"The CVT: Learn it and Love it"

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Originally Posted By: SteveSRT8
Someone explain how F1 has any relevancy here? Maybe it's still 4 wheels?

http://www.caranddriver.com/features/how-cvt-transmissions-are-getting-their-groove-back-feature


It's relevant because you said this:

Originally Posted By: SteveSRT8
Sorry, I meant serious levels of hp. If you check them out they are not used beyond certain power levels. Seems to be around that 300 hp mark or so.


I was making the point that an F1 car with 850hp seems like serious hp and it used a CVT. Sure it took a lot of time and money to get it right and it's probably not that practical, but I wouldn't consider any performance car that practical.

Point being, a CVT can handle tons of hp if it's designed to do so. Yes a CVT from a Subaru will blow up if you throw 500hp at it but so will the AT from a Dodge Caravan because it wasn't designed for that much power. It's nothing that's exclusive to CVTs.
 
^True. Subaru's CVT for the WRX and Forester XT are designed for the added power. Is it just a software variation or is there different mechanical hardware differences as well?
 
Originally Posted By: glock19
Originally Posted By: SteveSRT8
Originally Posted By: Win
Originally Posted By: SteveSRT8

With the ubiquitous ZF 8 speed in tons of cars, and nine speeds in Jeeps, then factor in the Ford/GM joint ten speed project, it's looking like the wild west out there for trans choices...


You could argue that they are moving to CVT one gear at a time, still I would prefer to have the discrete gear/clutch pack type transmission to a CVT.

I wonder how the CVT's do in a semi performance car? The sport mode on the GM 5L40E is just wonderful at holding gear and keeping the chassis stable through corners. If a CVT does not lock up and hold a gear, what does the chassis do in a hot corner?


They can be programmed to do anything you want, but they just won't be available in higher horsepower vehicles


They already tried a CVT in F1 and it got banned because it was too fast. While it took some time, they were able to get it to handle 850 hp...

http://www.auto123.com/en/news/f1-techni...eo?artid=137686


Very interesting link. Thanks!
 
Quote:
Because early automotive CVTs were limited as to how much horsepower they could handle, there has been some concern about the long-term reliability of the CVT. Advanced technology has made the CVT much more robust. Nissan has more than a million CVTs in service around the world and says their long-term reliability is comparable to conventional transmissions.
 
Originally Posted By: glock19
point being, a CVT can handle tons of hp if it's designed to do so. Yes a CVT from a Subaru will blow up if you throw 500hp at it but so will the AT from a Dodge Caravan because it wasn't designed for that much power. It's nothing that's exclusive to CVTs.



Please provide a link for ANY serious performance car with a CVT. (crickets)

Many conventional slushboxes can easily and reliably handle FAR beyond what they deal with in a stock car.

My car's gearbox with stock internals goes to 500 rwhp reliably and many others can do far better. Extremely easy mods make them even more reliable under serious torque. Merc used it all the way into their V12 twin turbo!

Despite an isolated singular example of ONE exotic race car using a specially designed and custom built CVT that is not even remotely related to a production automobile (and may have cost millions!), I have seen no real road cars with one if there is real horsepressure involved. Just as others do not consider high performing cars as relevant to the discussion I can also easily dismiss the example provided.

It is only Jatco's metal belt system that even allows a CVT to handle 300 hp, albeit with extreme levels of software protection and questionable reliability in enthusiastic driving.

Just look at the design. Pulleys and belts? Not likely to ever yield anything but smooth operation at low power levels.
 
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Originally Posted By: SteveSRT8
Originally Posted By: buster
^ not yet at least. WRX is using one.


Sorry, I meant serious levels of hp. If you check them out they are not used beyond certain power levels. Seems to be around that 300 hp mark or so. Wait till the boyz in da hood start ramping up the boost on a cvt equipped model!

Plus, many of the higher powered platforms that do use them have tons of torque management in their programming to protect the trans. This makes them drive funky.



That may put the engine builders out of business! Instead of blowing their engine when trying to push ridiculous boost numbers and N20 on stock engine internals, they'll just explode the CVT.




Originally Posted By: SteveSRT8
Originally Posted By: glock19
point being, a CVT can handle tons of hp if it's designed to do so. Yes a CVT from a Subaru will blow up if you throw 500hp at it but so will the AT from a Dodge Caravan because it wasn't designed for that much power. It's nothing that's exclusive to CVTs.


It is only Jatco's metal belt system that even allows a CVT to handle 300 hp, albeit with extreme levels of software protection and questionable reliability in enthusiastic driving.

Just look at the design. Pulleys and belts? Not likely to ever yield anything but smooth operation at low power levels.


I'm personally not sold on JATCO's cvts. Go to youtube and look for Nissan CVT failure or Nissan CVT overheat. There are a lot of videos of the things overheating when driving up mountain passes. Too many of them are in 4 cyl equipped vehicles, too.

I want to know what Nissan is going to pay in warranty replacements when people load up the new Rogue with 7 people and luggage and drive through the mountains ... or people with their new Pathfinder try to two while on vacation?

Make a CVT reliable and I'll be first in line to buy a vehicle with one.

I like the concept - fewer moving parts, engine always at a constant speed. Boring, but if someone could make one reliable, I wouldn't mind that.
 
Originally Posted By: buster
glock, do you have the CVT in your Legacy?


Yes, and despite my initial hesitations I actually like it for commuting.

Originally Posted By: SteveSRT8
Originally Posted By: glock19
point being, a CVT can handle tons of hp if it's designed to do so. Yes a CVT from a Subaru will blow up if you throw 500hp at it but so will the AT from a Dodge Caravan because it wasn't designed for that much power. It's nothing that's exclusive to CVTs.



Please provide a link for ANY serious performance car with a CVT. (crickets)

Many conventional slushboxes can easily and reliably handle FAR beyond what they deal with in a stock car.

My car's gearbox with stock internals goes to 500 rwhp reliably and many others can do far better. Extremely easy mods make them even more reliable under serious torque. Merc used it all the way into their V12 twin turbo!

Despite an isolated singular example of ONE exotic race car using a specially designed and custom built CVT that is not even remotely related to a production automobile (and may have cost millions!), I have seen no real road cars with one if there is real horsepressure involved. Just as others do not consider high performing cars as relevant to the discussion I can also easily dismiss the example provided.

It is only Jatco's metal belt system that even allows a CVT to handle 300 hp, albeit with extreme levels of software protection and questionable reliability in enthusiastic driving.

Just look at the design. Pulleys and belts? Not likely to ever yield anything but smooth operation at low power levels.


Clearly you have already formed your opinion about CVT's so I'll let this thread return to it's initial purpose.
 
From the Forester forum:

Quote:
I second the brilliance for the CVT. Since owning Subarus I've enjoyed a number of automatics and manuals. The STi's 6MT was the best manual I've ever driven, the WRX's 5MT not so much. Out of them all, from the driver's seat, the HDCVT in my '14 FXT constantly amazes me as something from the future. The 2.5i's CVT works just as well.

Even the STi, with all its glory and horsepower, could not maintain the absolute lack of concern for variations in mountain driving the FXT's CVT does. There doesn't seem to be a difference between level and steep. Using a small fraction of the throttle the CVT seems to discern your intentions, and next thing you're at the speed you intended. No shifting, lurching, matching throttles, dancing with the clutch, heel/toe... nothing. Sweet mechanical perfection.

Since I've been driving the 2.5i a lot lately I find it no different, other than the available power, which in-town means nothing. These are the finest cars to drive I've owned, bar none. The STi with over 300whp and its own brilliance was the most engaging, but the truth is I don't miss it.

All that and I'm still amazed when I turn off the car and see the trip mileage displayed. I regularly see 30+ from the FXT. How great it is.
 
I say put very reliable, fuel efficient CVT's in all everyday vehicles for all those that consider cars to be simple machines that transport people and a bit of gear. That covers almost everyone around you.

If you want to row your own gears pretending that it goes faster in a car made to transport people in a bit of gear, too bad. Modern technology has matched what you can do physically and is leaving you behind.

For all other high power or race applications, put in the best suited transmission, which will be the PDK type in the end.
 
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Originally Posted By: Jarlaxle
Want to impress me? Put a CVT in a class 7 truck!


Absolutely. Tremendous financial incentive to do so yet, it's just not happening. Even a half mpg across a fleet of trucks would save a ton of fuel. We would buy that here for our fleet in a heartbeat if it had any real fuel savings!

And it won't because the things are too rickety.

Take a look at a snowmobile sometime. Most of them are CVT's. It's a belt and two cone pulleys, it would be crazy to expect much out of it!

Too bad that Glock withdrew from the debate without providing any input. I am truly interested in the subject but unfortunately it is well publicized and unlikely to change unless someone can come up with something to beat the new many-speed trans' out there...
 
Originally Posted By: SteveSRT8
Jarlaxle said:
Too bad that Glock withdrew from the debate without providing any input. I am truly interested in the subject but unfortunately it is well publicized and unlikely to change unless someone can come up with something to beat the new many-speed trans' out there...


I did provide input, you chose to dismiss it. The fact is that CVT's are in a ton of cars and work reliably and efficiently every day. I haven't seen any proof that they have any higher rate of failure than traditional autos.

You continue to claim CVT's don't hold up and they're rickety. Sure you probably aren't going to see a bloated 2 ton muscle car with excessive hp rocking a CVT anytime soon but that doesn't make it a bad piece of technology. There were people afraid of new technology when the traditional auto came out and the tradition continues.
Click to expand...
 
Originally Posted By: glock19
Originally Posted By: SteveSRT8
Jarlaxle said:
Too bad that Glock withdrew from the debate without providing any input. I am truly interested in the subject but unfortunately it is well publicized and unlikely to change unless someone can come up with something to beat the new many-speed trans' out there...


I did provide input, you chose to dismiss it. The fact is that CVT's are in a ton of cars and work reliably and efficiently every day. I haven't seen any proof that they have any higher rate of failure than traditional autos.

You continue to claim CVT's don't hold up and they're rickety. Sure you probably aren't going to see a bloated 2 ton muscle car with excessive hp rocking a CVT anytime soon but that doesn't make it a bad piece of technology. There were people afraid of new technology when the traditional auto came out and the tradition continues.


Might want to re-read what I posted. The only remark I even made about reliability was at high power levels their durability is questionable.

Got any real things to add or do you just wish to attack me?

Go for it!
Click to expand...
 
Originally Posted By: 05ChevyI5
Call me old fashioned but I still like the 4L60E coupled with a 3.73 rearend. I loath the GM 6-speed truck tranny.


Everyone was just praising the new transmissions and criticizing my old style 2012 Silverado now we don't like the new stuff. I will stick with my old style until they get the bugs out.
 
Originally Posted By: millerbl00
Originally Posted By: 05ChevyI5
Call me old fashioned but I still like the 4L60E coupled with a 3.73 rearend. I loath the GM 6-speed truck tranny.


Everyone was just praising the new transmissions and criticizing my old style 2012 Silverado now we don't like the new stuff. I will stick with my old style until they get the bugs out.


Most complaints about new trans are about the programming, not the actual slushbox.

The 6L90E in our newer fleet vans is a wonderfully programmed gearbox that simply does great things. Absolutely NEVER in top gear unless you are going 53-55 mph no matter what you do.

In a 2500 Silverado it was so badly calibrated I would NEVER buy it! Ran for top gear like a scalded dog and really hobbled the drivetrain. Felt like garbage.

I also really liked the six speed in my buddy's CTS-V. It's super smooth and responsive.
 
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