Spec B vs. MS6 on Edmunds

[AWD_Rules3830]

exactly what models are you talking about?? Subaru has about 5 different AWD systems

DCCD in the STI, which allows the driveing to manual control how power is distributed with a variable transfer clutch.

VDC which i believe is in high end subaru wagons, this system uses the brakes to control the direction of the car in emergencies,

VTD which sends 55% of the engines power to the rear wheels in normal conditionsand and useing a hydraulic transfer clutch with a center diff. this is used in the Legacy GT,

Active which uses clutchs to send power to the front or rear wheels depending on accleration, and

Continuous which is a 50 50 split until slippage occurs and useing fluid to lock up differentials and send power where it is most needed.

 

none of these systems are haldex All Wheel Drives ...

[mbacis]

exactly what models are you talking about?? Subaru has about 5 different AWD systems

DCCD in the STI, which allows the driveing to manual control how power is distributed with a variable transfer clutch.

VDC which i believe is in high end subaru wagons, this system uses the brakes to control the direction of the car in emergencies,

VTD which sends 55% of the engines power to the rear wheels in normal conditionsand and useing a hydraulic transfer clutch with a center diff. this is used in the Legacy GT auto,

Active which uses clutchs to send power to the front or rear wheels depending on accleration, and

Continuous which is a 50 50 split until slippage occurs and useing fluid to lock up differentials and send power where it is most needed. Used in the LGT manual.

 

none of these systems are haldex All Wheel Drives ...

 

^^^Fixored^^^

[1quick1]

Well sadly they do have a point.

 

While the LGT is a great value the fact is the Spec B is overpriced, if Subbie would've split the difference between the LGT and the STI and made the Spec B 275 HP it *might* make a bit more sense.

 

You're also stuck with only 1 color, & a garrish red interior.

[direavenger]

Pretty much every automaker out there uses a haldex system for their AWD. (even subaru in the lower models)

 

rallispec, I'm really curious as to which models use this system. I'm not trying to pick a fight; I was just looking for some more subie info

[Architeuthis]

MS6 is a good package, I almost held off on the Subie, but in the end, Mazda = Ford. No thanks.

[Reagan]

The reduced noise levels and the upscale interior really make the case for the Subaru. The LGT acts like it is based on a more expensive platform than the MS6. A pebble hit the underside of the car we test drove and it sounded like it was going to come through the floor boards. Also, they are trying to do some type of fake graphite look with plastic and it comes across that way - fake.

 

On the other hand, that motor is a hoot! I think it is due to the fact that the gears are closer and it is always in the midrange. Add in the overall handling advantage, and it is really a pretty good car - until you get to the price. Compare it to the LGT (not the Spec B) and there is really no way you could justify the price difference. Actually, by saving the $2K on the GPS and putting it into the suspension, you could probably do better upgrading the Subie than even they did on the Spec B for the same price.

[rjoeser]

first mod on my spec B was a fat rear sway bar. It was a different car!! $250, 1 hour's time. If performance is the issue, the legacy has tremendous bolt on potential the mazda will never have.

[1quick1]

Who knows what kind of reliability the Mazda will have either, it's not like they are turbo/AWD experts at this point.

[victorx]

Who knows what kind of reliability the Mazda will have either, it's not like they are turbo/AWD experts at this point.

 

That's the point. You don't want jump into a car with brand new powertrain which is not tested enough yet.

[gt_ltd]

^ try posting that to any MS6 forum

[doteleven]

I have driven the MS6 and thought it was a nice car. I liked the highway ride a bit better than the Outback, but I found the steering to be a bit too heavy for cornering.

 

I see on Mazda's site that the center diff thingie they use is water cooled... I guess it heats up a lot as the car struggles to decide if it is a FWD or AWD car... lol

 

Subaru does not use a Haldex system, and I think that Audi is 100% Torsen on their AWD models. I would much rather have a rally-bred system (even tho it is slightly dumbed down from the true rally cars) than someone's first attempt at AWD that cycles on and off...

 

Having OWNED a car with Haldex (VW R32), I should clear up a few misconceptions here:

 

1) Haldex is utilized by a large variety of FoMoCo and VAG group products, including the Ford Freestyle/500 and Mercury variants of the same, and all Volvo products, including the S60R and S70R. Note that the S60R and S70R have a version of Haldex called "HPP", or Haldex Performance Part. This is a special Haldex controller that allows torque to proactively be distributed to the rear wheels before there is slippage. This is a new controller, not new clutch packs. See: http://forums.vwvortex.com/zerothread?id=1726315

 

2) Haldex doesn't "overheat" nor require any coolers for the differential. At least, they don't exist on an R32. Also, Haldex in stock formis plenty capable of handling very large amounts of torque, as in the EIP, HPA, and Streetwerk turbo applications as well as VF Engineering supercharged applications (~400ft-lbs+ depending upon mod).

 

3) Haldex is imperceptible in day to day usage. I've had two Audi Quattro torsen vehicles, a Haldex vehicle, and the Subaru. While there is a different feel to them, you absolutely cannot tell when Haldex is being engaged except at a full throttle clutch drop from a standstill. What you may notice with VAG cars (have not driven the MS6) is that ESP may begin to reign in shennanigans, and I agree that feels artificial (at least with earlier generation ESP systems such as that on the R32). But it is not Haldex you are feeling. Because when you disable ESP, Haldex is still on, and except for the aforementioned drop clutch standing start, you don't notice Haldex

 

4) Not all Audi vehicles (nor VAG products for that matter) are Torsen. Quattro is a marketing term only. Only products that have longitudinally mounted engines, such as the A4, A6, A8, and previous B5 and B5.5 variant Passats. Tranversely mounted applications, including the VR6 4motion Golf, R32, and Audi TT, also utilize Haldex. I don't know the type of system utilized in the Touareg and upcoming Audi Q7.

 

5) Haldex is indeed part time. Not only is it FWD most of the time, but it is also FWD when decellerating. Of course, some folks have figured out how to circumvent this, such as HPA, for track use only.

 

I'm not saying I'd rather have Haldex or that is a better system than full time AWD. For inclement and performance driving, Haldex is a pretty good system, and does have a few advantages (minor) over full time systems:

1) better fuel efficiency (since it runs in FWD most of the time)

2) allows slightly different circumference wheels (by 4%) to be utilized, allowing the use of staggered wheel setups. This is purely cosmetic of course, as a staggered wheel setup would only increase the understeer on a naturally understeering package such as the 63F/37R weight split R32...

 

Albert

[ilh]

Why is running in FWD mode better efficiency? The rear wheels still have to turn the rear differential and center driveshaft. Just as much metal is spinning whether or not the center "differential" is engaged.

[AWD_Rules3830]

well we are restarting this debate i guess ... i think it just depends on personal perference ... motortrend found the Spec B to bte the fastest and rated it 4 places higher in a comparision test ... soo

[praedet]

MS6 does not have a Haldex system. If you look at the documentation on it, it is quite dif. from the R32/S60Rs Haldex based system...

[Jedi Pimp]

Why is running in FWD mode better efficiency? The rear wheels still have to turn the rear differential and center driveshaft. Just as much metal is spinning whether or not the center "differential" is engaged.

 

There are two losses to take into consideration with an AWD vehicle which are the drivetrain losses you refer to above, but also the pumping losses which affect the engine having to turn those differentials, driveshafts, and rear wheels as well. In a Haldex or other FWD based AWD system, when the rear wheels are not being driven, the engine pumping losses are freed up considerably by just having to power the two front wheels. The freely spinning rear wheel driveshafts, rear differential, and main driveshaft do not make up significant losses.

[The B4]

MS6 does not have a Haldex system. If you look at the documentation on it, it is quite dif. from the R32/S60Rs Haldex based system...

 

 

someone should check... i was pretty sure it was.

[krzyss]

Subaru Haldex look alike system is present in all 4EAT vehicles.

 

Krzys

 

PS I should have added "that are not VTD". So all base Impreza, Legacy, Outback and Outback Sport that have 90/10 distribution.

[IwannaSportSedan]

Subaru and haldex shouldn't be in the same sentence, aside from a negative association.

 

4EATs do have a 90% Front bias, but that is still 10 percent actively going to the rear most of the time. Even some drive torque is different than none, in terms of reaction time, and the rear wheels going from reactive rolling, to actively driven. (like going from being pulled to being pushed. characteristics are different, and that changeover would do strange things, if the rear wheels were on a slick surface.

 

Besides that, it sounds like haldex's new performance controller that a previous poster mentioned, and the mazdaspeed 6's system is trying to further emulate Subaru and others with full time all-wheel drive to some extent, even with a minority fraction of the torque directed rearward "pre-emptively."

 

Give me a full time AWD with three good diffs (limited slip, active, DCCD, whatever, for the center and rear, even if the front diff is open), and an even or slightly rearward torque bias, and I think that is just great.

 

Heck, the STI 6MT rumored for the 07 Spec B is the only really big draw I have toward the 07 Spec B (suspension and interior can be retrofitted easier to an LGT than the trans and electronics...) with VTD, and hopefully the 06 STI's 65% rear torque bias, and maybe even a front LSD. I would love to see the S204's driveline in a Legacy. that would be hot. and with commensurate STI horsepower, it would DECIMATE MS6, and probably most other AWD performance cars short of a Porsche turbo or RS4 Audi. But Perrin has a Turbo H6...

[The B4]

Subaru Haldex look alike system is present in all 4EAT vehicles.

 

Krzys

 

PS I should have added "that are not VTD". So all base Impreza, Legacy, Outback and Outback Sport that have 90/10 distribution.

 

um no... The Subaru system is Never FWD only. That split second of traction or no traction makes the world of difference. And Active AWD constantly changes through throttle and braking... not slippage. BIG Difference. You would basically have to be on cruise control on the highway to see a static 90/10.

[Max Rebo]

Subaru does not use a Haldex system, and I think that Audi is 100% Torsen on their AWD models. I would much rather have a rally-bred system (even tho it is slightly dumbed down from the true rally cars) than someone's first attempt at AWD that cycles on and off...

Audi and VW share Torsen and Haldex systems. It goes something like this:

 

Haldex: Audi TT, A3 3.2; Current gen. VW Passat, Mk4/Mk5 R32

Torsen: Audi A4, A6, A8; Previous gen. Passat

 

Haldex actually works very well, at least in my R32, which I just traded in for a spec.B (baby on the way, and I wanted 4 doors). I'll have to dig up a video from VWvortex... one previous owner was drifting his R32 in an empty parking lot for about 5 minutes straight... The STIs had a bit more trouble holding the drift. That's not to say it isn't just as easy with the STI, but it's very easy in the right conditions with a good Haldex setup.

 

Also, VW is using an updated Haldex version in the current Mk5 Euro R32. It's basically a more aggressive system that sends more of the available torque to the rear much quicker. People have been installing upgraded Haldex performance controllers on their US-Spec R32s to achieve much of the same thing.

 

I wouldn't call Haldex AWD a "first attempt," either. It was quite deliberate. Haldex is used with transverse engine layouts because there isn't enough room for a Torsen system. OTOH, Torsen is generally used with longitudinal engine layouts. It has somewhat more to do with packaging.

 

Torsen isn't optimal for everyone, either -- it's only a center diff, while the front and rear are open. Left/right power distribution is handled electronically via EDL, ESP, etc. However, you can buy Quaife or Peloquin diffs for the front, which does wonders for track use. Heck... even for everyday it would be useful.