FWD or AWD ? Does It Make A Diff

[CXRabbit]

Maybe I understand this differently than you...

"Drive is through Mazdas advanced Active Torque-Split All-Wheel Drive system, which uses various sensors to signal control modules that automatically apportion torque to those wheels most able to provide solid traction. A computer-controlled coupling, connected with the rear differential, automatically adjusts the torque distribution, allowing up to 50-percent of the drive power to be sent to the rear wheels, depending on traction conditions. This all-wheel drive system is also used in the Mazda6 MPS and CX-7." (source)

and

"Vehicle safety starts with those four crucial 'contact patches' where your tires touch the ground. So to help provide optimum traction, regardless of weather or road surface, every Mazda CX-7 is available with Active Torque Split All-Wheel Drive. This advanced, computer-controlled, all-wheel-drive (AWD) system continuously monitors wheel speed, Anti-lock Braking System and Dynamic Stability Control operations as well as engine data, to distribute the optimal amount of torque between the front and rear wheels from 100:0 to 50:50." (source)

Also, TCS controls engine torque by lowering it when the system detects wheel slippage, helping them not to spin. It's very simply explained in the manual on page 5-22. I have no confusion over the difference between TCS and an AWD systems that isn't providing 50:50 torque full-time. 100:0 to me mean front wheel drive until conditions call for a different ratio of front-wheel to rear-wheel torque.

 

[singlemalt_18]

Maybe I understand this differently than you...

I have no confusion over the difference between TCS and an AWD systems that isn't providing 50:50 torque full-time. 100:0 to me mean front wheel drive until conditions call for a different ratio of front-wheel to rear-wheel torque.

Actually, I think you are mis-interpreting the "sales" literature.

The AWD is not a FWD that "kicks in" drive to the rear when needed. It is continuous and fluid. I would suggest to you that the 50:50 split, and the 100:0 to the front condition is "the range" of what the AWD delivers; Its no different than MANY other AWD systems in this regard. The 100:0 is not the "default". The AWD does control torque, but it does so thru "resistance". If it is reducing torque to a wheel, it is because it is applying the torque elsewhere.

When the TCS "controls" torque, it does so by applying brake pressure to a wheel when it detects it "spinning" faster than other wheels. Its the opposite of ABS that releases brake pressure to a wheel it detects that is not spinning or "locking up".

I think everyone is making too much out of these things... FWD or AWD, CX-7 owners have the choice -that's great! Drive them, and have fun... and feel safe, secure, and in control. Those that choose AWD are getting much more than just occasional assistance from the rear wheels. Its really that simple.

 

[njcx7]

also well said... AWD CX is just that. FWD is just that...

 

[Byrnie]

No snow in DC? :bs:

whoops I meant there's not enough snow here to warrant AWD

 

[Byrnie]

I live near Boston and I decided to go with FWD. Why? It's cheaper, and the added weight of the AWD equipment would take a bite (however small) out of gas mileage and acceleration.

And, for those few times a year when the AWD would actually make a difference? I've been driving FWD vehicles all my life and I've never managed to get stuck or spin out before. I'm quite familiar with driving in snow, and AWD just wasn't worth the money (upfront and in the long run) to me.

I second that!

 

[CX7_Scott]

Wait - so I need to realign my universe...?

I was under the (false?) impression that the AWD CX-7 acted as a Front-wheel drive vehicle until rear traction was necessary.

Now I'm reading here that it is 'NOT' that way, but it is full-time AWD with the ability to distribute power to the real up-to 50%...?

Now I'm really baffled. I don't know who to believe. My salesman told me it was front-wheel drive until the rear wheels were necessary, then the traction control would send power to them.

Not only that, I was told the it is safe to tow the car (in neutral, of course) rear-wheels down, but not to tow it front-wheels down (backwards) because of the damage that could occur.

I wish we had a Mazda GURU to shed accurate and definitive light on this subject.

 

[CXRabbit]

Don't think I'm misinterpretting anything.

"system continuously monitors wheel speed, Anti-lock Braking System and Dynamic Stability Control operations as well as engine data, to distribute the optimal amount of torque between the front and rear wheels from 100:0 to 50:50."

100:0 means just that... 100% front wheel drive, 0 rear.

What I do think remains unanswered is under just what conditions it's at 100:0, 50:50 and anywhere in between. But it is absolutely possible, as indicated, that the car at least sometimes is purely 100:0.

 

[singlemalt_18]

Item #1 - My salesman told me it was front-wheel drive until the rear wheels were necessary, then the traction control would send power to them.

Item #2 - Not only that, I was told the it is safe to tow the car (in neutral, of course) rear-wheels down, but not to tow it front-wheels down (backwards) because of the damage that could occur.

Scott,

1. Don't worry, he was just a salesman.

2. Always flatbed a CX-7 AWD! For that matter, flatbed all new vehicles.

 

[CXRabbit]

Right from the Owner's Manual, page 7-19:

A towed 2WD vehicle should have its front wheels off the ground.

A towed AWD vehicle must have all its wheels off the ground.

Educate your salesman

 

[njcx7]

Actually, I think you are mis-interpreting the "sales" literature.

The AWD is not a FWD that "kicks in" drive to the rear when needed. It is continuous and fluid. I would suggest to you that the 50:50 split, and the 100:0 to the front condition is "the range" of what the AWD delivers; Its no different than MANY other AWD systems in this regard. The 100:0 is not the "default". The AWD does control torque, but it does so thru "resistance". If it is reducing torque to a wheel, it is because it is applying the torque elsewhere.

When the TCS "controls" torque, it does so by applying brake pressure to a wheel when it detects it "spinning" faster than other wheels. Its the opposite of ABS that releases brake pressure to a wheel it detects that is not spinning or "locking up".

I think everyone is making too much out of these things... FWD or AWD, CX-7 owners have the choice -that's great! Drive them, and have fun... and feel safe, secure, and in control. Those that choose AWD are getting much more than just occasional assistance from the rear wheels. Its really that simple.

EXACTLY, AWD is just that......
FWD (bj)

 

[singlemalt_18]

How It Works !

To clear up some of the confusion, here is a link that can begin to put some of this urban legend to an end:

http://auto.howstuffworks.com/four-wheel-drive.htm

From this link you can even use the drop-down box to get deeper into "A Basic System & Lots More Information"... the animations in "Basic System" are good.

Happy driving...