Subaru Forester Owners Forum banner
1 - 20 of 23 Posts

·
Registered
2001 Forester Auto
Joined
·
15 Posts
Discussion Starter · #1 ·
Other car manufacturers have a type of all wheel drive but none other have Subaru's all wheel drive. Are there patents they can't get around? :confused:
 

·
Registered
2016 Forester XT Touring
Joined
·
550 Posts
the simplistic answer is that few other manufacturers use horizontally opposed engines that enable the driveshaft to come out in the center. Most front wheel drive four cylinder cars have transversally mounted engines (the driveshaft comes out on one side or the other of the car) with the pistons firing up and down instead of left and right. I am not sure about why so few manufacturers have chosen to use horizontally opposed engines, but their attributes have worked in subaru's favor over the years. They have lower centers of gravity which helps handling and improves resistance to rollover, and as you mention enables symmetrical AWD because driveshafts are easier to make equal lengths.
 

·
Premium Member
2014 2.0 XT yes
Joined
·
2,752 Posts
H4 engines are more expensive to produce than I4. They also have packaging constraints that affect the front styling of a car. Subaru adopting opposed engines is a historical quirk, and they decided to run with it to good effect.
 

·
Premium Member
2017 VW Golf SportWagen 5MT
Joined
·
10,784 Posts
As stated above, the engine orientation makes it difficult. The H allows you to have a "short" engine, with only 2 or 3 cylinders on each side. With an inline engine, you'd have a fairly long engine sticking out too far to the front. With a V6 engine, you'd only have 3 cylinders on each side but even that gets too long -- Audis have that and are well known for being nose-heavy.

Other reason is, it's much cheaper to have a transversely-mounted engine and have the option of either having or not having AWD for the same model of the car. With a Subaru, you don't need that since there are no models offered in either AWD or 2WD version.

Wikipedia has neat pictures:





Stan
 

·
Registered
2007 none auto
Joined
·
64 Posts
I think it comes down to sales... Why copy when there's no need to? Other vehicles sell just fine, without having to re-engineer a symmetrical setup....
 

·
Registered
2007 Forester Sports XT Manual
Joined
·
219 Posts
Other reason is, it's much cheaper to have a transversely-mounted engine and have the option of either having or not having AWD for the same model of the car. With a Subaru, you don't need that since there are no models offered in either AWD or 2WD version.
+1
Not many companies are willing to commit to the same drivetrain to all of their models(Subaru-Toyota lovechild aside).
 

·
Premium Member
2017 VW Golf SportWagen 5MT
Joined
·
10,784 Posts
Well, reality is not everyone needs AWD, so why would you not buy a car without it? I know this is a bit of a strange concept on here lol.

Audi, Mercedes and BMW all have AWD setups similar to Subaru's, longitudinally-mounted. Many trucks do as well.

Stan
 

·
Premium Member
2012 GTI DSG 6-speed
Joined
·
1,463 Posts
I think you've been sucked into "symmetrical" marketing. Step away from the cool-aid...
 

·
Registered
2017 Foz 2.5i CVT
Joined
·
2,230 Posts
Well, reality is not everyone needs AWD, so why would you not buy a car without it? I know this is a bit of a strange concept on here lol.

Audi, Mercedes and BMW all have AWD setups similar to Subaru's, longitudinally-mounted. Many trucks do as well.

Stan
This is true, but I think that the "symmetrical" term used by Subaru is based on front axle shafts being the same length, etc. The little models at the Subaru dealer show the power takeoff from a truck transfer case being offset to one side, which does make things asymmetrical with an independent front suspension. (With solid axles on the front, it is not so much of an issue.)

As for performance of Subaru AWD, a lot of its superiority is based on things like power bias, electronic actuation of clutches, etc, and the symmetry of the engine and trans would not truly be required. I bought my Foz with a stick because of the utter simplicity of a viscous center differential that works just like a limited slip axle in a good old American car.

One downside of the Subaru setup is the difficulty of a spark plug change. Transverse inline engines are usually a SNAP to change plugs on.

Overall, I am really happy with my Subaru drivetrain (so long as my head gaskets don't start leaking down the road) but that is not the primary reason I bought it. Also, the flat 4 does theoretically improve crash test results, because a hard front end hit makes it easier for the engine to get rammed under the floor of the vehicle instead of being pinned between the grille and the firewall.

George
 

·
Premium Member
2017 VW Golf SportWagen 5MT
Joined
·
10,784 Posts
This is true, but I think that the "symmetrical" term used by Subaru is based on front axle shafts being the same length, etc.
Yeah, but they aren't the only ones to do that, that's why I mentioned Audi, BMW, Mercedes and others.

Subarus are awesome cars. What sets them aside IMO is that they make emphasis on AWD, you can't get a 2WD Subaru in the US at all. They are the only ones who choose to do that, marketing has a large role in that IMO. I know the debate of "who's AWD is best?" will always exist and many points are valid, but IMO with electronics getting better and Subaru getting further and further away from relying on mechanical systems and using CVT, it's becoming less and less of a difference as far as capabilities go.

Stan
 

·
Registered
2017 Foz 2.5i CVT
Joined
·
2,230 Posts
Yeah, but they aren't the only ones to do that, that's why I mentioned Audi, BMW, Mercedes and others.

Subarus are awesome cars. What sets them aside IMO is that they make emphasis on AWD, you can't get a 2WD Subaru in the US at all. They are the only ones who choose to do that, marketing has a large role in that IMO. I know the debate of "who's AWD is best?" will always exist and many points are valid, but IMO with electronics getting better and Subaru getting further and further away from relying on mechanical systems and using CVT, it's becoming less and less of a difference as far as capabilities go.

Stan
Agreed. I don't follow the drivetrain layouts of BMW, Mercedes, and Audi these days but owned an early SAAB 900 and a Sonett, which had equal length axles and north/south engine orientation. They could have easily jumped a rear driveshaft off of those and ended up pretty symmetrical. (Actually, right before my Foz, I had a '98 Acura 2.5TL which was a north/south inline 5 cylinder engine with FWD too--I think the layout had the axles coming out right under the engine.)

And yes, with more etronics and stability control, I do believe that power distribution to wheels will equalize among different brands since it will all be controlled by etronics anyway. Subaru's only advantage may end up being a slightly lower center of gravity and tougher spark plug changes. :icon_wink:

George
 

·
Registered
2017 Foz 2.5i CVT
Joined
·
2,230 Posts
nobody is biting. This is very strange. How about this...:N_poke::evilatyou:

What causes torque steer in front wheel drive cars? [hehehehe]
Torque, with unequal half shafts making the problem worse. Nothing funny or contentious here, really...

As per my post above, the majority of my FWD cars over the years have been north/south engines with equal length halfshafts (2 SAABS and an Acura 2.5TL). My current vehicles include my '09 Foz, a '91 BMW 318is, and an '02 Ford E150 van, so I ain't got torque steer. (I did own a Dodge Lancer with a turbo engine but that didn't have *that* much power and as such was not a big deal.)

Still, with improved stability programs, a lot of torque steer issues can be minimized unless you have stuff like 300 HP in a front wheel drive car.

As an old drag racer, most of the old muscle cars would lift the right rear wheel because the power would twist the axle counterclockwise so torque has always wreaked havoc on traction. My favorite solution was the old Mopars (I had 2 426 Hemi cars back in the day) where they used leaf springs with a very short front spring length and a much longer rear spring length, and an extra leaf or two in the right spring on the front end. When you gave those cars gas, the leaf springs worked just like traction bars and pushed the rear tires into the ground. Forget cornering; these were drag racing cars.

There are a lot of solutions to traction problems....

George
 

·
Smooshed FOTY 2011
2005 Lifted 2.5 XT 5-Speed MT Dual-Range
Joined
·
5,732 Posts
Subaru isn't the only one that does a symmetrical layout, but they're the ONLY ones that do it with all of their cars permanently (save for the BRZ), at the affordable prices that they come at. Not to mention, it's permanent AWD as well. Subaru doesn't make their chassis any other way than for AWD. And with the boxer engine being very short (2 or 3 cylinders) sticking out over the front axles, it keeps the front weight down as well.

The boxer engine is also unique as that it would be ridiculous to mount it transversely as the engine is VERY wide. Mounting it transversely would be very tricky IMO.

The only other way you are going to get an AWD setup like that is go spend twice as much and get a Audi or other high end car with a similar setup. But with Audi, they have large V8's sticking out over their front axles, which is why Audi's have been notoriously understeery and nose heavy. Not familiar with BMW or Mercedes setups, but I've heard they are roughly the same.

The big thing here is that Subaru calls it "Symmetrical" AWD. That's the brand name that they have it marketed as. Trying to find a symmetrical AWD system at the prices Subaru sells their cars for? Forget it.
 

·
Registered
2012 Forester 2.5x automatic
Joined
·
180 Posts
I own a couple of newer Foresters (2012Base/2013XT) and it's all about performance in snow for me. Both of them do fine in that respect but I don't think either of my vehicles could do this:

I'm not a Subaru groupie; have more important things to be obsessing over. They're just cars.
 

·
Registered
2007 none auto
Joined
·
64 Posts
nobody is biting. This is very strange. How about this...:N_poke::evilatyou:

What causes torque steer in front wheel drive cars? [hehehehe]
To be honest, I think the reason you don't get much torque steer is because it's AWD, more so then equal driveshaft lenghts. I've never felt torque steer in any vehicle, that was AWD...

Don't kid yourself thinking Subie's can't have torque steer.. You have to remember, these vehicles, even FWD, all have open front diffs.. That means power is going to one side only. Now tell me how you can't have torque steer when it's either the left or right side pulling or pushing? And like I said before, the reason you don't feel it is because there's rear tire pushing too..
 

·
Premium Member
2014 2.0 XT yes
Joined
·
2,752 Posts
BMW use longitudinally-mounted engines, but their AWD is anything but symmetrical. Check out that driveshaft appendage coming out of the left side of the transmission:



On the other hand, a lot of weight is behind the front wheels which is a good thing.
 

·
Registered
2014 Forester XT CVT
Joined
·
186 Posts
BMW use longitudinally-mounted engines, but their AWD is anything but symmetrical. Check out that driveshaft appendage coming out of the left side of the transmission:

On the other hand, a lot of weight is behind the front wheels which is a good thing.
Not only that, but that allows them to put the front wheels much further forward than in Subarus. There's pros and cons for each design choice as always.
 
1 - 20 of 23 Posts
Top