A little curiosity usually weighs heavily on the pocket book

[natext6]

So I'm curious:

 

Now I very much like the FT4WD transmission in my xt-6, but what if, (without the differential lock engaged) instead of having the torque distributed as 90% to the front wheels and 10% to the rear, it were to be say.... 90% to the rear wheels, and then 10 % to the front? (or any other configuration, although, I'm mostly thinking that I'd like to make the car almost entirely RWD without the Dif lock engaged.

 

What kind of process would be involved in realizing this concept? Is it possible?

 

 

As if I don't have enough on my plate as it is

 

At the moment , I'm just curious, but once I start marking items off of the mod-list, this would be one freakin' cool project to undertake.

[GeneralDisorder]

There is no active torque distribution on a FT4WD transmission. Torque is not split front/rear. It just goes to the wheel with the least friction.

 

Since there is no mechanism in the transmission to split the torque - there is nothing to modify that will change said mechanism.... It's an open diff or a locked diff. There is no in-between with your tranny.

 

You can lock it into 4WD and remove the front axles to make it 100% rear wheel drive. But the tranny will not take that kind of abuse forever. You will strip out the 4WD transfer gears eventually. They weren't designed to take all the power the engine can make.

 

GD

[natext6]

Good info! But let's say I was rather set on the idea ( ) How could I potentially go about realizing this? It seems like this idea is pretty close to that of a 4x4. Could a modified (reads HEAVILY MODIFIED) on-demand transmission be made to work? Or are there any other methods that could be applied?

 

Now if only I knew what i was talking about

[GeneralDisorder]

The only way I know to do what you are asking is to install a transmission equipped with DCCD. That means a very rare JDM 5 speed with DCCD or a 6 speed USDM STi transmission with a standalone DCCD controller. Figure on spending about $3000 to $4000 for the transmission and standalone system.... plus installation and custom fab work, etc.

 

The AWD transmissions have a viscous coupler that is either made in 4Kg or 20 Kg versions apparently.... though all that 20Kg unit does is make it *more* like a 4WD and I've only heard they exist - I've never seen one and wouldn't know where to get one. It will not actively transfer more or less torque anywhere... just makes it harder for the front to turn independantly from the rear.

 

GD

Edited February 8, 2012 by GeneralDisorder

[natext6]

Thanks for the info! It's an interesting idea (IMO) too bad i would have to sell many of my organs to afford it Maybe one day, with another xt

[Numbchux]

Yep, DCCD is the only realistic way to have mostly RWD with some power to the front, like you describe.

 

A friend of mine has an '04 USDM 6MT with a DCCDPro controller in his '96 impreza. I got to drive it quite a bit on the ice a couple weeks ago. In full "RWD" mode, it doesn't feel at all like a subaru. It's very obvious that the front wheels aren't helping at all. We actually played a joke on a friend, left it in RWD mode, and told him to give it a try. He spun out about 10 times in one lap

 

 

 

 

The DCCD system uses an electromagnetically controlled LSD, combined with a mechanical rear-bias (usually 35:65, but some older models were 45:55). So, by releasing the LSD, the rear wheels will spin first. By tightening the LSD, it requires more force to get it to slip, which means the front wheels will help more.

 

 

 

GD, AFAIK the 20kg center diff was not installed in any factory transmission. But was available as an aftermarket part from STi. It can be ordered new from http://www.japanparts.com

 

One of the Ziptie Rally cars (bought used, as an already-built rally car) has one of these in it. I'm hoping to talk him into going to a 6MT with the new chassis, and buying it off him to use in my Brat.