Does CX-5 always start in AWD?

[Unobtanium]

Keep in mind that the fact the AWD clutch exists at all is to be able to modulate the power to the rear wheels without shock. The least likely time for it to overheat is when it's fully locked up. The design of the clutch is ingenious in that it uses a very small, low power solenoid to engage the rear drive. The small solenoid engages a small pilot clutch which begins to transmit torque to the rear wheels. This small transfer of torque on the small pilot clutch engages a special cam/ball mechanism that forces the larger main clutch plates together. This cam multiplies the force acting on the main clutch. The total torque applied to the rear wheels is modulated by pulsing the current (on/off) to the small solenoid and the cam mechanism therefore modulates more or less torque to the main AWD clutch plates depending upon the on/off duty cycle of the solenoid.





"4WD" refers to any mechanical system that direct coupled. The differentials do not need to be locking differentials to be considered "4WD". Most 4WD's have open differentials and sometimes limited slip differentials, locking differentials are quite rare. Most all 4WD's will have locking hubs. This is how the system is converted from 2WD to 4WD (along with engaging the transfer case). The locking hubs do not increase or decrease off-road ability, they simply allow the front wheel drive axles/front differential/front drive shaft to be disconnected when 4WD is not engaged to save fuel and wear on the driveline between the wheels and the transfer case.

The rear hubs on a AWD CX-5 are always locked and thus the rear axle/rear differential is always turning (when the vehicle is in motion). This explains most of the extra fuel burned by an AWD CX-5 vs FWD.

So how do you figure the awd system overheats if there is no slipping?
My jeep had two drove shafts and drove the fronts and rears nearly 50 50 and still only had a 1mpg rated difference on the freeway between rwd and awd...iI think mazda system is just inefficient.

As to your poly sheet 4 tire spin...on wet grass the mazda can't pull it off. The poly sheet is super low friction and doesn't overcome the torque bias of the mazda system. The wet grass isn't as slick, and it overpowers the mazda ability to drive all 4 tires.

 

[MikeM.]

Maybe not and that's why the cx5 has a bigger difference in mpg between awd and fwd compared to other cuvs. Also, does this offer any extra advantages? Quicker response and handling?

I don't think there is a significant difference in the MPG hit AWD takes on a CX-5 vs. other vehicles in it's class. The accurate way to compare this AWD hit between different brands is not in MPG because this distorts the difference in favor of CUV's that get worse MPG than the CX-5 (which is basically all of them). In the real world the actual hit is about 1-2 mpg (which is less than the difference between 2.0L vs. 2.5L. If the AWD hit was more than that, my AWD 2.0L wouldn't have a lifetime MPG average of 32.4 MPG. Keep in mind that a 3 MPG hit when your getting 34 MPG is the equivalent of a 2 mpg hit when your only getting 23 MPG. See how MPG distorts things? That's why most of the rest of the world uses liters per 100k. Because that's a linear way to measure fuel consumption.

The advantages of having fixed hubs is mechanical simplicity, reliability, cost and safety. One of the biggest advantages of AWD vs. 4WD is the full-time nature of AWD. My 4WD F-150 is a RWD truck 99% of the time. If I want 4WD I can't drive on bare pavement or a parking lot that has been de-iced. The CX-5 goes seamlessly between ice, patchy ice and bare pavement. If the hubs were disconnected and I hit an icy patch I would be in a FWD vehicle. It takes time and energy for the drive components to spin up and the time to do it is not while your sliding on a patch of ice. I suppose a CUV could be built with manual locking hubs that could be disconnected seasonally. This would entail more cost, weight and complexity. It would be less convenient. Also significant would be the double set of software that would need to be developed, one set for hubs locked, one set for hubs open. And there would need to be sensors on each hub to insure they were fully locked or fully open in order to tell the CU which software to load. I don't think most people realize the complexity of the operating software on an advanced vehicle like the CX-5.

I don't see the big benefit of adding all that complexity, cost and potential points of failure.

 

[MikeM.]

So how do you figure the awd system overheats if there is no slipping?

No one claimed the AWD clutch doesn't slip (that is the purpose of a clutch). However, your claim was that if only 50% of the torque could be applied to the rear wheels, then something has to be slipping. But this is false and exposes a fundamental misunderstanding you have about how the CX-5 AWD works. Because when the rears are receiving 50% of the torque the AWD clutch is locked up, it's no longer slipping, it's fully engaged.

The poly sheet is super low friction and doesn't overcome the torque bias of the mazda system. The wet grass isn't as slick, and it overpowers the mazda ability to drive all 4 tires.

No Grasshopper, by definition, open differentials don't have any torque bias. If you want to talk about wet grass, come here to the Pacific NorthWet, I mean Northwest. Plenty of that to go around and the CX-5 AWD works great on it. But your claim is that wet grass has too much traction which somehow magically "overpowers" the ability of the Mazda to drive all 4 wheels. That's just wrong and continues to expose your misunderstanding about how Mazda's AWD actually functions. Maybe this video I took will help:

This hill in the video is really steep and slick because it's cold and wet. Probably not as slick as most wet grass but, according to your theory, this should overpower the Mazda's ability to power all 4 wheels even more so than wet grass:

https://www.youtube.com/watch?v=bZCROYEK1DM

Please watch both attempts to climb this hill because the first time I high-centered on the chassis. The second time I adjusted my line slightly so I wouldn't high-center and the CX-5 chugged right up it. It would not have been able to do this without all 4 wheels driving and the proof of this is that I slid backwards 6 feet with all 4 wheels locked up with the brakes. In other words, the top of the hill was so steep and slippery that the brakes wouldn't even hold it there. But the CX-5 powered right up it with all 4 wheels driven and minimal wheel spin.

 

[Chris_Top_Her]

No one claimed the AWD clutch doesn't slip (that is the purpose of a clutch). However, your claim was that if only 50% of the torque could be applied to the rear wheels, then something has to be slipping. But this is false and exposes a fundamental misunderstanding you have about how the CX-5 AWD works. Because when the rears are receiving 50% of the torque the AWD clutch is locked up, it's no longer slipping, it's fully engaged.




No Grasshopper, by definition, open differentials don't have any torque bias. If you want to talk about wet grass, come here to the Pacific NorthWet, I mean Northwest. Plenty of that to go around and the CX-5 AWD works great on it. But your claim is that wet grass has too much traction which somehow magically "overpowers" the ability of the Mazda to drive all 4 wheels. That's just wrong and continues to expose your misunderstanding about how Mazda's AWD actually functions. Maybe this video I took will help:

This hill in the video is really steep and slick because it's cold and wet. Probably not as slick as most wet grass but, according to your theory, this should overpower the Mazda's ability to power all 4 wheels even more so than wet grass:

https://www.youtube.com/watch?v=bZCROYEK1DM

Please watch both attempts to climb this hill because the first time I high-centered on the chassis. The second time I adjusted my line slightly so I wouldn't high-center and the CX-5 chugged right up it. It would not have been able to do this without all 4 wheels driving and the proof of this is that I slid backwards 6 feet with all 4 wheels locked up with the brakes. In other words, the top of the hill was so steep and slippery that the brakes wouldn't even hold it there. But the CX-5 powered right up it with all 4 wheels driven and minimal wheel spin.

That video would be 100% more cool if the car had that lift kit and those mud wheels. No high center!

 

[Unobtanium]

No one claimed the AWD clutch doesn't slip (that is the purpose of a clutch). However, your claim was that if only 50% of the torque could be applied to the rear wheels, then something has to be slipping. But this is false and exposes a fundamental misunderstanding you have about how the CX-5 AWD works. Because when the rears are receiving 50% of the torque the AWD clutch is locked up, it's no longer slipping, it's fully engaged.




No Grasshopper, by definition, open differentials don't have any torque bias. If you want to talk about wet grass, come here to the Pacific NorthWet, I mean Northwest. Plenty of that to go around and the CX-5 AWD works great on it. But your claim is that wet grass has too much traction which somehow magically "overpowers" the ability of the Mazda to drive all 4 wheels. That's just wrong and continues to expose your misunderstanding about how Mazda's AWD actually functions. Maybe this video I took will help:

This hill in the video is really steep and slick because it's cold and wet. Probably not as slick as most wet grass but, according to your theory, this should overpower the Mazda's ability to power all 4 wheels even more so than wet grass:

https://www.youtube.com/watch?v=bZCROYEK1DM

Please watch both attempts to climb this hill because the first time I high-centered on the chassis. The second time I adjusted my line slightly so I wouldn't high-center and the CX-5 chugged right up it. It would not have been able to do this without all 4 wheels driving and the proof of this is that I slid backwards 6 feet with all 4 wheels locked up with the brakes. In other words, the top of the hill was so steep and slippery that the brakes wouldn't even hold it there. But the CX-5 powered right up it with all 4 wheels driven and minimal wheel spin.

I had thought I saw a video of what I described. Turns out it was the diesel cx5 and not the gas burner, though.

 

[Anchorman]

When I spoke about 50% drive to the rear wheels I was referring to a 50/50 split between front and rear axles. The rear axle coupling is able to fully lock (providing it doesn't get overloaded and reach its breakaway torque) so would therefor be able to transmit 100% of the available torque coming from the transfer box.

 

[MikeM.]

I had thought I saw a video of what I described. Turns out it was the diesel cx5 and not the gas burner, though.

I believe you're referring to this ridiculous video: https://www.youtube.com/watch?v=iSj9UEVYI8o

The problem with that video isn't that the CX-5 is diesel powered, it's that it's (once again) a test of tire traction on wet grass, not AWD capability. Again, the video evidence shows how important it is to have suitable tires for the intended usage. None of the three AWD vehicles tested could climb the hill from a standing start even though you could see both front and back tires spinning simultaneously on all of them (check out the CX-5 at 3:30).

Tip for climbing slippery slopes in a CX-5: Push the "TCS" (traction control) button (it will light up) before attempting a difficult climb. This turns off ONLY the portion of TCS that cuts power to the engine when too much power is applied for the available traction. However, it does NOT disable the portion of TCS that modulates individual brakes on the tire that is spinning. The application of a braking force to only the spinning wheel(s) causes the open differentials to AUTOMATICALLY transfer additional torque to the wheels with more traction whether this is front/back or side/side. Of course in this mode it is up to the operator to modulate the throttle appropriately to avoid excessive wheel spin because there are very few conditions where high speed spinning will work better than slight/negligible wheel spin. Wet grass is best climbed with negligible wheel spin. In the above video it is OBVIOUS the driver failed to switch TCS off in the first attempts. It looks like they may have figured this out in the final attempt (but of course even the most perfect AWD can not climb a slope from a standing start if the required tractive force exceeds the available tractive force). This is why suitable tires are rule #1.

Do not try to deduce off-road knowledge from videos produced by people who admit they do not have off-road experience. The video is meaningless except to illustrate the points I outlined above (TCS was not disabled on first CX-5 attempt and tires are key).

 

[bmninada]

Someone should REALLY, REALLY TAKE THE EFFORT to post a video in YouTube, once and for all where it shows CX-5's ability and talk about HOW to do it. Especially wet and icy surfaces.... man: those guys are nuts. Even I, with NO background in ice know to use low gears and go slow....

Thank Mike for the tip involving TCS. Never knew it. Check-list added: YES!

 

[MikeM.]

Even I, with NO background in ice know to use low gears and go slow....

Thank Mike for the tip involving TCS. Never knew it. Check-list added: YES!

You're welcome, it seems like common knowledge but it's typically not necessary to turn it off and it's easy to forget in the heat of the moment.

As far as using low gears for ice, unless this means go slow, it's the most common misunderstanding of all snow/ice "wisdom". The only thing that might be more common is that AWD is needed to be competent in snow/ice (when actually winter tires are far more important than AWD).

In fact the CX-5 AT has a special mode called 2nd Gear Fixed mode. This mode facilitates driving on very slippery roads by eliminating the normal downshift to 1st gear when coming to a stop. It will stay in 2nd gear right down to 0 mph. This assists starting out on ice because it naturally reduces engine torque due to the lower rpm's starting out.

To enter fixed mode simply put the AT in manual shift mode and select 2nd gear while stopped (or almost stopped). It will now not shift to low gear unless you do it manually. This is different from normal 2nd gear mode which will automatically shift to 1st every time you approach a stop.

 

[Lbear]

Someone should REALLY, REALLY TAKE THE EFFORT to post a video in YouTube, once and for all where it shows CX-5's ability and talk about HOW to do it. Especially wet and icy surfaces.... man: those guys are nuts. Even I, with NO background in ice know to use low gears and go slow....

https://youtu.be/4C8b6PHrVfQ

https://youtu.be/khYz8d5xY4o

https://youtu.be/_VrFAutcaig

 

[Kedis82ZE8]

Can't forget these two videos

 

[MikeM.]

Can't forget these two videos

I don't like abusing my vehicles but it's nice to know the CX-5 has the capability to perform under such conditions.

You never know when there might be a zombie apocalypse! (wink)

 

[Kedis82ZE8]

I don't like running through mud myself.

 

[MikeM.]

I don't like running through mud myself.

Even if the zombies were hot on your heels? (drive2)

 

[Kedis82ZE8]

At that point.... I'm not worrying about scratches, dents or a cracked windshield ;-)

 

[halfast3]

Even if the zombies were hot on your heels? (drive2)

At that point, they'd be zoombies ;o)

 

[Unobtanium]

I don't like abusing my vehicles but it's nice to know the CX-5 has the capability to perform under such conditions.

You never know when there might be a zombie apocalypse! (wink)

s***, mine couldn't even survive a little cold weather. I will say, though, while I had AWD, it was amazing how much traction it gave that I "took for granted". I've changed my tune on the CX-5's AWD system. It may be fragile and finicky, but when it works, it's great!

 

[Chris_Top_Her]

s***, mine couldn't even survive a little cold weather. I will say, though, while I had AWD, it was amazing how much traction it gave that I "took for granted". I've changed my tune on the CX-5's AWD system. It may be fragile and finicky, but when it works, it's great!

Orange virus tune? Which fuel?

 

[Anchorman]

s***, mine couldn't even survive a little cold weather. I will say, though, while I had AWD, it was amazing how much traction it gave that I "took for granted". I've changed my tune on the CX-5's AWD system. It may be fragile and finicky, but when it works, it's great!

It wasn’t the cold that made your diff fail, it left home because you made it feel dejected.

Seriously though Unob, there are thousands of those units operating in much colder conditions than yours. Maybe you were just unlucky.

 

[MikeM.]

It wasn’t the cold that made your diff fail, it left home because you made it feel dejected.

I think that's a good point. Unobtanium has spent the last few months telling anyone who would listen that the AWD on the CX-5 can't even handle a little wet grass, that it doesn't power all 4 wheels, that it's effete (powerless and ineffectual). These are odd accusations to make about your own vehicle, especially considering that not once did he say he had actually experienced it's deficiencies first hand even though he successfully used it to get up the rugged trail through the steep back section of his remote property. He has even doubted the CX-5's snow/ice performance (even though he's never driven it in those conditions and tons of owners have attested to it's sure-footed behavior in winter storms).

Now his tune has changed rather curiously. After fording a single creek that barely came up to the vehicles underbelly, his AWD unit needs replacement under warranty. Now that it broke, he says he has "changed his tune" on the AWD system. He claims the AWD system works "great" (and what a sudden change that it) but that it's "fragile and finicky" (based on a single failure). Not once in his ownership experience did he report a single glitch in his CX-5 or it's ability to successfully climb any hill. But now that his AWD had a single failure, a failure that I do not believe has been reported by a single other owner, his story is now that the system is "fragile and finicky" (but that it works great, when it works). I've never heard of anyone use the term "finicky" to describe the sudden catastrophic failure of a heavy component. This is quite a curious change in tune. Any thinking person can see that the story does not make rational sense.

For the next 3 months, instead of hearing repeatedly how the AWD doesn't drive all 4 wheels, how it's ineffective on wet grass, we will instead hear repeatedly about it's "fragile and finicky" nature. He will talk endlessly about how it works really good (when it's working) but that it's weak and unreliable. He will pop into any discussion that even mentions "AWD" and repeatedly tell us how weak and finicky it is. It will not bother him that his single failure is his alone, that no other owner has reported the failure of the AWD differential. Plenty of us use our CX-5's in rugged conditions in the Rockies and the Cascades without a single other owner reporting a failure. But this will not trouble the man on a mission to disparage the Mazda AWD system, he doesn't care how he plants the seed of doubt in peoples mind, or, whether it jibes with reality, as long as that seed of doubt has been planted, he will have done his job.

Seriously though Unob, there are thousands of those units operating in much colder conditions than yours. Maybe you were just unlucky.

A very reasonable perspective.

But that won't stop him from characterizing Mazda's AWD as weak and unreliable. No amount of reason will change his behavior. With all the video proof leaving his previous repetive claims about the lack of Mazda's AWD ability to drive all 4 wheels completely and utterly discredited, he has a new way to disparage the AWD system. This new mission cannot be proven wrong with simple video proof so he will share his sob story endless and speak as if this weakness and unreliability of the AWD system is well-known, as if it's a fact. No prospective owner will be able to visit this forum without hearing about his AWD failure. He would shout it from the mountain tops if anyone would listen.

The only question remaining is why. And I can't answer that.