What AWD will and will not do.

[Paul G.]

Kinda tired of reading silly threads complaining about getting stuck, and comparing different cars, when it is obvious there are plenty of posters who don't understand AWD at all.

 

The most important thing is to keep traction to as many wheels as possible. Clumsy driving will overcome technology anytime. Need proof?? Well expensive "traction control" systems are just regulators to keep you from screwing up.

 

Traditional 4WD trucks and Jeeps drive all 4 wheels with a transfer case--which is just a gearbox that allows the front and rear axle to be locked together mechanically. This allows them to pretty much go anywhere. The problem is, on hard dry pavement the front and rear diffs undergo a lot of stress, and steering becomes very difficult. That's why these vehicles allow you to disconnect the front axle at the case. It is not "full-time". These vehicles also have very heavy axle and differential assemblies to take a lot of stress.

 

AWD cars all have a way to allow the front and rear driveshafts to turn at slightly different speeds for pavement travel. This allows reasonable size and weight for the driveshafts and diffs. There are many different schemes. All of them work, but there are limitations.

 

Most "crossover" SUVs are essentially FWD. They usually have clutch packs which can send power to the rear wheels if the front wheels are spinning. They take a few seconds to kick in, after quite a bit of wheelspin. The problem is that spinning wheels are the opposite of what you need to keep from getting stuck. They work after a fashion, and are better than nothing. You can dig a nice rut, which will have a slick polished surface. Now your rears have more work to do to get you out.

 

A few years back I was in a bad storm. It had rained, the rain froze, then snow covered that. There was a horrible traffic jam. After 20 minutes I worked my way to the front. There was an intersection with a slight incline. At the front of the line of cars was a Jeep Grand Cherokee. Every time the light changed, the Jeep's driver hit the gas, hard. The rear tires started to spin, and the back of his car started to slide to the left. After about 3 seconds of this, the fronts started to work and the car lurched into the curb. The right front wheel hit the curb and twisted the car even further. It stopped perpendicular to traffic, blocking one side of the road completely.

 

Other cars backed away, or managed to get by, then (s)he backed away from the curb somehow and straightened out. Then the light changed and (s)he'd do the exact same thing again. There is nothing short of a tracked vehicle that could help this idiot.

 

Subaru's 3 basic AWD systems (as found on the 5MT, 4EAT and 5Eat) tend to act more quickly, in most cases preventing wheelspin. They cannot however overcome bad driving technique. Smooth careful power delivery is the key to moving through some pretty extreme conditions. You want 4 tires sharing the torque as much as possible.

 

As far as control, AWD will help somewhat in bad conditions, but no matter what, Newton's 3rd law still applies. The outside force to speed up, slow down or steer your car is the friction between your tires and the road, nothing else. If you overwhelm that force, bad things will happen. 2 tons of plastic, metal, glass and flesh is a lot of inertia.

 

Before I get off the soapbox, just one more thing--this thread, like almost all others will turn into an "RE92s suck" festival. I will state as an absolute fact that a good, thoughtful driver who pays attention to what the car, road and tires are telling him can literally drive RE92s around an irritable, hamfooted driver on any tire you want to name. Anywhere. Anytime.

 

You can buy a Stradivarius, but that won't make you Jascha Heifitz.

 

That is all.

 

P.

[lucas569]

good read

[zmarko]

good read

:iagree:

[Deer Killer]

AWD makes me invincible in the snow. If I crash or get stuck, it's because Subaru's AWD sucks.

 

Don't deny the truth.

[PhilT]

AWD makes me invincible in the snow. If I crash or get stuck, it's because Subaru's AWD sucks.

 

Don't deny the truth.

 

If you crash it's only because you had the RE 92's on

[forestir]

+1. A bit of finesse and Subaru's AWD-all-the-time FTW!

 

...

The most important thing is to keep traction to as many wheels as possible. Clumsy driving will overcome technology anytime. Need proof?? Well expensive "traction control" systems are just regulators to keep you from screwing up.

 

...

Subaru's 3 basic AWD systems (as found on the 5MT, 4EAT and 5Eat) tend to act more quickly, in most cases preventing wheelspin. They cannot however overcome bad driving technique. Smooth careful power delivery is the key to moving through some pretty extreme conditions. You want 4 tires sharing the torque as much as possible.

...

[f1anatic]

I am one of those who complained that he got stuck in the snow. I got stuck cause I had no tracktion and the snow was deeper than the ground clearance. I didn't blame the tires, I didn't blame the awd system. I blamed the car for being too light, too powerful and too low to the ground and I had no locking diff. on the front.

 

And Subaru's AWD, as found on the 5MT GTs and WRXs is antiquated.

[IwannaSportSedan]

Drive a 4WD truck. Then tell me my 5MT/Symmetrical AWD is antiquated.

 

It may be somewhat simpler than VTD/VDC/TRQ/PDQ/TNA....

 

But it works just fine. I have a lowered legacy, in IOWA. We get some snow, just as much as Chicago. I haven't been stuck once, and I have been through plowed drifts, and all sorts of things. My 4x4 truck will do it, too, but it complains every time it steers, and 4-hi doesn't suit dry or damp pavement. it has no front OR rear limited slip or locking differentials. I drive to work on rural roads and side streets every day. usually they are not the first to be plowed.

 

Don't confuse concise and effective with antiquated or inadequate.

 

VTD and DCCD, and what not, might be better. but symmetrical AWD is far from antiquated or inadequate.

 

I would take it over haldex-style rear-wheel assist, or 4x4 transfer-case drive any day of the week, and over 2-wheel drive even faster. My car is much more controllable than my truck, and the car has at least 50% more power, narrower tires, and MUCH less weight.

 

If you need more ground clearance than you have, I humbly suggest either swap your springs back, trade in for an outback with VDC 5EAT, or use a snow shovel.

 

So far I have had no trouble with the car on snow tires. and I have whiteline springs installed. MUCH lower than stock. And I have plowed some snow, forward and reverse. Not stuck once. I did rip the oil filter cover panel off the undertray, though... unfortunately found it in the plowed drift at the end of the driveway as I was clearing the driveway with a shovel.... oh... what's this... broken plastic rectangle from the bottom of my car...

[rao]

Antiquated? It is cheap, simple, requires no maintenance and it works.

 

No traction is no traction no mater how many wheels are spinning.

 

I think it is very funny that people want to lower these cars and are then surprised to find that they have less ground clearance - funny how that works

[SiMaster2003]

I'm not quite sure what is the difficulty in driving these cars in the snow. Right off the bat you have at least two wheels (almost always three with the LSD's) going for traction instead of the one that most FWD and RWD cars have. Add the fact that the motor makes a little torque down low to get you started without revving and you've got a pretty good setup for snow driving.

 

I've had no problem getting around on the sheets of ice we call roads here in KC in my Spec B even though I'm on RE50's. No problems getting up the nearly 30 degree grade of my dads driveway when I visited, which is completely iced over to the point that if you lose momentum on the sloped part you immediatly slide back down! It's all a matter of vehicle control and momentum. Now granted, when the conditions are exceptionally crappy, I will use my Titan until I get some snow tires, but it would have to be wrath of god type weather in my opinion as the Titan doesn't have the heated seats, windshield, mirrors that the Suby does.

[hogmeat]

hey I wanna...wanna sell me your Miata?

[Deer Killer]

And Subaru's AWD, as found on the 5MT GTs and WRXs is antiquated.

Yes I'd rather have ineffectual electronics made as a cost-saving measure and sold to me as an improvement.

[ebpda9]

if the front to rear diff will react a bit quicker it would be perfect. i do remember when i got stuck it was either the rear or the front spinning, then after 5-10 seconds they would switch.

[Fat Charlie]

As far as control, AWD will help somewhat in bad conditions, but no matter what, Newton's 3rd law still applies. The outside force to speed up, slow down or steer your car is the friction between your tires and the road, nothing else. If you overwhelm that force, bad things will happen. 2 tons of plastic, metal, glass and flesh is a lot of inertia.

 

...

 

You can buy a Stradivarius, but that won't make you Jascha Heifitz.

 

Can I get an amen?

[Aczwild]

Can I get an amen?

Can I getta sticky?

[amason]

Can I getta sticky?

 

Maybe if there was some revolutionary new info. Good read I suppose for those who need constant reminders, but I have 2 thoughts:

 

I do think that AWD helps, if only very slightly, in cornering and braking, due to that same distribution of force. My intuition is that you're less likely to lose traction on any given wheel if it's got at least a little bit of driving force. And you have the benefit that if you do happen to blow it, you can always try hammering on it and see what happens.

 

I also think the Stradivarius comment is off-base. A slightly more appropriate analogy (although still very flawed) would be that if you have the referenced violin guy a crappy instrument, he probably wouldn't sound so good. So I'm not saying that we're all virtuosos, but I still think that every single Legacy driver would benefit from better tires. Having said all that, I'm still on the stockers b/c I'm cheap (looking forward to the replacements though) and have done some laps, and they were handy for finding the most efficient line, in that they gave lots of audible feedback...

 

Andy

[Adamaxus]

I do think that AWD helps, if only very slightly, in cornering and braking,

 

lets be VERY VERY clear on this one point as everyone needs to know it. AWD does ZERO for your breaking ability. A Subaru takes just as long to slow down and stop as any other car on the road. It helps you get going once you have stopped but AWD WILL NOT help you stop - ever.

[Prod]

1.) AWD helps with acceleration.

2.) AWD helps with cornering, in that you can get better acceleration on the exit.

3.) AWD helps with cornering, in that if you get in trouble, gentle throttle application plus the correct steering inputs will get you out of trouble. There is a limit to which this works.

4.) AWD is completely unrelated to braking, except it makes the car heavier so an AWD car will likely take longer to stop than a 2WD version of the same car with the same tires and brakes.

[AWDpower]

lets be VERY VERY clear on this one point as everyone needs to know it. AWD does ZERO for your breaking ability. A Subaru takes just as long to slow down and stop as any other car on the road. It helps you get going once you have stopped but AWD WILL NOT help you stop - ever.

 

That's not entirely true. AWD does have an affect on braking. The front and rear wheels are tied together under decelleration just as much as acceleration, at least with the 5spd. system. That makes it a lot harder to get the front tires to the point of lock up. Cars have heavily front biased brake systems, which are safer but not optimal for shortest stopping distances. Now, the ABS system pretty much negates this, but I suppose that the effect will still lead to less ABS intervention, as the front wheels are less likely to lock. My DSMs didn't have ABS, but it took a lot to lock the wheels. One front would lock due to the open front diff, but to lock both fronts, you pretty much had to lock all four wheels. FWD DSM's without ABS were much easier to lock the fronts on. A Formula One race team tried to use a similar concept years ago. ABS was outlawed. So the team wanted to put front axles and a limited slip front diff in their car. They were not connected to the engine or tranny, but the idea was that the force on one wheel would be transfered through the diff to the other, keeping one wheel from locking prematurely. I don't know how far the idea made it, but it's the same concept on an AWD, front to rear. Side to side on an axle with a limited slip, too. So it does affect the braking ability of the car. But it won't save you if you exceed that ability, just like every other car.

[AWDpower]

if the front to rear diff will react a bit quicker it would be perfect. i do remember when i got stuck it was either the rear or the front spinning, then after 5-10 seconds they would switch.

 

If that was the case, then something is really wrong with your center diff. You shouldn't get more then about a half to one rotation before the power is sent the other way. Are you sure you were not just spinning one front tire due to the open front diff? Even then, the power should have been sent quickley to the rear, and you would have been spinning three. 5 seconds is an eternity, your viscous coupling would be toast. One way to help get un stuck is to lightly press the brake while giving it gas. This will keep the wheels from spinning, and send the power to the wheels with traction. This works on 2wd cars with open diffs too.

 

Opps, I just saw you has a AT, completely different drivetrain then I described. The brake trick should still help though.

[AlpineRaven]

AWD is worth having, I've driven so many cars (RWD/FWD/FWD with traction control & RWD with traction control) and tell you the truth, I've pushed all the cars above specially in wet or gravel roads and it can be tricky, with traction control can be annoying. I find AWD way better for handling, windy roads, wet surface etc. Subaru AWD is the best thing I've ever driven in and I will stick to it.

Cheers

AP

[Paul G.]

1. I'm not knocking AWD, I wouldn't give it up for anything. I'm trying to help people understand how it works, what it does and how their personal actions affect it.

 

2. Of course AWD helps in cornering, control and acceleration. I feel it and enjoy it. It is especially noticable on wet and/or rough pavement. It's just not the invincibility factor that some think it is.

 

I was going to go into a semi-technical explanation of why Subie's AWD schemes work so well, but that information is available all over the place for those who want to look for it.

 

P.

[Adamaxus]

Words

 

i totally understand what your saying, but we can't play this game as it can lead to horrible things by stupid people. I still believe that one should forget such a 'advantage' exists and act like it's any other car, because really it is and thinking otherwise may lead to trouble.

 

as an aside, common we've all seen the legacy's 60-0 numbers compared to everything, it's a little bit of a slouch, LOLZ.

[Prod]

i totally understand what your saying, but we can't play this game as it can lead to horrible things by stupid people. I still believe that one should forget such a 'advantage' exists and act like it's any other car, because really it is and thinking otherwise may lead to trouble.

 

as an aside, common we've all seen the legacy's 60-0 numbers compared to everything, it's a little bit of a slouch, LOLZ.

 

The LGT brakes are VERY good. The stock tires are not. This is what makes the braking numbers not so hot. When I'm on my Kuhmo MXs, my LGT will stop very quickly. Good rubber is everything.

[Metal2You]

Yes. Driving it home without good rubbers is very risky.