Automatic vs. Manual

Hyperbole.

VDC Outbacks may do something similar to that claim. VTC WRXs are fairly sophisticated too. The Impreza auto does use electronics to control the front/rear torque split (I've read various claims but it isn't clear to my how much control over that split it really has: can it deliver 90% of the torque to the rear? I doubt it), but it doesn't actually direct the torque to the slipping wheel. Of the 4 Subaru AWD systems I'm familiar with the basic auto trans system is the only one with no center differential. It works well (better than the similar system on a Saturn VUE for example), but it's arguably their least sophisticated AWD (of course you can argue the other way as well).

As a general comparison the manual transmission utilizes a viscous coupled center differntial giving 50/50 power to the front and back wheels (capable of 80/20 or 20/80 depending on wheel slippage). The automatic transmission uses a hyrdaulic controlled wet transfer clutch which supplies 90% power to front wheels and 10% to the back under normal conditions (this can change from 90/10 or 10/90 given certain conditions). The automatic transmission determines wheel slippage via sensors at the four tires. The viscous coupled center differential functions due to differential heating of a fluid within the differential to transfer power. While both are capable of transferring power front and back, the manual transmission should technically have a bit more lag than the auto. Further, the auto is designed to run pretty much as a front wheel drive (90% front, 10% back) until wheel slippage is detected. Frankly I prefer the initial 50/50 split on the manual which gives me the feeling that I have the power of a 4WD all the time whereas it seems as if the auto is working against me at times to keep the car in control. I am sure the newer automatics are getting better and better, but being an aggresive driver I will take the manual any day.

Well, the STi only comes in a manual but I know the AWD system works great. The DCCD stays in auto mode 99% of the time. I have switched it to 4 wheel lock when the snow gets really bad. I like having a manual transmission on really bad weather because it allows me more control. The opposite side is that with a manual transmission you have to be a little more judisious about clutch application. It doesn't take much to get into a 360. BTDT. All Subaru's are pretty good snow vehicles. Throw on a decent set of snow tires and you have a snow machine! BlueSTi "Scary-Fast"

I've had a manual Outback for 4 seasons now. It's simply phenomenal in the snow, much better than our Jeep Wrangler. You have nothing at all to worry about.

On a side not, my FIL has an automatic, and the manual version is much more fun in the rain on twisty roads, as it's AWD is truly engaged all the time.

Enjoy the car!

Barry

You made the right choice. We have several years of experience with two different manual trans Foresters in central NH. They are great in the snow and have the same 50/50 system that you have.

We have a steep 12% grade 600 feet long gravel driveway that demands good 4 wheel traction when snow covered. That is most of the winter.

Prior to buying the second Forester, we looked at all of the options out there, most of which were some form of "on demand" all wheel drive. I don't want a design that has to wait for the rear wheels to "slip" prior to transfer of power. Remember high school physics? The coefficient of static friction is higher than for sliding friction. Once a wheel slips you have lost some traction. On our steep driveway once any wheels spin, you have had it.

IMHO the manual trans is: 1. more reliable in itself; 2. gets better gas mileage; 3. has better acceleration; 4. is more fun to drive; 5. is less expensive; 6.offers better overall control and 7. is better in the snow.

Woody; 95FXDS

I agree with you on everything but the mileage.

Many automatic Subies get equal or better gas mileage than the manual version. I was very supervised when I learned this.

Barry

Purely a question - has anyone ever stood outside of the car and watched while someone drops the clutch in the snow hard enough to make the wheels spin to see if there's any lag between the front and rear?

My cars are a 1991 manual Legacy with 230K and WRX with 30K. I've hung my head out the door so I could see the rear wheel and hear the front and I can't notice that there's any lag between when the front and back begin to spin with either of the cars. I suspect what SOA means by "...3 revolutions before the viscous coupling fluid heats up enough to lock..." is that it's

3 revolutions of the driveshaft and not the wheels. Frankly, I like having something that's purely mechanical without the computer getting involved.

Mike

Damn spell check!

I was SUPRISED!

Barry

See the Aug 2004 Consumer Reports page 59 where six small cars were tested: manual vs. automatic for each of the six. For all six acceleration was better for manual. For five out of six fuel economy was better for manual. (there was no data on Subaru's)

I assume that the tests were "supervised".

Woody; 95FXDS

Might as well just quit while you're ahead :-)

I've got an Auto Subie and I've never seen or noticed any lag. I think the AWD system on the autos is also tied into the throttle somehow, in that giving 'er gas will send power to the *rear* first. This is based on frequent gravel starts, where I'll hear gravel being spit from the rear as I accelerate to match insane traffic near my home. (My fronts are generally on pavement during those starts so they don't spin as much, if at all.)

-Matt

We're talking SUBARU AWD cars, not just any cars!

What you say is true for most cars. Subarus use totally different drivetrains with an automatic than they do with a manual gearbox.

The manual tranny is ALWAYS driving all four wheels. The Automatic isn't, it's only driving the front wheels on clean, dry pavement.

Barry

Scroll down to mileage:

Barry

Ok I've been supervised. You are correct about there being a slight gas mileage advantage for the Subaru autos. First positive fact I ever heard about an auto transmission. Maybe when I get up into my mid 90's I'll consider one.

Must be the full time viscous coupling to the rear wheels that creates some drag on the open road. Not the fact that the tranny is an auto per se.

Reminds me that I miss the design on my wife's old 88 Loyale GL wagon, a real 4wd that you engage only when you need it and with low range available as well. Thankfully they still make real 4wd in full size trucks but my Dodge Ram 2500 hemi (also a manual) is another story as far as gas milage is concerned. It probably averages about 14.5 mpg overall where the auto may average about 14.4 mpg, with a tail wind in both cases.

Woody; 95FXDS

This topic gets brought up every couple of months on this newsgroup. Subaru actually has about three different AWD systems (4 if you count the one in the STi, but you could argue that it's a variation on the Outback VDC system).

Three of the four have a central differential to control front/rear torque split, and one that uses an electronic clutch instead. The one that uses an electronic clutch alone is the least sophisticated of the automatics. The least sophisticated of the manuals uses a central diff, with a hydromechanical slip control, otherwise known as a viscous coupler. The most sophisticated of the automatics and manuals all have central diffs, with computer-activated slip control, otherwise known as an electronic clutch. So in otherwords, all of the most sophisticated AWD systems make use of a central differential, their only difference is whether there is a hydromechanical or electronic slip controller. The least sophisticated system uses an electronic clutch, so that clutch basically performs double duty as the torque splitter (in lieu of a real differential) and as its own slip limiter.

So your 5-sp manual has a more sophisticated AWD system than the simplest automatic system.

Yousuf Khan

I doubt that the manual gets better gas mileage than the automatic. First of all, these days, all automatics have lock-up torque converters, which effectively eliminates inefficiency of the slippage in the torque converter. Second, I get the feeling that the manuals are setup more for performance than fuel efficiency. At 60mph, my 5 speed OBW 2.5L is rotating at around

3000rpm in 5th, when it should be doing 2500rpm or less in most other cars.

Yousuf Khan

Around town, a well driven manual Subie will kill an auto. On the highway, you are correct, and it is due to the final drive in fifth gear being too low.

Manual Subs spin their engines too fast on the highway. Shame they don't give us an overdrive. I'd like to test drive a new Turbo stick in the Outback to see if they have improved things.

nate

02 OBW MT5

I've never owned an automatic, but facts are facts. Another arena where the automatics win in Subarus are towing capacity. Many Subarus are rated for 10-20% higher towing capacity with the automatic tranny.

4wd low? They can keep it on the real trucks. I also have a '99 Wrangler Sport with solid axles and 4wd low. 4wd low is handy on beach and for pulling my enclosed trailer up a 45 degree incline out of my back yard. I bought the Outback because I wanted a _car_, for day to day driving, that would excel in all kinds of weather, seat 4 1/2 people, be easier than an SUV to get my bikes on top, get decent mileage, insure inexpensively, fit 10' lengths of valuable hardwoods INSIDE, and still have some overall fun to drive traits. I got all this for about $22,500, out the door, in December '01.

There are far better offroad vehicles than a Subaru, and making the Subaru better offroad would eliminate many of the reasons I bought it.

Barry