Detailed discussion of Toyotas awd system, specifically for the st205 Options

[enderswift]

hey everyone,

here's what I 'think' I know. The awd system fitted into the st205 is pretty ancient compared to today's cars, but was decent when it first came out and was organized out like this:

1. There was an open differential in the transversely mounted transmission that had a transfer case coming out of the rear.
2. No center differential but a center bearing instead. So it always had a 50/50 front/rear torque split
3. rear differential came with a torsen limited slip

lets compare this to other awd systems. Past and present. Subaru is really big on the fact that they have a symmetrical awd system. Do you guys think the fact that an st205s unequal front axles hurts the car?

and, could it be possible to fit the limited slip from an mr2 and have torsens front and rear? I think that would be interesting since apparently one of the biggest handling problems with the st205 is that the the inside front wheels spin on really sharp turns.

heres an interesting video comparing modern awd system:

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

[enderswift]

awesome this cleared up some misconceptions. I assumed the axles were unequal length because its a transversely mounted engine, and most of those have different lengths.

There is a center differential in the transmission, its located inside the transfer case. It is not fully open in the sense that if one wheel is free all the power goes there. It has a split between the front and rear, so if one wheel is free at the front, power goes to the back. You can further this by adding the LSD rear end which came optional in the st185, came factory on st185 CS/RC, and also st205 chassis.

I knew there had to be something like that. Its good to hear that if the fronts slip then the rear still gets power.

how do you guys think this system stacks up compared to modern cars with torque vectoring and the like? Personally I hate systems that use computers to take over. I prefer mechanical enhancements like lsd's that offer the driver more control as opposed to doing things for the driver.

[Hanyo]

awesome this cleared up some misconceptions. I assumed the axles were unequal length because its a transversely mounted engine, and most of those have different lengths.

There is a center differential in the transmission, its located inside the transfer case. It is not fully open in the sense that if one wheel is free all the power goes there. It has a split between the front and rear, so if one wheel is free at the front, power goes to the back. You can further this by adding the LSD rear end which came optional in the st185, came factory on st185 CS/RC, and also st205 chassis.

I knew there had to be something like that. Its good to hear that if the fronts slip then the rear still gets power.

how do you guys think this system stacks up compared to modern cars with torque vectoring and the like? Personally I hate systems that use computers to take over. I prefer mechanical enhancements like lsd's that offer the driver more control as opposed to doing things for the driver.

each of those systems have their strengths.

Mechanical awd systems are great for strength and power. When you add more power beyond what the computer is programed for the car will react the same. However awd system without computer control is a thing of the past.

In the real world there are too many road surfaces to deal with that one single system to work for all of them. Another reason why computer controlled awd systems are superior is the computers ability to control the way the car drives. Two good examples of smart awd systems are the Mitsubishi evo and the Nissan gtr. Both the cars rely heavily for the computer to each wheel.