Stupid idea.... for a RWD 4eat

James614 · Post by **James614** » Sun May 04, 2008 10:35 pm

I've been thinking..... It seems to me that if you remove the front axles, and make a Duty C lock-switch, a 4eat car should behave as RWD. I've read that when you use the lock-switch trick, the center diff is FULLY locked like a truck in 4x4 Hi (and similarly unable to maneuver on dry pavement), so it shouldn't really matter what traction is like upfront/outback, the front/rear drivelines are powered as a single rotating unit. So removing the front axles would just put all of the tractive stress on the rear tires instead of sharing it with the fronts.

Does this sound plausible? Or does the center clutch pack not work that way? I'm afraid I might sound like an idiot since it's been decreed in stone that 4eats can't be made RWD by any process accessible to mere mortals, but this has been on my mind for several days now and I need some input from people who actually know what they're talking about before I go crazy and actually try it (and subsequently blow up my trans)

ericem · Post by **ericem** » Sun May 04, 2008 11:05 pm

They have these special axle adapters which allow you to unlock and lock the front axles for towing purposes like on some 4x4 trucks. Definitely should work but would be alot better if it was 100% rear torque if your clutch is indeed fine then it will work.

BXSS · Post by **BXSS** » Mon May 05, 2008 12:39 am

I could have sworn Tony Rigoli's (TRP) 4eat did rear drive burnouts then took off in AWD.

http://www.tonyrigoliperformance.com.au ... ssion.html

I was right!

Murphy · Post by **Murphy** » Mon May 05, 2008 1:05 am

wow! thanks for the link i had never heard of anyone doing a thing like that before!

but in a stock transmission, is the clutch pack strong enough to not slip under 100% torque? i think that is the main thing i would be worried about, frying the clutches in a day or even a few feet.

what if you eliminated the clutches and put a direct linkage in its place?

James614 · Post by **James614** » Mon May 05, 2008 2:53 am

That TRP part sounds awesome.

I think that on a stock trans the clutch should hold under normal driving. Anyone willing to try it on a spare trans and see how it holds up under full turbo torque?

I didn't think about wearing out the clutch, I don't think I should try it on my daily driver. FWD is teh suck.

ericem · Post by **ericem** » Mon May 05, 2008 3:28 am

Murphy wrote:wow! thanks for the link i had never heard of anyone doing a thing like that before!

but in a stock transmission, is the clutch pack strong enough to not slip under 100% torque? i think that is the main thing i would be worried about, frying the clutches in a day or even a few feet.

what if you eliminated the clutches and put a direct linkage in its place?

If you fry it, it will weld the clutch together

93forestpearl · Post by **93forestpearl** » Mon May 05, 2008 6:10 am

Grounding the Duty C will cause full lockup, but its not quite what you think. There isn't exactly a lot of friction material there or a ton of clutches. You'll fry it, and then it gets interesting. Parts like to weld themselves together, or tear other things apart. Basically what I'm saying is that its a bad idea.

If you want rear wheel drive you can take it apart and weld a couple things together, violla, rwd.

Rigoli uses a reverse spool so its rwd or awd being rear biased. BMS transmissions in AU actually does it, with some input from Rigoli. BMS manufactures the parts and does the actual building of the transmissions. The parts for just the spool conversion are $2500

They also use the same tranny case as the Legacy SS. The newer stuff is different.

BXSS · Post by **BXSS** » Mon May 05, 2008 5:44 pm

Good info.

I have a feeling the rear axles +r-diff would probably die quickly if the car was RWD & making some decent power.

Burnouts get boring, keep the car AWD - interesting idea though!!!!

James614 · Post by **James614** » Wed May 07, 2008 12:38 am

My interest wasn't burnout-related. I had plenty of those in my '83 Chrysler New Yorker (that's all the 5.2L V8 was good for, as it made a balls-to-wall 130hp @ 3600rpm and leaned-out severely over 4000rpm. Electronically controlled carburetors and 3-cat peashooter exhaust systems FTW!).

Anyways, on dry pavement the AWD doesn't really do anything but introduce slight push in corners and give me 4 extra CV joints to worry about. There's no unpaved roads that I can find within reasonable driving distance, I don't play in the rain, and something this simple could be switched back when winter hits.

But yeah, it sounds like replacing the center clutch pack with something solid (not something I'd wanna switch out seasonally!), or engineering a special part with RWD/AWD toggle similar to Rigoli's is the only reliable way to go.

I think a DCCD 5spd/6spd swap might cure my woes better. I don't know why I'm thinking about RWD/auto so much..... cause I hate autos to begin with

ciper · Post by **ciper** » Sun May 11, 2008 9:50 pm

I've driven over 200 miles with 5 people in the car in rear wheel drive mode on a 4eat.

I'm sure the story is posted on this board somewhere but essentially i had a an out cv joint blow out so I ripped the axle shaft out of it and put the stub back in the trans. I then unplugged the center differential lockup solenoid and drove away.

I wouldn't trust it as a permanent solution but in a pinch it worked splendidly.

James614 · Post by **James614** » Sun May 11, 2008 10:15 pm

Was that on a turbo car?

ciper · Post by **ciper** » Sun May 11, 2008 11:15 pm

It was on an NA car . The center clutch pack on the auto tranny is extremely similar to a motorcycle clutch. Would you trust a motorcycle clutch on a vehicle weighing 4000 pounds (with cargo and passengers)?

If you could somehow create a single front axle with a lockable bearing in the middle it would be pretty easy to switch between AWD and RWD.

BTW I still have 2 perfectly bowl shaped dents from when the CV joint exploded and let its bearings out

To say I've driven the car until the wheels fell off is not an understatement. I've seen smoke and had a wheel with 2 inches of side to side play from failed bearings, twice actually! Once on the front left and once on the rear left. As you can tell I take many hard right turns.
If you don't drive it like you stole it you might as well not drive it at all.

James614 · Post by **James614** » Mon May 12, 2008 4:28 am

ciper wrote: If you don't drive it like you stole it you might as well not drive it at all.

+1!

Murphy · Post by **Murphy** » Mon May 12, 2008 5:26 am

but then again
if i drove my car like i stole it, i couldnt afford to drive it at all

93forestpearl · Post by **93forestpearl** » Mon May 12, 2008 6:04 am

True it can save you from a tow in a pinch. As far as hammering on it, I'm pretty skeptical about it's longevity.

ciper · Post by **ciper** » Mon May 19, 2008 7:19 am

You know? I think I made a mistake....

Now that I think about it, doesn't the center differential lock up at 100% duty cycle and go FWD with no voltage or is it the other way around?

If so oops.

BAC5.2 · Post by **BAC5.2** » Mon May 19, 2008 11:24 am

Don't just yank out the front axles... unless you want your wheel bearings to walk away from you...

If you REALLY want RWD, swap in a 5-speed and convert it to RWD. My Legacy was RWD for a while. It was a whole lot of fun, if odd. I remember driving it and doing full-boost, tail out slides thinking "Subaru's are only supposed to be this sideways in the dirt". Fun, but really different than any other RWD car I've ever seen.

Post by **Legacy777** » Mon May 19, 2008 6:08 pm

ciper wrote:You know? I think I made a mistake....

Now that I think about it, doesn't the center differential lock up at 100% duty cycle and go FWD with no voltage or is it the other way around?

If so oops.

They go FWD with 12v (100% duty cycle) applied to the duty c solenoid, and full AWD lockup with 0v.

Murphy · Post by **Murphy** » Mon May 19, 2008 11:59 pm

i think i when i get another Subie, or atleast another 4eat to tear apart, i want to remove the clutches and weld the pack together.

i think that would make a great off-road transmission. the clutches will slip when you are putting the transmission under a good load.
i was trying to do a hill climb with the clutches locked, but they just slipped and i was 1 wheeling

maybe i could make it unlockable with a switch or something so i could drive in FWD the rest of the time and it will not be like driving with a transfer case engaged

if i wanted to make it RWD i would definitely get a 5mt instead and just put a spool in it

ciper · Post by **ciper** » Tue May 20, 2008 4:08 am

Legacy777 wrote:They go FWD with 12v (100% duty cycle) applied to the duty c solenoid, and full AWD lockup with 0v.

I KNEW it. Does the FWD fuse actually go inline with the solenoid or is it just grounding a signal line from the TCU?

Where the heck are my wiring diagrams when I need them grr..

Edit: The fuse grounds a signal wire on the TCU.

James614 · Post by **James614** » Wed May 21, 2008 12:34 am

Murphy wrote:the clutches will slip when you are putting the transmission under a good load.
i was trying to do a hill climb with the clutches locked, but they just slipped and i was 1 wheeling

That's just the experience I need to know for certain that my idea isn't a good one. Of course, I'd never try hill climbing in a Subaru (lack of shortage of strong low-range transfer cases, lack of front/rear differential lockers, tight clearance for beefy treads, etc)

worunner · Post by **worunner** » Mon Oct 20, 2008 9:30 pm

So would i have issues driving my 4eat in FWD mode while im waiting to get the money to pay for the torque bind procedure? (its not present when i have the car in FWD mode)
I keep looking and i havent seen any problems with it.

93forestpearl · Post by **93forestpearl** » Mon Oct 20, 2008 11:20 pm

It is a good idea, and can save your transfer clutches if you have to wait quite a while.

James614 · Post by **James614** » Wed Oct 22, 2008 1:47 am

I've heard that the solenoid will stop working and you'll wind up with permanent FWD by doing that......

worunner · Post by **worunner** » Wed Oct 22, 2008 4:11 am

Has anyone looked into this or have they actually done that? currently theres been like 30 miles in FWD.

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Stupid idea.... for a RWD 4eat

Stupid idea.... for a RWD 4eat