High Torque CVT - Engineering Explained
- Thread starter StevieC
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Amazing. My head hurts, then I was made even more annoyed that I thought this was brand new technology....since 1999 ?
Is this special fluid $1000 per litre? made from free-range bed frame molecules?
Is this special fluid $1000 per litre? made from free-range bed frame molecules?
Nissan and Jatco had this out since the mid-2000s but it never saw deployment in a Infiniti or the JDM versions(Fuga and Skyline). It's a toroidal CVT that can take more power than a chain/belt based one.
I could see Subaru using this in an refresh of the Legacy/Outback/Ascent.
I could see Subaru using this in an refresh of the Legacy/Outback/Ascent.
It is still metal on metal contact. The difference is that this new arrangement can essentially have two cones dividing the torque between them. Throughout the majority of the video I kept thinking how they will cope with the friction forces as the contact area is even less than that of a CVT belt and that metal on metal contact, until he mentioned the special fluid. Basically it all rides on this fluid. I can only guess that Nissan will claim this a lifetime fluid as well.
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
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Just a wild guess. They cannot engineer one to a price point set by ...
Originally Posted by Char Baby
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
They are simple but very fussy if they don't have the right amount of friction and the high oil pressure to keep it engaged in the band type.
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
They are simple but very fussy if they don't have the right amount of friction and the high oil pressure to keep it engaged in the band type.
Originally Posted by StevieC
Originally Posted by Char Baby
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
They are simple but very fussy if they don't have the right amount of friction and the high oil pressure to keep it engaged in the band type.
Any suggestion to keeping them in tip-top condition?
Originally Posted by Char Baby
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
They are simple but very fussy if they don't have the right amount of friction and the high oil pressure to keep it engaged in the band type.
Any suggestion to keeping them in tip-top condition?
Originally Posted by Char Baby
Originally Posted by StevieC
Originally Posted by Char Baby
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
They are simple but very fussy if they don't have the right amount of friction and the high oil pressure to keep it engaged in the band type.
Any suggestion to keeping them in tip-top condition?
Change the fluid often and don't overheat them. That's the best advice. I would steer clear for Jatco / Nissan type although they are better and have better fluid than the first generation NS-3 is supposed to be good stuff according to Terry. Honda seems fine with a BITOG member here have 200K miles on his but he changes the fluid frequently, Toyota are fine and later Ford are fine, Subaru I think still has some bugs IMO with some being ok and others failing early.
Originally Posted by StevieC
Originally Posted by Char Baby
Ya know, I don't have any trouble with my CVT and I do like it very much however, Nissan/JATCO needs to get their "You Know What" together.
From my understanding, CVTs are quite a simple design. But then why are they so trouble prone.
They are simple but very fussy if they don't have the right amount of friction and the high oil pressure to keep it engaged in the band type.
Any suggestion to keeping them in tip-top condition?
Change the fluid often and don't overheat them. That's the best advice. I would steer clear for Jatco / Nissan type although they are better and have better fluid than the first generation NS-3 is supposed to be good stuff according to Terry. Honda seems fine with a BITOG member here have 200K miles on his but he changes the fluid frequently, Toyota are fine and later Ford are fine, Subaru I think still has some bugs IMO with some being ok and others failing early.
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That's funny...
My Nissan Altima VQ 3.5 with CVT is real close to 250k miles on the original CVT fluid... I'm not all too concerned either
It is a combination with the motor that matters a lot as well. Also... The computer programming matter quite a bit I believe.
NS-2 fluid by the way... It must not be total junk
My Nissan Altima VQ 3.5 with CVT is real close to 250k miles on the original CVT fluid... I'm not all too concerned either
It is a combination with the motor that matters a lot as well. Also... The computer programming matter quite a bit I believe.
NS-2 fluid by the way... It must not be total junk
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Originally Posted by bbhero
That's funny...
My Nissan Altima VQ 3.5 with CVT is real close to 250k miles on the original CVT fluid... I'm not all too concerned either
If you ever stop by Northern CA, I will change it for you for free so that I can grab a sample for a UOA.
That's funny...
My Nissan Altima VQ 3.5 with CVT is real close to 250k miles on the original CVT fluid... I'm not all too concerned either
If you ever stop by Northern CA, I will change it for you for free so that I can grab a sample for a UOA.
Originally Posted by buster
Interesting, I'll have to watch the video. Thanks for sharing.
I will say this, I drove the Subaru WRX with the CVT in sport mode using the paddle shifters and it was a blast to drive. Far better than the manual transmission.
Automatics and CVTs are catching up fast - Toyota uses a tweaked version of their 8-speed behind the 2UR-GSE V8 in the F(not F Sport) variants of the IS/GS/RC and the LC500, the ZF 8HP70/90 is finding use in high-powered Mopar SRTs and Euro cars(R-spec Jags, blown Range Rovers and fast but heavy Bentleys and Rolls come to mind). Mercedes is using their 7G/9G-Tronic without a torque converter in their AMG cars.
Interesting, I'll have to watch the video. Thanks for sharing.
I will say this, I drove the Subaru WRX with the CVT in sport mode using the paddle shifters and it was a blast to drive. Far better than the manual transmission.
Automatics and CVTs are catching up fast - Toyota uses a tweaked version of their 8-speed behind the 2UR-GSE V8 in the F(not F Sport) variants of the IS/GS/RC and the LC500, the ZF 8HP70/90 is finding use in high-powered Mopar SRTs and Euro cars(R-spec Jags, blown Range Rovers and fast but heavy Bentleys and Rolls come to mind). Mercedes is using their 7G/9G-Tronic without a torque converter in their AMG cars.
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Originally Posted by The Critic
Originally Posted by bbhero
That's funny...
My Nissan Altima VQ 3.5 with CVT is real close to 250k miles on the original CVT fluid... I'm not all too concerned either
If you ever stop by Northern CA, I will change it for you for free so that I can grab a sample for a UOA.
You got lucky as did a previous work colleague of mine that had the Jatco in his Caliber and it was all original at 300K KM.
Originally Posted by bbhero
That's funny...
My Nissan Altima VQ 3.5 with CVT is real close to 250k miles on the original CVT fluid... I'm not all too concerned either
If you ever stop by Northern CA, I will change it for you for free so that I can grab a sample for a UOA.
You got lucky as did a previous work colleague of mine that had the Jatco in his Caliber and it was all original at 300K KM.
I don't think it's luck.....
Operation conditions are favorable... Long highway runs... Temp low throughout doing that....
She does get a bit warm I guess when I go hammer down... But that is like only 1% of the distance driven.
Plus... The motor matters as well.... The 3.5s do better with CVT vs the 2.5s.. The bigger motors keep transmission in better operating band I believe.
Operation conditions are favorable... Long highway runs... Temp low throughout doing that....
She does get a bit warm I guess when I go hammer down... But that is like only 1% of the distance driven.
Plus... The motor matters as well.... The 3.5s do better with CVT vs the 2.5s.. The bigger motors keep transmission in better operating band I believe.
I remember reading about these toroidal CVTs years ago for the automotive realm. It's got to be a high cost situation at present or they would have taken over the belt/chain CVTs by now.
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Originally Posted by KrisZ
It is still metal on metal contact. The difference is that this new arrangement can essentially have two cones dividing the torque between them. Throughout the majority of the video I kept thinking how they will cope with the friction forces as the contact area is even less than that of a CVT belt and that metal on metal contact, until he mentioned the special fluid. Basically it all rides on this fluid. I can only guess that Nissan will claim this a lifetime fluid as well.
No it not actually. It is s special fluid that transmits the torque. There is no metal to metal contact in a well executed CVT transmission. The "tech" is all in the traction fluid.
It is still metal on metal contact. The difference is that this new arrangement can essentially have two cones dividing the torque between them. Throughout the majority of the video I kept thinking how they will cope with the friction forces as the contact area is even less than that of a CVT belt and that metal on metal contact, until he mentioned the special fluid. Basically it all rides on this fluid. I can only guess that Nissan will claim this a lifetime fluid as well.
No it not actually. It is s special fluid that transmits the torque. There is no metal to metal contact in a well executed CVT transmission. The "tech" is all in the traction fluid.
Originally Posted by DriveHard
Originally Posted by KrisZ
It is still metal on metal contact. The difference is that this new arrangement can essentially have two cones dividing the torque between them. Throughout the majority of the video I kept thinking how they will cope with the friction forces as the contact area is even less than that of a CVT belt and that metal on metal contact, until he mentioned the special fluid. Basically it all rides on this fluid. I can only guess that Nissan will claim this a lifetime fluid as well.
No it not actually. It is s special fluid that transmits the torque. There is no metal to metal contact in a well executed CVT transmission. The "tech" is all in the traction fluid.
Hence my last mention that it all rides on the fluid. Otherwise it's full metal to metal contact, just like with the steel belt CVTs. The moment that fluid overheats and shears down, the transmission is toast in quick order.
Originally Posted by KrisZ
It is still metal on metal contact. The difference is that this new arrangement can essentially have two cones dividing the torque between them. Throughout the majority of the video I kept thinking how they will cope with the friction forces as the contact area is even less than that of a CVT belt and that metal on metal contact, until he mentioned the special fluid. Basically it all rides on this fluid. I can only guess that Nissan will claim this a lifetime fluid as well.
No it not actually. It is s special fluid that transmits the torque. There is no metal to metal contact in a well executed CVT transmission. The "tech" is all in the traction fluid.
Hence my last mention that it all rides on the fluid. Otherwise it's full metal to metal contact, just like with the steel belt CVTs. The moment that fluid overheats and shears down, the transmission is toast in quick order.
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