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Guest Message by DevFuse
 

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Subaru AWD and Audi/VW Quatro


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14 replies to this topic

#1 Guest_ralph_*

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Posted 03 November 2002 - 09:02 PM

What is the difference between the Audi/VW Quatro and the Subaru AWD as used in the 2003 Legacy 2.5 GT?

#2 Guest_wjmgl10_*

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Posted 03 November 2002 - 10:07 PM

Audi/VW is transversely mounted and is totally inferior to SUBARU's AWD in every way.

SUBARU's AWD is logitudal, which is perfectly balanced.

MUHUHAHAHA!!! SUBARU Rules all.

#3 Guest_Stangman68inftc_*

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Posted 04 November 2002 - 02:15 AM

My mother has a 2000 VW Passat 4-Motion(Quattro), she has the 2.8 litre V-6, now there is a huge black plastic ugly cover obstructing the view of the engine, but i thought that the engine was not transversly mounted, wouldn't this mean that the driveline is longitudinal? I'm likely wrong but unsure.

#4 Guest_wjmgl10_*

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Posted 04 November 2002 - 07:16 AM

If the engine is transverse, so is the trany, and vice versa on the logitudal engine.

#5 Guest_Legacy777_*

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Posted 04 November 2002 - 09:23 AM

I'm sorry guys. You got your info wrong.

I'm going to compare audi's quattro AWD to subaru's standard AWD (not what comes in the VDC)

First off......the engine and transmission are mounted longitudinally in the Audi.....and I'm sure it's the same way in the volkswagon.......there's no other way to do it.....logically.

Ok.....let's start with the basics & history of subaru AWD.

Manual transmission: It uses a center viscious differential that normally has 50/50 power split. It can shift power front to rear, but can not do any side-to-side transfer. I believe max power split can be anywhere close to 100/0 or 0/100....in actuallity, 90/10 & 10/90 is the closest thing you'd get.

With the addition of limited slip differentials in the front or rear, you can obtain that side to side power transfer.

This is a pretty basic system, and is pretty much still the same today as when it was introduced in the first legacies.

Automatic transmission: It uses an extension housing on the end of the normal FWD auto transmission. The rear housing has a separate clutch pack, and a line that feeds pressurized tranny fluid to the clutch packs. There is a solenoid there to control how much pressure is applied to the clutch packs, essentially controlling the torque split fore & aft.

On the older transmissions the torque split is 90% front, 10% rear. The most it can transfer in one direction or another is 50/50.

The newer autos have VTD (variable torque distribution) and act more like a true AWD setup. They normally have 45% front, 55% rear. Again, I believe max torque split f/r is 50/50.

Both of these setups again only allow power transfer front to rear......they provide no side to side transfer, and again a LSD can be used to help with side to side power transfer.

This is subaru's current setup for AWD.....there is one setup I have left out, which is the VDC.....I'll touch base on that in the end.

Audi.

Their quattro system is pretty freakin nice. I'm not as familar with their system as I am with subaru's. So if there is stuff I have messed up on, or left out, please provide the info.

Manual transmission. I am pretty sure their manual trannys use a system that is very similar to subaru's manual tranny. Honestly.....I really don't know of any other way to do it for a manual transmission equipped car.

The difference though is that audi has gone one step further and added a traction control system that can brake the wheels that are spinning.....this will essentially send power to the other wheel.

Automatic transmission. Again I believe their tranny setup is similar to subaru's in that it has clutch packs for the rear driveline, and manipulates line pressure to control power split. Their normal power split is something similar to subaru's VTD, like 45/55 or 40/60.

The autos also incorporate the same traction control system, which allows them to transfer power side to side.


Now I purposely left out subaru's VDC (vehicle dynamic control) wagon because this is sort of in a class all by itself. It has pretty much the same or very similar traction control setup to what audi has, and can transfer power side to side.


So if you want to compare apples to apples, you have to compare audi's quattro system to subaru's VDC system....and if you were.....I'd say they were pretty equal.

In conclusion......

Take home message:

Older Subaru AWD system:
-No side-to-side power transfer
-Manual trans. 50/50 split normally
-Older Auto trans. 90/10 split normally
-Newer (VTD) Auto trans. 45/55 split normally

Brand new VDC AWD system:
-Newer (VTD) Auto trans. 45/55 split normally
-ability to transfer power side-to-side
-As of now....only available in automatic transmission

Audi quattro AWD system:
-Similar torque split to subaru's VTD 45/55
-Added traction control to provide side-to-side power transfer.

#6 Guest_unobtainium_*

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Posted 04 November 2002 - 11:02 AM

The best place to look for a comparison is here.

#7 Guest_SSJCody_*

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Posted 05 November 2002 - 12:30 AM

Nice post, Josh. Which, if any Subarus come stock with LSD?

#8 Guest_Legacy777_*

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Posted 05 November 2002 - 08:43 AM

unobtainium,

Nice link man! Lots of more in-depth info.

Cody, you mean for the rear diff?

I believe some of the early gen turbo legacies had them, and I think the new model GT's and possibly outbacks had them as well.

They're out there. Just gotta try and match the diff gearing and such with what you have in your car.

#9 Guest_Machine Age Victim_*

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Posted 05 November 2002 - 12:39 PM

Does any of the '96-01 Impreza 2.5RS' or '03 WRX's have a LSD?
I haven't had the oportunity to field test that yet.

#10 Guest_Legacy777_*

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Posted 05 November 2002 - 07:06 PM

the WRX has one.......not sure about the other imprezas though

#11 Guest_rallysquirrel_*

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Posted 06 November 2002 - 12:34 AM

Starting with MY 2002 Legacy Outback and WRX, those cars have a rear LSD. You can buy front LSD for about $1k + install.

The WRS Sti is supposed to have a front LSD and a middle LSD may be optional, and very pricey

#12 Guest_Suzam_*

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Posted 06 November 2002 - 09:52 PM

Our MY01 OB Ltd came with LSD standard, I beleve the MY00 LTD also did. Not sure if the Standard OBs were offer with it or not.

#13 Guest_renobk_*

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Posted 07 November 2002 - 01:22 PM

the rear LSD was optional with the cold weather package on outbacks starting in 2000, then in became standard on ALL outbacks in 2001. The Legacy GT was/is the only other current legacy model to have the LSD. The only Impreza with a rear LSD is the WRX.

#14 Guest_HondaH8er_*

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Posted 07 November 2002 - 11:33 PM

00-01 2.5RS came standard with a rear LSD, and all WRX's come with a rear LSD. New model RS's do not come with a rear LSD, nor do the 98-99 RS's.

#15 Guest_Machine Age Victim_*

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Posted 08 November 2002 - 10:53 AM

Sweet, I got one then :)




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