Can I "turn off" the AWD

[nismo887]

Some guys at Les Swab were telling me, that since I have one of those weeny spare tires, that when i put it on I need to pull a fuse to disable the AWD. Reason being that having the small tire on there would screw my car up.

[n00b on demand]

I think its ok as long as you dont drive it that way for too long.

[want-a-fast-svx]

Thought I've heard this as well, when the spare is used its supposed to be in fwd only mode by putting the fuse in.

[SilverSpear]

does it seems logical to you to remove the AWD fuse while driving on spare? does it say that in the SVX manual?

[dcarrb]

Originally posted by want-a-fast-svx
Thought I've heard this as well, when the spare is used its supposed to be in fwd only mode by putting the fuse in.

That's correct; putting IN the fuse holds the car in front-wheel drive. For normal, AWD operation, remove the fuse.

And if you must use the space-saver spare, which is intended for emergency use only, mount it in the rear and get a "real" tire back in place ASAP.

dcb

[SilverSpear]

Ok guys, what are the effects of putting a fuse and using only the FWD for traction? any effect?

[dcarrb]

You'll get better traction in AWD. And smoking the front wheels is probably detrimental to the health of the front differential.

dcb

[Wiz]

Originally posted by SilverSpear
Ok guys, what are the effects of putting a fuse and using only the FWD for traction? any effect?
I'f im not mistaken your fuse is for Diff. Lock not FWD because yours is not a USDM spec car. Consider your self lucky though. Your tranny is much better than the USDM one since you have a 35/65 torque split insted of 90/10. :)

[SilverSpear]

Originally posted by Wiz

I'f im not mistaken your fuse is for Diff. Lock not FWD because yours is not a USDM spec car. Consider your self lucky though. Your tranny is much better than the USDM one since you have a 35/65 torque split insted of 90/10. :)

how do you know that? come on somebody tell me!!! I do not know where my car came from or what are its specs !!!!

[Mr. Pockets]

Originally posted by dcarrb
You'll get better traction in AWD. And smoking the front wheels is probably detrimental to the health of the front differential.

dcb

I'd consider it much more detrimental to the transfer clutch's health. With the FWD fuse in, no hydraulic pressure can be applied to the clutch, so the plates just spin against eachother. Burn, baby, burn!

[dcarrb]

Originally posted by Mr. Pockets


I'd consider it much more detrimental to the transfer clutch's health. With the FWD fuse in, no hydraulic pressure can be applied to the clutch, so the plates just spin against eachother. Burn, baby, burn!

Yikes; that sounds bad. I said "probably" about the diff because that seems to be a prevailing opinion. Thankfully, I wasn't relating personal experience.

SilverSpear: Sorry... it often slips my mind that not everyone here's located in North America.

dcb

[mbtoloczko]

Originally posted by nismo887
Some guys at Les Swab were telling me, that since I have one of those weeny spare tires, that when i put it on I need to pull a fuse to disable the AWD. Reason being that having the small tire on there would screw my car up.

If the spare tire is a different diameter than the normal tire, then (for once) the guys at Les Schwab are correct. You'll definitely want to put the car in FWD mode. Otherwise, you'll smoke the center diff clutch.

[oab_au]

If the spare is at 60 psi, it will be the same diameter as the normal tyres. So it won't make any difference. The only caution is to limit the speed and distance that you drive, for the tyres sake only.

In the VTD version that Danny has, you can't turn off the AWD, you can only lock the center diff into 4WD, so both versions are designed to run the spare without any trouble.

I reckond that the US version would be in more danger of hurting the front diff, by using the fuse, than hurting the Transfer clutch plates.

Harvey.;)

[Mr. Pockets]

Originally posted by oab_au
I reckond that the US version would be in more danger of hurting the front diff, by using the fuse, than hurting the Transfer clutch plates.

In normal driving, I'd agree that using the fuse wouldn't damage the transfer clutch any more than when the system is operating normally. It is, after all, designed to slip constantly - for tens of thousands of miles, even. But wouldn't spinning the front tires cause exceesive slipping in the transfer clutch plates, damaging them? Or do you tihnk they're designed for it, so they can take it?

[oab_au]

Originally posted by Mr. Pockets


In normal driving, I'd agree that using the fuse wouldn't damage the transfer clutch any more than when the system is operating normally. It is, after all, designed to slip constantly - for tens of thousands of miles, even. But wouldn't spinning the front tires cause exceesive slipping in the transfer clutch plates, damaging them? Or do you tihnk they're designed for it, so they can take it?

Hi Nick, well they did fit the fuse for purpose of runnng it on a two wheel dyno for emissions testing. So it can take some 100% slipage. But spinning the front wheels is a no no. I mean it is cheaper to replace the transfer clutch plates, than a front diff,

:) I'm smiling, because the VTD can't have this problem.:)

Harvey.;)

[Wiz]

Originally posted by SilverSpear


how do you know that? come on somebody tell me!!! I do not know where my car came from or what are its specs !!!!
Because you said you had a diff-lock fuse in your car at one point. Only the USDM cars have the FWD. All non USDM SVX's have a different center differential and some other small differences in the tranny.

[SilverSpear]

Originally posted by oab_au


Hi Nick, well they did fit the fuse for purpose of runnng it on a two wheel dyno for emissions testing. So it can take some 100% slipage. But spinning the front wheels is a no no. I mean it is cheaper to replace the transfer clutch plates, than a front diff,

:) I'm smiling, because the VTD can't have this problem.:)

Harvey.;)

If you say that our model is better than the US model, why the hell did Subaru do two SVX versions? is it because having a traction of 90:10 of the USDM's has a better snow grip (required especially in Canada and USA) than other equatorial countries?

[SilverSpear]

Couldn't they do something in between like 60:40 ? I would have preferred that because our VTD's do not have a very good grip in raining conditions especially going an uphill in raining considtions.
Sometimes I feel like my car is floating on water rather than the road when going an uphill which will cause inadequate handling...
(or is it because of my large wheels and tyres = 17 x 8.5 ?)

[b3lha]

Originally posted by SilverSpear
Couldn't they do something in between like 60:40 ? I would have preferred that because our VTD's do not have a very good grip in raining conditions especially going an uphill in raining considtions.
Sometimes I feel like my car is floating on water rather than the road when going an uphill which will cause inadequate handling...
(or is it because of my large wheels and tyres = 17 x 8.5 ?)

It's probably something to do with your tyres. My car has extremely good traction in the rain on standard size tyres.

[SilverSpear]

Originally posted by b3lha


It's probably something to do with your tyres. My car has extremely good traction in the rain on standard size tyres.

this is probably the reason...
the surface of 7.5" wheels is better than that of the 8.5", smaller surface = more grip.
But though you wouldn't imagine the water on the streets here when it rains heavily, especially when you are going an uphill and the water coming to you in a downstream...

[oab_au]

Originally posted by SilverSpear


If you say that our model is better than the US model, why the hell did Subaru do two SVX versions? is it because having a traction of 90:10 of the USDM's has a better snow grip (required especially in Canada and USA) than other equatorial countries?

Well when they developed the SVX, they designed the VTD AWD to go with it. This is the same AWD that Subaru is now using in the newer models. Unfortunatly the US only had dynos to run two wheel drive cars, and as they have to run the car on a dyno to check the emissions, the VTD could not be used there, as it is allways All wheel drive.

So they went back to the older Transfer Clutch AWD, because it can have the rear wheels turned off, to run the front on a two wheel dyno.

The Varied Torque Diff is the best system, that is why General Motors is using this system under licence in there new models.

Harvey.;)

[odepaj]

I thought our cars (USDM) had a 60/40 split, ive read in many magazines and such that state that.


Out of Autoweek August 12, 1991 Issue
The SVX all-wheel-drive system uses front and rear differentials and a multi-plate transfer clutch. The standard torque split is 60/40 front/rear to compensate for the coupe's forward weight bias and smaller effective rolling diameter for the front tires. Still, the distribution of power can range from 95/5 front/rear to 50/50. The mix is constantly variable according to throttle angle, speed, wheel grip and other inputs.

please someone explain this to me, are we 60/40 or 90/10? 60/40 seems more reasonable to me.

dustin

[oab_au]

Originally posted by odepaj
I thought our cars (USDM) had a 60/40 split, ive read in many magazines and such that state that.
please someone explain this to me, are we 60/40 or 90/10? 60/40 seems more reasonable to me.

dustin

Yes Dustin, confusing isn't it.

This is just auto writers, with no technical expetise, writing technical reports. They read other reports, like the Road and Track Guide, and repeat the same misinfomation.:eek:

The people that wrote the Guide tried their best, but just did not understand the very technical nature, of the developements, that were released in this car. The transmssion AWD was one, the IRIS was another. I don't think they understood that there were two different AWDs used, for the reason that I have stated in the previous post. So in the expanation that they gave, they mixed the two together.

They talk about the multi plate clutch, of the US mod, but give it the torque split of the VTD, back to front, :(

The VTD is mainly rear wheel drive, it is actually 36%/ 64% front to rear, tighting to 50%/50%.
The US model is front wheel drive, with rear wheel assist. Can go from 90%/10% front to rear to 50%/50%.

Any sign of slipage between the wheels, causes the drive on both versions, to tighten towards 50/50.

There was a report done in Australia last year on James's SVX, and sure enought, there was the info from the Road and Track guide being reported again.:rolleyes:

Harvey.;)

[Seraph]

How's this:

It was snowing like hell last week and while visiting one of the car lots, I hit the front wheel on the curb. I can't see crap since the entrance and side look all alike under the snow. That location had like 1.5 - 2 ft of snow.

Cut the long story short, I got a hole on the side wall. Time to change the tyres again. :( The bad thing is that they are like 6 months old so I can't just replace one of them.

[odepaj]

Originally posted by oab_au


Yes Dustin, confusing isn't it.

This is just auto writers, with no technical expetise, writing technical reports. They read other reports, like the Road and Track Guide, and repeat the same misinfomation.:eek:

The people that wrote the Guide tried their best, but just did not understand the very technical nature, of the developements, that were released in this car. The transmssion AWD was one, the IRIS was another. I don't think they understood that there were two different AWDs used, for the reason that I have stated in the previous post. So in the expanation that they gave, they mixed the two together.

They talk about the multi plate clutch, of the US mod, but give it the torque split of the VTD, back to front, :(

The VTD is mainly rear wheel drive, it is actually 36%/ 64% front to rear, tighting to 50%/50%.
The US model is front wheel drive, with rear wheel assist. Can go from 90%/10% front to rear to 50%/50%.

Any sign of slipage between the wheels, causes the drive on both versions, to tighten towards 50/50.

There was a report done in Australia last year on James's SVX, and sure enought, there was the info from the Road and Track guide being reported again.:rolleyes:

Harvey.;)


I knew the VTD was rear biased while the USDM tranny is front biased and i know the torque split varies on both, but what im trying to figure out is, is the USDM tranny split 60/40 on a straight, flat road, or at 90/10? im just trying to figure out what the "standard" torque split for the USDM SVX is.

I just noticed you said they give the USDM the VTD's torque split but back to front. But the USDM does vary from 90/10 all the way to 50/50 and anywhere in between but is the car normally drive at 90/10? Are you completely sure that they post the VTD's split just backwards or is the "norm" for the USDM really 60/40? im not trying to question anyones knowledge, i would just like to know as much about my beautiful SVX as i can and i would also like to know that i am speaking the truth about my car and not misinformation, basically i just want to have the best understanding of the SVX that i can and this website has been great help in getting me to my goal so far. thank you all.


dustin

[oab_au]

Originally posted by odepaj



I knew the VTD was rear biased while the USDM tranny is front biased and i know the torque split varies on both, but what im trying to figure out is, is the USDM tranny split 60/40 on a straight, flat road, or at 90/10? im just trying to figure out what the "standard" torque split for the USDM SVX is.

I just noticed you said they give the USDM the VTD's torque split but back to front. But the USDM does vary from 90/10 all the way to 50/50 and anywhere in between but is the car normally drive at 90/10? Are you completely sure that they post the VTD's split just backwards or is the "norm" for the USDM really 60/40? im not trying to question anyones knowledge, i would just like to know as much about my beautiful SVX as i can and i would also like to know that i am speaking the truth about my car and not misinformation, basically i just want to have the best understanding of the SVX that i can and this website has been great help in getting me to my goal so far. thank you all.


dustin

Yes well when they quote the torque split for the VTD, they seem to put it as 40% 60%, instead of the actualy 36/64 that it is. Now I suspect that this was, then applied to the Transfer system, the other way around.

The Transfer system torque split varies with a number of inputs. Selected gear, road speed, and throttle opening. The split is highest with the lowest gear, the lowest speed and the highest throttle opening.

To put this into numbers, when it is in 4th at 30mph/60kph, and you are accelerating hard, the split would be around 60/40, as the road speed rises, the split will reduce to say 75/25. As soon as you lift the foot, the split will reduce to 90/10.
When you are taking off hard in 1st, the split is 50/50, as there is a high chance of wheel spin, so the torque split is increased to max. As the speed rises, the split reduces.

So mate it is hard to state what the standard split would be, just driving down the road. If you are just crusing, it would be 90/10, hit the throttle to overtake, it would go to say 70/30, lift the foot, back to 90/10. It will allways vary to suit the conditions, though it allways needs some drive to the rear, to prevent the rear drive line from shunting.

Harvey.;)

[odepaj]

Originally posted by oab_au


Yes well when they quote the torque split for the VTD, they seem to put it as 40% 60%, instead of the actualy 36/64 that it is. Now I suspect that this was, then applied to the Transfer system, the other way around.

The Transfer system torque split varies with a number of inputs. Selected gear, road speed, and throttle opening. The split is highest with the lowest gear, the lowest speed and the highest throttle opening.

To put this into numbers, when it is in 4th at 30mph/60kph, and you are accelerating hard, the split would be around 60/40, as the road speed rises, the split will reduce to say 75/25. As soon as you lift the foot, the split will reduce to 90/10.
When you are taking off hard in 1st, the split is 50/50, as there is a high chance of wheel spin, so the torque split is increased to max. As the speed rises, the split reduces.

So mate it is hard to state what the standard split would be, just driving down the road. If you are just crusing, it would be 90/10, hit the throttle to overtake, it would go to say 70/30, lift the foot, back to 90/10. It will allways vary to suit the conditions, though it allways needs some drive to the rear, to prevent the rear drive line from shunting.

Harvey.;)


ok, thanks for all the info. do you think you could give a detailed discription like that of the VTD? all this interests me very much.

dustin

[rob_4187]

Good thing my spare is a bridgestone potenza!

[oab_au]

Originally posted by odepaj



ok, thanks for all the info. do you think you could give a detailed discription like that of the VTD? all this interests me very much.

dustin

Yes mate, working on that one now. Gunna need a drawing for this one.

Harvey.;)

[odepaj]

Originally posted by oab_au


Yes mate, working on that one now. Gunna need a drawing for this one.

Harvey.;)

ko0l, thank you for all your help.


dustin

[SEA Sleeper]

Originally posted by SilverSpear
Couldn't they do something in between like 60:40 ? I would have preferred that because our VTD's do not have a very good grip in raining conditions especially going an uphill in raining considtions.
Sometimes I feel like my car is floating on water rather than the road when going an uphill which will cause inadequate handling...
(or is it because of my large wheels and tyres = 17 x 8.5 ?)


Want to trade center differentials? :D

[Matthewmongan]

Originally posted by dcarrb
You'll get better traction in AWD. And smoking the front wheels is probably detrimental to the health of the front differential.

dcb

with the car in the "limp home fwd mode" the torque is reduced to the point that you cant spin the tires and damage the car. or atleast thats what the dude at suberu told me.....

[oab_au]

Originally posted by Matthewmongan


with the car in the "limp home fwd mode" the torque is reduced to the point that you cant spin the tires and damage the car. or atleast thats what the dude at suberu told me.....

There might be a few with broken front diffs, that may disagree with them.:)

Harvey.;)

[jb21585]

in the manual for the svx it says to put the spare on the front and the full size on the back , dont f*** with fuses, the front diff should be fine, but the back diff strains under a smaller tire.