Permanent "conversion" AWD to FWD?

K

kaplan3jiim

If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.
 
If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.

It will have very little effect on gas mileage; you are still dragging
around all of the AWD parts with all of the fiction and losses it entails.
So all you will accomplish is keeping all of the disadvantages with AWD
(increased gas consumption etc) and lose the benefits of AWD. About the
only way you could do it is to have all of the AWD parts removed... but why
not just buy an FWD in that case?
 
If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.
Hi,
If you remove all the mechanical parts associated with AWD.
Extra weight is detrimental on gas mileage. I always buy
AWD vehicle knowing it has less mileage compared to 2WD.
Added safety is worth the bit more gas consumption. Most cause
of poor gas mileage is poor driving habit, not keeping the vehicle
in tip top shape. When is the last time you checked the tire air pressure?
 
If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.

I have seen a forum post with a photo-series showing how to
convert the centre diff for RWD only. Not recommended unless
you're a dedicated drifter, but interesting to know it can be
done. It leaves the front diff alone, and as others have said,
you still carry all the extra front-end weight.
 
Hi,
If you remove all the mechanical parts associated with AWD.
Extra weight is detrimental on gas mileage. I always buy
AWD vehicle knowing it has less mileage compared to 2WD.
Added safety is worth the bit more gas consumption. Most cause
of poor gas mileage is poor driving habit, not keeping the vehicle
in tip top shape. When is the last time you checked the tire air pressure?

Probably should check the tire pressure more often, especially during
the seasons of falling temps. The figure I've seen though regarding
tire pressure effects on mileage are just a few percent.

The vehicle is maintained per schedule. I drive pretty light
footedly, especially once under way and for the last couple of years
when getting under way from a stop. In winter in Chicago, the
strictly city driving MPG is around 17-18 and always has been If I
use cruise on level highway trips I can get 30-31 in the summer.

This a '97 Legacy Brighton wagon, 2.2l engine, AT.


Jim
 
Probably should check the tire pressure more often, especially during
the seasons of falling temps. The figure I've seen though regarding
tire pressure effects on mileage are just a few percent.

The vehicle is maintained per schedule. I drive pretty light
footedly, especially once under way and for the last couple of years
when getting under way from a stop. In winter in Chicago, the
strictly city driving MPG is around 17-18 and always has been If I
use cruise on level highway trips I can get 30-31 in the summer.

This a '97 Legacy Brighton wagon, 2.2l engine, AT.


Jim
Hi,
You are doing good. Ever tried Iridium plugs? Put them in and forget
about plugs long time.
 
You are doing good. Ever tried Iridium plugs? Put them in and forget
about plugs long time.


They are supposed to last longer but nobody seems to say
how much longer precisely. Manufacturers focus on better
Iridium performance but as opposed to Platinums which
are good for up to 100k miles, Iridiums' change intervals
are not specified more exactly.

I put Iridium NGK's 25k miles ago on my '00 Impreza
2.2L. Made a huge difference, car runs very smooth,
(old ones were Champion crap), but I am not sure when
am I to change these.

At 60k intervals? 100K?

Anyone have any suggestion?

M.J.
 
M.J. said:
They are supposed to last longer but nobody seems to say
how much longer precisely. Manufacturers focus on better
Iridium performance but as opposed to Platinums which
are good for up to 100k miles, Iridiums' change intervals
are not specified more exactly.

I put Iridium NGK's 25k miles ago on my '00 Impreza
2.2L. Made a huge difference, car runs very smooth,
(old ones were Champion crap), but I am not sure when
am I to change these.

At 60k intervals? 100K?

Anyone have any suggestion?

M.J.

I have them in the STi. The recommended interval for them is 120K miles in
that car at least.
 
JD said:
I have them in the STi. The recommended interval for them is 120K miles
in that car at least.


Thanx for the info.

I'd be a bit apprehensive keeping them that long (potential
welding-in issue- or is this an urban myth?), but 80k miles
would seem like a good bet.

M.J.
 
If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.

I had a '92 AWD Plymouth Grand Voyager, and we 'converted' it to FWD by
removing the rear driveshaft. However, it was pretty easy. It looks a mite
more difficult on a Suby...
 
If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.

There's a forum post somewhere detailing a method to modify the centre
diff/clutch to provide RWD only. Basically the clutch plates are removed
so no drive goes forward, and the clutch is welded shut, IIRC.
It was done for drifting, but would provide mileage benefits.
 
There's a forum post somewhere detailing a method to modify the centre
diff/clutch to provide RWD only. Basically the clutch plates are removed
so no drive goes forward, and the clutch is welded shut, IIRC.
It was done for drifting, but would provide mileage benefits.

The fronts on a subie auto always get power, the clutch determines how
much (up to 50%) goes to the back.

So you need to lock the clutch somehow, and figure out how to remove
power to the front- probably by removing a pinion gear, or the ring
gear, or some such.

I don't think you can just pull the axles out of the front pumpkin...

You would def. need stub axles on the front hubs to keep the wheel
bearings together.

Dave
 
The fronts on a subie auto always get power, the clutch determines how
much (up to 50%) goes to the back.

So you need to lock the clutch somehow, and figure out how to remove
power to the front- probably by removing a pinion gear, or the ring
gear, or some such.

I don't think you can just pull the axles out of the front pumpkin...

Who are you calling Pumpkin ??
 
Who are you calling Pumpkin ??

Could be you, sweetie!!! ;P

Um, everyone seems to be focusing on RWD here, but the OP was asking about
FWD only. Like I said, disconnect the rear drive shaft!
 
Could be you, sweetie!!! ;P

Um, everyone seems to be focusing on RWD here, but the OP was asking about
FWD only. Like I said, disconnect the rear drive shaft!- Hide quoted text -

- Show quoted text -

Simply disconnecting the rear drive shaft will not do it. He also
needs to lock the differential. That is how the rear wheel drive
conversion is done. You lock the fore/aft diff and pull the front
shafts out. Locking the diff requires removing it from the
transmission and welding it together. You also get to remove a few
moving parts.

I really don't think this conversion would be worth it though. The
only rotating mass you would be removing is a little from the
differential, and the drive shaft. Not an appreciable bit. It mgiht
make a difference in mileage, but I don't think it woudl be enough to
justify the work involved. Especially if you are paying someone to do
it for you. You'd never recoup that through saved gas money.

As far as simply pulling the fuse, the parts would still be moving,
even if there wasn't torque applied to them by the drive train, it
would be applied to them by the road acting through the freewheeling
wheels, and those ultimately get their energy from the drive wheels,
so there wouldn't be any real gain there.

I'm not sure when subaru switched to fancy clutches to control the
amount of torque routed to different places, but I'm 99% sure that in
95(the year my car is) the differentials were open, and the traction
control was managed simply by applying brakes to the spinning wheels.
Basically the wheel speed sensors from the ABS system were used to
monitor the wheel speed, and any wheel more than 7% different from the
others(I dont' remember if it is the average of the others, or the
slowest, but that is trivial.) gets its brake applied to slow it down.
So if 97 used the same system, then pulling the fuse will likely only
kill the traction control, but not affect the amount of torque applied
to the rear wheels. So you'd be able to spin your wheels at different
speeds, but not save any money. I wonder if this would have any ill
effects on ABS.

If you want to save fuel by driving a front wheel drive ccar, then
sell the subie and get a front wheel drive car with amazing mileage
like an aveo or fit or something like that.

As for handling, killing the traction control will allow you to spin
the inside tires exiting corners if you have the power to do so. Like
in the Oh-so-often instance that you are doing 45 in second gear and
accelerating out of a really tight turn. So unless you race this on a
course, then you will ikely never notice a difference on dry pavement.
I still would just leave it alone though.

Just my two cents.

Good luck with whatever you decide.

Bill
 
Thanx for the info.

I'd be a bit apprehensive keeping them that long (potential
welding-in issue- or is this an urban myth?), but 80k miles
would seem like a good bet.

"Welding' in is not a myth - but ALL plugs should have anti-seize lubricant
applied to the threads before installing, and the threads in the head holes
should be chased. Few shops do it, which is why only I do my
repairs/maintenance.
 
If I were to disconnect the fuse that then leaves my Subaru with FWD
what negative effects would there be. (After 12 years) I am thinking
about this as a way to improve mileage (2 wheel engine braking vs 4
wheel?). Would there be any potential harm to the car making this a
permanent conversion? Would it compromise handling beside the obvious
advantages of AWD in snow? I could stick the fuse back in if we
exppected significant snow.

Any real world experiences with this.

For the most part, you're running primarily FWD anyways, especially in
the summer when it's dry. But it's unlikely you'll have noticed any
mileage benefit, since you're still dragging all of the AWD equipment
anyways.

I drive a 2000 OBW w/ 5MT, it's got a different AWD system, it's
full-time, stays on all of the time, wet or dry or snow. The automatic
transmission version is an on-or-off type of AWD.

Yousuf Khan
 

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