CVT June 24, 2014 02:35PM
Just curious if one would be outlawed in some classes if made to run or not. Not saying it would work, just curious. If able to run it as the CVT then the need for the clutch would be gone and a simple speed pedal could be used in place to operate it. I don't think it would last long running like this though and many would cry that its unfair. If that was deemed unfair what about setting your CVT ratio at the line so it acts essentially like any other trans in a fixed gear ratio, then using a clutch as normal. This may be considered unfair by some, but in order to back up you need to be able to reverse the CVT direction. Many may say thats unfair as you get to watch everyone then decide your ratio last minute, which would lead to a rule stating you can't reach the control from the seat, thus you would run into the issue of reverse. A reverser or something would have to be added in order to back up.

Again, not saying it would work or be the best idea, but my enjoyment is building and thinking outside the box, versus doing what the winner is doing so I can be the 1st to 2nd place. Pulling is getting pretty boring to watch, but I have nothing against the buy it versus build it guys. I hope I covered some of them above as I tried to include the many complaints they may come up with should the idea sound advantageous to them but outside their "thinking". Sorry if I sounded a bit rude, just read the EFI thread from awhile back and realized the narrow focus some seem to have.
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Re: CVT June 25, 2014 02:44AM
Do modern CVT trannys put the power to the ground efficiently? Can they put even more power to the ground? Hydro trannys are innefficient as heck, which makes them unsuitable against anything but stock hp machines. And honestly they have little advantage on a very well built track.
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Re: CVT June 25, 2014 07:23AM
Depends on how you are running it. For the Fendt CVT the slower you are going, the more hydrostatic power you are using, the faster you go the more mechanical power you use. At full speed the hydros are simply holding the ring gear stationary and all of the power is going through the sun gear and out to the rear end. Its direct 100% mechanical at that point and the efficiency is stated to be up to 94%. I don't know how this stacks up with a standard pulling trans and I do not know how efficient it is when using more hydrostatic power. I know fuel useage at lower speeds under full power is comparable to a powershift as is the work that gets done per gallon burned so I wouldn't say its grossly inefficient like a true hydro. The hydro component on the CVT is slightly different that most traditional hydros. They use a variable displacement pump and variable displacement motors that run at very high pressure and have a much larger swing angle than any others (that's largely what their patent protects, the 45* swing angle, its also the reason they are the only one that can go 0-60kph with shifting or steps). They also swing the pump and motors instead of the swash plates.

I wasn't thinking about a pure power class like heavy supers, more along the lines of lighter classes where its more about setup and control versus raw power. May not be a winner everytime, but if you can easily adjust your ratio for the track conditions right before you hook, you may be more consistent and do better points wise at the end of the season.

I'm not thinking it would be the next big thing, or do good at all. Just thinking outside the boring box.
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Re: CVT June 25, 2014 07:54AM
I've thought for a while now that CVT would be the way to go. But I believe it would be way to heavy and way to expensive if it were made to handle 2000+hp
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Re: CVT June 25, 2014 03:08PM
I thought I read somewhere that the valtra pro stocks over the pond were using the cvt but I could have dreamed it. Sometimes I have some wild things happen while sleeping.
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Re: CVT June 26, 2014 03:33PM
I remembered something about the Valtra's but looked them up and they all say they run the Hi Tech powershift. The 900hp Scania the one team has looks like as much fun as one of the tractors though.

My butt has always felt like the Fendt's did not have as much power as the Massey's that went to the ground. I have never measured the amount of work done between them though. Maybe it is the difference of the Duetz 7.8 versus the Sisu 8.4, maybe its just a head game too. I think the smoothness of the Fendt has a lot to do with why it feels so gutless to a point.The MF has the identical transmission, but the computer controlling things is different and evidently not as smooth.

Butt dyno with a CVT in something like TMS mode is often very flawed because of the way your brain thinks. With a powershift as the load increases the engine bogs down, as the load decreases the engine revs up. With TMS and a CVT as load increases the engine revs up but only to the limit you set or the peak power that is needed at the time. Fendt has an auto mode that just figures it all out for you, otherwise you can set a certain % that it will drop the RPMs. Lets say 1800. As the load increases it will rev to 1800 but never go over because there is no need. With the electronic engines they will simply increase power at 1800rpm as needed until peaked out then the transmission will start to slow down to keep the engine at peak power. As the load decreases the rpms begin to drop to save fuel. With a tractor in a fixed gear you get the seat of the pants feeling of the tractor being worked as you feel it get pulled down then you feel it rev back up. This is the feeling of "power" in many peoples brains as its been that way since the beginning of tractors. The CVT with TMS defies that natural feeling. I'm not saying it puts the same or more power to the ground, but the results are not as drastic as some people feel simply from the seat of their pants. If you simply lock the CVT at a certain ratio and throw the throttle to the max as you would in a powershift under max load, you could get a much better idea of the power transmission. That is not a CVT's advantage though, they were designed for efficiency and reliability with road transport. The efficiency with a CVT comes from when you do not need the power, under load they can be just as inefficient.
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Re: CVT June 26, 2014 03:19AM
I run a Fendt in the field and I feel it is pretty weak compared to a comparable hp gear drive tractor.
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