« previous next »
Pages: [1] 2   Go Down

Author Topic: CVT -small engine or large?  (Read 6270 times)

0 Members and 1 Guest are viewing this topic.

Offline fabr

  • Administrator
  • *
  • Posts: 93168
CVT -small engine or large?
« on: December 14, 2008, 02:47:49 PM »
I've been thinking about a post I saw elsewhere. It had to do with the reason for a CVT(constantly variable transmission) being desirable. The poster said it was always in the right gear.I agree but that brings up the question of is a cvt as beneficial on a larger,automotive engine/superbike engine as compared to a smaller 2 stroke or small 4 stroke engine.I don't see the need for a CVT or even the desirability on the larger engines with nice flat ,broad, torque bands as compared to a smaller engines narrower torque band.THe smaller engine I  agree is likely to be best with a cvt . In other words WHO would think it beneficial to run a larger engine at peak torque(high rpms) for long periods of time.Seems very inefficient  and unnecessary to me .
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

LiveWire

  • Guest
Re: CVT -small engine or large?
« Reply #1 on: December 14, 2008, 04:53:10 PM »
The one thing I think you are missing based on the last question is that when you are cruising, torque load reduces and RPMs drop. The driven clutch is torque sensing.

I will choose a CVT up to as high a power as I can get clutches and belts to support it.
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93168
Re: CVT -small engine or large?
« Reply #2 on: December 14, 2008, 05:09:05 PM »
I understand what you're saying. But as to how far you can go I'd think that at some point the belts would be the limiting factor . Personally I've driven both and will say that a blanket statement of I'll always choose one over the other is not IMO correct.Both have their pros and cons that will at times dictate one over the other. 
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

Admin

  • Guest
Re: CVT -small engine or large?
« Reply #3 on: December 14, 2008, 06:24:42 PM »
I have heard of a belt form aaenperformance support well over 350 hp. I will say like the ecotech and stuff, a cvt will ultimatley make a much smaller package, you could put one on a bus trans etc but then the length and weight double..
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93168
Re: CVT -small engine or large?
« Reply #4 on: December 14, 2008, 06:51:46 PM »
Can't argue with that but it still doesn't make A CVT  the best option for all uses.
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

Admin

  • Guest
Re: CVT -small engine or large?
« Reply #5 on: December 14, 2008, 07:26:04 PM »
I dont believe the cvt is the best for all uses. In a minibuggy it is very well suited tho.  ;D
Logged

SPEC

  • Guest
Re: CVT -small engine or large?
« Reply #6 on: December 14, 2008, 07:28:17 PM »
A well tuned CVT will make a power plant feel like it is twice the size and out put that it is...a poorly tuned CVT will kill a killer engine... the no-shift concept takes a pipey, unmanangable power plant...and make it drivable... example...165 horse tripple...zero bottom end grunt...CVT tuned to 6500 engagement...smokes the tires out of the hole...5000 engagement...little hard out of the hole but driveable thru the tight stuff...4800 engagement...doggy on hill-starts but easily powers thru the ugly stuff...Kinda like driving a stalled auto on the street, Belts, primary,secondary, shift pionts can be trickey ...but patients and some knowledge will get you thru- it...No shift in the woods is the only way to go...shifting and dodging trees can be a BITCH
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93168
Re: CVT -small engine or large?
« Reply #7 on: December 14, 2008, 08:33:09 PM »
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

Offline fabr

  • Administrator
  • *
  • Posts: 93168
Re: CVT -small engine or large?
« Reply #8 on: December 14, 2008, 08:35:48 PM »
Quote from: SPEC on December 14, 2008, 07:28:17 PM
A well tuned CVT will make a power plant feel like it is twice the size and out put that it is...a poorly tuned CVT will kill a killer engine.. the no-shift concept takes a pipey, unmanangable power plant...and make it drivable... .example...165 horse tripple...zero bottom end grunt...CVT tuned to 6500 engagement...smokes the tires out of the hole...5000 engagement...little hard out of the hole but driveable thru the tight stuff...4800 engagement...doggy on hill-starts but easily powers thru the ugly stuff...Kinda like driving a stalled auto on the street, Belts, primary,secondary, shift pionts can be trickey ...but patients and some knowledge will get you thru- it...No shift in the woods is the only way to go...shifting and dodging trees can be a BITCH
I certainly agree with that most of the time.
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

SPEC

  • Guest
Re: CVT -small engine or large?
« Reply #9 on: December 15, 2008, 05:13:21 AM »
I have driven both in the sand and the woods
I like a fast back-shifting CVT and a hard mid-range hit power plant in the woods...In my opinion Cvt for the woods is the only way to go...Now on the Sand...That is another animal all together...I thought that the CVT sorta sucked...and liked driving the bike powered car...It was easier to me...to not up-shift the bike motor when I thought things were going to get hairy...Where the CVT wanted to back shift... altho that was my fault I had never had that buggy on the sand before, so it wasn't clutched for the sand and the constant drag that sand has...
Alot of people's woods riding is different than mine I range from branches slapping both sides of the cage and hitting saplings with both tires at the same time to fire roads they have water tankers driving down
Logged

Admin

  • Guest
Re: CVT -small engine or large?
« Reply #10 on: December 15, 2008, 05:19:27 AM »
your expirence in the sand was apples to oranges tho, busa to 80 hp cvt, i got to imagine a rx1 or something making 150-180 hp would much be better suited to compare with a busa...
Logged

SPEC

  • Guest
Re: CVT -small engine or large?
« Reply #11 on: December 15, 2008, 05:32:27 AM »
Yup your right there...Mostly ::)...With the CDI going out on that trip it was a truley unfair comparison I went from just over 100hp. to prolly 35 to 40.
But I still think a bike motor in the sand is the way to go...Thats why there is a CBR 1000 sitting in my shop
Now for sand dragging I think that a bike motor with a CVT would be the clear shit just like you and I talked about...It would be easier on the clutch basket and you would have a shit load of gear choices, with the advantage that all of the spinning mass in the trans already in motion, and with the motor close to its peak torque before the buggy ever moves...
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93168
Re: CVT -small engine or large?
« Reply #12 on: December 15, 2008, 06:15:55 AM »
I can't disagree with bug or spec on the last couple of posts.
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

LiveWire

  • Guest
Re: CVT -small engine or large?
« Reply #13 on: December 15, 2008, 06:32:41 AM »
I have driven a quad with a group of Odysseys and Pilots on the sand. It seemed like I was shifting more than I was in any gear. Go up the dune down shifting as I lost speed then back down up shifting between one blip of the throttle.

The CVT parts for the lower HP stuff has more internal friction than the stuff for high HP. So it has to be tuned more specifically to the terrain. A theoretically perfect system with no internal friction would have one perfect tune and adjust to the terrain. A Cat roller driven and a 102C, 108C or any current sled clutch drive is pretty close. A steel ramp and rollers in the driven will put it even closer.
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93168
Re: CVT -small engine or large?
« Reply #14 on: December 15, 2008, 06:39:57 AM »
I think we are seeing a trend.Smaller stuff respond well to a cvt while for real HP and a nice broad tq.curve a manual COULD be preferrable. The only point I am trying to make is that we shouldn't make sweeping generalizations about anything without knowing the specifics of the application AND what the driver desires.
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"
Pages: [1] 2   Go Up
« previous next »
 
SimplePortal 2.3.7 © 2008-2024, SimplePortal