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Subaru Impreza WRX

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  • Thanks for the link ! That was really good.

    Later...AH
  • paisanpaisan Posts: 21,181
    I believe it samples at 10ms intervals, I know that is what the ECU does on the TOD on my Isuzu, I'm pretty sure that the subaru ECU does it in similar refresh rate. I think that is faster than the VC can react, not that the VC system is slow per-say or bad, just more reactionary than the AT systems.

    -mike
  • I didn't get a chance to read that link yet, in fact I was typing the previous message before you posted it. I'm at work right now so I won't be able to read it until tonight. I'm still rather foggy on how a system can estimate the friction coeffecient without inducing some wheelspin.

    And hunter001, yes I did use subaru's site for that description because I couldn't find any other materials on the web for the information. I do not think that your theory about sales canniblization is correct however.

    People buy regular impreza's because they can't afford WRX's (there really is no other reason).

    People buy foresters over the VDC outback because they need/want the extra room that it provides. Otherwise the other outback owners most likely simply can't afford the VDC outback (I think the H6 engine is more compelling a reason to buy it than the AWD system).

    For years Subaru has marketed the "wheels that slip to the wheels that grip" tirade. I don't know how they could market the VTD any better than that.

    One other point before I really have to go for the entire day. What happens in this situation?

    The computer learns that you floor it out of curves, therefore always planting the majority of the power to the rear when you exit turns. However, just as you are accelerating this time, you rear wheels encounter a low traction situation (ice, gravel, whatever). Can the system transfer the 90% of power that may have been in the rear (since it learned that it should have 90% in the rear out of turns) faster than the VC can transfer it's default 50% power? Seems as though the system has to be faster because it may have to transfer alot more power quickly.
  • paisanpaisan Posts: 21,181
    is only 80/20->40/60
    not sure of the VTD variability.

    There aren't steering inputs so it would be based on speed/weight/throttle position not steering. (AT system)

    -mike
  • bluesubiebluesubie Posts: 3,497
    The Outback has more room than the Forester. Bad example. :-)
    Some people prefer higher displacement over total h.p., so I don't buy your WRX over other Imprezas argument either.

    A lot of this speculation would be put to rest if Subaru put out some detailed information on all of the AWD systems. Audi does this (or used to) for the Quattro system. It would probably just lead to more internet AWD arguments anyway. :-)

    -Dennis
  • "There aren't steering inputs so it would be based on speed/weight/throttle position not steering. (AT system)"

    Still, the point still stands though, the curve was just incidental, it just learns that from going a relitivly lower speed, you step on the throttle to accel quickly and should therefore transfer power to the rear.

    I'm also kinda curious if the system changes the default power distrubtion when slippage is detected rather than use the electic clutches to transfer power. For example, in my situation i posted above, would the system keep the default power distribution it assigned for that situation and then manage the power with the clutches or would it change the power distribution and only invoke the use of the clutches on a limted scale?

    From what I'm understanding now, the regular AT system can only transfer power though the use of the clutches while the VTD can change the power distribution without the use of the clutches, only using them to react very quickly or to change the power distribution a little from the default. (This may all be talked about in that .pdf that i haven't been able to read yet though)
  • People buy foresters over the VDC outback because they need/want the extra room that it provides. Otherwise the other outback owners most likely simply can't afford the VDC outback (I think the H6 engine is more compelling a reason to buy it than the AWD system).

    For your information, there are 2 H6 Outbacks. One of them is the VDC-Outback with the VTD-AWD and the other is the LL Bean-Outback, with the regular-Auto-AWD. The VDC-Outback costs $2400 more than the other H6-equipped LL-Bean Outback.

    People who buy the LL-Bean-Outback equipped with the H6 engine, think they are saving thousands by not going for the VDC-Outback. Most buyers, I am sure, are not even aware of the differences and the advantages of the underlying hardware; and the salespersons - who are also equally ignorant - are not helping either. In reality, are the folks who buy the LLBean getting a good deal (by not going for the VDC-Outback ? I don't think so. They are simply getting a different vehicle, at a different price-point, that incidentally share the body and an engine with the other vehicle. 2 different AWD-hardware, 2 different price-points. Is Subaru really doing its part in trying to explain why they are charging that $2400 extra for the VDC-Outback over the LL-Bean-Outback ? Are they really explaining the differences in the underlying hardware ? Nope !! Except for some brief marketing statements, that make absolutely no difference.

    When people buy the Auto-WRX over the Auto-RS, they are getting a completely different AWD system, in addition to a turbo-engine and LSD, which is well worth the 1000s of dollars additionally charged for.

    Later...AH
  • edge01edge01 Posts: 28
    Not to take away from your VDCvsVTC discussion, but has anyone else experienced a great deal of snow/ice build up in the wheel wells and wheels themselves that causes thier WRX to go out of balance and shake like a washing machine on spin cylce?

    I've driven my WRX and a friend's 97 Rally Sport and they both have this problem.

    Just wondering if this might be a design flaw and if there's anyway to avoid/fix it.

    ryan
  • bruticusbruticus Posts: 229
    does the MT5 also have the LSD? Sorry for sounding like a dunderhead; it's just that I am a dunderhead.

    DjB
  • For years Subaru has marketed the "wheels that slip to the wheels that grip" tirade. I don't know how they could market the VTD any better than that.

    They are not marketing the VTD specifically by the above slogan. They are marketing the AWD in general. What I meant earlier, is that they should provide more detail about the VTD-AWD and how it rates vis-a-vis the other AWD systems employed by Subaru.

    Later...AH
  • Yes, the MT5 has the LSD too. But it shares the same AWD with the RS-MT5. In the Auto-WRX vs Auto-RS, the AWD is also completely different, in addition to the turbo and LSD due to which the premium charged over the Auto-RS is well worth the extra.

    Later...AH
  • bluesubiebluesubie Posts: 3,497
    Some folks here at Edmunds wax the inside of their wheels. This keeps the snow and crud from building up as bad. I get the same thing on my OBS.

    -Dennis
  • It seems that all outback models (except the sport) have an LSD.

    "H6-3.0 L.L.Bean Edition models have an electronically managed continuously variable transfer clutch and limited-slip rear differential." (the same is true for the other Outback models except sport)

    So we have:

    2.5RS, 2.5TS, Outback Sport
    AT - Active AWD
    MT - VC

    WRX
    AT - VTD + LSD
    MT - VC + LSD

    Outback (except VDC and Sport)
    MT - VC + LSD
    AT -Active Awd + LSD

    Outback VDC
    VTD + VDC

    Forester L
    AT - Active AWD
    MT - VC

    Forester S
    AT - Active AWD + LSD
    MT - VC + LSD

    Legacy L Models
    AT - Active AWD
    MT - VC

    Legacy GT Models
    AT - Active AWD + LSD
    MT - VC + LSD

    I wonder who decides (and for what reason) which system goes on which car. I do think the reason why the VDC doesn't have an LSD is because it would interfer with the system.

    Personally? I would not buy a VDC model, ever. AWD and power transfer is one thing, engine limiting and automatic braking is another. The later two have no place on a car I drive.

    Also, the price difference may also have to do with the 11 speaker mcintosh sound system as well.
  • paisanpaisan Posts: 21,181
    Eventually you will have a form of VDC on every car you can get, it's becoming more and more std, like ABS. My guess is over the next 10 years almost all vehicles will have it in one form or another.

    -mike
  • I noticed Sport Compact Car included the WRX on their annual list of "eight great cars" for the second year in a row. It appears as though it is their favorite of the eight as well (but maybe that is just my read).

    Car and Driver, if I recall correctly, bumped the WRX from their top 10 for the revived T-bird. Now what the hell were they thinking?
  • dsm6dsm6 Posts: 813
    C and D picked the WRX in their top ten. You are thinking of Motor Trend, who picked the t-bird as their car of the year.
  • AWD and power transfer is one thing, engine limiting and automatic braking is another. The later two have no place on a car I drive.

    I agree. In fact, the first version of the VDC did not have a "VDC Off" button but they have added it to the latest version of it. If my car came with a Stability Control system, I would switch it off, if I wanted to do some really aggressive driving. But such systems do have their place, but I personally would not want it, especially due to its intrusive braking and ability to cut engine power.

    Given a choice between choosing the VDC(stability system) or an LSD, I would hands-down prefer the LSD, especially on a car like the WRX. But I would not mind having the VDC, in addition to the LSD, as long as it has an "Off" button. At the time of resale, it might win me some points !!

    Later...AH
  • paisanpaisan Posts: 21,181
    It turns the system back on when you reach 30mph. Mercedes can turn off the ESP system but it only turns off the braking portion and a small % of the throttle control, it will still cut the throttle at some point. I'm not a big fan of these systems myself. Last weekend while in the Pine Barrens http://isuzu-suvs.com/events I had to spin my way out of a mud-pit where I was burried over the frame of the trooper. I just punched it in 2nd gear and it kept bouncing off the rev-limiter but got me through it!


    -mike

  • "Eventually you will have a form of VDC on every car you can get, it's becoming more and more std, like ABS. My guess is over the next 10 years almost all vehicles will have it in one form or another."

    My god I certantly hope not.

    The thing is, it may be a nice thing to have for no brainer driving, but it is not in any way shape for form necessary.

    I live in western pa (right now, down near pittsburgh but I went to school north of the snow belt). Aside from REALLY deep snow (8 inches has really been my max), I've driven in just about every weather condition imaginable. And this isn't just with an AWD car, I've done it with three different FWD cars and a RWD van.

    You simply do not NEED these intrusive systems. If some want them, fine, but I hope they all come with a way to disable them.
  • paisanpaisan Posts: 21,181
    Yep we don't NEED radios, heated seats, power windows, ABS, disc brakes, etc. etc.

    :)

    I understand your point and agree with you, unfortunately it's a likely reality.

    -mike
This discussion has been closed.