Constant 4wd V Awd

[cinky]

A guy asked me this the other day and i was a little stumped. I could explain the differences on where to use them but i couldn't exactly explain the differences of how they actually work. so now its my personal mission to find out.

 

Any one know?

Edited June 7, 2010 by cinky

[philbey]

same shit different name.

 

It's like Hi-Cams. Just some jerkoff in the marketing department flogging their same old same old product to the Hipsters who want to jerk off over specifications in their little bourgeouis laneway bars.

[Hiro Protagonist]

In general, you get 4WD on a proper off-roader like a Landcruiser (constant or switchable), and AWD on a car-based vehicle like an Audi or Subaru. Technically there isn't really a difference (afterall you can easily get constant AWD cars and switchable 4WDs and vice versa), but often you'll find that an AWD car will be some kind of poser that is normally 2WD but will automatically switch to 4WD when the conditions demand it (but often too slowly, I'm looking at YOU Honda CRV...).

Edited June 7, 2010 by Hiro Protagonist

[cinky]

same shit different name.

 

It's like Hi-Cams. Just some jerkoff in the marketing department flogging their same old same old product to the Hipsters who want to jerk off over specifications in their little bourgeouis laneway bars.

sorry should of explained that a little better.

cars in question

Subaru Forester symmetrical AWD

 

80 series landcruiser wagon constant 4wd

[Raven]

The Forester is constant 4WD.

 

Depending on the Land cruiser and what hubs its running and what range the transfer case is in (this is what people are forgetting) all depends on if its driving all 4 wheels or if its driving just the rears.

 

The transfer case engages and disengages the front axle, thats why you have a 2WD/4WD shifter for the transfer case and high and low range gearing.

 

Manual locking hubs on older 4WD's are required to give it the constant drive on all 4 wheels whereas most 4WD's these days auto-lock the front hubs which is also dependent on the fancy schmany electronics the vehicle may or may not have.

 

Hope that helps a little bit!

[altezzaclub]

There are quite a few different ways of running the centre diff in terms of how and when it locks. Some will have control of the diff so you can lock them or vary the torque split, but cheap ones are automatic in operation.

 

My 4WD Nissan Pulsar wagon was FWD with a silicon centre diff. It would give a quick chirp of the front wheels under acceleration then the centre diff would power the rear diff and it would just get up and go. All the rest of the time it was just FWD.

 

I think most of the Jap saloons are like that, VW use a Haldex wet clutch centre diff in their 4-Motion system and Audi use a Torsen.

 

All of them are AWD or 4WD, both terms mean the same thing.

[altezzaclub]

...and the Forester is the same as my Nissan, a silicon centre diff that drives the front wheels unless there is wheelspin.

 

MODELS WITH FIVE-SPEED MANUAL TRANSMISSION – CONTINUOUS ALL-WHEEL DRIVE: A viscous-type locking center differential and limited-slip rear differential help distribute torque – normally configured at a 50/50 split front to rear.

 

The WRX STi has a planetary gear system, so they can vary the torque-

 

The STI uses an electronically managed multi-plate transfer clutch and a mechanical limited-slip differential in conjunction with a planetary-gear-type center differential