True 4WD/AWD?

[LoneRanger]

That's "real world"?.... using steel runners on a hockey rink? Subaru usually proves superior over venza in the "real" real world.... i.e. hill climb, off-roading, heavy snow, etc.,You know, outside in nature where cars are actually driven day to day.

Originally Posted By: UG_Passat
My subie fanatic friends ignores the existence of this video.

http://youtu.be/orysh1VuueU

The Venza has Toyota's Active AWD system, which is shared with the old RAV4, Sienna and certain model years of the RX350.

the old RAV4 and the RX350 that have it, also have a simulated "lock" function. This simulates a 60/40 lock.

the new RAV4 gets Dynamic AWD which is supposed to be more responsive and the "lock" can lock to 50/50.

TFLcar mashup, RX350 vs Allroad, where Nathan mentions the lock function
http://youtu.be/Ub05viju334

 

[rjundi]

My personal observations of Toyota AWD (Sienna, RX350) is it struggles in tough conditions like deep snow. Even my MDX with SH-AWD struggles compared to my wife's Subaru with pure mechanical AWD and LSD. The key on MDX is disable traction control and then it does better.

 

[Da Game]

What about Audi's QUATTRO system?

 

[Rand]

keeping in mind if you buy good snow tires it will make a bad winter car better than most AWD on standard all-seasons.

Obviously Im not talking about cars that have 2" of ground clearance etc.

But you could take something that was fairly hideous in the winter like a 1995 ford thunderbird v8 or 1986 olds cutlass.

Throw a set of 500$ snowtires and wheels on it.. and it would be as good as most of these newer awd wonders on oem tires.

 

[rjundi]

Originally Posted By: Rand
keeping in mind if you buy good snow tires it will make a bad winter car better than most AWD on standard all-seasons.

Obviously Im not talking about cars that have 2" of ground clearance etc.

But you could take something that was fairly hideous in the winter like a 1995 ford thunderbird v8 or 1986 olds cutlass.

Throw a set of 500$ snowtires and wheels on it.. and it would be as good as most of these newer awd wonders on oem tires.


For on road agreed. However steep roads/driveways, mud or deep snow winter tires with FWD/RWD falter. AWD seems to find some traction. My wife's Subaru with all-seasons simply claws its way through things with an uncanny ability. Stopping and turning is not it forte as Subaru AWD does nothing for that.

 

[Sequoiasoon]

Many of the systems that use the brakes and traction control hurt you in the long run. Tirerack did some tests with snow tires and showed that there best grip came with 45% slip but TC limited the cars to like 5% which is why they say to turn it off to get unstuck so you can spin some. Some new jeeps have Eaton Lockers that can transfer 100% to either wheel or full lock to all. I've seen them in the offset gullies on 2 wheels just crawl through and they were new unmodified vehicles. Subaru's have always been great in snow and dirt.

Get something you like with many 4WD versions you can get ARB air lockers installed. Seeing and trying a couple vehicles with ARB in strange situations and you can really appreciate them. I've seen older Subaru's with ARB's installed and except for that low clearance thing they are awesome.

 

[supton]

TC seems to not be identical between vehicles. Duh I know. But this weekend I got to "play" with both of my Toyota's: a 4x4 Tundra and a FWD Camry. About as apples to oranges as it gets.

The Camry will let me spin the tires at will in snow. I can hear faint attempts at it pulling the brake lines, but as far as I can tell it will let me spin as long as I want. Is that because it's FWD, or because it's a stickshift? Now, it will cut power at times; best I can tell it does that when the front end slides to the left or right.

The truck though has hyper-aggressive TC which seems to cut power at whim. Of course, in RWD it's apt to bring the rear around suddenly, so perhaps it's intentionally programmed to be stupid-aggressive? Needs to cut any wheelspin really fast? I tried disabling just TC, but it still cuts power if VSC is on. Turn off all the nannies and suddenly it seems to act much, much better at getting-going. Once going though I bet it's best to leave TC/VSC on... Too bad I have to be stopped in order to disable all nannies (it's a 10 second affair on top of that too).

Interesting bit about 45% of slip being "best" for traction. I've always read that it's best to have some wheelspin but in my experience it always seemed like it was a lot more than just a little. Not tire smoking 9 grand on the tach wheelspin, but a lot more than just a little.

 

[Peted]

Originally Posted By: Olas
Subaru have some clever AWD systems, but if you want true 'go anywhere ability' it's hard to beat a Land Rover Defender.

Full time 4wd, low range box, lockable front, centre and rear diffs, and individually articulating/locking wheels in any combination with/without putting the diffs in.

Its been good enough for the British Army and all our farmers for the best part of 50 years!


Hello friend!

and Yes this sir is correct. The Land Rover Defender (and Discovery) is truly the Best 4x4xFar.

Though, in the USA Defenders are pricey, you can pick up a cheap Discovery I (which is a Defender 90 with a different body) or a Discovery II which is it's own beast but Very similar.

 

[Peted]

Originally Posted By: Cujet
I have an 09 F150 4x4 with the tow package
I also have an 03 Jag X-Type with AWD

The Ford has a 3.55 clutch based limited slip diff in the rear with an electronic locker. I believe it has an open diff in the front. When 4WD is engaged, the front and rear diffs are connected and there is no center diff. So turning on dry pavement is slightly more difficult. When 4WD-Low is engaged, the electronic locker in the rear makes both rear tires spin exactly the same speed, when that happens turning on pavement is nearly impossible. And if forced, all sorts of binding occurs and big, ugly noises, like snapping metal sounds.


I hate doing this but there are some wrong facts in this post.

The rear either has a Limited Slip OR an Electronic Locker it cannot be both. and Yes all 4x4 IFS trucks come with an open differential from the factory. and Yes there is in fact a Center Diff per se. That would be the Transfer Case, now there are different kinds of T-Cases, some with an Actual differential in them and some with something a little more complicated yet similar. I'm not sure which the Ford has. My Land Rover had an actual differential in the T-Case.

 

[OVERKILL]

Originally Posted By: Peted
Originally Posted By: Cujet
I have an 09 F150 4x4 with the tow package
I also have an 03 Jag X-Type with AWD

The Ford has a 3.55 clutch based limited slip diff in the rear with an electronic locker. I believe it has an open diff in the front. When 4WD is engaged, the front and rear diffs are connected and there is no center diff. So turning on dry pavement is slightly more difficult. When 4WD-Low is engaged, the electronic locker in the rear makes both rear tires spin exactly the same speed, when that happens turning on pavement is nearly impossible. And if forced, all sorts of binding occurs and big, ugly noises, like snapping metal sounds.


I hate doing this but there are some wrong facts in this post.

The rear either has a Limited Slip OR an Electronic Locker it cannot be both. and Yes all 4x4 IFS trucks come with an open differential from the factory. and Yes there is in fact a Center Diff per se. That would be the Transfer Case, now there are different kinds of T-Cases, some with an Actual differential in them and some with something a little more complicated yet similar. I'm not sure which the Ford has. My Land Rover had an actual differential in the T-Case.


Ford uses a chain-style Borg-Warner T-case (at least in the 4x4 Ford's I've owned) with a high and low gear-set in them. The one in my Expedition has a clutched setup for A4WD where it can instantly "turn on" the front wheels (they are always driven/attached to the shaft, just no power goes to them unless it detects wheel slip or you use the switch). Using the switch the front and rear wheels are coupled either in direct (1:1 T-Case and Transmission) or low (significant gear reduction in the T-case).

It is a relatively simple and reliable setup. I have the clutched rear diff (T-Lok), I don't believe an electronic locker was an option.

 

[IndyIan]

Originally Posted By: supton
TC seems to not be identical between vehicles. Duh I know. But this weekend I got to "play" with both of my Toyota's: a 4x4 Tundra and a FWD Camry. About as apples to oranges as it gets.

The Camry will let me spin the tires at will in snow. I can hear faint attempts at it pulling the brake lines, but as far as I can tell it will let me spin as long as I want. Is that because it's FWD, or because it's a stickshift? Now, it will cut power at times; best I can tell it does that when the front end slides to the left or right.

The truck though has hyper-aggressive TC which seems to cut power at whim. Of course, in RWD it's apt to bring the rear around suddenly, so perhaps it's intentionally programmed to be stupid-aggressive? Needs to cut any wheelspin really fast? I tried disabling just TC, but it still cuts power if VSC is on. Turn off all the nannies and suddenly it seems to act much, much better at getting-going. Once going though I bet it's best to leave TC/VSC on... Too bad I have to be stopped in order to disable all nannies (it's a 10 second affair on top of that too).

Interesting bit about 45% of slip being "best" for traction. I've always read that it's best to have some wheelspin but in my experience it always seemed like it was a lot more than just a little. Not tire smoking 9 grand on the tach wheelspin, but a lot more than just a little.

The TC on the Focus works pretty well, it allows quite a bit of wheelspin in 1st but at speed in 2nd or 3rd, cuts in just right to keep the wheel spin reasonable, but not slow you down.
As for best amount of slippage, IME it depends on the amount of snow and what's underneath it. Sometimes 100%+ tire speed is needed to clear out the snow fast enough to bite into the surface below to keep your momentum. Sometimes 5% is too much like on ice.

 

[IndyIan]

Originally Posted By: OVERKILL
Originally Posted By: Peted
Originally Posted By: Cujet
I have an 09 F150 4x4 with the tow package
I also have an 03 Jag X-Type with AWD

The Ford has a 3.55 clutch based limited slip diff in the rear with an electronic locker. I believe it has an open diff in the front. When 4WD is engaged, the front and rear diffs are connected and there is no center diff. So turning on dry pavement is slightly more difficult. When 4WD-Low is engaged, the electronic locker in the rear makes both rear tires spin exactly the same speed, when that happens turning on pavement is nearly impossible. And if forced, all sorts of binding occurs and big, ugly noises, like snapping metal sounds.


I hate doing this but there are some wrong facts in this post.

The rear either has a Limited Slip OR an Electronic Locker it cannot be both. and Yes all 4x4 IFS trucks come with an open differential from the factory. and Yes there is in fact a Center Diff per se. That would be the Transfer Case, now there are different kinds of T-Cases, some with an Actual differential in them and some with something a little more complicated yet similar. I'm not sure which the Ford has. My Land Rover had an actual differential in the T-Case.


Ford uses a chain-style Borg-Warner T-case (at least in the 4x4 Ford's I've owned) with a high and low gear-set in them. The one in my Expedition has a clutched setup for A4WD where it can instantly "turn on" the front wheels (they are always driven/attached to the shaft, just no power goes to them unless it detects wheel slip or you use the switch). Using the switch the front and rear wheels are coupled either in direct (1:1 T-Case and Transmission) or low (significant gear reduction in the T-case).

It is a relatively simple and reliable setup. I have the clutched rear diff (T-Lok), I don't believe an electronic locker was an option.

Unless the OP has some extreme conditions or situations(Emergency doctor living on the wrong side a mountain pass in the rockkies?) I don't see the need for anything beyond what your Expedition has.
If he has to climb a slippery grade for half an hour, then the slip sensing AWD systems have to have a lock mode where it stays in AWD. The unlockable ones I imagine must be prone to overheateding as the cycle on and off constantly. Other than that almost any AWD system is good enough for snow covered road.

 

[CurtisB]

Originally Posted By: Peted

I hate doing this but there are some wrong facts in this post.

The rear either has a Limited Slip OR an Electronic Locker it cannot be both.


Sorry Peted you are actually the one wrong in this case, the new Ford F150's can come equipped with a LS and an E-Locker. My 2013 F150 has both and it is labeled as such on the factory build sheet.