How does the CX-5 AWD System work?

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blaznivy

Member
So I'd like to better understand the AWD system and I'm hoping someone can give me some insight.

1. How does the vehicle know when to kick in AWD
2. How long does the AWD last and what effectively turns it off
3. Are there any indicators on the dash that let you know when AWD is on
4. Has anyone encountered a situation when AWD kicks in, and what are their thoughts?

Thanks guys!
 
blaznivy said:
So I'd like to better understand the AWD system and I'm hoping someone can give me some insight.

1. How does the vehicle know when to kick in AWD
2. How long does the AWD last and what effectively turns it off
3. Are there any indicators on the dash that let you know when AWD is on
4. Has anyone encountered a situation when AWD kicks in, and what are their thoughts?

Thanks guys!
Click to expand...

1. Wheel slip under acceleration. Wheel speed sensors.
2. As long as the front wheels get slip
3. No
4. Yes. Grip.
 
Gives some transmission detail.

http://www.awdwiki.com/en/mazda/#CX_5

I have had the front wheels slip towing on wet grass before the AWD cut in, not something that would happen with a T31 Xtrail, but the XT was equipped with all season tyres, not summer tyres like the CX-5.
 
How do you define slip and how sensitive is the sensor? For example, when I drove the Ford Escape AWD recently, there was a display that would show the power (torque?) to each wheel. Even under normal accelleration from a stop, the AWD system would kick in at first during accelleration then resort to FWD after that. Is the CX5 similar?
 
Spin without movement.

Same as you cannot find much on the Mazda system.

I do know the CRV always starts of in 4wd, then resorts back to fwd.
 
I drove my through many snowstorms and definitely tried to push it a few times. This was back when I had the stock 19'' toyos and they, along with the AWD system performed very well. It was extremely hard to notice when the AWD "kicked in" because it happens so fast and so smoothly. But, it definitely happens after it senses slip, something like thousanths of a second. If I'm not mistaken, the new CR-V with AWD has all wheels powered up until 18mph no matter what - then it goes to front wheel. This is to provide maximum traction during starts when you need it most. I wish the CX-5 had this feature as well. Actually, I wish it had AWD all the time, like my old Subaru WRX had. You could fishtail that thing no problem in the snow! (When you wanted to). The CX-5's AWD definitely wants that thing to remain straight and no back end whipping out (which is the safer bet for most drivers).

Of note - I recently watched an episode of the American verision of Top Gear, (UK version is waaaaay better) where Tanner Foust took a stock Mini Pacer w/ AWD to a rally race and competed in one of the legs (~11 miles). He really struggled to get the back end around to properly drift through the corners. The car kept wanting to straighten itself out which reminded me of trying to do donuts with the CX-5. It wasn't until he broke the dynamic stability control that he was able to whip that thing around like a true AWD system. Oh well, I'm very satisfied with the AWD system - I haven't gotten close to being stuck yet and I have taken it through multiple storms of 6'', 8'' and 12'' of snow. I'll try again this winter!
 
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Does the AWD CX-5 feature a rear LSD? I don't know a thing about the CX-5's AWD system.

If so, it provides mechanical slip correction in the rear, in addition to electronic and hydraulic slip correction to the front wheels, in the event slippage occurs.
If it is like Mazda's other recent AWD systems, torque to the rear is actuated through an electromagnetic clutch pack, just before the rear gear set/diff.
And there really isn't any "kicking in" to the AWD. It is full time, and torque is always delivered to the rear, though it is heavily front biased. The DS is always rotating.

Least ways, that is how it functions on the MS6/CX-7.
On my MS6, T/C, DSC and the AWD system all work in harmony to split torque.
For example, under certain conditions, the ECU closes the throttle plate to limit power, uses the HCU (ABS) to subdue slippage at certain wheels, limit tq delivered to the rear, through the rear clutch, then, of course, mechanical LSD at the rear diff.
 
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The BMW X3 is permanent 4wd, so that's what I would expect.

I'd also be interested in how the latest CRV does as that sets off in 4wd.

Subaru usually show well in these sort of tests.
 
IHeartGroceries said:
Does the AWD CX-5 feature a rear LSD? I don't know a thing about the CX-5's AWD system.

If so, it provides mechanical slip correction in the rear, in addition to electronic and hydraulic slip correction to the front wheels, in the event slippage occurs.
If it is like Mazda's other recent AWD systems, torque to the rear is actuated through an electromagnetic clutch pack, just before the rear gear set/diff.
And there really isn't any "kicking in" to the AWD. It is full time, and torque is always delivered to the rear, though it is heavily front biased. The DS is always rotating.

Least ways, that is how it functions on the MS6/CX-7.
On my MS6, T/C, DSC and the AWD system all work in harmony to split torque.
For example, under certain conditions, the ECU closes the throttle plate to limit power, uses the HCU (ABS) to subdue slippage at certain wheels, limit tq delivered to the rear, through the rear clutch, then, of course, mechanical LSD at the rear diff.
Click to expand...

No, it does not have a rear LSD nor a front LSD. Both diffs are fully open. It is electronically controller coupling unit which just about everyone else uses as well. I do NOT believe it is always coupled (so it almost always a FWD vehicle). This is mainly due to the fact that in order for the MazdaSpeed 6 to be always coupled (yes it's always transferring some power with a REAR bias) they actually had to setup additional cooling for the front transfer case. That does not appear to be the case for the CX5.

So although the drive shaft is always rotating (since it's hooked into a transfer case) power is NOT always being transfer to the rear via that drive shaft (since it's not always coupled to the rear diff). That's why AWD vehicles get less mpg ... heavier and there is energy "wasted" by spinning a drive shaft that isn't really propelling the car at all.

If you drive one, you'll get the sense that you really do need to have some forward slip before anything happens. In my limited testing so far, soon as you get some front slip it seems to really engage and take off.
 
That is also what I notice. At my job I need to get on a moderate trafic road from standing on a gravel patch very quickly as soon as a gap presents itself between cars, and jump to 50 mph as fast as I can. I almost always feel a slight slip of the front wheels, just a fraction of a second, before the car starts to grip and accelerate nicely.
 
vroom said:
That is also what I notice. At my job I need to get on a moderate trafic road from standing on a gravel patch very quickly as soon as a gap presents itself between cars, and jump to 50 mph as fast as I can. I almost always feel a slight slip of the front wheels, just a fraction of a second, before the car starts to grip and accelerate nicely.
Click to expand...

On a patch of gravel even a 4WD will spin it's wheels some, especially from a standing start in 1st gear when the drive lines apply maximum torque to the wheels. AWD and 4WD is not immune from spinning wheels. What you are feeling is not the delay switching from FWD to AWD, that happens faster than you can detect, it's measured in milliseconds.
 
FWIW I was already moving when I was testing it out (5km/h or so), not just slamming the gas from a dead stop. I see your point about easily being able to spin when you start from a dead stop, but it's a lot less likely when you already have some forward momentum going.
 
MikeM. said:
On a patch of gravel even a 4WD will spin it's wheels some, especially from a standing start in 1st gear when the drive lines apply maximum torque to the wheels. AWD and 4WD is not immune from spinning wheels. What you are feeling is not the delay switching from FWD to AWD, that happens faster than you can detect, it's measured in milliseconds.
Click to expand...

You might be right MikeM, but the slip I feel pretty much always the same lenght of time before grip becomes 100%. Always the same pattern. And it is very short, it feels like the front wheels make maybe a quarter or an eight of a turn before it all grips. Just enough time for me to hear a few rocks being thrown back.
 
phoned said:
No, it does not have a rear LSD nor a front LSD. Both diffs are fully open. It is electronically controller coupling unit which just about everyone else uses as well. I do NOT believe it is always coupled (so it almost always a FWD vehicle). This is mainly due to the fact that in order for the MazdaSpeed 6 to be always coupled (yes it's always transferring some power with a REAR bias) they actually had to setup additional cooling for the front transfer case. That does not appear to be the case for the CX5.

So although the drive shaft is always rotating (since it's hooked into a transfer case) power is NOT always being transfer to the rear via that drive shaft (since it's not always coupled to the rear diff). That's why AWD vehicles get less mpg ... heavier and there is energy "wasted" by spinning a drive shaft that isn't really propelling the car at all.

If you drive one, you'll get the sense that you really do need to have some forward slip before anything happens. In my limited testing so far, soon as you get some front slip it seems to really engage and take off.
Click to expand...

Just so it is clear, the Speed6 is a front biased system. Yes, the PTO is oil and water cooled. I just replaced the unit in my MS6, which was a major undertaking.
A percentage of torque is ALWAYS being delivered to the rear on the Speed6, through the clutchpack. Up to 50%, under heavy load. Yes, more negligible percentage to the rear under low load. It is actuated by a solenoid/duty cycle. The only situation in which the rear is completely disengaged at the clutch is when the car is performing low speed maneuvers (parking), when the e-brake is engaged, or when the control module detects a malfunction, such as overheated oil in the rear differential.

Though, it is all water under the bridge if the CX-5 does not share any of this technology.

Open t-case and diff is teh suck.
 
vroom said:
You might be right MikeM, but the slip I feel pretty much always the same length of time before grip becomes 100%. Always the same pattern. And it is very short, it feels like the front wheels make maybe a quarter or an eight of a turn before it all grips. Just enough time for me to hear a few rocks being thrown back.
Click to expand...

I have only had the front wheels spin once, pulling of a wet grass site with the caravan on the hook.

The wheels rotated more than once before I assume the rear wheels took up some load, only then the car move forwards.

The system certainly isn't as sensitive as a Xtrail T31, that system would detect wheel spin in less than one revolution, that was Nissans claim, which appeared to be true because I never had any wheel spin on wet grass or anywhere else for that matter. It also had a lock selection if required.
 
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IHeartGroceries said:
Just so it is clear, the Speed6 is a front biased system. Yes, the PTO is oil and water cooled. I just replaced the unit in my MS6, which was a major undertaking.
Click to expand...

I don't know, all the speed 6 guys pointed me to this document this seems somewhat official and seems to go against what you think:

MS6 Technical Training Manual (http://www.stable-networks.com/ms6r/images/forum/ms6-101/speed6guide.pdf)

- Many AWD systems in FWD cars require front wheel slip (viscous couplings) before power is transferred to the rear, MAZDASPEED6 has a strong rear wheel bias in most driving conditions
- Almost constant torque to the rear requires a water cooled transfer unit
 
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