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- 2022 2.5GT
Really? Show me a diagram.
Does CX-5 always start in AWD?
- Thread starter wbw
- Start date
If your interpretation is correct, then both rear wheels are driven off of the same side of the FWD differential (the same side that drives the right front wheel). That's curious because the very design of an open differential is to split the torque 50/50. It CAN'T split the torque any other way without some sort of limited slip mechanism. Your interpretation requires the left front wheel to get 50% of the total torque and the remaining 3 wheels to share the remaining 50% of the torque.
Please explain how the vehicle can drive normally if the left front wheel is always getting 50% of the total torque. (uhm)
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- RDX Aspec Adv.
Yep! That is my plan, as well. I want to retire by around 50 to part-time/when I want. I already technically only work when I feel like it, but it will be nice to have less bills.
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- 2022 2.5GT
Your diagram is good because it shows the transfer box hooked up yo a gearbox whereas my two pdf’s refer to the manual and auto FWD boxes. Anyway, I have made a rough sketch over your diagram with my cheep drawing app.
The red line shows the drive shaft passing through the transfer pinion and picking up on the diff gears. The blue line shows that the transfer pinion is splined to the diff cage and bypassing the drive shaft and the diff gears;
I’ve also shown here with a drawing from the RAV manual which is easier to make out;
As you say, picking up of one drive shaft simply wouldn’t work.
So since the CX-5 doesn't have a way to lock it into AWD/4wd, is the car just constantly turning AWD on and off when driving in snow. Meaning, car starts to slip, AWD activated. Car becomes stable and than just fwd, slip than AWD. And so on and so forth. This seems crazy to be this way but not sure any other way. Unless the car can sense it's constantly slipping and just leaves it in AWD for an extended amount of time until it finds no slippage. Curious as to how this works.
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- 2022 2.5GT
I suspect you didn’t read all the posts in this thread but the clutch on the rear axle is constantly variable. It is locked in AWD when the clutch is fully engaged. The car always starts in AWD and backs off gradually as the speed increases and the torque demand decreases. However, it can engage the clutch when greater torque is applied (through the throttle) and to deal with wheel slip that is detected through the TRC, the VSC and the ABS. Rest assured that AWD system on your CX-5 is very high tech and very capable.
Not sure your interpretation of the CX-5 AWD system is right, at least based on what I have read. What I've learned is that the CX-3 has the new iActive AWD that ALWAYS starts in AWD, but the CX-5 does NOT. Now, I would LOVE to be proven wrong because I think always starting in AWD is awesome. But when I read sporadically here and on another forum is that only the CX-3 does this, and CX-5 does not start in AWD. Which sparked my curiosity of the CX-5 AWD system and how it manages during snow. When obviously you need AWD constantly.
OK, it's clear that the propeller shaft is driven through the front differential and that an AWD CX-5 only has two, not three differentials.
But your description of the load path doesn't make a lot of sense to me. If the transfer pinion was splined to the rotating differential cage, then any torque applied through the transfer pinion would add torque to one front driveshaft and reduce torque to the opposite front driveshaft. In a differential, it is necessary for the rotating cage to rotate freely, any load applied to it would mess with the 50/50 torque split of the front wheels.
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- 2022 2.5GT
Forget the transfer pinion for a minute. The normal diff gears (I was always taught to call them sun and planet wheels) are located on pins that pass through the cage. That means the drive shafts splined into the planet gears can climb around the sun wheels contained within the cage - the red path in my diagram.
Now consider the hollow transfer pinion. The drive shafts pass through as a matter of convenience. The transfer pinion is splined to and turns as one with the diff cage - nothing to do with the diff gears inside it. The cage is bolted to the drive gear and the drive gear is meshed with the gearbox - the blue path in the diagram.
Does that make sense?
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- 2022 2.5GT
This goes on a bit but describes the system from the Toyota and is exactly the same as Mazda use on the CX3/5
http://youtu.be/BMv_v9IBugU
http://youtu.be/BMv_v9IBugU
Yes, it does, thanks for the explanation! This means the propeller shaft has a direct (no-slip) connection to the transmission output shaft.
But it leaves one question unanswered.
If the vehicle was high-centered such that both front wheels were off the ground, and you eased on the throttle, the AWD computer would detect the front wheels spinning and bring the AWD clutch plates together which would apply torque to the rear wheels. However, at this point the front wheels have zero torque applied (assuming their speed of rotation is constant) and ALL of the torque produced is sent to the rear wheels. But Mazda claims the rear wheels never get more than 50% of the torque. What am I missing?
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- RDX Aspec Adv.
What if it disabled everything, like a Subaru CVT when you try to accelerate against a chock(*sp)?
From the video it sounds like there is a single differential for the front wheels and a single one at the rear and none between them. The Power Transfer Unit does not vary (on its own) the amount of torque sent to the back.
If so, when the front wheels spin and the rear wheels are stationary, the AWD clutch at the rear must be slipping. Is this correct?
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- 2022 2.5GT
Where did they state this Mike? I presume they mean when all four wheels are on the ground as the best the system can do is lock the clutch. In your hypothetical situation, the front wheels spinning would cause the clutch to lock and apply drive only to the rear wheels which could be seen as 100% but as we said earlier in our discussions, this is not a rock crawler and no doubt the clutch would have a breakaway torque limit.
The situation is and should be, highly unlikely.
Mazda has always said their Active Torque Split AWD can direct "up to 50%" of the torque to the rear wheels. Here is just one example (bottom of page 9):
http://www.mazda.no/assets/uk/cars/brochures/cx-5/mazda-cx-5-brochure.pdf?epslanguage=en
Even assuming all four wheels are on the ground, the scenario I mentioned could still (effectively) happen. For example if the vehicle was parked with both front tires on a patch of wet ice and the rear wheels on bare pavement. I'm not claiming the AWD couldn't deal with such a situation but this too would be an example of the rear wheels receiving (nearly) all the torque. The stance that Mazda's stated 50% torque limit refers to the "breakaway torque limit" of the AWD clutch does not mesh with the fact that Mazda refers to this 50% limit across all models in their line-up regardless of engine size. This is why I assumed there was an open differential between the front and rear powertrains.
I know firsthand that Mazda's AWD works, and works well, but I'm trying to come to terms with the 50% torque limit if it's not due to a differential. Is it possible that the front differential on AWD's functions as two differentials in one case?
Based on the video in #194, the presenter claims most CUVs, use the same system. I know the CX-5 has a PTU, based on a service experience I had. Assuming it works the same way, then there is no 3rd differential and the front differential is almost identical to the FWD version and only does its thing for the front wheels.
Perhaps the system never completely locks the AWD clutch when the front wheels spin as part of its program and that is why rear wheels could be stationary when the front is spinning. In other scenarios it might actually lock the clutch completely. This will explain the video I posted well: TCS limits engine output to regain traction, AWD clutch pack not fully engaged -> vehicle can't climb the hill / rear wheels don't spin on wet grass while front wheels do.
Perhaps the system never completely locks the AWD clutch when the front wheels spin as part of its program and that is why rear wheels could be stationary when the front is spinning. In other scenarios it might actually lock the clutch completely. This will explain the video I posted well: TCS limits engine output to regain traction, AWD clutch pack not fully engaged -> vehicle can't climb the hill / rear wheels don't spin on wet grass while front wheels do.
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- 2022 2.5GT
No, there is only one diff and that drives the front drive shafts. Tight corner braking is catered for with the drive unit clutch which backs off the more the lock is turned.
Chris_Top_Her
Contributor
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- San Antonio, Texas
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- '15 CX-5 Miata AWD
SO what are some other owners experience with the AWD for road performance? Especially those with some type of handling mod? I have been extra conscious lately about causing the diff to be engaged (indeed I've gotten used to the little thump it makes). Who else makes good use of the AWD aside form the 1 time a month driving in an adverse condition or offroad where it actually made a real difference? lol
