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#3428197 - 07/18/14 07:15 AM Re: CVT with shift sensation [Re: d00df00d]
Hokiefyd Online   content


Registered: 06/24/04
Posts: 11702
Loc: North Carolina
Originally Posted By: d00df00d
Do you just not like it, or do you really think it represents greater isolation? Those are two different ideas.


I don't like it because, among other things, I feel more disconnected from the powertrain. I know that the engine is as connected to the wheels with a CVT compared with a stepped automatic. But the engine flaring that goes along with true stepless operation is something I don't like. I'd rather be able to load the engine down with a locked torque converter than have its speed rise.

Originally Posted By: d00df00d
Assuming the stepped transmission in question allows manual gear selection, this part makes sense.

If we're comparing a CVT to an automatic WITHOUT manual gear selection, I don't see how a stepped transmission offers any non-trivial kind of additional control.


Yes, I agree with this. Every automatic I've owned allows pretty much full control over the ratio selection. If all I have is "D" and nothing else, then I'm lost. Note my "lack of like" of the 8-speed in the rental Chrysler 300 I had. All you had with that silly electronic shifter was D and L. The vehicle offered the driver zero control over ratio selection. And as I said in another post, the programming was horrible as well...you either had to cane or idle it around for the shift schedule to not drive you batty.

I would drive a clutchless manual transmission. I don't mind shifting gears. In fact, I ENJOY shifting gears. The primary reason I don't have a clutch in my car is because of my wife's previous foot injury (we trade cars often enough that it'd present a problem if mine had a clutch).

Originally Posted By: d00df00d
Why have a CVT at all, then? A decently programmed 8-speed automatic, let alone a DCT, would blow it away in the manual mode without giving up much efficiency.


I agree completely. As I said to demarpaint earlier in this thread, I'm not advocating for CVTs here. I prefer conventional stepped transmissions. I'm advocating for manual control if the only available "automatic" transmission is a CVT.
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#3428208 - 07/18/14 07:28 AM Re: CVT with shift sensation [Re: demarpaint]
Miller88 Offline


Registered: 04/09/08
Posts: 7169
Loc: Onondaga County
Originally Posted By: demarpaint
Originally Posted By: d00df00d

Why have a CVT at all, then? A decently programmed 8-speed automatic, let alone a DCT, would blow it away in the manual mode without giving up much efficiency.


Good question. I'd also be willing to bet the 8 speed would be stronger, last longer, and have a higher tow rating than a CVT. That's what I'd be looking for.


The 8 speed in the "ram" trucks is rated to tow more than ANY automotive application CVT ...
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#3428227 - 07/18/14 07:40 AM Re: CVT with shift sensation [Re: wing0]
Papa Bear Offline


Registered: 08/11/05
Posts: 6159
Loc: Leamington, ON, Canada ..... r...
I have a 4T65E with CVT sensation ..... popcorn
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#3428310 - 07/18/14 09:11 AM Re: CVT with shift sensation [Re: Hokiefyd]
d00df00d Offline


Registered: 10/20/05
Posts: 9344
Loc: PA
Originally Posted By: Hokiefyd
Originally Posted By: d00df00d
Do you just not like it, or do you really think it represents greater isolation? Those are two different ideas.


I don't like it because, among other things, I feel more disconnected from the powertrain. I know that the engine is as connected to the wheels with a CVT compared with a stepped automatic. But the engine flaring that goes along with true stepless operation is something I don't like. I'd rather be able to load the engine down with a locked torque converter than have its speed rise.

It seems like your definition of "connected" mainly involves the side-effects of gear changes in a stepped transmission. That's not a definition I can make sense of, but if I accept it then I can see why you feel that CVTs "feel less connected." If that's not what you mean, then I have no idea what you mean.

Back on-point, I still don't see how there's any point to manually selectable ratios in a CVT. It seems to me that either you want a CVT, or you want a good stepped transmission... shrug
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#3428356 - 07/18/14 09:52 AM Re: CVT with shift sensation [Re: d00df00d]
glock19 Offline


Registered: 03/12/13
Posts: 385
Loc: Virginia
Originally Posted By: d00df00d
Back on-point, I still don't see how there's any point to manually selectable ratios in a CVT. It seems to me that either you want a CVT, or you want a good stepped transmission... shrug


Driving in the mountains.
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#3428411 - 07/18/14 11:11 AM Re: CVT with shift sensation [Re: glock19]
d00df00d Offline


Registered: 10/20/05
Posts: 9344
Loc: PA
Go on...
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#3428455 - 07/18/14 12:25 PM Re: CVT with shift sensation [Re: d00df00d]
Hokiefyd Online   content


Registered: 06/24/04
Posts: 11702
Loc: North Carolina
Originally Posted By: d00df00d
It seems like your definition of "connected" mainly involves the side-effects of gear changes in a stepped transmission. That's not a definition I can make sense of, but if I accept it then I can see why you feel that CVTs "feel less connected." If that's not what you mean, then I have no idea what you mean.


Maybe I can explain it differently. With a stepless transmission, there is no consistent relationship between engine speed and road speed (unless you're really going fast and it's at the lowest point of its range). Take driving through the mountains or twisty corners. As you press the gas, the engine is quite free to spin up and down without any meaningful change in road speed. The engine usually spins up before the CVT starts reducing the ratio (that rubberband effect), so there's a point where you're wasting time spinning the engine up so that it can fall back down because of the tightening CVT belt.

You also can't hold the engine at a certain speed range with a CVT. Say you are driving on curvy roads and you want to hold the engine at 2500-3500 rpm for better response. With the automatics I own, I'd put them in "3" and drive 55 mph through the corners. I have engine braking going down hill, the engine is already set up for an uphill run, and I have a certain level of control over the car. Stepless operation means the engine might fall down to near idle when off the throttle, and might zing up past were it really needs to be to regain momentum. I drive CVTs every day at work (though they're in hybrids). They're fine for putzing around, but they don't suit a more aggressive style of driving at all.

I think I'm inter-mingling the terms "control" and "connectedness". To me, you can't have control without being connected to something, and being connected to something implies a certain level of control. I don't have ANY level of control over the engine with a stepless transmission, and I therefore feel disconnected from it.

Originally Posted By: d00df00d
Back on-point, I still don't see how there's any point to manually selectable ratios in a CVT. It seems to me that either you want a CVT, or you want a good stepped transmission... shrug


I agree. As I said earlier, I don't WANT a CVT. I don't PREFER a CVT. I want a good stepped transmission. But if I'm forced into a CVT with a car purchase...if the only available automatic transmission is a CVT...then I want the ability to select ratios.
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#3428466 - 07/18/14 12:36 PM Re: CVT with shift sensation [Re: d00df00d]
SteveSRT8 Online   content


Registered: 10/10/08
Posts: 15404
Loc: Sunny Florida
Originally Posted By: d00df00d
Back on-point, I still don't see how there's any point to manually selectable ratios in a CVT. It seems to me that either you want a CVT, or you want a good stepped transmission... shrug


Absolutely agreed, at least as they are currently delivered.
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#3428470 - 07/18/14 12:41 PM Re: CVT with shift sensation [Re: d00df00d]
glock19 Offline


Registered: 03/12/13
Posts: 385
Loc: Virginia
Originally Posted By: d00df00d
Go on...


Driving down a mountain you want to force the CVT to hold a higher ratio so you don't burn up your brakes.
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#3428476 - 07/18/14 12:46 PM Re: CVT with shift sensation [Re: glock19]
Quattro Pete Offline


Registered: 10/30/02
Posts: 26477
Loc: Michigan
Originally Posted By: glock19
Originally Posted By: d00df00d
Go on...


Driving down a mountain you want to force the CVT to hold a higher ratio so you don't burn up your brakes.

And CVT can't do that?
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#3428488 - 07/18/14 12:55 PM Re: CVT with shift sensation [Re: Hokiefyd]
d00df00d Offline


Registered: 10/20/05
Posts: 9344
Loc: PA
Originally Posted By: Hokiefyd
Originally Posted By: d00df00d
It seems like your definition of "connected" mainly involves the side-effects of gear changes in a stepped transmission. That's not a definition I can make sense of, but if I accept it then I can see why you feel that CVTs "feel less connected." If that's not what you mean, then I have no idea what you mean.


Maybe I can explain it differently. With a stepless transmission, there is no consistent relationship between engine speed and road speed (unless you're really going fast and it's at the lowest point of its range). Take driving through the mountains or twisty corners. As you press the gas, the engine is quite free to spin up and down without any meaningful change in road speed. The engine usually spins up before the CVT starts reducing the ratio (that rubberband effect), so there's a point where you're wasting time spinning the engine up so that it can fall back down because of the tightening CVT belt.

You also can't hold the engine at a certain speed range with a CVT. Say you are driving on curvy roads and you want to hold the engine at 2500-3500 rpm for better response. With the automatics I own, I'd put them in "3" and drive 55 mph through the corners. I have engine braking going down hill, the engine is already set up for an uphill run, and I have a certain level of control over the car. Stepless operation means the engine might fall down to near idle when off the throttle, and might zing up past were it really needs to be to regain momentum. I drive CVTs every day at work (though they're in hybrids). They're fine for putzing around, but they don't suit a more aggressive style of driving at all.

I think I'm inter-mingling the terms "control" and "connectedness". To me, you can't have control without being connected to something, and being connected to something implies a certain level of control. I don't have ANY level of control over the engine with a stepless transmission, and I therefore feel disconnected from it.

I see what you're saying.

You're used to linking engine RPM with speed. A CVT links engine RPM with acceleration. There's still a connection; it's just to somthing else.

Regarding the delays on throttle tip-in, you pretty much described what I dislike about all automatics. It plays out slightly differently, but isn't the effect generally the same?

On gear/ratio holds and engine braking, you're completely right. This is largely a matter of programming. I remember reading that some Subarus are starting to use their CVTs to engine brake. It should be solvable in the near future, as should the delays as the hardware gets better.

Completely agree that control and connectedness are related.

This is mainly an academic discussion for me as well, as only an injury like what you described would get me to drive anything but stick.
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#3428489 - 07/18/14 12:57 PM Re: CVT with shift sensation [Re: Quattro Pete]
d00df00d Offline


Registered: 10/20/05
Posts: 9344
Loc: PA
Originally Posted By: Quattro Pete
Originally Posted By: glock19
Originally Posted By: d00df00d
Go on...


Driving down a mountain you want to force the CVT to hold a higher ratio so you don't burn up your brakes.

And CVT can't do that?

They could, sure. It's just that the majority don't. Steve's "as they are currently delivered" caveat is important here. wink
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#3428502 - 07/18/14 01:26 PM Re: CVT with shift sensation [Re: d00df00d]
SteveSRT8 Online   content


Registered: 10/10/08
Posts: 15404
Loc: Sunny Florida
Originally Posted By: d00df00d
They could, sure. It's just that the majority don't. Steve's "as they are currently delivered" caveat is important here. wink


Exactly, as this is an area of intense research and innovation. I am a big believer in new tech and my thoughts are that when we need something technology becomes available.

I can't wait to see the new stuff coming...
_________________________
"In a democracy, dissent is an act of faith."
J. William Fulbright
Best ET-12.79 @ 111 mph
4340 pounds, Street tires
Just like we go to Publix

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#3428511 - 07/18/14 01:34 PM Re: CVT with shift sensation [Re: wing0]
leeharvey418 Offline


Registered: 08/05/11
Posts: 680
Loc: Southeast Michigan
The first time I ever drove a CVT-equipped rental car, I was shocked that under hard acceleration it doesn't just hold engine speed at the torque peak at first, then gradually ramp down the ratio as more power is needed. I wondered why any OEM would go to the trouble of developing a CVT, only to make it mimic a geared automatic.

Then I remembered that 95% of car buyers probably don't even know what a CVT is, let alone what the real advantages are (or what they should be).
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#3428535 - 07/18/14 02:21 PM Re: CVT with shift sensation [Re: d00df00d]
Hokiefyd Online   content


Registered: 06/24/04
Posts: 11702
Loc: North Carolina
Originally Posted By: d00df00d
You're used to linking engine RPM with speed. A CVT links engine RPM with acceleration. There's still a connection; it's just to somthing else.


Correct, and an excellent observation.

Originally Posted By: d00df00d
Regarding the delays on throttle tip-in, you pretty much described what I dislike about all automatics. It plays out slightly differently, but isn't the effect generally the same?


Sometimes, and to some degree. If the torque converter is unlocked, there will be some engine speed flare. In the automatics I've owned, though, a lower gear selection still keeps the engine percolating at a speed where I like it, so it seems to find that "fluid connection" faster. Like you correctly observed, a stepped transmission links engine speed with road speed, so throttle tip-in quickly resumes the engine to its correct road speed equivalent, even if there is some extra speed flare due to an unlocked torque converter. The CVT must match engine speed to how fast it thinks I want to accelerate, and that seems to contribute to that rubberband effect.
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Jason

2008 Honda CR-V EX-L (Peak 0W-20)
2005 Acura MDX Touring (VNG 5W-20)

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