
peter |
Brad Russell (Bradnc)
| | Posted on Tuesday, April 02, 2002 - 11:22 pm: |
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I see how if all your wheels are spinning that it wouldn't work at all, but i truly think that if you have at least one wheel with traction and you're in a place that you are stopped you could try this method and it would work, although i'm not sure to what degree. All ETC is is anti-lock breaking to the wheels that are spinning the most, which is the exact same thing that would be occurring here... |
Milan
| | Posted on Wednesday, April 03, 2002 - 09:47 am: |
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Brad,
It will work somewhat but not enough to bother with it. You can just try it next time out and see what I mean. For the open diff to transfer the torque to the wheel that's not spinning, it takes a lot of brake and by using the brake you're also braking the wheel that you want to start spinning/moving. Then you have to use a lot of gas and that strains all the components involved for a measly result. If you could brake just the spinning wheels, that would be better and not as stressfull for the drivetrain - hence ETC.
However, if the foot-on-the-brake method helps you get unstuck great but if you are really stuck, it won't be enough and you may break something on top of being stuck. Just my 2 cents. Also, like I said before, ABS will not come into play while doing this. |
Willie Joubert (Willie)
| | Posted on Wednesday, April 03, 2002 - 01:37 pm: |
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Basic's, first let's confirm that it does only pulse one wheel and not all.
Scenario, software can be installed to do this, I have someone interested in working with us on such a project, a computer guy...
If it pulses all wheel's it clearly is a waste of time.
If it pulses one wheel we can make it work with the CDL in place.
Any one know if it pulses all wheels at the same time????
BTW, the string till now have been trying to make use of brakes and gas. It won't work, power still goes to the wheel with least resistance even if you apply brakes. I have tried that..... |
p m
| | Posted on Wednesday, April 03, 2002 - 02:03 pm: |
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Willie,
no, LR takes its pride in "developing the world-first four-channel off-road ABS" (i hope i quoted them right).
don't waste your time making poor shitty ABS lock your spinning wheels, it is cheaper and less labor-intensive to install a locker.
FWIW, the brakes and gas technique works okay, you haven't tried hard.
peter |
Milan
| | Posted on Wednesday, April 03, 2002 - 04:47 pm: |
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Additionally, the ABS pulses the wheel that is approaching lock up. ETC reverses that. It lock up a spinning wheel. That's what you try to do with pressing the pedal. Only doing so you also lock up all the other 3. That's why it works but not so well. I agree with pm that rather than getting the ABS to work, install lockers. Or if you're really keen on having ETC, retrofit one from a D2 and then install dual TTs. I really think that would work very well but I'm not gonna try it. Alternative solution would be a 5 way valve with a joystick allowing you to lock any one or two brake lines thus allowing the equalization of torque to take place. I think, either way (ETC/ABS or sophisticated cutting brakes) makes for a complicated system where I for one would rather have non-ABS brakes and separate lockers. |
p m
| | Posted on Wednesday, April 03, 2002 - 05:03 pm: |
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Milan,
I've been thinking of a joystick thing for a while, but here's a very common situation: you're going up a very steep hill with checkerboard-patterned ruts. Do you think you'll have time to fiddle with the joystick (especially when you're having a hard time keeping the steering wheel in your hands)?
So, while the joystick could be a nice feature when you drive so slowly that you actually know which wheel to brake, it is hardly a substitute for a couple of TTs or DL/TT. And it is much more difficult to implement, with all liability involved with butchering the brake plumbing on a street truck. And retrofitting the ETC to a D1 seems a really ass-backwards solution (even if ETC worked like on paper).
peter
p.s. there's one such hill on a road called 2N17X in San Bernardino Mountains. I've never heard of a D2 making it up that hill - any SoCal D2'ers done it? |
Brad Russell (Bradnc)
| | Posted on Wednesday, April 03, 2002 - 05:47 pm: |
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Well it was just a theoretical question I had...something to provoke a little thought over spring break. I'm not sure it would work all too well now, possibly not at all. I guess i'm just a dork for thinking about stuff like that. Haha.
Brad |
Willie Joubert (Willie)
| | Posted on Wednesday, April 03, 2002 - 06:00 pm: |
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Peter,
I gather you drive a D1?
Put one front wheel on a rock, or shall I say half way up a rock. The other front wheel clear off the ground as well as the oposing rear. In other words a full twist with resistance in front of the wheel on the rock......You will not get over it...I guarantee you. Brakes and gas work when you have an reasonable amount of traction on all fours with liitle forward resistance.
The idea was to have option of traction controll that can be switched on or off at any time.
Yes lockers are the cheap easy way out but they too have limitations. |
Milan
| | Posted on Wednesday, April 03, 2002 - 08:48 pm: |
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pm...zzzzzzzactly
Willie.....zzzzzzzactly
Brad,
yes you're a dork but this was a good discussion and it's good to turn the stale brain cells once in a while, so no foul. Hehehehe |
Brad Russell (Bradnc)
| | Posted on Wednesday, April 03, 2002 - 10:57 pm: |
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you didn't have to tell my i'm a dork, i know that.....but i'm also a punk rocker, jock, computer nerd, smart ass, and genius, so i get to pick and choose who i'm gunna be....haha |
muskyman
| | Posted on Thursday, April 04, 2002 - 12:36 am: |
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ARB's....your done...as far as limitations...thats why they turn on and off |
Milan
| | Posted on Thursday, April 04, 2002 - 11:09 am: |
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Oh I can be a smart ass too. And most often I'm just an ass...hehehe |
p m
| | Posted on Thursday, April 04, 2002 - 02:43 pm: |
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Willie,
you're sort of half-way correct.
Let me have a try.
All an open axle diff provides is exactly equal torque on both wheels. So, when one wheel's in the air, there's nothing to counteract this torque, and the wheel would spin. The other wheel will get just as little torque as the one that spins.
Now, apply the brakes. THe wheel that's in the air now encounters some resistance, and it takes some torque to overcome it. The open diff makes sure that the other wheel gets just as much torque, which is much more than the same without brakes applied.
So, the outcome of whether i'll get over that rock or not depends on how much torque does it take to get over it. It may or may not be enough.
Same idea applies to "bringing the limited slip into its operating range." The limited slip will do its best to minimize the difference in rotation rate of the axleshafts, but it will only transfer so much torque to the wheel that has traction. You can help it a lot by applying brakes. Hard! It won't be easy on the axles, but it will be better than pulsating load by ETC.
peter |
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