Awd systems.

[ifnt420]

I'm just curious if the AWD system on the Subaru Forester is the same as the XCs?

From the Subaru website:
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Manual transmission models have a viscous-coupling locking center differential. Automatic transmission models have an electronically managed continuously variable transfer clutch. 2.5 XS and 2.5 XT models have a limited-slip rear differential.[/QUOTE]<span id='postcolor'>

My question, what is an electronically managed continously variable transfer clutch? is that the same idea as the Haldex system on the XC70?

And the VC locking center differential, is that the same as the older V70XC except it's permanent AWD becuase its &quot;locked&quot;.

And some interesting comments about Volvo AWD. (http://www.4x4abc.com/4WD101/volvo.html) http://xc70.com/iB_html/non-cgi/emoticons/confused.gif

[jkochis]

http://www.beat-the-road.com/

2003 and 2004's use this AWD and possibly some 2002's.

Nope.

VW
Audi
Bugatti
Skoda
Seat

[littlewaywelt]

Subarus with manual use vc systems, but the split is 50-50 for normal driving where Volvo is 100-0 until the fronts start to slip.
Subarus with autos use electronic systems, but the split remains 50-50.

I went shopping for Subarus with my mother in law two weeks ago and my brother has one. &nbsp;While not nearly as luxurious as a Volvo XC, they will cover 95% of the same terrain.
The new Forrester received the highest scores in all categories and is probably as safe as any Volvo ever built, accding to NHTSA.

[Big]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (jkochis @ Oct. 23 2003,08:08)</td></tr><tr><td id="QUOTE">http://www.beat-the-road.com/[/QUOTE]<span id='postcolor'>
I notice the site says: &quot;Off-road. - Instant activation with high torque transfer for maximum traction. Alternative, separate off-road mode (switch) to lock the coupling.&quot;

An off-road mode would be nice. There's a little slip as the rear wheels react on steep, loose ground. Haven't tried Haldex in snow yet but it works well on moderate off-pavement excursions.

[kayaking]

Real interesting.
I'm sooooo curious as to what winter traction situations will actually be like...(my first year owning this vehicle).
Isn't there some information on this site about some clubs or organizations that are using the xc70 for the first time this year in off road (ski area?) conditions? Does anyone remeber this? Or maybe I saw it on the corporate site?

[SpudRacer]

Mas71 has been planning to do some serious testing of the VC vs. Haldex systems once the snow is sufficient for testing, with video for all to judge the results.

What do you say Mas71? &nbsp;Is it time yet? http://xc70.com/iB_html/non-cgi/emoticons/hehe.gif

Tom

[hrd_rok]

my 2 cents,

i thought xc70 went 90/10 to 50/50 , not all the way to 100/0

re the haldex in snow, i live @ 1100 m in a snow belt, and the haldex awd is awesome, i did a few reverse uphill snowbank climbs just to see how far into the bank i could get,

i jammed out before the car the car gave up, &nbsp;so no worrys,

h_r

(and no dstc)

[mas71]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (SpudRacer @ Oct. 25 2003,01:49)</td></tr><tr><td id="QUOTE">Mas71 has been planning to do some serious testing of the VC vs. Haldex systems once the snow is sufficient for testing, with video for all to judge the results.

What do you say Mas71? *Is it time yet? http://xc70.com/iB_html/non-cgi/emoticons/hehe.gif

Tom[/QUOTE]<span id='postcolor'>
We're getting there, however, the snow I wrote about is just about gone, but more is to come I'm sure!

/Magnus

[kayaking]

I think the engagement of all wheels in reverse is more &quot;locked-up&quot;...yes ? no?
I really think a true &quot;lock-up&quot; mode would be awesome....but then again, I haven't really tested the existing '04 system for its reliability and grip.

[William]

Volvo's Haldex system is a split of 90-95 front and 5-10% rear until slippage occurs.

When slippage does occur it only takes one seventh of a comple turn of the wheel for power to be transferred. *Volvo's R Models are even quicker in their transfer of power. *For comparison... the next closest competitor to Volvo in the speed of transfer of power is the BMW X5... which takes one complete rotation of a wheel before power is transferred.


William

[Filibuster]

Volvo might write that the torque split (front/rear) is something like &nbsp;90/10 or 95/5 when driving whithout wheel slip but that is just some marketing guy that got it wrong. The torque split it is 100/0 when driving normally without wheel slip. &nbsp;The haldex clutch will engage and try to lock when wheel slip occurs thus moving up to 100% of the availible torque to the rear wheels.

[xclogan]

Sorry its sooo long...but it's why I got a 99 insteadof a 2001+ XC...

Here is the description that I had on how the Volvo AWD works on the early (98 to 00) models (V70XC AWD, V70R AWD, V70AWD and S70AWD):

System Mechanics
Three key mechanical components make up this unique Volvo system: a transfer differential, viscous clutch, and an independent rear suspension with locking differential. The main component is the viscous clutch. In simple terms it is a type of turbine in which power that normally drives the front wheels is instantly transferred to the rear wheels to help maintain optimum vehicle traction. It is the key to Volvo's AWD system. It normally allows 95 percent of the engine power to remain directed to the front wheels and five percent to the rear wheels under conventional driving conditions. But as soon as a wheel spin is detected, the viscous clutch adjusts torque distribution to all wheels and when necessary, and can transfer up to 95 percent of the engine power to the rear wheels. This all takes place in milliseconds -- well before a driver would be capable of making such a decision. No special technical or driving skills are required to operate the all-wheel drive system. The entire action is completely transparent to the driver. In fact, the action is similar to what occurs in an automatic transmission.

The viscous coupling, which is located ahead of the rear differential, appears as a long tube filled with silicone oil and contains a large number of discs. The viscous clutch is designed to use the silicon oil's viscosity to transfer power between the discs to the rear or front wheels. Every other disc is connected to the front wheels and the alternating discs are connected to the rear wheels. When the discs connected to the front wheels revolve at a different rate than the discs connected to the rear wheels, the silicone oil in which the discs rotate becomes more viscous and thus increases the pressure. As this pressure increases, torque is transferred to the rear wheels.

If the viscous coupling is subjected to intensive slipping, the silicone oil and discs become very hot. The coupling then locks to prevent any slippage. It also acts as a middle differential, allowing a speed difference between the front and rear axles, as when driving through a curve. Volvo engineers have also incorporated a locking differential for the independent rear axle and Traction Control System (TRACS) for the front axle to help ensure that the correct amount of power is distributed as needed at low speeds. TRACS, based on an ABS feed back system, is designed to work at speeds of less than 25 mph and is especially useful in helping to prevent front wheel spin at vehicle launch. The locking rear differential senses minute differences in rear wheels rotational speed and at speeds less than 25 mph automatically locks to transfer engine power to the rear wheel with the best traction. Both these systems in combination help to prevent wheel spin at every corner of the V70 AWD.

Volvo has also engineered into the drive line system a freewheel component. This unit disengages the rear drive during braking to help ensure optimum braking performance during engine braking or while coasting downhill. Another refinement when it comes to this freewheel is that it also has a locking function. This means that the V70 AWD is always four-wheel driven when it reverses.

[xclogan]

and no... in 60+ k miles this year, in snow (8+ inches deep), ice, mud, sand, water (hub deep), rocks (very limited), and STEEP STEEP inclines.. I have not had any problems in getting to my intended destinations...yet...

[mas71]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (fly by day @ Oct. 27 2003,21:35)</td></tr><tr><td id="QUOTE">Volvo might write that the torque split (front/rear) is something like *90/10 or 95/5 when driving whithout wheel slip but that is just some marketing guy that got it wrong. The torque split it is 100/0 when driving normally without wheel slip. *The haldex clutch will engage and try to lock when wheel slip occurs thus moving up to 100% of the availible torque to the rear wheels.[/QUOTE]<span id='postcolor'>
The 95/5 thing describes the viscous coupling, not the Haldex.

For the VC to even be able to respond on brief slips that is the way it has to be engineered so the rear wheels axel spins with a slight slower speed than the front wheels.

5% seems to be enough for icy surfaces while a dry hill climb shows it's limitations.

[roger roger]

I have a 2003 XC70, and recently (I thought it was me to start with) I have been getting front wheelspin. &nbsp;On a wet uphill start it will easily spin the front wheels with little forward motion. &nbsp;It seems my 4wd is not engaging, or is this wheelspin possible as the rear wheels are still only getting &nbsp;50% of the power? &nbsp;It feels like a frontwheel drive.

[TrueBlue]

roger, roger,

Very strange - what you are reporting was typical of the older VC models which stopped shipping in late 2002, the AWD did not engage from a standing start. If yours truly a 2003 MY car, then it should be fitted with the Haldex system which does not exhibit this problem.

I did some tests last year to compare the VC and Haldex systems to confirm this.

However, could it be that you have the brakes on while performing the start? The manual says that the AWD is disconnected if the brakes are applied ( dunno why ?), and if you are executing a hill start you may have the parking brake or foot brake applied until you move off. In this case the AWD may be disabled - the handbook says &quot;brakes&quot; without making clear if this is a global term. A sensor switch will remain on even though there is no practical braking effort in effect.

Just a thought

[roger roger]

Mike,

It has the Haldex system. &nbsp;It also happens if I am already moving. &nbsp;No brakes involved.

I will take it to Volvo to check it out.

Roger

[budrichard]

I have XC's with both systems. I initially tested both together in 4&quot; of new snow. No measurable differences in acceleration or braking.
We had a lot of snow in February. Went hunting and as usual followed the normal track off road through about 10
&quot; of snow. Vehicle came to a complete stop and could not go forward or backwards. Interesting to watch the steam coming off the brakes as they brake the slipping wheels and no throttle because of spin control. Had to get barn shovel from my farmer friend and completely shovel out under &nbsp; and around the vehicle. Had run into a drift of about 2.5' &nbsp;of packed snow and driven the vehicle up on the aluminimum skid plate i have installed in the front, I was high centered. A true 4x4 system like in my Jeep Cherokee would have done better because I could have locked out the the third differential and kept on spinning. I also need tires(P ST's on now) with more off road grip(traction lugs) which i am going to acquire. While the on road handling and traction are fantastic, the Holdex AWD system and Vovlo wheel articulation are not as good as true 4x4 systems which are becomeing increasingly hard to find on vehicles. -Dick

[Mr_Westlake]

Budrichard! Did you at any point tried to deactivate the SC-control? (You deactivate the Stability Control function, with the &quot;DSTC&quot;-button) It usually helps a lot when driving in really deep snow. If you are driving in deep snow with the SC-function active it will reduce the torque going to the wheels. First time I drove I deep snow myself I was surprised how the car “died” and slowed down. Not good! Well after a while I found the DSTC-button and that solved things for me. http://xc70.com/iB_html/non-cgi/emoticons/smile.gif

/Mr_Westlake

[rogerrabbit]

I thought my 2003XC 4WD wasn't right! &nbsp;Volvo have just replaced the Haldex control electronics (part cost $4,000 - under warranty of course). &nbsp;No more front wheelspin! &nbsp; http://xc70.com/iB_html/non-cgi/emoticons/smile.gif . &nbsp;What surprised me was the lack of error messages, warning lights, or other indication all was not well. &nbsp;http://xc70.com/iB_html/non-cgi/emoticons/unhappy.gif

rogerrabbit

[AWD*V70XC]

Go global or die. That seems to be Detroit's working theory. The idea is that a car company needs variety, and that the way to do this while controlling costs is to have many vehicles share a common architecture and other components.

For example, Saab dealers are now getting a version of the Subaru Impreza; heading their way next year is a sport utility vehicle based on Chevrolet Trailblazer underpinnings. I think that General Motors has lost so much money on Saab that it's not terribly interested in what happens to Saab's &quot;brand DNA.&quot;

Ford Motor is also going overboard on platform sharing. For example, the Jaguar S and Lincoln LS are brothers, and the Mazda3, Volvo 40 and European version of the Ford Focus are sisters. Ford is also gearing up to build a new crossover, a car-based sport utility, the Ford Freestyle, at its Chicago assembly plant. The Freestyle is derived from Volvo architecture, and now we hear that Ford is thinking about building a future Volvo crossover in the same Chicago facility. This one bothers me.

Auto companies say that while they may share basic architecture among several models, they can make each vehicle distinctive. At its best, that's what General Motors did in the old days, using a few basic frames to create unique cars for each of its divisions.

At its worst, platform sharing is nothing more than what we call &quot;badge engineering.&quot; You take one car, make a few cosmetic changes and put a new name or badge on it. For example, throughout its history most Mercurys have been little more than badge-engineered Fords. Sometimes this approach works; sometimes it doesn't.

I admit that Ford can save money by sharing vehicle architecture between its Ford and Volvo brands. And I must admit that the new Volvo 40 does not show much resemblance to the European Ford Focus. But my worry is that over time Volvos will become little more than mildly disguised Fords.

Volvo's strength is its reputation and image--the Swedes take extraordinary steps and spend whatever is necessary to build safe, peppy cars with the latest in supplier technology. Ford, on the other hand, is known for hating to pay top dollar to parts makers.

I have talked to many Volvo people over the years. Their great struggle isn't against competitors; it is against Ford, and the eternal battle between making great cars and making &quot;the numbers.&quot; I doubt that Volvo executives will win many disagreements over component costs once Volvos are built in a Ford plant.

I can understand why Ford is thinking of assembling Volvos in the U.S. Volvo is profitable, but not profitable enough to justify the $6.5 billion that Ford paid. What's more, the way Ford shows its figures, Volvo's profits cover the losses at Ford's Jaguar and Land Rover operations. Making more money is the goal, so Ford wants to expand Volvo's lineup. Another motivation is the weak dollar: Volvo currently builds its vehicles in Sweden and Belgium, two high-cost countries.

BMW and Mercedes-Benz are assembling vehicles in the U.S., but there is a difference. These models are genuine German vehicles--not offshoots of some cheaper brand. Toyota *recently began building the Lexus RX 330 at a factory in Canada that also builds smaller Toyota models, but Toyota spent months rebuilding this plant and retraining the workers to make sure the build quality was up to Lexus standards.

Ford has yet to prove that it can successfully share vehicle architecture between its European and American brands. Ford flopped with its CDW27 platform, the $6 billion car program, built in the 1990s in the U.S. and Europe (the car was called the Ford Mondeo over there, the Ford Contour and Mercury Mystique here). This vehicle was a flop in America and was dropped from the U.S. market. The Jaguar X, a derivative of the Mondeo that's still built in Europe, has disappointed, too.

In Europe Volkswagen has a problem because consumers have figured out they can pay a lot less for the Spanish or Czech variants of the VW Golf.

There's something else worth noting in these globalization efforts. Manufacturers don't make the Europeans or Japanese use our architecture. We have to use theirs. So U.S. designers must make compromises in order to accommodate foreign platforms. The Ford/Volvo plan is a bit different. The Volvo would be built from the Ford, but the Ford underpinnings were derived from Volvo.

Volvo is having a burst of success with its new sport utility vehicles, and sales in Europe and the U.S are up 10% in aggregate from the prior year. It's one thing for GM to take chances boosting Saab's volume with vehicles from its other operations. But Volvo is a success, so the risk is greater.

Maybe I am behind the times, but personally, I call this the slippery slope.

- J Flint