All UTV's CVT clutch performance

[dmcmark]

That car was a total joke!!!! I made the mistake on buying one because I believed in the program. First thing I ever tried to buy turn key and ended up being the biggest mistake of my life. Absolutely could not keep the drive train together. Even had the local Team Ind. Guru check it out, and could never get it to work. I ended up cutting the whole back of the car off and made a tail dragger out of it with a bus tranny, had to completely re-wire it, fix the geometry on the front suspension including shocks, and had to re-hang the rear arms because they had used .065 mild steel and they egged out and cracked. Hate to admit I was ever involved in one of those cars, (what a pile).

Her is my take... Yes you can put HP behind a belt drive system, but what about torque? Snowmobiles do make some serious HP but the torque numbers are pretty low. Also we are talking about a Sled the doesn't weigh near what a SXS does. Put that same set up on a UTV that can weigh in close to 2000lbs, big tires etc. and you are simply pushing the limits of the system. Pretty sure that is why you hear more about 4 seaters popping belts than you do 2 seaters.

Look at the CTV on the Predator X18 buggy's. Its a modified version of the Arctic Cat snowmobile CVT. I think it used parts from Team Ind, and from someone else? I know Write Gearbox was or is a dealer for the transmission in these cars. The engine in the Predator X18 is the Chevy 2.4 Ecotec, which is about 170 hp. The CVT is matted with a VW type 2 R&P dif and turns 33 inch tires. Years ago I had talked & helped Eamon the owner of Predator when they were looking to adapt this car to be able to race in Baja. Typicaly this car ran with no CVT cover, just a belt guard. But when racing in Baja or Dakar a cover was needed. Belt temps were a concern a slight issue until a simple Parker Pumper style system was plumbed to the cover blowing air on both the primary & secondary units.

 

[badassmav]

I am bound not to give out secrets that make our car go, be it fast or slow. So, I thought it would be a good exercise to divulge the mechanics of the technologies we are challenged by, and let the reader use their own minds to find a solution that best suits their needs. C'mon guys, lazy minds need not attend!

We're getting much closer to realizing what it takes to attain reliability in a cvt system. Although there are many components that affect overall performance of a cvt drive system, the two that are most at our disposal are belt tension, and environmental cooling. Although I haven't the time to fully understand belt tension, and all of the springing and weighting techniques that accompany it, I do have experience in the exchanging of air, i.e. moving air into and out of a given area. It doesn't take much to introduce a positive pressure in a controlled area.
Unlike the traditional box fan that cools us down as we lounge in our easy chair, which cools us by the means of blowing air over and across our bodies, an enclosed environment is kept cool by the exchanging of air within its environment. This is best achieved by introducing a positive pressure into the "room" that you are trying to cool by forcing in air that simulates the temperature you are trying to achieve, then evacuating the air in said "room" by mechanical means. It is physically easier, and certainly much cheaper, to "push" air, then to "pull" it. This becomes painfully obvious when comparing the price of an air compressor to a vacuum pump.
That being said, let us focus our minds on the task of pressurizing our cvt's, and then evacuating the excessive air that was introduced to it. All cvt systems are designed to draw ambient air from outside its cover, into the clutching area via either the primary or secondary clutch. It is done on the rear side of said clutches because it is easier to form an enclosed and efficient ducting system from behind the pulleys by shaping the rear cvt cover around the diameter of the inner sheave, and casting or machining directional vanes or blades on the back side of the rotating sheave to manipulate, or direct the flow of air across it. I understand that the Maverick primary draws somewhere in the range of 300 cfm, when operating in the higher rpm limitations of the motor. That's alot of air filling a void that is 100 times smaller than said volume. But still, the area needs to be evacuated efficiently in order for that air to be effective in sufficiently cooling large chunks of metal and/or aluminum that can reach temperatures upwards of 300 degrees F, and in the case of the Maverick, be contained in an "oven" with ambient air temperatures easily in the 150 degree range.
The current xp 1000 layout has the secondary clutch pulling air into the cvt enclosure from the back side of the pulley, through a vent that attaches to the top, outer quarter panel of the rear end. The cover then has an adjacent duct that allows for the evacuation of the air, based on the principles of positive pressure. It has of late, added a third penetration directly over the face of the secondary clutch that I refer to as a "fart" hole. A vent with no real direction of air feeding it. So, basically we have one intake, one exhaust, and one breather vent in our system, the intake being the only one that mechanically does any work. The key here is to compliment the intake by helping get the air out of the enclosed area, so it can nave a more efficient time of supplying additional air into the enclosure. Also, by adding additional air into the system, we can further increase the positive pressure in the system, allowing for easier evacuation of said air. I'll stop at this point because I've said all that needs to be said in order for a layman's to benefit from this lesson.
Happy ducting, and please add to what I've offered. I'm getting bored not sharing something!

 

[BiggJim]

I am bound not to give out secrets that make our car go, be it fast or slow. So, I thought it would be a good exercise to divulge the mechanics of the technologies we are challenged by, and let the reader use their own minds to find a solution that best suits their needs. C'mon guys, lazy minds need not attend!

We're getting much closer to realizing what it takes to attain reliability in a cvt system. Although there are many components that affect overall performance of a cvt drive system, the two that are most at our disposal are belt tension, and environmental cooling. Although I haven't the time to fully understand belt tension, and all of the springing and weighting techniques that accompany it, I do have experience in the exchanging of air, i.e. moving air into and out of a given area. It doesn't take much to introduce a positive pressure in a controlled area.
Unlike the traditional box fan that cools us down as we lounge in our easy chair, which cools us by the means of blowing air over and across our bodies, an enclosed environment is kept cool by the exchanging of air within its environment. This is best achieved by introducing a positive pressure into the "room" that you are trying to cool by forcing in air that simulates the temperature you are trying to achieve, then evacuating the air in said "room" by mechanical means. It is physically easier, and certainly much cheaper, to "push" air, then to "pull" it. This becomes painfully obvious when comparing the price of an air compressor to a vacuum pump.
That being said, let us focus our minds on the task of pressurizing our cvt's, and then evacuating the excessive air that was introduced to it. All cvt systems are designed to draw ambient air from outside its cover, into the clutching area via either the primary or secondary clutch. It is done on the rear side of said clutches because it is easier to form an enclosed and efficient ducting system from behind the pulleys by shaping the rear cvt cover around the diameter of the inner sheave, and casting or machining directional vanes or blades on the back side of the rotating sheave to manipulate, or direct the flow of air across it. I understand that the Maverick primary draws somewhere in the range of 300 cfm, when operating in the higher rpm limitations of the motor. That's alot of air filling a void that is 100 times smaller than said volume. But still, the area needs to be evacuated efficiently in order for that air to be effective in sufficiently cooling large chunks of metal and/or aluminum that can reach temperatures upwards of 300 degrees F, and in the case of the Maverick, be contained in an "oven" with ambient air temperatures easily in the 150 degree range.
The current xp 1000 layout has the secondary clutch pulling air into the cvt enclosure from the back side of the pulley, through a vent that attaches to the top, outer quarter panel of the rear end. The cover then has an adjacent duct that allows for the evacuation of the air, based on the principles of positive pressure. It has of late, added a third penetration directly over the face of the secondary clutch that I refer to as a "fart" hole. A vent with no real direction of air feeding it. So, basically we have one intake, one exhaust, and one breather vent in our system, the intake being the only one that mechanically does any work. The key here is to compliment the intake by helping get the air out of the enclosed area, so it can nave a more efficient time of supplying additional air into the enclosure. Also, by adding additional air into the system, we can further increase the positive pressure in the system, allowing for easier evacuation of said air. I'll stop at this point because I've said all that needs to be said in order for a layman's to benefit from this lesson.
Happy ducting, and please add to what I've offered. I'm getting bored not sharing something!

The only thing I took out of that mess was a "fart hole" LOL

 

[badassmav]

The only thing I took out of that mess was a "fart hole" LOL

That's because your stomach is bigger than your brain! Ha ha. You know you'll be looking at the next contingency.

 

[NIKAL]

You have to wonder what the S3 guys came up with as I do not believe they had any belt issues on their Turbo Can Am. Or is the stock clutching that much better on the new Can Am's that they are not replacing belts like the Monster Mav was?