interesting CVT behavior

dallasjhawk

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Wilbur, that's just not the case. Here's a blurb directly from the original press kit for the Gen X Civic sedan:

"S-Range Control

To allow the driver to alter the operation of the CVT, the console-mounted gear selector includes an "S" or Sport mode that provides a sport-shift schedule that delays upshifting for more available power, and provides greater engine braking."


http://hondanews.com/releases/2016-honda-civic-sedan-press-kit-powertrain?page=2
They used to call it 2nd on the CVT for other models without paddles, its been changed in the owners manuals to remove "Second" from the nomenclature.
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a c i d.f l y

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S and L hold a higher base rev, with a much stronger engine brake; L holds a much higher base rev. The "false shifting" at high rpm is to maximize power, as power drops over the peak curve, so it's still doing its job in maximizing power. Holding at 6500rpm doesn't result in the best performance between 45-80+ mph, as power would drift and drop as acceleration occurs. Dropping rpm to pick up torque over the rpm curve makes complete sense when operating at the top of the curve, hence the "false shifting". Something you don't see, but is also happening at lower RPMs, albeit much more quickly. From 0-45 it will hold the peak torque/Hp curve around 6000rpm, but once it reaches the critical point (speed, acceleration, torque, v-tech), the CVT adjusts to continue maximizing power to the wheels as efficiently as possible. Above 100mph it gets pretty interesting when v-tech is perpetually engaged up to and over 100mph. Between vtec, cvt, I can definitely tell you it's doing its job up to and over 135mph.
 
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Charley-TX

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Every other car with PRNDSL, S means sport or sportier driving dynamic, as in higher revs, delayed upshift and so on.
On other cars with the good ol' 4 speed automatic slushboxed, it would prevent 4th gear/overdrive to engage and keeping it in 3rd gear so the trans does not go into lazy mode.- overdrive.
I am pretty sure Hondas intention was to indicate sportier drive- it actually is.
 

dallasjhawk

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Every other car with PRNDSL, S means sport or sportier driving dynamic, as in higher revs, delayed upshift and so on.
On other cars with the good ol' 4 speed automatic slushboxed, it would prevent 4th gear/overdrive to engage and keeping it in 3rd gear so the trans does not go into lazy mode.- overdrive.
I am pretty sure Hondas intention was to indicate sportier drive- it actually is.
nope it doesn't, here is the Fit CVT

Honda Civic 10th gen interesting CVT behavior upload_2018-9-5_13-43-22
 


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Charley-TX

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nope it doesn't, here is the Fit CVT
I can not accept that answer.:what::cry:
Therefore ...
"I reject your reality and substitute my own!" :spaz: In my Civic...S will remain and stands for Sport !
They can keep S for "second" in the FIT>

Honda Civic 10th gen interesting CVT behavior srange-del.JPG
 
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SoCalCivicSI

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scintillating response. but isn't all this shifting bad for the transmission.
Especially bad for a CVT since imop and my experience with 2 CVT cars, they are fragile transmissions.
I also would NOT tune a car with a CVT.

My opinion of course and I wish you all well if you have a CVT. :D
 

Scathe

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Try doing a flat out run in L as well... it totally gets rid of the simulated shifting, and according to tests, actually produces the quickest 0-60 times of the 3 drive modes. Sport is actually the worst for 0-60 runs and is better put to use once you're already rolling (i.e. passing, going uphill, quick bursts of acceleration). D and L do better from a stop.
It it ok to just shift it all willy-nilly from D to S to L while the car is actually moving and being driven? I'm not being sarcastic, just asking, as I'm coming from auto transmissions all my life into CVT and wondering if it's safe to just shift it like that?
 

MarcOTT

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It it ok to just shift it all willy-nilly from D to S to L while the car is actually moving and being driven? I'm not being sarcastic, just asking, as I'm coming from auto transmissions all my life into CVT and wondering if it's safe to just shift it like that?
I have done this many times on my good'ol 7th gen civic ( 275K miles) and few times on my 2.0L Civic EX with no issues. I am no transmission engineer but the transmission is continually shifting while driving so shifting from D to L or S position alters the computer program to a "mode" that allows the engine to rev longer in acceleration and to maintain higher RPMs during cruising speed at the S and L positions. I wouldn't try shifting from D to L at high speeds. Anyone try this ?
 

RobbJK88

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It it ok to just shift it all willy-nilly from D to S to L while the car is actually moving and being driven? I'm not being sarcastic, just asking, as I'm coming from auto transmissions all my life into CVT and wondering if it's safe to just shift it like that?
Of the 2 CVT civics i've had, it's never caused issues. These transmissions are totally computer controlled and they won't "shift" unless the computer deems it safe to do so. Its the same way cars with paddle shifters will stop drivers from down shifting too far at certain speeds. I believe they even tested this on myth busters, shifting an automatic into park or reverse during driving, the car came to almost a complete stop before the transmission allowed itself to shift. And those are a lot more extreme than just shifting into L or S which really just changes the computers throttle mapping, it doesn't physically alter anything except the computers shift ratios.
 


Scathe

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Of the 2 CVT civics i've had, it's never caused issues. These transmissions are totally computer controlled and they won't "shift" unless the computer deems it safe to do so. Its the same way cars with paddle shifters will stop drivers from down shifting too far at certain speeds. I believe they even tested this on myth busters, shifting an automatic into park or reverse during driving, the car came to almost a complete stop before the transmission allowed itself to shift. And those are a lot more extreme than just shifting into L or S which really just changes the computers throttle mapping, it doesn't physically alter anything except the computers shift ratios.
I keep forgetting nothing is actually connected anymore, so the shifter isn't directly connected to the transmission like it used to be. Another example: I was describing the driving experience to my friend the other day, and I was like "the steering is so tight and responsive. It feels almost exactly like when we used to play those driving games in the arcades, you know how the wheel was really tight and responsive? Exactly like that..." -- then, it hit me. It feels exactly like the arcade games because it IS exactly like the arcade games :lol:, it's an electronic steering system that's not connected to the wheels in any way, and they can actually engineer the exact feel and feedback and entire experience of it however they want, just like they did with the arcade games.
 

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It feels exactly like the arcade games because it IS exactly like the arcade games :lol:, it's an electronic steering system that's not connected to the wheels in any way, and they can actually engineer the exact feel and feedback and entire experience of it however they want, just like they did with the arcade games.
The steering system is mechanically connected to the wheels :what:. It's electric assist, not fully electric steering.
 

davo97

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I keep forgetting nothing is actually connected anymore, so the shifter isn't directly connected to the transmission like it used to be. Another example: I was describing the driving experience to my friend the other day, and I was like "the steering is so tight and responsive. It feels almost exactly like when we used to play those driving games in the arcades, you know how the wheel was really tight and responsive? Exactly like that..." -- then, it hit me. It feels exactly like the arcade games because it IS exactly like the arcade games :lol:, it's an electronic steering system that's not connected to the wheels in any way, and they can actually engineer the exact feel and feedback and entire experience of it however they want, just like they did with the arcade games.
The steering is still physically connected I thought?? The rack has an electric powered motor to assist in power steering though.
 

Scathe

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The steering system is mechanically connected to the wheels :what:. It's electric assist, not fully electric steering.
The steering is still physically connected I thought?? The rack has an electric powered motor to assist in power steering though.
Ah ok, that actually surprises me and makes it even more impressive that it feels like it does, then. I just assumed everything was probably electronic by now and just wired directly into the computer.
 

davo97

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Ah ok, that actually surprises me and makes it even more impressive that it feels like it does, then. I just assumed everything was probably electronic by now and just wired directly into the computer.
most things are. These days cars are pretty much all controlled through no physical connections! breaks, accelerator, shifter for example..
It's good to see advancements, as long as that's what it is! advancements. I'd hate to see some major malfunction with something like that.
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