Subaru Outback VDC

doppelbike · November 2001

Thanks for that explanation. Sounds like a very cool solution.
Has anyone in the group ever been saved from the tow truck
by their VDC?

db

ateixeira · November 2001

You mean, any one here humble enough to admit that? ;-)

-juice

hunter001 · November 2001

The AWD system in the VDC outback is exactly the same as the one present in the Automatic WRX. Instead of the VDC that would brake and redistribute power, the Auto WRX has a rear Limited slip differential, which in association with the VTD-AWD system, would distribute power from side-to-side/front-to-back/back-to-front. The VTD-AWD system (present in the Auto WRX and the VDC outback), is the same AWD system present in the Subaru Rally cars. The rally cars, of course have a much more heavy duty version of it.

The manual WRX however, has an AWD that is present in all other manual Subarus, with a Viscous coupling AWD system.

Later...AH

paisan · November 2001

Does the WRX cut power to the engine in slipping conditions? I'm pretty sure that it doesn't.

Also I'm not so sure you are correct on the rally cars using the VTD system. Any sources for the info?

-mike

hunter001 · November 2001

No, the WRX does not cut engine power in slipping conditions. However, the LSD would enable the active transferance of power side-to-side, from the slipping side to the side with grip.

I read in one of the Aussie/British/NZ site about the VTD-AWD system and a technical explanation of it. The Torque bias in the Rally cars however (unlike the lighter duty regular 45/55 WRX auto VTD-AWD system), is driver adjustable upto about 35/65 or so, from what I recall. The principle and basic hardware are exactly the same. I will try and dig out that article.

The World Rally cars also have an auto-manual transmission, that is closer to the Auto-transmissioned Subarus than the manual Subarus, that make the basic AWD setup of the Rally cars, better adaptable to the Auto Subarus. Maybe in the future they would come out with manual Subarus also sporting the better AWD system. Currently, the set-up in the manual Subarus are okay and definitely get the job done, but nowhere near the sophistication (or effectiveness)of the AWD systems present in the Automatic Subarus, especially the VTD-AWD equipped Auto Subarus.

The "manual brigade" would gloss over this or even go into denial and jump all over you, when you point this out, but facts are facts, however un-palatable !!! Subaru would not be winning too many Rallys with the kind of AWD set-up found in the manual-equipped Subarus !

Later...AH

paisan · November 2001

I think the AT-manual in the rally cars is more like the ferrari one than to our ATs. So what does the VTD system do in the WRX other than give the better torque split and better variable tourque. Also how does this relate to the manu-matic in the JDM subies?

-mike

PS: I'm an AT tranny guy so you are preachin to the choir

ateixeira · November 2001

Actually, the rally cars have a manually adjustable torque split, unlike the VTD. Though you can brag about the rear biased power split.

The WRX does not cut power to the engine under slippage, only the VDC system does that, as well as employ the brakes on the wheels that slip.

I believe the tranny on the rally cars has a sequential shifter unlike any road-going Soob. Car & Driver had a short article about it. The rally car was also wearing 15" wheels!

-juice

doppelbike · November 2001

Is there any reason why one should not mount 15" wheels
on a VDC? I realize that it will push the speedometer speed
up a little (16/15 is about 6%) and drop the clearance
by .5". I have a good set of (four) mounted
snowtires from a 98 OB and I would like to use them on a
new VDC. Is that advisable?

ateixeira · November 2001

Well, a new Legacy GT runs fine with smaller diameter tires.

Just make sure you swap all four tires. Swapping two would create a mess.

-juice

dill6 · November 2001

Are there any issues with the first year VDC that would make an '02 more desireable?

rsholland · November 2001

has an on/off switch for the VDC, whereas the '01 model doesn't. There may be some traction situations whereby you may want to turn off the VDC. With the '02 model you can do that.

Bob

hunter001 · November 2001

"I think the AT-manual in the rally cars is more like the ferrari one than to our ATs. So what does the VTD system do in the WRX other than give the better torque split and better variable tourque. Also how does this relate to the manu-matic in the JDM subies?"

Basically, as juice pointed out, the AT-manual system is a sequential clutch-less manual similar in operation to the BMW SMG auto-manual system and the Ferrari system. But the significant thing about this is that the under-lying AWD system is better adaptable to the Automatic equipped Subarus than the Manual equipped Subarus, even though arguably, the transmission in the WR Subaru cars are truly clutch-less manuals.

In the "reactive" AWD system of the manual transmissioned Subarus, the central Viscous Coupling needs slippage , which then shears the Viscous fluid of the Central Viscous coupling, thus transferring the power backwards or forwards as needed. A very simple system which "gets the job done". Nothing to brag about or to write home about.

The Automatic equipped Subarus have 2 seperate AWD systems, the most advanced among them being the VTD-AWD system present only in the Automatic equipped WRX and the VDC Outback. The other Automatic Subarus have a different AWD system, that is definitely more advanced than the Manual Subarus.

The VTD-AWD system (of the Auto WRX and VDC Outback) is a pro-active AWD system, unlike the "reactive" system of the manual Subarus. It features continuously variable electronic multi-plate hydraulic transfer clutches linked to a true planetary gear-type center differential (NOT a Coupling filled with Viscous fluid like the Manual AWD!), which is able to pro-actively "sense" impending slip by constantly and continuously monitoring and taking its inputs from various sensors that read the position of the throttle, the speed differentials between the various wheels through 4-wheel speed sensors, the specific gear you are in etc. and in association with analysis by a Micro-processor, proactively re-distributes torque by varying the clutch-pack lock-up before slip occurs. The beauty of this is that this happens un-obstrusively and continuously under differing road-conditions, and the user is insulated from the under-lying complexity of this advanced AWD system. In normal driving, it provides a slight rear-biased Torque split (45/55) which gives a slight RWD "feel". The other Auto Subarus provide a 90/10 torque split under normal driving conditions.

I still have not got hold of that technical article about the system. Let me dig a bit further. That is a lot more detailed and is thoroughly impressive.

Hope this helps.

Later...AH

jschat · November 2001

Hi all,

After 6 months of reading the post, I finally got my 2002 VDC, so far, my experience has been very positive, love everything about the car except one minor thing(I hope). The car seems to be pulling to the right slightly. My dealer already checked it once and found alignment was off, got the car back but it's still doing it. Is anyone out there with this problem at the beginning?

Chat

ateixeira · November 2001

Well, the VC in the manual cars is pro-active because it starts out by giving each axle 50% of the torque, i.e. it's not FWD to begin with.

Then the adjustment in that split is reactive, but if you think about it, it's less likely to slip in the first place.

The 45/55 VTD system is more sophisticated, for sure. The 90/10 basic auto AWD system feels more like FWD than the VC in the manuals, though, so I'd pick the VC between those two.

Chat: alignment is tricky to get right. It could also be the tires are out of round or unbalanced.

-juice

paisan · November 2001

Yes the VTD is the same or similar to the one in my trooper which is set to a 15%f 85%r torque split with up to a 50/50 split.

15" wheels I don't think can be mounted on the VDC, not due to the tire diamter problem, but due to the brakes not being cleared by 15" wheels. Also you can get 15" tires that will be the same diameter as the 16" ones, just more sidewall.

-mike

ateixeira · November 2001

That's right, they have some rather large 12.7" front rotors, with calipers wrapped around those.

-juice

arnold6 · November 2001

I'm interested in the 2002 VDC. I'm not sure about the wagon or sedan. Would appreciate help in the price in the Chicago area. Is it possible to get the car under invoice or close to the invoice price? Thank you very much.

Arnie

happyh6 · November 2001

It took my dealer two attempts to get the alignment and balance correct. If the dealer does not handle many VDCs they may not know that the alignment is not the same as on the other models. Look in your manual and you will see what I mean.
Once the dealer got it right the car is just a dream to drive.
Hope this helps.
Paul H.

ateixeira · November 2001

In the DC area they for near invoice. The 2001s had a $750 incentive, so those were below invoice by about that much.

Anyone here buy in Chi-town?

-juice

cptplt · November 2001

I know people who got an 01 VDC earlier in the summer at Gary Lang in McHenry and Schuamburg Subaru for close to invoice.

otis123 · November 2001

I recently saw a used 2001 H6 with wood (plastic) trim around the seat heater switches/buttons in a Subaru lot. Besides the cosmetics, it appears to stop the problem of accidently turning the seat heaters on in August. I asked the Subaru parts employee to look it up, but no such Subaru part...

Anyone know where I can surf to for such a part?

Thanks!

Ralph

trocco · November 2001

I've been trying to find the gear ratios for the new outbacks, but all i could find was this site from subaru.uk:

http://www.subaru.co.uk/outback/6_1.htm

It has the ratios for both automatic and standard.

Now, if you pay attention, you'll see that the ratio on First for standard transmission is about 25% higher than automatic. This means that it has about 25% more torque on first!!!!

(30% more on 2nd

50% more on 3rd)

Has anybody testdriven both automatic and standard? Could you tell me if you see that much difference in starting torque?

Matias

(this is why i wish they had a standard transmission option on the 3.0L)

ateixeira · November 2001

That's precisely the advantage of having more ratios. I'd like to at least see a 5 speed auto in a near-luxury car like the VDC.

-juice

trocco · November 2001

I guess i would have to agree with you. 5 speed auto would do it.

But given the options we have:

2.5L 166 lb.-ft. @4000 rpm (at the engine)
3.0L 210 lb.-ft. @4400 rpm (at the engine)

If you account for the difference in gear ratios, then we have:

166 lb.-ft. x 3.454 = 573 lb.-ft (at the wheels)
210 lb.-ft. x 2.785 = 585 lb.-ft (at the wheels)

Which is almost identical!

*note that this is for 1st. If we did the same for 2nd and 3rd, then the 2.5L standard would have even more torque than the 3.0L auto!!!

Now the difference comes when we take into account power. What i mean is this, eventhough they might have the same torque on 1st, the 3.0L has them at 212 hp. What this does is have it accelerate faster.

However, when towing uphill at a constant speed, or going off road into steep rocky hills, they should both perform pretty much the same. Since in neither one of these two cases we need acceleration, all we need is torque.

Now, here's my question. If you do the kind of driving mentioned above is it really worth it to spend almost 10,000 more?

I gotta say, these numbers make me think twice about the 3.0L. I think what it comes down to is more acceleration at the same torque, and smoother driving. But not much better, "SUV" type performance.

Please feel free to correct my numbers or theory, I might be wrong in my reasonning.

Matias

PS: I think i would still buy the VDC though, the smooth driving, acceleration, VDC, and other features make it a really attractive car.

rsholland · November 2001

I've driven both the H-4 and H-6. In normal stop-'n-go driving they do feel similar from a power standpoint. The H-6 certainly feels better when you "floor" it, and is a much more refined engine.

We've been saying here for forevergive us a 5-speed automatic Subaru!

Bob

ffsteve · November 2001

Matias,

The first gear ratios are only part of the story. There is a reason that the input bit on an AT is called a torque converter. It allows the engine to spin higher than the numerical gear ratio would tell you. Eliminates the clutch, and lets the engine toil at higher RPMs in the fat part of the torque curve.

It is not a fixed connection, the converter lets the engine rev higher when needed. If you look at the tachometer of AT vs MT cars, they will both show the RPMs at 2500 or so (I'll let others supply the exact numbers) when starting out in first. As a matter of fact, the AT and torque converter will actually be able to put more torque to the rear wheels under conditions where the MT clutch is purposely slipped by the driver to get the same effect.

Steve

trocco · November 2001

Steve,

I always wanted to know how AT's worked in detail.
So you are saying that the mechanical gear ratio in an AT is not always the "true" torque convertion? (From the Engine to the wheels that is)

Do you know where i can read more about this?

Thanks!

Matias

paisan · November 2001

usually are Locking Torque Converted. Meaning in 3rd and 4th gear the TC locks up and you get that ratio. On my trooper it will also lockup in 2nd IIRC.

-mike

lstp · November 2001

Probably not a VDC specific problem, but hey, I just bought one. A friend who owns a Legacy Wagon told me he had to mount his Yakima racks backwards so that the rear door glass wouldn't hit the rack when open. He did not buy the standard rack from Subaru because he wanted a rack that attached to the front forks, not the frame, to avoid problems carrying all those funky mountain bike tube sizes that are out there now. I've seen one bike thread this year on this site, so hopefully there are some folks who can shed some advice on bike racks for the Subaru VDC Wagon. One more thing, I also own a canoe.

Thanks,

Steve

kens · November 2001

Matias,

Check out this great site on how ATs work:

http://www.howstuffworks.com/torque-converter.htm

Ken

trocco · November 2001

Thanks Ken!

I got it now.

(I feel pretty stupid now, I guess i should have known this stuff)

I would still like to see a 5 speed auto VDC.

matias

yellowbikedon · November 2001

I own a Yakima "Copperhead" rack (which is roof mounted) on my LL Bean. It works well and the fork is held securely by the clamp. There is also a locking model for a few dollars more. I suggest you stop into a good bike shop where you should be able to get all your questions answered.

With one rail attached to the cross bars, you should also be able to attach a rig to hold your canoe. Again, a good bike shop should be able to help.

Don

sbcooke · November 2001

Some automatics double the ratio (I am not sure of the mechanics or viscous coupling, but...) under 10 mph to make up for the fact that manuals have a much higher 1st gear ratio. While you are calculating torque conversions, acceleration, off-road performance, etc.

ateixeira · November 2001

Matias: interesting, except the price difference. An Outback Ltd wagon with auto costs only $2150 less (at invoice) than the LL Bean model, plus you get a few extras besides the H6.

Still, a 5 speed auto to go along with that H6 would make the $2150 price difference much easier to swallow.

-juice

ffsteve · November 2001

Kens - That's a neat site! Much more detail on torque converter that I'll ever need to know, but still fun to read. I wandered around the other subjects and found them equally fascinating. I'll be returning there often.

Thanks,
Steve

theob · November 2001

Get the Subaru-branded round-bar kit from Liberty Subaru or SubaruParts.com. It's actually a Yak set of four DoubleCross towers, two 48" round bars, four SKS lock cores, and an airfoil. Should be able to get it for $40-50 less than the Yak branded version. All of the parts in the Sube kit say "Yakima" on them, just in muted letters. With that setup you can put any Yak bike rack up on top. I have two SteelHeads mounted outside the towers pointing forward, an Anklebiter inside the towers on one side pointing back, and two forks (one each, front and back bar) on the other side to hold the front wheels of the bikes in the SteelHeads. If I put it on properly, nothing touches my spoiler which allows less space than a non-spoiled hatch.
HTH, Theo in Colo.

tidester · November 2001

ffsteve,

Maybe you could ask them how 150 lb-ft of torque is enough to push a 3,000+pound vehicle even though the tire radius is only about 1 foot. Then report back to us!

tidester
Host
SUVs

trocco · November 2001

tidester,

Weight is a vertical force.
Torque is an indication of how much force a rotating body can produce, tangential to its radius. Since the road is tangential to the wheels, this force translates to horizontal movement.

That's why you don't need to apply 3000+ lb to move a car. (Unless you want your car to lift itself up!)

Hope this helps.

matias

paisan · November 2001

3000lbs of torque would rock!

-mike

hypov · November 2001

mike- the G-Force would definitely put a smile on your face (right out of a scene from "Spies like us"). |-)

-Dave

revka · November 2001

some you may also be interested in this ongoing Town Hall discussion: Auto101: How To and How it Works! ;-)

Revka
Host
Hatchbacks / Station Wagons / Women's Auto Center Boards

trocco · November 2001

anybody knows why subaru doesn't offer a towing package on the VDC Sedan?

and also, in the case of the outback, what sets the 2000lb towing weight limit? power, breaking, rear end structure, ...?

subaru doesn't differentiate between break assisted towing, so i guess i has to be either a power limitation, or a rear end integrity issue.

Matias

paisan · November 2001

I believe it's the structure, that is generally the limiting factor in towing contrary to popular belief. Also 1500lbs or greater needs to have brakes on the trailer.

At 2000lbs there is no need for a towing package per-say on the subies,just put a hitch on and you are set.

-mike

trocco · November 2001

yeah that's what i meant, a hitch. But if you look in the subaru website, it's not offered in the sedan.
Is that just a mistake in the site?

matias

ffsteve · November 2001

tidester,

matias/trocco took the words right out of my mouth!

revka - I'll check out the other forum, but I'll bet it's not as interesting and fun as these Subaru forums. Ya!

paisan - 3000 lbs of torque would be great, now how to lay it down onto the ground and put it to best use? 12 dozen tires?

Steve

paisan · November 2001

There are hitchs for the sedans. Best bet is probably an aftermarket one, much cheaper.

-mike

ateixeira · November 2001

paisan: the Isuzu diesel, at 520 lb-ft, is pretty close!

Matias: I'm sure the sedan will accept the hitch. I have the OE hitch and the nice thing is the custom fit and the 7 sturdy bolts that attach it, plus the wiring harness comes with it. Aftermarket hitches from DrawTite and Hidden Hitch get the job done, usually with 4 bolts, but they cost half as much.

I do long for an actual complete package, though, with a tranny cooler and bigger brakes.

-juice

paisan · November 2001

my Hidden hitch on my trooper only has 5 bolts and it tows 5200lbs

w/o upgraded brakes or tranny cooler

hee hee

(paisan rubs it in for juice a bit, right up til we hit the gas pump)

-mike

ateixeira · November 2001

I was going to think of a clever come back, but you did that for me. Thanks. ;-)

-juice

rsholland · November 2001

not 1500 pounds, if your trailer doesn't have brakes.

Bob

Subaru Outback VDC

Comments

Helpful Tools

Most popular vehicles

Your Privacy