hey everyone - I want something for my AWD conversion, and I'll be buggered if I can find it, but I know it must exist.... I want a small drive coupling that I can turn on and off electronically, to replace the current viscous coupling in the centre of the tailshaft. Ideally, I'd like one that is variable, so I can control how much of the power goes to the back wheels. I have an idea of how I can do the same for the front wheels too - I just need the coupling! only needs to handle about 200nm of torque

how about a switch on the dash that lets me select between FWD or RWD or 4WD, with a variable torque split.... .

come on then - whose got contacts?

_________________
did I tell you that I won a trophy?

The Nissan Bluebird Atessa has a variable control for the drive split as they are AWD I think the furthest you can have the bias is like 25:75

_________________
"Show me the Mini!"

yeah, I've been looking under all the AWD's I can find at the local car yards, and they're all integrated into the gearboxes - hence I'm looking outside the auto industry

_________________
did I tell you that I won a trophy?

To get the option of front, rear, or all wheel drive (without taking out drive shafts) doesn't this mean you will need four diffs?

1 for front wheels, 1 for rear wheels, one to stop/go drive to rear wheels one to stop/go drive to the front wheels.

I was thinking of a clutch pack type diff you would have to take these appart to change the torque split.

How are you going to work it? I mean your rear wheels have to be able to spin some amount slower that the front wheels so you don't get problems going round corners right?

The last page of this article has some links that might let you know what is available.

http://auto.howstuffworks.com/differential11.htm

Hope it helps

Bye Arrin

_________________
---
Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

Hmmmmmm, yair. I was going to suggest the Mitsubishi electronic diff, or the new MY05 Subaru "dial in" ctr diff, but they are in the gearbox.
Some of the Torsen diffs as fitted to some Audis and Jensen FFs are seperate, but are not adjustable & are rare as rocking horse "stuff".

Will have a look through my Fenner & SEW Eurodrive catalogues....

Mike

_________________
Too many cars, and too little time.

I do kinda need 4 diffs, 2 of them are real diffs, and 2 switchable couplings. The existing viscous coupling gets over the problem of the rear wheels spinning slower than the fronts when going around corners - it always has a degree of slip in it. Hopefully whatever coupling I can find will be able to have a little slip in it, or maybe set it at 30% of the power when on tarmac, and 50% when on dirt

The problem with the existing viscous coupling is that it's only working when the rear wheels are going a different speed to the front wheels (more than just the speed difference when turning), so it is fairly slow to react, basically only working when you're already in trouble. I'm looking to replace that with something more 'proactive', as in "I'm about to do something where I want 4wd", instead of "I'm doing something where 4wd might be a good idea.... oh, now would be a good time..... any time soon would be nice....."

The awd gear I have has a driveshaft length equaliser shaft across the back of the motor, which I reckon is perfect for fitting another switchable coupling in-line. If I was to turn that coupling off, all the drive from the front diff would go to the inboard side of that coupling (as it's the easiest path), so none of the drive would go to the front wheels at all

_________________
did I tell you that I won a trophy?

I read a little about the audi ones, I'll have to look into them further - I might be able to locate something.... depends how big they are also

see what you can find in your catalogues - I'll get you a case of coronas delivered as a finders fee if you find me the right solution

_________________
did I tell you that I won a trophy?

They tighten up the viscous coupling by running a slightly larger? diff ratio on the rear wheels compared to the front this means in normal operation that the back wheels seem to be going slightly slower than fronts which means that the viscous coupling stays tight and cuts in earlier shortening the reaction time.

The other one I heard was the Skyline diff was apparently quite revolutionary as it allowed the car to behave and have the handling traits of a RWD but as you started to loose traction the diff came into operation and dragged the car out of the corner. I don't know where I was reading about it though

_________________
---
Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

what about some of the 4wd stuff? can't think of any models specifically but a few of them use this type of system usualy on the front shaft, don't know if it is part of the transfer case or not but it might be an option?

cheers steve

_________________
Cheers Steve.


1973 south african mk3, 1275 +30 (1300), RE13 cam, hif44, mildy worked head with s sized valves, pulsar dizzy, 1.5:1 minispares forged rockers.

that's interesting.... it would work to do that, they reckon overuse of the coupling makes it overheat and damages it - maybe I'll try that first and if it dies then I'll do something else. I want to look for a taller diff anyway, the standard one I've got is really low (like 5.2:1) and the donor car runs 13" rims - on 10" rims it'll scream



skylines are a 70/30 rear/front split, and it is able to vary too, they're really flash.... but the technology is out of my reach, it's all in the gearbox, computer controlled etc. etc. - too complex

Stevandsash, I've looked at heaps of them, they're all integrated into the gearbox, but let me know if you find one

_________________
did I tell you that I won a trophy?

MY05 STi has the Driver Controlled Centre Diff (DCCD) - can split torque from 50:50 to 65:35 rear bias.

It also has an auto mod that uses a yaw sensor to determine how to distribute torque - great on wet roundabouts!!!

_________________
"Show me the Mini!"

Not too much success at tracking something down
- have pm'ed you with contact details in Motion Industries who may be able to help you.

Mike

_________________
Too many cars, and too little time.

late model AWD vovlos have them but they will set u back a pretty penny

_________________
FOR SALE MInidlx, 1293, GR head, RE-13, GR worked Redline Manifold, 45 mm DCOE,pulsar dizzy , "S" Disc's, Mk II "S" box, 3.65 diff. Minator 10X6's On the loose

Some of the US ATVs use a torque coverter that is based on electro fluid coupling that changes viscosity with current. Just something for the back of the mind.

Maybe you could look at the 4WD air lock diffs, personally have no idea of the config but they may be variable.

Good Luck

PS Trike calipers will foul inner wheel well