LETS clear something up

[tjpete04]

I have always thought subaru's had part-time AWD, but some subaru mechanic told me the other day that they are full-time AWD, i'm assuming he's wrong, right?

[gil_ong81]

he's right.

[shazapple]

Continuous AWD: Subaru manual transmissions use Continuous AWD, normally 50/50 front-to-back power split and use a mechanical viscous center differential to to vary the power split when there is a loss of traction.

Active AWD: Subaru's automatic transmission use Active AWD, mostly front wheel drive (90/10 front/back) and uses traction sensing computer input to electronically vary the front to rear power split via a hydraulic multi-plate transfer clutch.

[Huffer]

He's right SOME of the time.

shazapple listed two versions of Subaru drivetrain - the DCCD version found on the STi's is a variation of the continuous AWD.

Point to note, none of the UK-built STi's received the DCCD unit until the blob-eye arrived (STi 8/9).

[scottzg]

:?:

They're both full time awd... you can't disengage it. Even the autos are full time awd, they just have a fwd biased torque split when nothing is slipping.

Unless at some point the car has 100:0 or 0:100 torque split, it's full time awd.

[badbasser98]

Unless at some point the car has 100:0 or 0:100 torque split, it's full time awd.

100:0, or vise-versa is impossible on a stock tranny, wether it be MT or AT. The MT can go 90:10 either way, and the AT can go from 90:10, front:rear, to 50:50. The auto is also 50:50 in first and second gear. According to local techs.

-BB98

[shazapple]

50/50 in 1st 2nd and R

[tjpete04]

i don't want to sound like a dumbass, but i remember watching subaru comercials and they seemed to indicate all the power went to the wheels that had tractions but when there is no slipage all the power goes to the front wheels. Thats what i thought part-time AWD was, when the front wheels slip the power goes to the rear automatically. I prolly sound like a dumbass because i am not very mechanically knowledgable when it comes to drivetrain.

[scottzg]

Here, imagine this:

In the auto car, the front wheels are directly hooked up to the transmission, but between the rear wheels and the trans the engine is controlling a clutch. This clutch is barely engaged all the time (like when you first start rolling and have to bring the revs up), except for when slip is detected, when the ecu drops the clutch more, so more power can be transferred to the back.

In the manual, instead of a clutch, it has some goop that thickens when it heats up. When all the wheels go the same speed, the goop spins along, but when there is a speed difference, the wheels have to shear the goop, and the resistance the goop provides transfers the power to the back. If the front wheels were off the ground, the goop, if its in good shape, can transfer all the power backward.


This is a very ugly description, but hopefully its good for giving an idea whats going on.

[Wiscon_Mark]

i don't want to sound like a dumbass, but i remember watching subaru comercials and they seemed to indicate all the power went to the wheels that had tractions but when there is no slipage all the power goes to the front wheels. Thats what i thought part-time AWD was, when the front wheels slip the power goes to the rear automatically. I prolly sound like a dumbass because i am not very mechanically knowledgable when it comes to drivetrain.

part time AWD/4WD would indicate that the default setting on the drivetrain would be FWD/RWD.

and yes, power can be transfered to the different wheels, however, the power doesn't go all to the front wheels, or all to the rear wheels, just more of it does.

[GT Wagon]

100:0, or vise-versa is impossible on a stock tranny, wether it be MT or AT.

Correct me if I am wrong but I believe the auto tranmission can be put into 100% FWD by invoking LIMP MODE. You pull the fuse and it disengages the rear wheels. I recall reading it in my 91's manual somewhere.

[Legacy4Life]

This is all very interesting! What about side to side? How does it accomplish that?

[shazapple]

limited slip differentials

[Huffer]

100:0, or vise-versa is impossible on a stock tranny, wether it be MT or AT.

Correct me if I am wrong but I believe the auto tranmission can be put into 100% FWD by invoking LIMP MODE. You pull the fuse and it disengages the rear wheels. I recall reading it in my 91's manual somewhere.

That's correct, but that isn't what I would consider a natural function of the transmission. You can run the car like that - it disengages the transfer clutch packs - but I wouldn't expect stuff to last too long that way.

[Wiscon_Mark]

limited slip differentials

I want one of those too :P

do we have a front LSD on our cars?

[badbasser98]

That's correct, but that isn't what I would consider a natural function of the transmission. You can run the car like that - it disengages the transfer clutch packs - but I wouldn't expect stuff to last too long that way.

Exactly, And I would have to say DO NOT DRIVE YOUR 4EAT IN FWD MODE! Not good for the tranny at all. Its only ment for if you have to tow the car with a set of wheels on the ground rather then flat bedding it. You cannot tow the car with all four wheels on the ground without some damage to the tranny.

[Wiscon_Mark]

would you just put it in neutral in a 5MT then?

doesn't that disengage everything? (front from rear?)

[GT Wagon]

You cannot tow the car with all four wheels on the ground without some damage to the tranny.

I thought it was "you cannot two the car with two wheels suspended" since they all need to turn at once ?

[badbasser98]

You cannot tow the car with all four wheels on the ground without some damage to the tranny.

I thought it was "you cannot two the car with two wheels suspended" since they all need to turn at once ?

That's why there is that fancy little fuse you put in to make the auto's FWD... Because you can't tow with all four tires on the road (atleast on the AT's, not sure 'bout the MT's) It binds the transmission and strips the gears when you go round corners towing it with all four tires on the road. My friend learned from experience.

PS - When all else fails, read the manual.. What I stated above is what my manual says :wink:

[GT Wagon]

PS - When all else fails, read the manual.. What I stated above is what my manual says :wink:

The manual is in the car, which is in the garage, which is cold :D

[Perdue]

Just to clarify, you have to use a flatbed if you need your subaru towed. The only acception is if you have an auto and you've placed a 15 amp fuse in the fuse holder, normally located between the firewall and passenger (USDM) side strut tower, which disengages the rear wheels. Towing a subaru with the front or rear wheels on the ground will JUNK the center differential, leaving you with a hefty repair bill. The best rule of thumb: use a flatbed.

[scottzg]

limp mode gives full power to duty solenoid C, iirc, that can burn out; so its unwise to do it anyway.

A 5sp can't be disengaged, tow it with rear wheel dollies.

We don't have a front LSD, and personally, i wouldn't want one.

[Sarra]

100:0, or vise-versa is impossible on a stock tranny, wether it be MT or AT.

Correct me if I am wrong but I believe the auto tranmission can be put into 100% FWD by invoking LIMP MODE. You pull the fuse and it disengages the rear wheels. I recall reading it in my 91's manual somewhere.

Correct, partly. The 4EAT (not sure about the 5EAT) has a TOW mode, not limp mode, and you insert a fuse into a fuse slot. On the dash, "FWD" lights up, indicating you're in Tow mode. :) It's used if you need to tow the Subaru, or if you like doing FWD burnouts.

Tow mode disables one of the clutch cylinders, which in turn, disengages the clutch in the center diff, meaning the rear wheels are no longer connected via differential to the front wheels. So, technically speaking, the 4EAT is a part time AWD system. :)

[Sarra]

Just to clarify, you have to use a flatbed if you need your subaru towed. The only acception is if you have an auto and you've placed a 15 amp fuse in the fuse holder, normally located between the firewall and passenger (USDM) side strut tower, which disengages the rear wheels. Towing a subaru with the front or rear wheels on the ground will JUNK the center differential, leaving you with a hefty repair bill. The best rule of thumb: use a flatbed.

Incorrect; When my 1995 Subaru was towed, it was towed on a 'front lift' style tow vehicle. However, the parking brake was locked, and it was left in gear. The tow tech used a pair of tow wheels under the rear wheels of the car, so the rear wheels on the car woudln't spin.

Where the fuse needs to be inserted varies by year, but in my mom's Outback, you have to put a 15 amp fuse into a (normally) empty fuse slot on the very back end of the fuse box.

[Wiscon_Mark]

Just to clarify, you have to use a flatbed if you need your subaru towed. The only acception is if you have an auto and you've placed a 15 amp fuse in the fuse holder, normally located between the firewall and passenger (USDM) side strut tower, which disengages the rear wheels. Towing a subaru with the front or rear wheels on the ground will JUNK the center differential, leaving you with a hefty repair bill. The best rule of thumb: use a flatbed.

Incorrect;

how is what he said incorrect?
You still have to keep the rear wheels from spinning. You just suggested another way.

[tjpete04]

WORD

[shazapple]

We don't have a front LSD, and personally, i wouldn't want one.

Why not? My friends Sentra has a front LSD, and it seems to do just as good if not better than my car in the snow

[Perdue]

I would prefer to have both front and rear LSDs if I had a 5 speed.

And, Sarra, so you don't HAVE to use a flatbed, but it's a pretty good choice. Parking brakes can slip, a strap on the wheel dollie could come loose, among other things. I'd insist that my car be towed on a flatbed, just in case.

[Tokio]

holy christ armchair mechanics!

all a front lsd will do for our cars is increase torque-steer/understeer. spend the $1k on better things... like parts to correct the problems you created by lowering your car. :)

[Wiscon_Mark]

holy christ armchair mechanics!

all a front lsd will do for our cars is increase torque-steer/understeer.

more grip to the front = more understeer, okay

what if you got a rear LSD as well?

[ivwarrior]

Eh, I'd rather have front and rear air lockers, for when you really need power to the wheels that grip. :D

[Tokio]

even if you also equipped a rear lsd, the front would still cause problems.

a rear lsd by itself, however, is LOADS of fun.

[Perdue]

more grip to the front = more understeer, okayI agree with Mark. If they created understeer, why would subaru put them into some of their transmissions (IE, a lot of the JDM WRX and STi drivetrains use front and rear LSDs)?

And an armchair mechanic I am not. I prefer to do my own work to my car, and I didn't see any performance loss from lowering my car, just as I didn't see any loss from the intake I have that you swear doesn't work.

[Wiscon_Mark]

just as I didn't see any loss from the intake I have that you swear doesn't work.

lets close that can of worms, right now.

I wasn't being sarcastic about the front LSD causing understeer, actually, I can see how that works. As for the STi, its suspension is way over engineered (gotta love it :D) and I'd imagine the dynamics are different from our Legacies, so understeer might not be as much of a problem. Also, the DCCD is there so you can create more oversteer.

[Tokio]

LMAO!!!!

a JDM WRX or STI your 4eat "L" is not...

...dont like my opinion? try talking to someone else with experience on the matter. (i.e. NA 2.2/2.5 + front LSD = retarded)

...as far as your intake...where to start...i guess i would say, first im pretty sure i stated my opinion in regards to the 2.5 motor, not the 2.2. second, if you throw 3-4 more hp at a 2.2 whats the difference/who cares? lol.

...and finally, per-douche, any monkey can hold a wrench... that doesnt make you a mechanic. what makes someone an armchair mechanic is pointless bickering like this. get outside for once and try some things out if you dont agree with me. and even if you dont agree with me, thats OK...lmao, shoot e-daggers at me all you want. i could use the laugh. :lol:

[Wiscon_Mark]

unless someone can suggest a possible helpful suggestion to the original question, I think this thread will stay locked.

If you're angry about it, PM me.