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12-27-2012, 01:19 AM | #26 |
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I have the factory service manual, but it's against forum rules to post any of it. Why are you interested in the rear diff?
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12-27-2012, 03:07 AM | #27 | |
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how did you get the fsm? electronic or paper? i've been wondering how to get it in an electronic format, there are some that sell it for seemingly cheap but they seem pretty shady, so i don't really want to go that route. |
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12-27-2012, 08:26 AM | #28 |
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It's a massive PDF and you can get it for <$20. The CD on the 5MT is in the transmission. There's nothing unusual about the rear diff.
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12-27-2012, 09:04 AM | #29 | |
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Quote:
http://www.ebay.com/itm/2012-Subaru-...-/110921987742 BTW, 50:50 torque split is what you get with an open differential. Torque is force times distance, so if one side is in the air the other side gets nothing. |
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12-27-2012, 09:54 AM | #30 |
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Torque is just a turning force. You can have torque without motion, for example, using a torque wrench on a seized bolt. When you combine torque with motion (RPM), then you have power since work is being done.
Open CD systems don't necessarily have to be 50/50. Changing the rear differential ratio will change the torque split between front and rear (while all the wheels have traction). Changing the rear ratio on the 5MT will cause problems because the plates in the VC would move much faster relative to each other and possibly overheat. |
12-27-2012, 09:59 AM | #31 | |
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12-27-2012, 12:04 PM | #32 |
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Wow! very interesting, so which is a better AWD the CVT or the manual Impreza 2.0i ?
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12-27-2012, 09:46 PM | #33 | |
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are these ebayers people who got the fsm from subaru and are reselling it? |
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12-27-2012, 10:10 PM | #34 | |
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Manual. The 50:50 split and viscous coupling center differential is a more rugged (metal plates and hardening fluid) and performance oriented system. The Evo 8 had a viscous coupling center prior to the current ACD. |
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12-27-2012, 10:33 PM | #35 |
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Snow Drift, that's a great diagram. The only thing I could find was the transfer case showing the clutch plates. The Evo's CD is in the transmission.
Follow the power flow from "Transmission". It goes straight into "Center Differential" in the gearbox. From there it goes to "Front Wheels" and "Rear Wheels", but if you keep following the arrows past the first branch, you'll see that "Hydraulic multi-plate" straddles the front and rear axle. In the Evo, most of the power going to the rear wheels flows through the CD (like in the 5MT Impreza). In the CVT Impreza, all of it flows through the MPT clutch as it doesn't have a CD. When the Evo's clutch disengages, the rears still have full power (in good traction). When the CVT's does the same, the rears have no power at all. A similar diagram for the CVT would look like: Transmission -> Front Axle -> MPT Clutch -> Rear Axle Clutches modulate torque transfer between two shafts. Differentials transfer motion between three shafts. You can see this in your diagram where both "Front Differential" and "Center Differential" have three connections each, and "Hydraulic multi-plate" has only two. Last edited by Commander Keen; 12-27-2012 at 10:42 PM. |
12-27-2012, 10:40 PM | #36 |
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CK, all ill say is this:
The center diff shown is just the transaxle allowing the transmission to make a 90deg turn to connect. The clutch packs still regulate the power distribution. Also the rears of the CVT are never 0%. It's 60:40 under normal conditions to 50:50 when fully clamped. |
12-27-2012, 10:50 PM | #37 | |
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Yellow: Rear drive Green: Front drive Purple: Left front axle Blue: Right front axle Two concentric shafts (green and yellow) exit from the CD to the right. As CVT owners have reported in this thread, when the MPT has no power, neither do the rear wheels. Last edited by Commander Keen; 12-27-2012 at 11:02 PM. |
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12-27-2012, 11:24 PM | #38 | ||
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Are their any exploded views of our system in both the CVT and the 5MT? either here or someplace else? Quote:
Anyone : I'd like to buy the FSM but if the ebayers are simply stealing from subaru by reselling copies then i'd rather not feed them. Anyone have an idea on this? |
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12-28-2012, 12:16 AM | #39 |
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On the 5MT you'd have to weld the CD and remove the driveshaft to convert to FWD.
You could always call your dealer about the FSM. In any case, if I pay $20K+ for a machine, I'm getting the documentation for it one way or another. |
12-28-2012, 12:53 AM | #40 | |
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I agree, however, having read about how unsavory groups fund their operations by using our willingness to take advantage of a deal, I'd always wonder. |
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12-28-2012, 12:55 AM | #41 | |
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12-28-2012, 02:26 PM | #42 | |
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does it make a difference if its stick vs auto? i assume it shouldnt since its dependent on the AWD system when traction is lost. bc the videos above shows the same test but up hill and it climbs fine |
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12-28-2012, 11:56 PM | #43 |
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I skipped thru that large video, but was the only one to make it out of the side rollers a Volvo AWD?
Wow...I really thought Subbies would get out of that situation but it was a dang Volvo.... sad Panda I realize they didn't test every vehicle of all time, but really...did anything else make it out. I saw the WRX fail. |
12-29-2012, 12:45 AM | #44 |
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Anything that has open diffs on the front and rear, without VDC or equivalent, will spin on those rollers all day long.
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01-23-2013, 01:58 PM | #45 | |
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The only AWD system that fits the profile of "Legendary" by Subaru is the STI's AWD system and the the VTD AWD systems found on 4EAT GD WRXs and 5EAT 05-09 LGTs and Outback XTs. They all have a planetary gear center diff with a rear lsd (clutch type lsd on the WRX, LGT, XT, and 04-06 STI; Torsen T2 on the 07+ STI). In the STI, the driver has the ability to manually lock its center diff and manually change its degree off lockup. All STIs have a front helical type lsd. These systems, paired with a VDC (essentially e-diffs) are extremely competent systems which direct the most torque to the wheels with the most traction. Now take the rest of the automatic transmission AWD systems. There's a mutliplate clutch in the center and acts proactively (many here have argued that it's not called a differential-I really couldn't care less about semantics). I have no problem with this system. My fiance owns a 4EAT Impreza. The clutchpack provides ample torque transfer between the front and rear axles and works fine as a daily driver. For the price of the vehicle, it's great, even though it's not the most technologically advanced unit. If it ain't broke, don't fix it. The front and rear axles have open diffs backed by e-diffs. I've never been stuck with this car, but I never had the opportunity to test it in really icy conditions as I don't drive it often. Nonetheless, for the price of the car, I know that it does what it's supposed to do. Is this AWD system legendary? I think it's just rhetoric when comparing it to other systems that I've driven in the ball-park price range. It's basic, but it's put together well. This system will probably fail a roller test whereby the left front and rear wheels are on 0 friction rollers on an incline. The e-diffs will most probably be defeated. I'll even venture on to say that it will fail the same tests in the video, minus the ones where the fronts or rears are on rollers. We know the clutchpack works fine. E-diffs can only do so much. Now take all the manual tranny AWD systems. Having owned a 5MT 07 Leggy, I can tell you that it's absolutely awful. What I mean by awful is that it's simply the worst AWD system that I've ever driven short of a completely open diff setup. The real joke is that it's pretty much the same as an open diff setup. I remember a thread called "5MT AWD=All wheels disconnected?" by sajohnson and his experience was exactly like mine. The 4kg viscous coupling diff is so awful at regulating any speed differences between the two axles that Subaru may as well have given us open diffs to save weight, as the VCU is useless with the sole purpose of increasing the car's curb weight. I swear to god, you can take any center diff on the market and it will be better than that awful piece of garbage found on manual models. Even the newer models with VDC are terrible, because the braking done by the e-diffs simply is not enough to compensate for the lack of lockup in the center diff. The only reason I still own a Subaru is because I own a 2010 STI, which has a fantastic, albeit pretty old AWD system. I mean it really stomps face. That's the only high end AWD system provided by Subaru though, and I paid almost as much as a base Audi S4 for it. Last edited by sti2010rl; 01-24-2013 at 12:54 PM. |
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01-23-2013, 02:34 PM | #46 |
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post #330 and #334 in that thread seems to sum it up, it seems like it was locked for a reason, and you've decided to reopen it here...
http://forums.nasioc.com/forums/show...325909&page=14 Midway in that thread is a discussion about the possible source of the OP's loss of traction issues, a cooked viscous coupler, but he would not know anything about that given how he kept testing it to see how much it failed... I have a 5 speed AWD Impreza with VDC. I have driven it into and out of snow banks and through parking lots flush with snow. I have drifted a little, while hearing the car try to make me stop. The traction seems steller, and the car is an absolute tank in the snow with snow tires on it. Better than any other car I have driven, and I have a little experience driving in the snow (30 years), though I am not in Quebec. Sorry I cannot take your post at face value, I'm gonna side with the thousands of Subaru owners who are willfully ignorant while they drive their viscous coupler equipped 5 speed Subarus down the snowy roads of the world. Last edited by Zeeper; 01-23-2013 at 03:15 PM. |
01-23-2013, 03:31 PM | #47 |
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So STI2010....you are saying that the only Subbie worth buying for the AWD is the STi? The rest are no better than any other AWD system correct? This is why the WRX failed the side rollers among many others except for what I saw in the Volvo. What model Volvo was that?
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01-23-2013, 03:51 PM | #48 | |
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I'm not debating whether manual Subarus can handle snow. I've seen plenty of 2WD vehicles get through the winter. If your standard of an AWD system is simply "I can plough through tons of snow" then you don't even need a VCU. Open diffs work just fine. My 2.5i Touring 07 Leggy worked just fine. Except I paid over 30k CAD for the car before taxes for an AWD system that was just cheap, and patently worse than any other AWD system out there. I didn't know how bad the 4kg VCU was back before I bought the car, but I definitely know now. Hell, even a cheap and light Haldex unit is better than the VCU setup as it can lock up 100% and has less parasitic drivetrain loss. I can totally understand using the VCU on the lowest end models for under 20k. But at the time, you could spend 48 thousand dollars Canadian on a Legacy Spec B with a VCU. 48 thousand. At the time, the base Audi S4 was starting at 52.5k Canadian. Really? Ok, so if I use your logic, the VCU AWD system is good because you and thousands of other "ignorant Subaru drivers" like the way the car handles through snow, even though the vast majority of said snow conditions could be conquered with an open diff AWD setup. This still has no bearing on how the VCU does virtually nothing. So it manages to transfer ~3 lb/ft between axles. Yay! Next time some STI driver posts something about blowing ringlands, I'll side with thousands of STI drivers, including myself, who do not have blown ringlands. Therefore, STIs never experience blown ringlands. Last edited by sti2010rl; 01-24-2013 at 12:58 PM. |
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01-23-2013, 04:00 PM | #49 | |
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01-23-2013, 04:03 PM | #50 |
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I guess I'm an ignorant Subaru driver then, and it appears that your definition is a Subaru driver who is easily satisfied because his/her car climbs steep snow-covered grades, and doesn't even flinch when driving in condition that are leaving many other drivers in the ditch (this was my situation when driving through PA this past Monday).
So yes, I'm ignorantly satisfied with the 5-speed manual AWD system in my Impreza that does everything I've asked it to do without complaint or drama. Am I wrong to be satisfied that my car easily does what I ask it do, while other drivers on the same roads are clearly struggling? |
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