AWD --> FWD Fuse

Post by **Alex** » Mon Mar 29, 2010 4:56 pm

i always knew this was there in my gen3 lib, where basically you put a fuse into a free position in the fuse box under the bonnet and it makes it FWD.

My understanding is that this is mainly for towing where the front wheels are off the ground and the rears are still in contact with the road to prevent centre diff damage.

My question is, is it safe to drive around in FWD? Will my car be more economical?

To be honest i dont mind driving around in fwd, i rarely drive her hard enough to make awd a totally viable, obviously in rain and stuff id have it on full time.

Is it okay to hook it up to a switch? I also dont mind the odd gravel fwd skid

I think itd be cool to have it switchable from fwd to awd inside the cabin of the car.

thanks

and im open for positive and negative comments on it so dont be shy

alex

maxxair · Post by **maxxair** » Mon Mar 29, 2010 5:29 pm

Al, I have the 4EAT from a 94 SVX, and it has the same fuse. Im thinking along the same lines of the switch, hooked to the handbrake light, and rw hydaulic handbrake.

so the front keeps pulling and the rear is locked. The awd is controlled by the 'duty solenoid C' in the extension housing on the back of the gearbox, and controlls torque by oil pressure on a clutch plate pack. or to my understanding. I have been told though that the TCU will decide what it does, and when though. im not too sure.

Post by **TOONGA** » Mon Mar 29, 2010 5:43 pm

heres an interesting read from the rs25 board

http://www.rs25.com/forums/f8/t99075-4e ... -lite.html

TOONGA

thatsgoodsquishy · Post by **thatsgoodsquishy** » Mon Mar 29, 2010 5:53 pm

My understanding is that the solenoid isn't up to scratch for regular/permanent use and will eventually burn out. Really only designed for temporary use. This came from somewhere on the net though, not my experience so take it with a grain of salt

Gannon · Post by **Gannon** » Mon Mar 29, 2010 6:17 pm

The auto TCU is pretty clever at determining the split ratio. I doubt you will gain much in fuel economy because the rear diff, tailshaft ect are still spinning and absorbing power. When you are cruising, the split is about 85:15 front/rear.

I made a duty cycle meter and hooked it up to the duty transfer output of the TCU in my 01 Outback. It shows percentage of pressure to MPT clutch.
So 30% on the display means a torque split of 85:15.
50% on the display means 25:75
75% on the display means 37:63
100% on the display means a 50:50 split

http://www.youtube.com/watch?v=x4k9KIH55fo

The video is of me driving up to an intersection at moderate throttle at around 60km/h, slowing down and indicating left and accelerating at WOT to 100km/h

On sealed road surfaces, the results are pretty predictable and are mostly proportional to throttle position, but on loose surfaces, the speed sensors take over and on really loose gravel, i see readings in the 80s and 90s, even at moderate throttle. Its also very quick, jumping up to almost full lock, even before i could feel the wheels spin

Oh and apologies for the sideways video

maxxair · Post by **maxxair** » Mon Mar 29, 2010 6:49 pm

WOW!! I want one. lol

Gannon · Post by **Gannon** » Mon Mar 29, 2010 7:09 pm

I got it from Jaycar electronics, but its discontinued and i was lucky enough to get a guy to search for old stock and got it posted from a Sydney Jaycar store. He said there were only 3 left in Australia.

SuBaRiNo · Post by **SuBaRiNo** » Mon Mar 29, 2010 9:55 pm

i want one too... thats cool.

Dave

Point · Post by **Point** » Mon Mar 29, 2010 10:06 pm

well seeing as this topic has been brought up....

I have a '93 gen 1 lib that has 'torque bind' issues. I thought I might be able to bypass it temporarily with the FWD fuse but I can't for the life of me find the damn thing. I believe it is supposed to be around the pass side strut tower. I have followed the loom around but can't find it at all. Can someone tell me (or even have a piccy) where it comes out of the loom and what it looks like?

maxxair · Post by **maxxair** » Mon Mar 29, 2010 10:11 pm

Toonga, YOU, are my hero. GREAT thread.

Gannon · Post by **Gannon** » Tue Mar 30, 2010 5:20 am

Point, unless your torque bind is caused by a faulty speed sensor, the FWD fuse wont help you. Putting in the fuse tells the ECU to unlock the MPT, it doesnt bypass it.

Your torque bind is most likely caused by a faulty DutyC solenoid.

I'll find you a tech manual to test it out

Post by **Alex** » Tue Mar 30, 2010 10:23 am

my fwd fuse is in the black fuse box under the bonnet near the battery.

ive seen them in WRX's tho in the top left corner next to the strut top.

alex

Subafury · Post by **Subafury** » Tue Mar 30, 2010 4:49 pm

and u tell me off for wanting to make the rexy RWD alex. saying AWD is the best and not to weld up my centre diff lol u contradicting ****

Post by **Alex** » Tue Mar 30, 2010 4:54 pm

my car isnt a rex matt. If i was running turbo i wouldnt even contemplate fwd.

RWD rex = gay.

alex

maxxair · Post by **maxxair** » Tue Mar 30, 2010 7:08 pm

Try the drivers side firewall, behind the strut tower. I have the TCU manual if you like I can email it to you. really really good. pm me your address.

Duty solenoid C sounds the culprit for sure. A workmates Grandads 02 Lib has been shredding tyres, and I assume its the same thing.

Cheers, Rohan Maxim

Point · Post by **Point** » Tue Mar 30, 2010 10:38 pm

I already have the workshop manual in .pdf . Just had another look and found a piccy just like you said maxxair. Went and looked again at the car and found three plugs. I always assumed they were for the air suspension, but it turns out that one of them was for the fuse.....but the fuse holder was missing. No wonder i couldn't find it. Just looked like any other random unused plug, and on the other side of the engine bay.

now to drive it and see if it makes a difference. I really want to fix this thing without having to pull the gearbox apart. If I have to spend money on it it will be getting a manual conversion....I so hate autos...

ScubyRoo · Post by **ScubyRoo** » Wed Mar 31, 2010 8:03 am

Point wrote:well seeing as this topic has been brought up....

I have a '93 gen 1 lib that has 'torque bind' issues. I thought I might be able to bypass it temporarily with the FWD fuse but I can't for the life of me find the damn thing. I believe it is supposed to be around the pass side strut tower. I have followed the loom around but can't find it at all. Can someone tell me (or even have a piccy) where it comes out of the loom and what it looks like?

It's in the engine bay fuse box (which is where the headlight and A/C relays and the like are found), forward of the passenger strut tower. Look on the inside of the lid and it'll tell you what is what. I believe the furthest forward fuse is the one your after (should be empty), but yeah, check the lid.

Point · Post by **Point** » Wed Mar 31, 2010 9:29 am

ScubyRoo wrote:It's in the engine bay fuse box (which is where the headlight and A/C relays and the like are found), forward of the passenger strut tower. Look on the inside of the lid and it'll tell you what is what. I believe the furthest forward fuse is the one your after (should be empty), but yeah, check the lid.

Not in my gen1 it isn't. As I said in my previous post it's behind the drivers side strut tower. Just the fuse holder was missing...