AWD questions "kinda long"

[solarsvx]

i put a post on the dsm page also , for the subaru svx, AWD systems must use ABS to control wheel spin corect , for the svx its 60/40 split right? and it can put up to 90% power to one wheel if it needs it,

for dsm the AWD is 50/50 i think all the dsm AWD i seen has ABS with the AWD but i think u can get them without ABS. can u buy a subaru svx without ABS,

well in the rain the other day , i had some fun , hit the gas hard in a turn, but the frount wheels only spun never went to the rear, it has been doing this off and on, i think my AWD system is messed up i literally had to let off the gas to stop it from spining, the tires are in good shape, i just feel it should have spun all 4 or should have transfered the power

thinks for any help on this matter,, just wanted to get your guys input,

[Mr. Pockets]

The ABS sensors have nothing to do with AWD operation in the SVX. Slippage is detected inside the transmission.

Standard toque split while maintaining speed with no slippage at any of the wheels is 90/10. Torque can be divided as much as 50/50.

[kuoh]

Well the good news is that you won't have a problem with binding in turns. The bad news is that your transfer case is probably toast. Or it might just be the duty solenoid if you're lucky.

KuoH

[solarsvx]

kuoh i just changed all 3 difrential fluids whene i bought the car, kuoh what should i check for, what symptons if its a duty cycle slynoid or a difrential gone bad, they dont go bad do they ,

is it 90 % frount 10% rear at all times, and if it detects any slip it just locks it up 50/50 % hmm well i never new that mr pockets thanxs for the info

if its 90% frount thats why it spun whene i hit the gas, maybe it just didnt detect it, at some pointes

[Mr. Pockets]

Originally posted by solarsvx
kuoh i just changed all 3 difrential fluids whene i bought the car, kuoh what should i check for, what symptons if its a duty cycle slynoid or a difrential gone bad, they dont go bad do they ,

is it 90 % frount 10% rear at all times, and if it detects any slip it just locks it up 50/50 % hmm well i never new that mr pockets thanxs for the info

if its 90% frount thats why it spun whene i hit the gas, maybe it just didnt detect it, at some pointes

You misunderstood me because you read too much into my response. The typical torque split is 90/10, yes, but if it detects slippage it doesn't just lock into 50/50. That would cause slippage by itself. Torque split is variable anywhere between 90/10 and 50/50.

As for how quick it should respond, I can answer that, too. My SVX and my wife's Legacy act very differently, even though they use the same AWD system. My SVX will transfer torque to the rear instantly if the front wheels slip. But that car has been taken care of by its owners. The Legacy, abused as it was by its previous owners, acts differently. In snow, for example, the front wheels will sometimes slip for a full second before the transmission engages the rear wheels with a rather glamour-free <thump>.

[solarsvx]

yea im getting it now LOL well its imposible to do 50/50 also cause u would have to weld the diffs together, well yesterday whene mine spun,, the rear never kicked in at all,, i had to let off the gas the frount wheel spun spun and spun, i hit it again then i felt the AWD it does this some times ,some times it works sometimes it doesnt,, also if u have traction control then it usses the ABS wheel sensors and ABS system,, what i am learning,

on the dsm b.b they where saying the new evo 7 incorperates active AWD using, ABS wheel sensors, and brakes along with the AWD system, and drive bye wire ,some of the race cars weld there center difrential,, yes i know this is insane,but for drag race use only , and no i have no intentions on doing that LOL

does all subaru AWD use the same system for all there line ups or each one varries in difrent ways


james the learning grasshopper,,

[Beav]

Don't assume that all AWD systems are/act the same. Vast differences. Anyway in the SVX the programming 'sees' that the car isn't moving and when throttle is applied it instantly splits torque 50-50 in order to avoid torque steer, something that probably isn't a huge issue in the Legacy.

The torque split occurs in the transfer case, there is no center differential in the SVX. The front diff is 'open' meaning that the wheel with no traction gets the power. The rear however has a ferguson type limited slip that removes power from the slipping wheel and applies it to the wheel with traction.

True, traction control is an operation of the ABS system on cars with that feature. However on cars with an AWD system designed by someone other than Mickey Mouse it isn't required. Traction control limits speed and power, why would a drag racer want that? Kind of a duh thing when you stop and think about it.

[svxcess]

Seems there are varoius configutations for Subaru AWD systems. Our new Outback VDC Sedan has a split of 55% to the rear and 45% to the front when the VDC is endgaged (which is all the time, controlled by a switch on the dash)

Even with its 60 series tires and high ground clearance it will take curves at speeds I wouldn't dream of taking in the SVX.

[svx_commuter]

No RWD? Get the transfer pressure checked. If you got pressure the clutches are going bad. If you have no pressure the transfer valve is bad. I changed mine myself

The AWD system for the svx is 90/10 or 50/50. The front wheels always have power but the rears wheel will vary. The amount of RWD depends on the pressure to the transfer clutches. This pressure increases in reverse, 1st, if slippage is detected (that is front /rear) and under rapid acceleration and when the ABS signal is detected but it doesn't apply brakes to the wheels.

From what you say the rear wheel drive is going out. Do not load your tranny up until you get it fixed. You will damage the front dif and axles.

The SVX drive system can not put 100% power to any one wheel. The best it can do is 25% to any wheel when the AWD tranfer pressure is at max. Except for the limited slip rear end. That could put 50% to one of the rear wheels but only when transfer pressure is max.

[Mr. Pockets]

Originally posted by solarsvx
does all subaru AWD use the same system for all there line ups or each one varries in difrent ways

There are basically two types of AWD system offered in Subaru cars. The short story is that which type is in which car depends on the transmission choice - manual or auto. There may be exceptions, but that definition will suffice for now.

The type found in Subarus with automatic transmissions is that which was installed in the SVX. Sensors in the transmission detect wheelspin from either the front or rear and adjust torque split accordingly.

The type found in Subarus with manual transmissions is not electronically-controlled. It uses a viscous coupling. Standard torque split is 50/50, but wheelspin at either the front or the rear axles causes more torque to be sent to the wheels which aren't slipping.

Of course there are different flavors of these offered, but the above are basically the two types.

[Mr. Pockets]

Originally posted by svxcess
Seems there are varoius configutations for Subaru AWD systems. Our new Outback VDC Sedan has a split of 55% to the rear and 45% to the front when the VDC is endgaged (which is all the time, controlled by a switch on the dash)

Even with its 60 series tires and high ground clearance it will take curves at speeds I wouldn't dream of taking in the SVX.

What's the skidpad rating for the Outback VDC? I hear that the VDC system does 'miraculous' things in bad weather, but I have a hard time believing that the car outperforms the SVX on the skidpad.

[solarsvx]

thanxs for the input i got a pretty good idea on how things work ,, ill probably bring it to subaru dealership to have them run a test on it, just to be shure it might just be my driving or something else,, it only did it in the rain so maybe, sliped more then the car handle

as for welding the center diff its a popular modifation in the dsm world, but its only used for race aplications, or weekends cars, the center diffs break runing over 500 hp range on dsms, so thats the best way to fix it, i know a local guy who broke his at the track , but he also hold the fastest 60" time here, 1.40

[svx_commuter]

The SVX has no front to rear dif It uses the transfer clutch pack to allow for the turns. This is why the transfer pressure drops when the car is turning. One of the members here removed teh front axles and welded the transfer clutch to get RWD.

Originally posted by svx_commuter
The SVX has no front to rear dif It uses the transfer clutch pack to allow for the turns. This is why the transfer pressure drops when the car is turning. One of the members here removed teh front axles and welded the transfer clutch to get RWD.

what member did this? i miss rear wheel drive i wish the svx was split like the wrx...45 front/55 rear. lol...or my deceased grand cherokee...rear all the time/can put it into 4 wheel i've driven the wrx a few times...it's a nice ride...haven't been out in one of the outback vdc's yet though. they look nice...maybe this week i'll pretend i'm interested in one

[solarsvx]

sounds good to me, take me along LOL , i llike the wrx verry much AWD turbo 4 door, but im still likng the galant vr4 AWD turbo also,, and if mitsu come out with the evo7 like they said they were wrx has a new competion in town,

the galant vr4 are verry very rare, but they run hi 14s out of the box, AWD AWS turbo 4cyl,, it has the 4g63 engine wich wich is the popular dsm turbo motor, used from 89-99 eclipse/laser/talon cars,

ohh do u guys no, abought a turbo svx in orlando florida here, a freinds knows him, all i heard is rumors never seen him or anything