('11+) explain imprezas AWD?

[sti2010rl]

Originally Posted by Commander Keen

Also, the VCU will never lock. It's not supposed to.

I'm aware of this. I used "locking" colloquially when I really meant "coupling".

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[Commander Keen]

I was just just trying to point out (in response to your claim that the VCU is not on or off like a clutchpack) that the onset significant torque transfer of a VCU is gradual, and not abrupt like a clutchpack, and furthermore, because of the behavior of the VCU, you should not have experienced binding when turning in a wet parking lot. Maybe there would be some instant torque transfer as you claim, but as per the source that I posted, it would be so insignificant that it would not interfere with a turn.

The transfer is gradual and fluid, so a quick turn into a wet parking space causes scrubbing/chirping. The same turn taken slower will not. For a 4WD vehicle, the same turn at any speed will.

You've been arguing with several people on here about what a car they own and drive every day, should or should not do. I suggest driving your friend's 5MT before deciding how capable it is. I think you might be surprised.

[foghelmut]

Relating to the wet parking lot donuts -

What are the main signs of a "bad" center diff?
Clunking and banging of the drivetrain during slow tight turns when the transmission is warmed up seem to be the most common sign.

What are the main causes of diff failure?
Doughnuts or driving the car with mismatched tires (different levels of tread or brands). These two problems are responsible for overheating the differential

How do those things cause the diff to fail?
When the front and rear wheels are spinning at different speeds, the fluid inside the diff heats up. If it overheats, this fluid will break down and wear out. The clunking and binding is a result of worn fluid trying to do it's job, and then failing and releasing. It grabs, slips, grabs again, and slips.


http://www.subaruforester.org/vbulle...ce-them-46979/

[Commander Keen]

Donuts are definitely bad.

A quick turn into a parking space won't get close to overheating the fluid.

[sti2010rl]

Originally Posted by Commander Keen

You've been arguing with several people on here about what a car they own and drive every day, should or should not do. I suggest driving your friend's 5MT before deciding how capable it is. I think you might be surprised.

I owned a 5MT for 3 years without VDC. Without VDC, it thought it was mediocre. I'm only talking about mechanical components here. With VDC, maybe the car works much better in ice or snow, but that still says nothing about the mechanical components that it uses. It says that VDC is good, and that's all. If I were to test a 5MT and like it knowing that the AWD components are the same, then it would only convince me that VDC is good.

Again, my only contention was the the VCU used was bad. It wasn't even that all VCUs are bad; only the 4kg one that Subaru uses.

[Commander Keen]

I owned a 5MT for 3 years without VDC. Without VDC, it thought it was mediocre. I'm only talking about mechanical components here. With VDC, maybe the car works much better in ice or snow, but that still says nothing about the mechanical components that it uses. It says that VDC is good, and that's all. If I were to test a 5MT and like it knowing that the AWD components are the same, then it would only convince me that VDC is good.

Again, my only contention was the the VCU used was bad. It wasn't even that all VCUs are bad; only the 4kg one that Subaru uses.

The VCU is just one component of the AWD system, as is VDC. Do you have proof that it wasn't revised by Subaru since your car was built? Also, its performance depends on other parts in the system, like the front and rear differentials.

Drive your friend's car and let us know what you think.

[soobie doo]

Imma check into this discussion briefly...

I live in southeastern PA. We don't get all that much nasty conditions here, around 20 inches of snow/year on average.

I do make frequent trips to upstate NY, sometimes in inclement weather in the winter, to a town that averages about 60 inches of snow/year.

Nobody's disputing your claim that the STI has a better AWD system that the Impreza, or that there are a variety of other cars that can also outperform an Impreza in inclement conditions.

The typical small-car buyer is not looking at a $35K+ STI. They're looking at a $20K impreza, or a civic, or an elantra, or a corolla, or a mazda3, etc. This is reflected in the cars that I see on the roads, both at home and in upstate NY. Compared to those other cars, the impreza does damn well in slippery conditions.

Nobody's ever been shopping for a $17K civic, decided they'd like AWD, and gotten an Audi S4 for $52K. They're just entirely different classes of vehicles. Nobody cross-shops between them.

Among cars available in the USA, in a price and size range comparable to an impreza, it's tough to find something that can outperform the impreza in most inclement conditions.

[Commander Keen]

The STI's AWD system would noticeably outperform the Impreza's in situations that nobody buys an Impreza for.

[Zeeper]

Not to twist the screw any deeper, but a car with narrower tires, and even the 'crappy' AWD found in the Impreza, probably performs as well or equal to the superior STI AWD system in most winter driving conditions found on paved roads.

There is such a thing as too much power to be useful, and wide makes for great snow shoes, but not road traction, which is why the tire warehouse suggests downsizing the winter wheel/tire combo.

[stevehnm]

Originally Posted by Commander Keen

None of this applies to the CVT.

What I've noticed with the CVT is a little skipping/bucking with hard, i.e. close to locked, turns when cold. It feels more like front to rear differential though. Are you saying that should not happen either?

[Commander Keen]

What I've noticed with the CVT is a little skipping/bucking with hard, i.e. close to locked, turns when cold. It feels more like front to rear differential though. Are you saying that should not happen either?

By "this", I meant the things mentioned in that specific post.

[Dirt Bringer]

Originally Posted by sti2010rl

I owned a 5MT for 3 years without VDC. Without VDC, it thought it was mediocre. I'm only talking about mechanical components here. With VDC, maybe the car works much better in ice or snow, but that still says nothing about the mechanical components that it uses. It says that VDC is good, and that's all. If I were to test a 5MT and like it knowing that the AWD components are the same, then it would only convince me that VDC is good.

Again, my only contention was the the VCU used was bad. It wasn't even that all VCUs are bad; only the 4kg one that Subaru uses.

What you have to remember here is that the Impreza is a car, not an SUV, not a truck. It does not need locking diffs, in fact in some situations a locking diff would only add expense to a system that would benefit more from viscous couplings, for example. The point of the manual subaru and its 50:50 split are a couple of things. First, it generally feels more alive and fun than a comparable FWD car because of the power distribution (and there are exceptions yes of course), and second, due to it being fully symmetrical and having a combination of VDC and VCU it returns one of the best performing AWD designs and performance results of any car in its price segment. The point here is not that the Impreza has an extremely advanced AWD system (manual or auto), but that it is pretty much the best in its segment for use in a car. If this were a jeep, we would be having a completely different discussion. However, price for performance, this simple system brings a lot to the table. I also have read in the past about various center differential systems and a well written up article on the various designs put the Subaru manual design in the top three (mechanical) designs out there (for cars). I'm not suggesting you are wrong in what you have stated about its design and performance, but I'm certainly on the fence on both camps, and have seen several examples suggesting that the VDC and VCU or auto combinations used in Subaru mainstream vehicles are not only sufficient, but easily the best on the market for the money. If you are willing to explain to me why this is not the case however, I'm willing to listen.

[Guzzi 1]

Originally Posted by Commander Keen

The STI's AWD system would noticeably outperform the Impreza's in situations that nobody buys an Impreza for.

I know the STI is a little different, but I felt that my '13 CVT did better than my '03 WRX 5MT even before I put the winter tires on the '13. Of course with the winters, there is no comparison. I bought the '03 new and had it until I opted for cheaper fuel and better economy. I had 10 years to eval the rex. The first siginificant snow left me very impressed with the '13. (Note: The '03 was certainly no slouch on bad roads. I just feel the new car is even better.)

Most of the time, NOT slipping and sliding is the goal. Parking lots are a place to play once in a while. For that, the '03 wins! But for getting safely and easily from A to B, the '13 uses a good system.

John

edit: BTW, I agree with your statement. Few will ever exploit the STI to its full potential, or a WRX for that matter.

[ZachH94]

I fully agree my 03 Wrx is amazing and can turn like no other.