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Re: I want LSD!
Posted: Tue Feb 12, 2008 12:35 pm
by Green1
So, what "basic" 4wd equipment (LSD?) will keep ME from getting stuck in that scenario?...
ok, quick lesson in differentials here, a differential lets the 2 ends of a shaft spin at different speeds, this is important when you are trying to turn corners so you don't damage anything. the disadvantage being that if 1 end looses traction and starts spinning it gets all the power and the other end goes nowhere.
now a quick lesson on drive trains, on a "modern" 4wd system there are 3 differentials, one on the front axle, one on the rear axle, and one in the middle joining the 2. in this case any one wheel spinning gets all the power, and the other 3 get nothing. The upside being that you can leave the vehicle in 4wd at all times even on dry pavement with no problems.
The Delica uses an older 4wd system, whereby there are only 2 differentials, one on the front axle, and one on the rear axle, the drive shaft connecting the 2 does not have a differential, so both axles must spin at the same speed. In this case you need one wheel spinning on both the front and rear axles before you get stuck (already an advantage over the ford you saw stuck). the down side being that you can't use the 4wd on dry pavement without damaging things.
Locking differentials are a way of "disabling" the differential making both wheels spin at the same time, it gives you the best of both worlds, unlocked you can use the differential to avoid damaging the vehicle by driving on surfaces that don't "give" as you turn, while still giving you the option to lock the differential to make sure both ends spin at the same speed. the "perfect" off-roader would have locking differentials on both the front and rear, and either a locking centre dif, or like us, no centre dif.
You can also think of a LSD as a "partial" diff-lock, they let you have the advantage of the 2 wheels being able to move independently, while limiting how much spin the one wheel can get (directing some of the power to the non-spining wheel)
So in short, you're already ahead of what you saw on that road, but a locking dif would improve it more.
Re: I want LSD!
Posted: Tue Feb 12, 2008 7:25 pm
by jwfchase
That was pretty much my understanding of how LSD would affect things. I am still hoping to find a Deli equipped with LSD, but I won't go to the ends of the earth to retrofit one. We actually just got Delica#1 yesterday, but we are already looking for #2, since this one, as much as we already love it, doesn't have 3-point seatbelts, which will be an issue when our little one graduates from full carseat to a booster seat. So, we'll take our time looking for the next one, it must have shoulder belts, and will hopefully have the LSD too!
Oh yeah, it's good to know I'm better off than the scenario I mentioned... unless I happen to get both wheels on one side into the loose stuff?....
Re: I want LSD!
Posted: Tue Feb 12, 2008 7:36 pm
by EricN
Real world answer to your scenerio, LSD will be almost useless with that little traction. You would need to ride the parking brake for sure to get any kind of action out of the thing.
Re: I want LSD!
Posted: Tue Feb 12, 2008 7:53 pm
by Green1
Oh yeah, it's good to know I'm better off than the scenario I mentioned... unless I happen to get both wheels on one side into the loose stuff?....
That's the theory, however the other risk is that with one wheel dropping in to a hole like that, the opposite corner wheel no longer has enough weight on it (it lifts a bit) and you have the same problem. (been there, done that, front left wheel fell in a hole and lifted the rear right wheel off the ground, was stuck until I could get some weight on that rear corner to get some traction on that wheel (this wasn't in the Delica however, so I don't know if LSD would have saved me or not... as it was a friend sitting on the rear bumper is what got me out))
Re: I want LSD!
Posted: Wed Feb 13, 2008 10:10 am
by jwfchase
The moral of all this: always travel with friends.
Re: I want LSD!
Posted: Wed Feb 13, 2008 6:33 pm
by rdub
and a shovel

Re: I want LSD!
Posted: Sat Feb 16, 2008 9:03 am
by Erebus
On a slightly related note, I can confirm that the auto hubs will lock even if you aren't moving, it is driveshaft turning, not wheels turning that lock them up.
I was making a 3-point turn yesterday on a snowy road, I put the front wheels into stuff that was softer than I expected. When I put it in reverse, the back wheels didn't have the traction to pull back. Put it in 4WD High, and the hubs caught and I backed out no sweat.
Here's the caveat though: I gave it a little more gas than I intended, and when the hubs locked, the gears ground for an instant before locking with a hard clunk. Next time, I'll keep the throttle lower, more like idle, just enough to let the wheels slip to engage the hubs more gently (I hope).
Re: I want LSD!
Posted: Sat Feb 16, 2008 10:54 am
by Stewart
I did the same thing and was horrified by the sound. I hope there's no damage, it seems to work fine but I don't want to do that again.
Stewart
Re: I want LSD!
Posted: Sat Feb 16, 2008 11:45 am
by EnviroImports.com
why dont you just put on manual locking hubs? then you have actual control over the hubs and they are MUCH stronger and you will get better milage since your not driving in 4wheel all the time, YA YA, i know your not technically in 4wd all the time, but your still putting power to the hubs and everything is turning, you burn more fuel with the stock hubs.
I will post some picts on my site of them, we keep them in stock.
Noel
Re: I want LSD!
Posted: Sat Feb 16, 2008 2:04 pm
by Green1
you burn more fuel with the stock hubs
\
I'm curious as to your logic on that one... the stock hubs aren't always locked, they only lock when in 4wd.
They should burn no more fuel than manual hubs, and you gain the benefit of not having to get out of the vehicle when you want to lock/unlock them.
Your other arguments are correct though, they would be more reliable, and provide better control (won't accidentally unlock your hubs by reversing in 2wd when you still wanted them locked) (I have considered it, but I don't really have a need for them for my application)
Re: I want LSD!
Posted: Sat Feb 16, 2008 2:21 pm
by EnviroImports.com
it comes down to where the axel locks into the hub, we have transfercases with shifters and not vacume actuators like jeeps so they should fully disconect and not turn the front drive shaft into the diff then diff into the axels, but they dont, its called turning in sympathy, you are still powering your front axel a bit,
to test this , tie piece of string to the front drive shaft coming out of the T-case and to the frame, drive around the block the string will be broken, but only use string, dont use rope or anything with an actual load on it, .....but also only try this at your own risk to damage.
Re: I want LSD!
Posted: Sat Feb 16, 2008 2:55 pm
by Green1
regardless of that though, manual hubs won't change that part at all. (they are after all hubs, not transfer cases or differentials)
I'm not disagreeing that manual hubs are better, I'm just saying that fuel economy isn't one of the reasons.
Re: I want LSD!
Posted: Sat Feb 16, 2008 4:14 pm
by EnviroImports.com
perhaps a mechanice would be able to explain it better than I can, but ive run both and get better milage with manuals, the auto hubs keep everthing turning all the time the ring and pinion, the axel shafts them selves, your parts wear out faster, everything is turning, Manual hubs make your front end like a 2 wheel drive until you turn the hub and activate the spring.
Re: I want LSD!
Posted: Sat Feb 16, 2008 4:43 pm
by Green1
ummm... the whole point to the auto hubs is that they make your vehicle like a 2wd until engaged... You're trying to tell me that no matter what I do with the selector I'm still in 4wd on the Delica... I don't buy that for a minute.
I think you're confusing the fact that manual hubs will be more efficient than a vehicle where the hubs are always locked (many 4wd and all awd vehicles) but the auto-hubs are just a different way of doing exactly the same thing as the manual ones, just without having to get out of the vehicle.
Re: I want LSD!
Posted: Sat Feb 16, 2008 5:14 pm
by Erebus
As I understand it, with both manual and auto hubs, friction in all the parts will still have the drive shaft turn slightly. Perhaps the manual hubs will have slightly less friction, but the transfer case is still the same.
I really don't see a big difference being possible.
As for convenience, yes it is nice with manuals to be able to make the decision, and it stays there, and doesn't unlock until I want it to do so. But with auto, I don't have to get out.
I would suspect the fact that you have to get out to lock them means that you will spend more time with them locked, negating any possible gain in fuel economy.
I've had a couple of older Subarus (1982 and 1986) that had no hubs, so the rear drive shaft was always driven by the wheels, and the transfer case only engaged the shaft to the transmission. (The Subarus were front- and 4-wheel drive, not rear and 4 like the Delica.) Very convenient, but yes, that always-moving mass did cut into fuel economy. But if I had been that concerned, I wouldn't have bought the 4x4,