Last post on Mar 09, 2004 at 11:54 AM
You are in the Future Vehicles - Archived Discussions
This discussion is ARCHIVED. To reactivate the discussion, post a request in the Lost? Ask the Future Vehicles Host for Directions! discussion.
What is this discussion about?
Subaru Legacy, Sedan, Wagon
#65 of 95 VDC: How much difference does it make - really? More important than AWD?
Feb 25, 2004 (10:37 am)
My 95 Legacy has AWD - I felt safe. It transferred power "from the wheels that slip to the wheels that grip." But now, what do I really need: AWD, AWD + VDT, AWD + VTD + VDC. What's next, M-O-U-S-E? What's right 4UNMe? Part of the "Beauty of All Wheel Drive" was not having to think about it. Let's see what AWD systems Subaru offers:
Manual Transmission: viscous-coupling locking center differential to distribute the power 50/50 front to rear.
4-spd Auto: electronically managed continuously variable transfer clutch to actively control power distribution in response to driving conditions
5-spd Auto: Variable Torque Distribution (VTD). A planetary center differential works with an electronically controlled continuously variable hydraulic transfer clutch to manage power distribution
Outback 3.0r VDC Limited: Vehicle Dynamics Control (VDC), an advanced stability system that controls VTD operation and integrates an electronic four-wheel traction control system
All of this stuff sounds like great technology but how much difference does it really make? In New Zealand, where the Legacy 2.5i won AA Autocar's Car of the Year Award: http://www.subaru.co.nz/news/index.html?id=606, they said that Subaru’s basic AWD is just fine (see excerpt):
"Unlike the Accord and 350Z, the Legacy has no traction or stability control…nor does it need any. It’s a complete package just as it comes, an all-wheel-driving machine that eschews gizmos simply because it has the most physical grip of any new car released in 2003."
Don't get me wrong, I love technology but I get worried when it starts sounding like that old Saturday Night Live parody about the "Triple-Trac" razor (when twin blades were hot). "The first blade pulls the whisker away from your face so the 2nd blade could then pull it out further so that the 3rd blade...". "Why do we do this?" Pause. "Because you'll believe anything!" Then the triple blade became a reality and last year Schick introduced the "Quattro" with 4 "precisely synchronized blades." Why - because we'll believe anything!
So, come on, if all this stuff is so important that it really makes a difference to the safety of its drivers, Subaru should just put it on all their cars - standard. I'd like to see some side/by-side tests of Subaru’s various AWD offerings to see if there's really any significant difference in handling and performance. Or does all this just drive up the price without improving the drive?
Feb 25, 2004 (1:53 pm)
My Forester is plain ol' AWD with 2 open differnetials and I've never been wanting for more traction. So you have a point.
In fact if I had VDC I'd want an off switch to be able to play around once in a while.
However, it is a great safety feature for emergency avoidance manuevers. I can say I'm fortunate enough that I've never needed it up until now, but I can't say I'd never be able to benefit from it.
Guess you could call it diminishing returns. You get a lot of bang for the buck by getting your basic AWD. A rear LSD adds a little extra, and then VDC would add an even smaller margin of safety beyond that.
Feb 25, 2004 (8:01 pm)
I am pleased to see the nice discussion. Judging from some of the reaction I take it you would prefer that SOA not include VDC in their top of the line sedan, that SOA expects to snare a bigger share of the market. I am puzzled as to why such strong reaction. Wouldn't it be preferable to have the option to choose? No matter--we all have our opinions ! I have a M/T OB that even with AWD and ABS does nice crabwalks in sleet and ice...yes I have driven several subies and even raced some (G/L) and this happens even with TC and AWD. These two technologies are not meant to correct the car's vector; only to help apply power to the ground. TC does not correct the direction of the car it just ensures that the wheel w/o power is controlled. VDC and other technologies will be incorporated in more and more cars (even GM is including it in most of their Epsilon platform). The IIHS and NHTSA have recommended that car manufacturers include stability control to prevent rollover in addition to its ability to assist the driver in controlling the car. SOA should consider providing this option to the customer. My point is that the technology is available and is part of SOA's current offering in the 3.0 VDC but only in the OB. I am glad that we have encyclopedias in the forum so that we can expect good discussion. To those who have not done so yet I ask that you try to navigate a good slalom setup in a frozen and icy parking lot with a car with stability control and one w/o...you may be surprised as to what the combination of throttle, brake, and engine power can do. Anyway, I am looking forward to the new Legacy and am curious how it will compete against cars of similar size and price. Cheers
#68 of 95 computer aided driving
Feb 26, 2004 (7:59 am)
so what does the new legacy come with? Traction Control?? I am sure antilock brakes. we know it doesn't have Vehicle Dynamics Control? So with AWD and Traction control the only think missing with the absence of VDC would be distributed braking is that write or am I wrong??
Traction Control isn't intended to keep the car on the road?? or it isn't intended to make decisions for the driver? I mean the idea of TC is to prevent a need to over correct right? which is something humans are great at doing in an extreme situation, therefore the directional vector is not corrected because there was no need, with TC and AWD?
I am not arguing I am making sure I have an understanding. I am thinking very seriously about getting a Legacy, but it is competing with some cars that do have some kind of "VDC" but not awd so I am trying to make sure I don't need some kind of VDC.
AND the car I buy with or without VDC, will need HEADROOM!!!
great discussion thanks!
Feb 26, 2004 (8:11 am)
TC is really just designed to get you moving forward in low traction situations, and won't help if you skid.
Feb 26, 2004 (8:38 am)
Regarding headroom in the new Legacy- Elm form the board here is over 6' and sat in the new Legacy with no problem. I know he was concerned about the comfort factor as well.
Feb 26, 2004 (9:30 am)
Just a quick clarification-
Toyota's VSC has been deemed by many as too QUICK to react, and intrusive (as you state). Its only supporters are the hyper safety oriented Consumer Reports editiors. Car and Driver, Motor Trend, et al. dislike the system because its non-defeatable in almost all applications, beeps at you annoyingly when its activated, which occurs too early and too intensely in performance testing.
I'm interested to know what the differences between VSC and VDM actually are. VDM is said to allow a much greater performance envelope. I'm sure CR will disapprove.
#72 of 95 TC on an AWD car??????!!!!!!!!!!!!
Feb 26, 2004 (9:52 am)
As Consumer Reports and others have stated, Traction Control is just a feeble attempt to compensate for lost traction on cars that do not have AWD. (Yes, they did say that TC was very much inferior to AWD for traction).
The only advantage I can see with TC added to an AWD car, is that it would cut power for gradual take-offs so you do not spin all 4 tires.
VDC would be nice to have, but would hope it had a turn-off switch, or I would not want it. VDC cuts in to spirited driving. Also AWD has a little bit of VDC built in it, delivering power to "the wheels that grip" to increase stability. It does help in slippery or tumulious conditions though.
#73 of 95 Re: computer aided driving
Feb 26, 2004 (10:32 am)
New Legacys should be hitting the lots soon and the showrooms around late March. You will have to try out the headroom bit...A friend of mine who is 6'5" had to settle for a Maxima because of his height.
As to the computer aided driving...if you want the Legacy and wish to have electronics that can help you with traction then you should choose the car with an automatic. The manual tranny will send 50 percent of the power to each axle AT ALL TIMES and in icy conditions it creates for interesting driving...white knucle experience on a frozen overpass with no divider.... You want an AWD system that can control the power distribution front to back and side to side. For you that is the A/T Legacy. As someone pointed out in earlier posts Subies differ from other companies in that the front to back can be 100 percent. Volvo uses the Haldex provided tranny and in some applications can shift 100 percent power back and forth. Audi, I believe, can also do that in some applications. VW in their passat 4Motion can send some percentage back and forth (67%?). I am not sure if VW does side to side. Another impressive application is the Infiniti AWD in the G35x.
Finally, you can turn off the VDC in the 3.0 OB. I tried it with and without. W/O it you can definitely spin the OB around very quickly as pointed out in the Consumer Report article. A fully loaded OB with 8.4 inches (new truck classification) of clearance is going to need the VDC...Other SUV makers are rushing to put those electronics in because of INSURANCE COSTS and LIABILITY and also because of competitive pressure. Volvo one upped everyone with the Rollover Control software...
#74 of 95 manual is a must
Feb 26, 2004 (11:05 am)
Zoomer headroom in the 04 I tried was definitely not enough is that what your friend that bought the Maxima tried?? I am hoping the 05 has more and headroom and better lowering seats then the 04. From what I have read in this discussion headroom is better in the 05.
as far as M/T got to have it. you can't buy a quick car and then give it a disadvantage!
as far as 50/50 power distribution all the time I don't know if I agree? the M/T has a "Viscous-coupling locking center differential"
now I don't know a whole lot about locking differentials but I do know that they do allow some slipping, therefore some power fluctuation between the front and back would be permitted right??
as far as needing full traction control.. never had it therefore I don't know what I am missing, yet I will take it if I can turn it off and it is offered!.. the fact that all four wheels have power will be better then what I have now. besides in day to day I will probably have TC off so I can play, I mean what is the point in having 250 horses:)!