The Nutty Professor
10-03-2007, 04:09 PM
I was reading a post asking which transmission was better the CVT or the Manual. I've always ridden bikes with manual transmission. That only 2 wheeled ride I've owned without it was a Honda Espree (?) that I rode from the age of 15-16 when I got my license. It seemed like it took for freakin ever for it to get up to speed. Now that I'm with Mid's it seems to get the most out of the little bugger's you need a manual...but wait! I started researching CVT's because that's what comes on the X22 and boy did I confuse myself even more. Here's a post from F1 Tech and it seems to put it in prospective:
As much as I love the advantages of the CVT, i've driven two now, the Nissan variation, and the Audi one, and frankly, i love the endless toque on both, but I just hate with a passion the uninspired drive. They dont feel sporty. With the Audi i was peddling,(not my car, didint want to write it off), but in the Maxima, I was pushing the envelope, and I was unimpressed with the lack of emotion in it. I will take my 6-speed manual any day over almost any gearbox, aside from a Ferrari sequential paddle shift. \
So it's not the transmission but the spirit that's moving the debate. Well in for a penny in for a pound. I think I know one area I'm going to be different. I may up the size of my motor but I'm going to see what I can do with the CVT before I think about going manual. It may be the path of a fool but no one ever accused me of taking the easy way out of anything.
Here's other opinion's from a different post:
"At present, straight cut gears with a clutch are the least power robbing components available for the drive train. Torque converters, automatic transmissions and the like rob more power from the engine than the above mentioned components. So for sheer performance and racing applications, straight cut gears and a clutch are the way to go. (at present) It must be assumed that a CV system would have more drag, steal more power from the engine. And usually, with more drag, there is more heat generated within the transmission.
But with a theoretically practical racing CV system, braking effort through the engine could easily be programmed in, giving a very good engine braking system.
As mentioned in the previous post, the engine would probably run at a constant RPM, and that's the beauty of it, allowing an engine designed for just one operating condition. But there may be problems, if the torque delivered is more than the tires can grip under adverse conditions. And that could lead to some form of traction control with fuel or RPM cutoff to allow the tires to grip, and not spin wastefully".
"Surely the traction problem would not be much different to now - Ok, the engine is always in the fat part of it's torque curve - but it's probably pretty close most of the time these days - the ultimate torque controller remains at the throttle pedal just as now, so a driver could control wheelspin by modulating his right foot. This leads me to think that you would have to get the engine braking side of the transmission spot on - how would it deal with someone riding out a drift using the throttle working between more/less throttle and needing instant changes to the engine braking/acceleration to play with weight transfer?
EDIT: I just re-read that you said "under adverse conditions" - I wonder if the thing could be "demand driven", so on smaller throttle openings the gears tend to stay slightly higher to soften the delivery (assume I understand you correctly in thinking you mean situations where you might use a higher gear than normal to get less torque to the track?)"
"But then, the engine RPM would be changing. It would no longer feed a constant horsepower and torque to the transmission, but one changing on load and/or driver input. If so, then what's the advantage of using a VT transmission?
Present transmissions shift at lightning speed, and assuming that straight cut gears and a clutch are the components that still have the least drag (compared to CV), then suddenly a CV looks a lot more complicated in it's application, and acceptance.
Of course, a CV transmission could select an almost infinite ratio between the engine and output shafts, and that may have tremendous advantages in long acceleration parts of the track.
So maybe a CV for racing applications is approximately equal in cornering, but superior in sustained acceleration. And it should be noted that a CV would probably add more parts, and mass, as compared to present transmissions."
Let the debate begin banghead
As much as I love the advantages of the CVT, i've driven two now, the Nissan variation, and the Audi one, and frankly, i love the endless toque on both, but I just hate with a passion the uninspired drive. They dont feel sporty. With the Audi i was peddling,(not my car, didint want to write it off), but in the Maxima, I was pushing the envelope, and I was unimpressed with the lack of emotion in it. I will take my 6-speed manual any day over almost any gearbox, aside from a Ferrari sequential paddle shift. \
So it's not the transmission but the spirit that's moving the debate. Well in for a penny in for a pound. I think I know one area I'm going to be different. I may up the size of my motor but I'm going to see what I can do with the CVT before I think about going manual. It may be the path of a fool but no one ever accused me of taking the easy way out of anything.
Here's other opinion's from a different post:
"At present, straight cut gears with a clutch are the least power robbing components available for the drive train. Torque converters, automatic transmissions and the like rob more power from the engine than the above mentioned components. So for sheer performance and racing applications, straight cut gears and a clutch are the way to go. (at present) It must be assumed that a CV system would have more drag, steal more power from the engine. And usually, with more drag, there is more heat generated within the transmission.
But with a theoretically practical racing CV system, braking effort through the engine could easily be programmed in, giving a very good engine braking system.
As mentioned in the previous post, the engine would probably run at a constant RPM, and that's the beauty of it, allowing an engine designed for just one operating condition. But there may be problems, if the torque delivered is more than the tires can grip under adverse conditions. And that could lead to some form of traction control with fuel or RPM cutoff to allow the tires to grip, and not spin wastefully".
"Surely the traction problem would not be much different to now - Ok, the engine is always in the fat part of it's torque curve - but it's probably pretty close most of the time these days - the ultimate torque controller remains at the throttle pedal just as now, so a driver could control wheelspin by modulating his right foot. This leads me to think that you would have to get the engine braking side of the transmission spot on - how would it deal with someone riding out a drift using the throttle working between more/less throttle and needing instant changes to the engine braking/acceleration to play with weight transfer?
EDIT: I just re-read that you said "under adverse conditions" - I wonder if the thing could be "demand driven", so on smaller throttle openings the gears tend to stay slightly higher to soften the delivery (assume I understand you correctly in thinking you mean situations where you might use a higher gear than normal to get less torque to the track?)"
"But then, the engine RPM would be changing. It would no longer feed a constant horsepower and torque to the transmission, but one changing on load and/or driver input. If so, then what's the advantage of using a VT transmission?
Present transmissions shift at lightning speed, and assuming that straight cut gears and a clutch are the components that still have the least drag (compared to CV), then suddenly a CV looks a lot more complicated in it's application, and acceptance.
Of course, a CV transmission could select an almost infinite ratio between the engine and output shafts, and that may have tremendous advantages in long acceleration parts of the track.
So maybe a CV for racing applications is approximately equal in cornering, but superior in sustained acceleration. And it should be noted that a CV would probably add more parts, and mass, as compared to present transmissions."
Let the debate begin banghead