Permanent "conversion" AWD to FWD?

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.

Reply to
kaplan3jiim
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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?

Reply to
JD

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?

Reply to
Tony Hwang

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.

Reply to
Clifford Heath

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

Reply to
kaplan3jiim

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

Reply to
Tony Hwang

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.

Reply to
M.J.

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

Reply to
JD

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.

Reply to
M.J.

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...

Reply to
Hachiroku

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.

Reply to
Clifford Heath

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

Reply to
spamTHISbrp

Who are you calling Pumpkin ??

Reply to
bugalugs

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!

Reply to
Hachiroku

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

Reply to
weelliott

"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.

Reply to
Invalid

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

Reply to
Yousuf Khan

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