Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





4WD and AWD systems explained

1575860626372

Comments

  • ateixeiraateixeira Posts: 72,587
    I can't believe you're still using the 2003 NY Times chart as a reference.

    Can you at least admit they were wrong about "Audi all"?

    It's hard to have an intelligent conversation about AWD if you cannot acknowledge the difference between a Torsen and a Haldex. :sick:
  • kdshapirokdshapiro Posts: 5,751
    Those last few posts are about the 4EAT power split of 90/10 – 50/50

    Correction the last few posts are about the 80/20/80 split, which hasn't changed lately. Except I'm guessing in the 2009 Forester, based on the latest video, one wheel possibly could drive the car.
  • chelentanochelentano Posts: 634
    >> Correction the last few posts are about the 80/20/80 split, which hasn't changed lately.

    No evidence of that, unless you could post some credible links. Quite contrary: all sources I posted suggest 90/10 - 50/50 split since nineties.
  • chelentanochelentano Posts: 634
    >> The correspondence from Subaru stated they were going to revise the marketing materials because the whole power split issue was being misinterpreted.

    Well, untill they revise it, we not going to make stuff up and we use the available info.


    >> Traction control does not affect Front/Rear power split ratio
    >> Not true. In fact, Toyota uses open diffs and relies on traction control primarily to shift power.

    Are you sure or you it's your guess? Forget Toyota, does the Subaru traction control affect the Front/Rear power split ratio?
  • chelentanochelentano Posts: 634
    >> It's hard to have an intelligent conversation about AWD if you cannot acknowledge the difference between a Torsen and a Haldex.

    It's hard to have an intelligent conversation about AWD if you say that VDC is AWD.
  • kdshapirokdshapiro Posts: 5,751
    My credible link is Mike the host. What credible link are you using? A 2003 NYT article.
  • kdshapirokdshapiro Posts: 5,751
    It's hard to have an intelligent conversation about AWD if you say that VDC is AWD.

    Did you review the video posted? Here is a short course on AWD. AWD is an acryonym for all wheel drive. There are many variations of AWD, but it refers to the ability to have any or all wheels powered at the same time. How many wheels are powered at the same time and under what conditions are all implementation details and there are many different ways of accomplishing the end of keeping a vehicle moving. However, some ways are better than others.

    The terms for this are on-demand and part-time. In addition some systems give the ability to lock the f/r ratio. However the use of this is very limited and usually results in system damage if used on a non-slippery surface.

    In addition, some systems can vary the f/r ratio based on acceleration and deacceleration. Other systems can vary the f/r ration based on accelerator position. Some systems assist with LSD (limited slip differential), others assist with the anti-lock braking mechanism. BMW for example, does both.

    Having said that Subaru has multiple types of AWD systems. The ones we are debating are the one attached to the automatic. 2009 has a different system than 2008 and earlier. 2008 and earlier always power 4 wheels. According to the information presented there is always fluctation between front and rear from 80/20 to 20/80. Mitsubishi as Subaru is not very forthcoming with information about their AWD system. But much of that functionality seems to be based on accelerator position or slippage. 2006 Outlander models and earlier seems to be at the level of the RAV4/Highlander, which incidentally call their systems 4WD.

    I'm not 100% clear on 2009 Subie system yet, except that I'm guessing any one wheel can power the vehicle.

    I hope this short explanation helps with some of the terminolgy and concepts. Feel free to ask additional questions.
  • paisanpaisan Posts: 21,181
    Obviously we are bench racing here discussing stuff rather than actual real world use. I've worked on 100s of Subarus, raced them, and have many many contacts inside Subaru as well as Subaru Engineering. I didn't just make up the 90/10 to 10/90 numbers from the top of my head. Believe me if you wish or don't.

    This is my final post on this subject.

    However the statement from Subaru that Bob referenced was actually from a marketing guy who may or may not know the engineering behind his statement.

    -mike
  • kdshapirokdshapiro Posts: 5,751
    Believe me if you wish or don't.

    Just to set the record straight, I have been following these forums for a bit and by your posts I know you know what you are talking about.

    It's not me who is questioning the veracity on the information given on the Subie f/r split.
  • paisanpaisan Posts: 21,181
    It's not me who is questioning the veracity on the information given on the Subie f/r split.

    I know, just was responding to the thread in general. It's sad that I am here to help folks, yet some refuse to believe me. Frustrating at times actually. :(

    -mike
  • rshollandrsholland Posts: 19,658
    However the statement from Subaru that Bob referenced was actually from a marketing guy who may or may not know the engineering behind his statement.

    More than marketing; Mike McHale, being the Corporate Communications Director, is ultimately responsible for anything that SOA sends out to the public in terms of product and corporate information. I'm sure anyone in that position will make sure they have their facts straight before making pronouncements.

    Could he be wrong? Of course. He's human after all. Still, knowing how important AWD is to the brand, I'd put my money is on him being correct on this point.

    Bob
  • ateixeiraateixeira Posts: 72,587
    Well, untill they revise it, we not going to make stuff up and we use the available info.

    I've offered up some new info - the FWD mode for the Forester.

    Remember, you were the one that said the Outlander could go 100/0 because of its FWD mode, right?

    For the same reason, the Forester can, to.

    I'm using your own rule to prove that 100/0 is possible, so the 90/10 limit cannot exist.

    Let me find a photo of the instrument panel with the "FWD" mode lit up...I'll share if I can find one, otherwise I'll take photos myself next time I see a Forester. I'll go ahead and get the photo of the trailer pre-wiring since you didn't believe that either.
  • ateixeiraateixeira Posts: 72,587
    It's hard to have an intelligent conversation about AWD if you say that VDC is AWD

    VDC is just a marketing term, and Subaru did use it to describe the integrated systems on the early Outback VDC and Tribeca.

    They stopped when they started offering traction/stability control on other models.

    It's confusing, yes, but they did use the term VDC early on.

    By the way, Nissan has used the name VDC to describe its AWD system.
  • ateixeiraateixeira Posts: 72,587
    Paging wwest, paging wwest.

    I'll try to find him. :shades:
  • chelentanochelentano Posts: 634
    >> My credible link is Mike the host. What credible link are you using? A 2003 NYT article

    Post by Mike or Joe or whoever on some message board is not an evidence. I already posted many links from credible publications. Mike said that 80/20 split was only on 1998-2000 4-speed auto Subaru.

    So I offered total 6 credible sources, covering 2000 models of 4EAT Forester and Outback (read previous posts), incl. Wikipedia, NYTimes, Car and Driver, Popular Mechanics and Edmunds.com. They all say that split was 90/10 to 50/50.
  • chelentanochelentano Posts: 634
    >> I'm not 100% clear on 2009 Subie system yet, except that I'm guessing any one wheel can power the vehicle. I hope this short explanation helps with some of the terminolgy and concepts. Feel free to ask additional questions.

    Why would I ask questions someone form a message board who is "not clear yet" and who is "guessing"? I would rather get some credible sources.
  • chelentanochelentano Posts: 634
    >> Believe me if you wish or don't.

    Well, "believing" in this is appropriate for someone who is into Subaru religion. So, yes, some would believe.
  • chelentanochelentano Posts: 634
    >> More than marketing; Mike McHale, being the Corporate Communications Director, is ultimately responsible for anything that SOA sends out to the public in terms of product and corporate information. I'm sure anyone in that position will make sure they have their facts straight before making pronouncements.

    Great point
  • kdshapirokdshapiro Posts: 5,751
    Why would I ask questions someone form a message board who is "not clear yet" and who is "guessing"? I would rather get some credible sources.

    No need to rely on my knowledge, just check out the video. I'm guessing the 2009 Forester will be able to accomplish the same thing. Have you looked at the video.

    BTW, I feel the same regarding one who uses a 2003 NYT article as the gold standard. Doesn't really matter, the 2009 Forester seems to be racking up a number of awards, and for good reason.
  • paisanpaisan Posts: 21,181
    An aside, my guess is that wiki, NYT, and the other "credible" sources, all are feeding off each other to get their facts.

    -mike
Sign In or Register to comment.