CVT -small engine or large?

[Admin]

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.

It all boils down to opinion anyhow, so there is no right or wrong answer regardless...

[fabr]

bingo.We have a winner.

[SPEC]

And I don't bring a knife to a gunfight

[Whiplash]

Unless the gun owner does not expect you to fight!! LOL!

[SPEC]

 

[b.c.bugger]

mfabber, what would kind of power do you mean when you say "big power, broad powerband"? I.M.O. there is no downfall to running "big power" in front of a c.v.t., thousands of turbo yammy sleds run250-350+ horsepower with basically no mods done to the clutch, (other than a lot more weight swinging) on the factory belt which was designed to harness 150 h.p.
Again it is a matter of opinion as to whether you prefer to shift or not, but I would guess that most people who have experienced well set up cvt clutches on several different motors with varying h.p. would have a hard time convincing themselves that the manual shifter is the way to go.

[fabr]

It's all a matter of personal preference .Period.  A cvt WILL enable a small motor to act as if it is larger. IMO that's the only advantage to a CVT beyond that it is just personal preference.  IMO.  If you like hearing an engine running at full throttle much of the time you will like them. If you like the increased fuel consumption you will also like a CVT. If you like precise throttle control you will not. If you like to be able to really feel and use the varying torque from the engine at different rpm's you will not like a CVT. As I said,personal preference will dictate what a person uses. There is no right or wrong answer.

[Islander]

I'll take shifting every time    The drone of CVT tends to grate on me, just my preference!

[fabr]

FINALLY ! Someone that agrees with me. I was beginning to think I was the only one!

[LiveWire]

The driven clutch is torque sensing. When there is low load, the driven clutch will not restrict upshifting like it does under a high load. So the system will upshift and lower the RPMS. In Olav Aaen's clutch tuning handbook, which is often referred to as the bible of CVT tuning, there is a rule of thumb proved with a mathematical formula. More spring load and more cam arm weight that are still matched to each other will make the clutch operate more efficiently. The springs in a typical clutch have very little pre-load. The cam arms at low speeds primarily are pressing on the pivot pins and not the rollers that cause it to shift. Therefore, a typical CVT is at it's worst efficiency at low speeds. This is where high engagement speeds are common for fast take off. I use Heel Clicker clutch kits which come with very long springs and have a portion of the weight on the outside of the roller. The center of mass of the cam arm is now farther out from the pivot at engagement/low speeds. So the kit increases effective cam arm force and spring load at low speeds improving the efficiency of the clutch during engagement and at low speeds. On two machines, my engagement is lowered over 1000 RPMs. One gained 3 lengths in a 300 foot drag race and the other gained 2 lengths over their previous setups even though the engagement is so much lower. I can also now putt around at low speeds and lower RPMs than before. When I nail the throttle it does not bog like it would with standard arms and calibrated with a low engagement. The lower the power curve is, the bigger the difference it will make. The most significant gain I have gotten was on a 3 cylinder Geo powered buggy. I did not measure it, but would guess it picked up at least 5 lengths in a 300 foot drag. On an Ecotech, I would run a Comet 4-Pro with 4 arms instead of 3 and use Heel Clickers on that.