Continuously Variable Trannys for drag racing
12-23-2006, 03:59 PM
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Continuously Variable Trannys for drag racing CVT for short. These little puppies have no shift shock and no real gears. I think they are pretty cool. I was thinking the other day, if you could program one to stay at the peak torque RPM, could you hypothetically shave alot of time off the 1/4?
This means keeping the engine at 3500 rpm or whatever the dyno graph says, and having the tranny do the accelerating. Good idea? Thoughts? Questions? Comments?
This means keeping the engine at 3500 rpm or whatever the dyno graph says, and having the tranny do the accelerating. Good idea? Thoughts? Questions? Comments?
12-23-2006, 04:57 PM
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Currently I don't believe that the designs on the market allow for much torque. They are usually in small engined cars.
Here is a quote from Mr Wiki "CVT torque handling capability is limited by the strength of their belt or chain, and by their ability to withstand friction wear between torque source and transmission medium for friction-driven CVTs. CVTs in production prior to 2005 are predominantly belt or chain driven and therefore typically limited to low powered cars and other light duty applications."
Looks like there is another trans called an IVT though which handles more torque.
Here is a quote from Mr Wiki "CVT torque handling capability is limited by the strength of their belt or chain, and by their ability to withstand friction wear between torque source and transmission medium for friction-driven CVTs. CVTs in production prior to 2005 are predominantly belt or chain driven and therefore typically limited to low powered cars and other light duty applications."
Looks like there is another trans called an IVT though which handles more torque.
12-23-2006, 07:52 PM
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it definitly would be boring.
my question was hypothetical and i know the CVT currently sucks. i just wanted some opinions from the greatest minds on the net
my question was hypothetical and i know the CVT currently sucks. i just wanted some opinions from the greatest minds on the net
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12-23-2006, 08:38 PM
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Originally Posted by NHRATA01
If they run sleds at your strip, thats the trans every sled has, and some of those things run pretty damn quick (10s/11s isn't uncommon).
They all clicked off times in the 10's. Simply amazing!!!
I think those things are one of the cheapest ways to get into the 10's. They have a low Cg and a lot of traction.
12-24-2006, 12:57 AM
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Yeah, if they could build one that can handle that kind of power, it would work well for drag racing. If they run sleds at your strip, thats the trans every sled has, and some of those things run pretty damn quick (10s/11s isn't uncommon).
12-24-2006, 01:18 AM
#12
If you look at a diagram of what a CVT is, you'll see there is a limit to what it can handle in terms of stress. Imagine moving your whole car with the belt drive from a supercharger. It's sorta like that. It works fine for low power cars or really lightweight stuff like bikes and snowmobiles, but I doubt it could ever work for drag racing with cars.
12-24-2006, 08:12 AM
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my mom has a Nissan Murano and it has a transmission like that, they call it their Xtronic CVT. It doesnt shift at all. If you stand on it from a stop the rpm goes up to redline and it just keeps accelerating. If feels kinda wierd, but it runs good for an SUV.
12-24-2006, 04:34 PM
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my polaris scrambler had the same type setup. these systems are completely tuneable, in that the engagement rpm, shift speed, more/less aggressive acceleration rate, more/less rpm on top end, etc...are adjustable. the launch can even be setup to hit pretty hard by notching the flyweights. non-linear progressive rate roller helix cams for the secondary clutch can make the acceleration rates on these light weight machines unbelievable.
12-24-2006, 05:38 PM
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Originally Posted by black_knight
If you look at a diagram of what a CVT is, you'll see there is a limit to what it can handle in terms of stress. Imagine moving your whole car with the belt drive from a supercharger. It's sorta like that. It works fine for low power cars or really lightweight stuff like bikes and snowmobiles, but I doubt it could ever work for drag racing with cars.
im aware that in their current state they blow ***. i know a guy with a Saturn Vue that has gone through 3 of em. but if they could be improved with some kind of steel belt or made of more sturdy materials, i think they would be really quick trannys(pun intended)
12-25-2006, 06:00 PM
#19
The slider clutches in Top Fuel dragsters and funny cars keep the rpm around the same level for the entire run. They are kinda like a CVT that handles over 6000 hp.
For us sportman racers, a 2 speed Powerglide tranny does a pretty good impression of a CVT when it has the right converter.
For us sportman racers, a 2 speed Powerglide tranny does a pretty good impression of a CVT when it has the right converter.
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