poboyracer
Member
Just wondering what your opinions are on the SMC red 2disc clutch. I have one and really like it. I don't see many of them and was wondering if there was a reason for it.
SMC red 2 disc
- Thread starter poboyracer
- Start date
I don't have that particular clutch, but we do have the black SMC's. You're right, you don't see very many of them. However we switched to them since they're easier to maintain and I don't feel like we've lost anything performance wise.
I think the bulley's and similar spinoffs are more popular, but that doesn't mean they're any better when properly setup.
I think the bulley's and similar spinoffs are more popular, but that doesn't mean they're any better when properly setup.
poboyracer
Member
Does the black have a smooth engagement or the snap like he bully?
alvin l nunley
Site Supporter
I've heard that term used before "snap engagement" but I don't know what it means exactly, can you explain?
I'm no clutch expert, but my experience is this:
poboyracer - it is more of a smooth, but strong engagement, although there is still a slight snap its not as drastic as bully. I could see this helping on low hp engines like predator especially?
Al - he is referring to how hard it engages. Some clutches engage hard like bully, some smoother, more gradual pull like smc vortex. Thought process is that hard engagement could temporarily waste power on lower hp engines, whereas a constant smooth engagement allows the engine to stay up on power.
My opinion is both designs work and have won at the highest level, just depends what you, your motor builder, parts availability to which is the best choice.
poboyracer - it is more of a smooth, but strong engagement, although there is still a slight snap its not as drastic as bully. I could see this helping on low hp engines like predator especially?
Al - he is referring to how hard it engages. Some clutches engage hard like bully, some smoother, more gradual pull like smc vortex. Thought process is that hard engagement could temporarily waste power on lower hp engines, whereas a constant smooth engagement allows the engine to stay up on power.
My opinion is both designs work and have won at the highest level, just depends what you, your motor builder, parts availability to which is the best choice.
alvin l nunley
Site Supporter
Thank you for the try, but I still have questions. Define engagement? My definition of engagement is when the shoes first contact the drum and the kart starts moving. From your explanation, I'm thinking (and I could be wrong) you mean when the shoes stop slipping and the clutch locks up.
I've always use the term "stall" to describe the point at which the clutch holds the engine on the start. At the point where the axle and engine reach the same rpm, divided by the gear ratio course, is what I call full engagement, the shoes are no longer slipping. It's just a matter of different definitions for the same thing.
poboyracer
Member
I have a bully also. It does do well on my stock engine. The vortex is on my open engine. They both do really well. Just no a big fan of the snappy engagement. Seems like it would be harder on the engine.
Hey Al, yes, your definitions are correct, however they miss the point of what he is asking. He wants to know the "how", you're defining the "when".
Stall is the correct term for "when", but by the phrase of "how hard it engages" means just that, "how" strong it grabs when it decides to. Its not a binary operation of on or off or else you would be spinning wheels or kill the engine. We are talking about disk clutches, there are no "shoes" in these design clutches and they are a little more complex in "how" they engage.
Some like the vortex like to be a little more gradual to keep the engine up in power verses the bully which engages a little stronger.
So, you could visualize the "how" by plotting on a graph the time period from "when" the clutch decides to engage at the stall rpm until full engagement. Vortex might be more of a smooth straighter line, vs bully which would have some sort of curved line showing more aggressive at the stall rpm and tapering off after that.
Stall is the correct term for "when", but by the phrase of "how hard it engages" means just that, "how" strong it grabs when it decides to. Its not a binary operation of on or off or else you would be spinning wheels or kill the engine. We are talking about disk clutches, there are no "shoes" in these design clutches and they are a little more complex in "how" they engage.
Some like the vortex like to be a little more gradual to keep the engine up in power verses the bully which engages a little stronger.
So, you could visualize the "how" by plotting on a graph the time period from "when" the clutch decides to engage at the stall rpm until full engagement. Vortex might be more of a smooth straighter line, vs bully which would have some sort of curved line showing more aggressive at the stall rpm and tapering off after that.
alvin l nunley
Site Supporter
Thank you for the well written response, I appreciate it.
Something I discovered in the early 70s; a clutch, coming out of a corner, that is slipping at just exactly where you want it, (peak torque) but then, at some point, the clutch locks up, and the rpm drops and then you continue to accelerate, is not the way it should work, and I discovered this with an oil bath shoe clutch. The disc clutch had not been invented yet. I have this idea that, with the disc clutch, this is not nearly as much of a problem.
When you feel that clutch lockup and rpm drop off, it was my discovery that the engine was too lean on the low-speed. Understand this is with with a Mac 101, but as I opened the low-speed needle, that clutch lockup and rpm drop-off went away. There was almost a perfect transition from clutch slip to clutch lockup. To this day, I have vivid memories of that moment when I discovered this phenomena.