So who else does 4WD well?

[Fred Boer]

Hello all!

I realize that a Subaru newsgroup may not be the best place to get unbiased
opinions, but..

I have sometimes read that not all 4 wheel drive systems are created
equally. I've seen them characterized as "just too late" as compared to the
Subaru system. I am not technically knowledgeable, so I wonder if some of
the more informed members of the group might help with a question about
this. Is this a valid issue? What are the differences in 4WD systems?

Suppose my experiences with my Subaru have left me unhappy and wanting to
try a different brand of automobile. Who else has a 4WD system that is
comparable to that of the Subaru?

 

[Al]

Hello all!

I realize that a Subaru newsgroup may not be the best place to get
unbiased opinions, but..

I have sometimes read that not all 4 wheel drive systems are created
equally. I've seen them characterized as "just too late" as compared to
the Subaru system. I am not technically knowledgeable, so I wonder if
some of the more informed members of the group might help with a
question about this. Is this a valid issue? What are the differences in
4WD systems?

Suppose my experiences with my Subaru have left me unhappy and wanting
to try a different brand of automobile. Who else has a 4WD system that
is comparable to that of the Subaru?

I've been buying Jeeps since '86 and Subarus since '96. The '86 Jeep was
a dud and lasted 5 years. The '91 lasted 16 years. The '96 Subaru was a
dud. The '03 Subaru is good. And the '07, well, the jury is still out as
it has less than 3K miles on it.

The Jeeps are much better in punching through high snow. Otherwise they
meet our needs just fine. We started with the Subarus as my late 80's
mother-in-law could not get into the Jeep.

So, it depends on your needs.

BTW, my '71 XKE got me home in the '78 blizzard in NE when most got
stuck; I drove 17 miles to get home from work. I think it was that the
car was small and heavy so I got to the pavement through the snow. And
the positraction rear drive was fabulous.


Al

 

[houndman]

Hello all!

I realize that a Subaru newsgroup may not be the best place to get unbiased
opinions, but..

I have sometimes read that not all 4 wheel drive systems are created
equally. I've seen them characterized as "just too late" as compared to the
Subaru system. I am not technically knowledgeable, so I wonder if some of
the more informed members of the group might help with a question about
this. Is this a valid issue? What are the differences in 4WD systems?

Suppose my experiences with my Subaru have left me unhappy and wanting to
try a different brand of automobile. Who else has a 4WD system that is
comparable to that of the Subaru?

I'm interested also, and more interested in the difference in how
the setup in the auto and manual transfer case perform.

Yesterday a friend with a 4X4 pickup asked if mine was active all the
time, or shiftable.

VF

 

[houndman]

I've been buying Jeeps since '86 and Subarus since '96. The '86 Jeep was
a dud and lasted 5 years. The '91 lasted 16 years. The '96 Subaru was a
dud. The '03 Subaru is good. And the '07, well, the jury is still out as
it has less than 3K miles on it.

The Jeeps are much better in punching through high snow. Otherwise they
meet our needs just fine. We started with the Subarus as my late 80's
mother-in-law could not get into the Jeep.

So, it depends on your needs.

BTW, my '71 XKE got me home in the '78 blizzard in NE when most got
stuck; I drove 17 miles to get home from work. I think it was that the
car was small and heavy so I got to the pavement through the snow. And
the positraction rear drive was fabulous.

Al

one time driving to a hilly are in the city in an 8" snow, in a RWD,
I decided to take a street that was a more gradual hill than the
usual, which was mighty steep, and got stopped half way up. A bus was
spinning its wheels at the top of the hill. Headlights came up behind
me, and kept getting closer, and next thing their bumper was on mine,
pushing me up over the hill. It was a city cop in a Jeep, I believe an
old Cherokee. When I got near where I was going, to see a GF who
didn't want to drive in the snow. I couldn't get up the hill there. I
Turned Around and Backed up the hill, like there wasn't any snow.
Guess I made it a sorta FrWD.

VF

 

[KLS]

Suppose my experiences with my Subaru have left me unhappy and wanting to
try a different brand of automobile. Who else has a 4WD system that is
comparable to that of the Subaru?

Audi is the best of the best with their quattro system: I really miss
my 98 A4 (stolen 3 weeks ago) in this icy winter weather. The 99
Legacy OBW is pretty good, but the Audi was far superior. And with 4
dedicated snow tires, it was perfect in the winter.

 

[Stewart DIBBS]

No they are not. One of the most important differences is whether the system
is a 4WD (ie mostly FWD or RWD) or partial AWD or full-time AWD.

Audi Quattro, Mitsubishi AWD (Talon/Eclipse/Lancer EVO series) are all
fulltime AWD with a center differential action, as AFAIK the various types
of Subaru AWD. All these are (AFAIK) 50/50 torque split with the exception
of some older Mitsu's which are 65/35 F/R.

The center diff is generally lockable in some fashion. Mitsu and some Subaru
use a viscous coupler. Other Subaru's use a wet clutch system with
electronic control. EVO's and WRX use (AFAIK) a Torsen torque split system.
The advantage here is that when one end starts to slip, the centre locks up
gradually.

Older Subaru and Mitsu used a simple Front/Rear lock system ie 4WD not AWD.
Some have a viscous front diff too.

EVO and WRX have locking rear diffs, the base models don't usually unless
optioned.

Then there's the Honda CRV system that's about 70/30 split, with a hydraulic
clutch system in the rear diff that locks up gradually. ie the CRV is really
FWD with occasional AWD.

The Chrysler/GM minivan systems use a system that runs off one side of the
front diff, and it only works because the ABS system also handles the
traction control. Torque split is about 80/20 at best, and they really are
FWD system with pretentions of being AWD according ot the marketting
departments.

There's the BMW system and Jaguar systems about which I know nothing at
present. Anyone?

Lets not forget Jeep Quadratrack. Anyone?

SD

 

[houndman]

Audi is the best of the best with their quattro system: I really miss
my 98 A4 (stolen 3 weeks ago) in this icy winter weather. The 99
Legacy OBW is pretty good, but the Audi was far superior. And with 4
dedicated snow tires, it was perfect in the winter.

Curious as to what the Audi did different, and whether autos or
manuals?

VF

 

[Fred Boer]

Thanks for all the responses. I wonder about Volvo as well... There was some
video I saw that showed a Volvo going nowhere while a Subaru zipped by -
although there was plenty of discussion about whether that was a fair
comparison.

Yes, I wonder if the AWD listed as available for minivans is actually
effective. As much as I have misgivings about Subaru (given my experiences
of unacceptable reliability), the AWD has been an obvious benefit IMHO. A
recent snowstorm confirmed that much...

 

[Rui Pedro Mendes Salgueiro]

On Thu, 3 Jan 2008 13:49:13 -0500, "Fred Boer"

If you meant 4WD for fast cars (like the Impreza STI) the Mitsubishi
Evo has an even better system. But I think you meant slower cars.

Audi is the best of the best with their quattro system:

Attention: only the longitudinal engined Audis have a center differential.
The transverse engined* ones (A3, TT) have an Haldex system (based in a clutch)
even when called "Quattro" which have issues** with the traction control.

[* BTW, this is an Audi/VW choice, not a technical need. Mitsubishi with the
Evo, Lancia with the old Delta Integrale, etc. didn't have any problem
fitting a center diff in the transverse gearbox.]

[** The clutch can only send power to the rear axle if it detects
slipping of the front wheels. But if it detects slipping the traction
control will brake the front wheels or slow the engine to stop the
slipping. There have been cars (IIRC a Renault Scenic some years ago)
in which the system simply didn't work (I suppose it was a victory of
marketing over engineering). ]

4WD systems can have (in increasing order of sophistication):

- a mechanical rigid connection between the front and rear axles.
This is the classical system (partial time 4wd). Can only be engaged
in slipping conditions. I think most pickups still use it.

- some kind of clutch (electronic controlled or viscous coupling)
between the front and rear axles. As I said above it has issues with
the traction control system and it also means some waste of energy
in normal conditions since the two axles need to rotate at different
speeds in corners. I think many manufacturers are using it now (Volvo,
BMW ?) and I have read here that some of the Subarus also have it.

- a center differential. This is the proper solution, because it can send
torque to all wheels _before_ they start slipping but then it also needs
some kind of locking (LSD, Torsen, manual locking, traction control)
for difficult conditions.

For off-road low-range gears are also useful.

 

[KLS]

Curious as to what the Audi did different, and whether autos or
manuals?

5-speed manual, and this is a good explanation:

http://en.wikipedia.org/wiki/Quattro_(all_wheel_drive_system)

Basically, the Torsen design is what makes it stellar. It's not the
best for off-roading (which I don't do), but it was perfect for my
needs.

 

[suburboturbo]

Hello all!

I realize that a Subaru newsgroup may not be the best place to get unbiased
opinions, but..

I have sometimes read that not all 4 wheel drive systems are created
equally. I've seen them characterized as "just too late" as compared to the
Subaru system. I am not technically knowledgeable, so I wonder if some of
the more informed members of the group might help with a question about
this. Is this a valid issue? What are the differences in 4WD systems?

Suppose my experiences with my Subaru have left me unhappy and wanting to
try a different brand of automobile. Who else has a 4WD system that is
comparable to that of the Subaru?

Don't have experience with other AWD systems, but have owned a
Pathfinder, Cherokee and Samurai, all with 4WD, low range and manual
transmissions, and they were all very competent in snow, especially
deep snow with their high ground clearance. However, the reason I'm
posting is to say that my all time favorite "snow-mobile" was a 1965
Corvair. With 65% of its weight over the rear wheels, a limited slip
differential and quality snow tires, it was absolutely unstoppable,
despite the fact that I had lowered it about an inch for
autocrossing. In deep snow, you just rammed through it until you
carved a path. Used to go looking for the steepest hills I could
find, and there are quite a few here in the Hudson valley, and it
NEVER found one it couldn't handle. Only problem I ever had was an
ice rut that put a hole in my gas tank. What makes the Subaru a so
attractive to me is performance on any slick surface, especially when
equipped with tires that perform well in rain (not the original
equipment Bridgestones). With power distributed back to front and
side to side, it's never at a loss for traction and immune to torque
steer. Even on ice, where the conventional wisdom is that AWD
provides no advantage, it gives you four driven wheels instead of two
to catch a piece of dry pavement.

 

[Dano58]

That's the difficulty with this terminology - AWD, 4WD, etc. They are
used interchangeably and even to describe different systems. As noted
above, even Audi's quattro system ( and VW's 4Motion) are 2 different
systems, depending on which car you buy! As also noted, as far as I
know, only the Audi longitudinal-engined quattro system, the Subaru
AWD and the Mitsubishi EVO system are the only passenger-car full-time
all-wheel drive systems. By this I mean that all 4 wheels are driven
all the time. Systems like Mercedes-Benz 4Matic and BMW's X-Drive are
2-wheel drive with the other 2 wheels getting power when slippage is
detected. Most systems advertised as 'AWD' are this - 2WD until AWD is
needed.

The difference between AWD and 4WD is that the former is generally
handled automatically while the latter is manually switchable. That's
how I usually think of it and that is how the auto writers usually
refer to the function.

Dan D
'99 Impreza 2.5 RS (son's)
Central NJ USA

 

[Fred Boer]

Yes, as far as I am concerned, slower cars... probably a wagon (I've owned
Loyale wagon and Legacy wagon). Someone at work has a tidy looking Audi
wagon.

Fred

On Thu, 3 Jan 2008 13:49:13 -0500, "Fred Boer"

If you meant 4WD for fast cars (like the Impreza STI) the Mitsubishi
Evo has an even better system. But I think you meant slower cars.

Audi is the best of the best with their quattro system:

Attention: only the longitudinal engined Audis have a center differential.
The transverse engined* ones (A3, TT) have an Haldex system (based in a
clutch)
even when called "Quattro" which have issues** with the traction control.

[* BTW, this is an Audi/VW choice, not a technical need. Mitsubishi with
the
Evo, Lancia with the old Delta Integrale, etc. didn't have any problem
fitting a center diff in the transverse gearbox.]

[** The clutch can only send power to the rear axle if it detects
slipping of the front wheels. But if it detects slipping the traction
control will brake the front wheels or slow the engine to stop the
slipping. There have been cars (IIRC a Renault Scenic some years ago)
in which the system simply didn't work (I suppose it was a victory of
marketing over engineering). ]

4WD systems can have (in increasing order of sophistication):

- a mechanical rigid connection between the front and rear axles.
This is the classical system (partial time 4wd). Can only be engaged
in slipping conditions. I think most pickups still use it.

- some kind of clutch (electronic controlled or viscous coupling)
between the front and rear axles. As I said above it has issues with
the traction control system and it also means some waste of energy
in normal conditions since the two axles need to rotate at different
speeds in corners. I think many manufacturers are using it now (Volvo,
BMW ?) and I have read here that some of the Subarus also have it.

- a center differential. This is the proper solution, because it can send
torque to all wheels _before_ they start slipping but then it also needs
some kind of locking (LSD, Torsen, manual locking, traction control)
for difficult conditions.

For off-road low-range gears are also useful.

--
http://www.mat.uc.pt/~rps/

.pt is Portugal| `Whom the gods love die young'-Menander (342-292 BC)
Europe | Villeneuve 50-82, Toivonen 56-86, Senna 60-94

 

[Fred Boer]

Yes, I agree regarding the terminology. So, would you say that the full-time
all wheel drive systems are superior? I am assuming "yes". Are other
2wheel/4wheel drive systems any good at all? The impression I have is that
they do little - but I don't really know. Would they be worth the added
complexity/weight etc.?

Cheers!
Fred

 

[Frank]

To add to thread, I'll add my son's new Mercedes with AWD. He said it
preformed well in recent snow. It's a beautiful car but cost as much as
my 2 Foresters combined. His only complaint is that he is only getting
17 mpg. I average 23 mpg in my '03 Forester.

Frank

 

[P T]

That's the difficulty with this terminology
AWD, 4WD, etc. They are used
interchangeably ... Most systems
advertised as 'AWD' are this - 2WD
until AWD is needed.

Furthermore, unless you have a limited slip d. like "vjp1" maybe RWD is
best considered One Wheel Drive. Many times I've seen a car stuck in
the snow spinning one wheel freely, with the other side immobile :-( By
the way, will Front Wheel Drive perform the same? By this standard,
how many wheels on my Forrester are really providing traction?

 

[isquat]

the snow spinning one wheel freely, with the other side immobile :-( By

crappy tires perhaps?

the way, will Front Wheel Drive perform the same? By this standard,

sure, unless there is an lsd it's one wheel drive

how many wheels on my Forrester are really providing traction?

3 if you have LSD, 2 if you don't
4 if the previous owner installed an LSD off an sti/aftermarket
on the front axle

 

[George Mills]

I currently drive Jeeps (both CommandTrac and SelecTrac), formerly a Pontiac
Sunrunner (which is a Suzuki Sidekick) and Subarus (Forester currently and
Impreza previously) which are a good cross-section of full time 4WD,
part-time 4WD, and AWD, and not really surprisingly like Subarus the
best...but my FAVOURITE winter cars were my 65 Corvairs (coupe and convert
with autos) and 66 convert (with 4 sp).
-I once drove 35 miles/60 km in the 65 Coupe when there was 3 FEET of fresh
soft snow, ie to bottom of side window. Under those conditions, the front
end lifted off the ground and the wheels acted at 'rudders', and the rear
wheels dug down. At about 15 mph/25 kph, it acted like a motorboat, and
handled accordingly. Back off the throttle, and the front went down, exactly
like a motorboat. On that particular 'necessity' trip, I was one of three
vehicles on the road over 3 hours, and the other two were monster trucks
with balloon tires and 2-3 ft ground clearance.
-I once pushed a police cruiser up a 5% icy hill with my 65 convertible with
just a tied rimless tire as the pushing cushion.
-I regularly "parked" my convertibles nose in, in shallow ditches when
regular parking spaces vanished in mid-winter...can't remember how many
times people wondered if I needed a tow truck, but I just got in, shoved it
in reverse, and backed out--never ever got stuck in Corvairs with big snow
tires on them--and with stiff shocks, good radials and the right air
pressure, they were just amazing in summer

Anyone know from personal experience if the Suzuki SX4 AWD 5 door hatchback
m/t is as competent as a Subaru Impreza 5 door hatchback m/t?

Jim on PEI

Hello all!

I realize that a Subaru newsgroup may not be the best place to get
unbiased
opinions, but..

I have sometimes read that not all 4 wheel drive systems are created
equally. I've seen them characterized as "just too late" as compared to
the
Subaru system. I am not technically knowledgeable, so I wonder if some of
the more informed members of the group might help with a question about
this. Is this a valid issue? What are the differences in 4WD systems?

Suppose my experiences with my Subaru have left me unhappy and wanting to
try a different brand of automobile. Who else has a 4WD system that is
comparable to that of the Subaru?

--
Fred Boer - Amateur Access Enthusiast
Interests: Library software / Z39.50 / Web Services
Freeware Small Library Application available
here:http://www3.sympatico.ca/lornarourke/

Don't have experience with other AWD systems, but have owned a
Pathfinder, Cherokee and Samurai, all with 4WD, low range and manual
transmissions, and they were all very competent in snow, especially
deep snow with their high ground clearance. However, the reason I'm
posting is to say that my all time favorite "snow-mobile" was a 1965
Corvair. With 65% of its weight over the rear wheels, a limited slip
differential and quality snow tires, it was absolutely unstoppable,
despite the fact that I had lowered it about an inch for
autocrossing. In deep snow, you just rammed through it until you
carved a path. Used to go looking for the steepest hills I could
find, and there are quite a few here in the Hudson valley, and it
NEVER found one it couldn't handle. Only problem I ever had was an
ice rut that put a hole in my gas tank. What makes the Subaru a so
attractive to me is performance on any slick surface, especially when
equipped with tires that perform well in rain (not the original
equipment Bridgestones). With power distributed back to front and
side to side, it's never at a loss for traction and immune to torque
steer. Even on ice, where the conventional wisdom is that AWD
provides no advantage, it gives you four driven wheels instead of two
to catch a piece of dry pavement.

 

[Guest]

Furthermore, unless you have a limited slip d. like "vjp1" maybe RWD is
best considered One Wheel Drive.  Many times I've seen a car stuck in
the snow spinning one wheel freely, with the other side immobile :-( By
the way, will Front Wheel Drive perform the same?   By this standard,
how many wheels on my Forrester are really providing traction?

If you hsve four-wheel-drive with an unlocked front-rear differential
and open axles, its still 1WD when you get stuck!


Dave

 

[houndman]

5-speed manual, and this is a good explanation:

http://en.wikipedia.org/wiki/Quattro_(all_wheel_drive_system)

Basically, the Torsen design is what makes it stellar. It's not the
best for off-roading (which I don't do), but it was perfect for my
needs.

That's a good bit to digest and understand.

Wondering with ABS, if applying the brakes when stuck and one wheel is
sliping, would it work like traction control, and transfer the torque?

VF