Track Tac

Clutch engagement RPM?

I think Al made it easy. Set it to peak torque.

The only hard part, could be to learn what rpm your engine develops peak torque.

And Al covered that to by explaining about the scale method to find peak torque. Sounds about as cut and dry as you can get. IMHO, it makes setting your clutch the only cut and dry thing in karting.
 
that link was showing the clutch engagement info, not the bathroom scale stuff. I was searching for the measuring torque with a bathroom scale when I came across that...
 
rab3rd said:
that link was showing the clutch engagement info, not the bathroom scale stuff. I was searching for the measuring torque with a bathroom scale when I came across that...
Click to expand...

Read my post toward the top of this page, it explains it mostly. pm me if you want full detail
 
alvin l nunley said:
I’m wondering what your definition of “fully engaged” is?
When you hit the gas, with the brakes applied, and the engine spins up to some RPM, I call that the “stall” RPM. To me, the term “Lockup” is when the clutch stops slipping, and that would be when the engine and the axle, divided by the gear ratio, are turning the same RPM. Of course it remains a mystery if there is every a point where there is no slip at all.
Comments, compliments, criticisms and questions always welcome.
Click to expand...

I thought that was pretty self explanatory.
 
So now that I am totally confused after reading all of this. My engine builder gave me a dyno sheet that shows the following:
Maximum HP of 10.48 at 4575rpm Torque of 12.02
Maximum Torque of 13.72 at 3375rpm

So where do I try and set my clutch engagement using a Fury clutch?
 
Double E Ranch said:
So now that I am totally confused after reading all of this. My engine builder gave me a dyno sheet that shows the following:
Maximum HP of 10.48 at 4575rpm Torque of 12.02
Maximum Torque of 13.72 at 3375rpm

So where do I try and set my clutch engagement using a Fury clutch?
Click to expand...
Why not try them all, see who really knows what they’re talking about.
Comments, Compliments, Criticisms and Questions always welcome.
 
Double E Ranch said:
So now that I am totally confused after reading all of this. My engine builder gave me a dyno sheet that shows the following:
Maximum HP of 10.48 at 4575rpm Torque of 12.02
Maximum Torque of 13.72 at 3375rpm

So where do I try and set my clutch engagement using a Fury clutch?
Click to expand...

based on the little I have come to understand I'd say about 3000 for the slip point. That would put you at about 3100-3200 lock up.
 
Double E Ranch said:
So now that I am totally confused after reading all of this. My engine builder gave me a dyno sheet that shows the following:
Maximum HP of 10.48 at 4575rpm Torque of 12.02
Maximum Torque of 13.72 at 3375rpm

So where do I try and set my clutch engagement using a Fury clutch?
Click to expand...

your max torque or peak torque is at 3375, so you want your clutch to engage at that rpm or as close to it as you can get. I use the fury clutch myself, and you can get it to lock up at about 3300 if you use 2 black springs and 2 white springs if i remember right. You want the 2 black springs across from each other and the 2 white springs across from each other, not the same color springs side by side on the clutch. Actually, im thinking the white and black springs combo has that clutch engaging at about 3250, that is how i have mine set up. Ill let you know what the engagement is after this weekend if i can remember to check.
 
lock up and fully engaged are both saying the same thing. setting your clutch at 3000 is probably the best, based on your numbers. and if i'm not mistaken, the bathroom scale and wall trick will give you good numbers to work with and help in showing where you would want to to set slip point at.....at least that's what i gathered from it. i tryed it and set my son's clutch to come in and he felt it first time out....
 
"lock up and fully engaged are both saying the same thing."

Interesting and I think a very good point. If the clutch can start to kill the engine at a particular lower rpm when the engine is putting out peak torque, how's it not going to also be able to want to kill the engine when it's spinning faster? I don't think there is a way.

Unless maybe somehow a super charger kicks in at a higher rpm and makes the engine put out a ton more? Maybe a tuned pipe on a 2cycle could do it at an rpm or speed higher then green flag go speed?

Or another thought on it. Let's say you start to coast into a high speed turn, could the drive you get to the clutch from the tires when coasting disengage it? If it did disengage, then there would be a new engagement and time to engage before engine power would again drive the rear wheels. Maybe making that a reason to keep your foot on the go pedal and brake at the same time? Sure it's already done but could this be a reason why it works ok, because it eliminates time needed to re-engage the clutch to go?

Fun stuff to think about.

The thing about should you engage a little bit below peak torque or at peak torque is just another of those tough things to think about.

You have to or at least I have to force myself to look at it one way or another. I really and very strongly want to say, start engaging the clutch early so it's ready to go at peak torque. But then why wait and put engine effort into spinning it up, when you want to go like right now? If you have the luxury to spend time getting it to the right speed before putting power to it then yes, but the other side of my brain says your bringing it up to speed with less then maximum available power to do it, so how the heck can it be faster? darn tough to think about. ... :)
 
Something I discovered way back in the late seventies; when coming off a turn, and the clutch is slipping right where you want it, and as you come off the corner, and the RPM drops, thus the clutch locks up at a lower RPM and you take off. I’m sure we have all seen or experienced this. Well the reason for the drop in RPM is the engine goes lean, thus a drop in torque, thus the clutch locking up at a lower RPM. Making the low speed mixture richer will most likely cure this. It did for me and I never had that RPM drop off coming out of a corner again.
I was at a race at Burnsville when I first noticed this. I was not racing, only watching. In the pro race, I noticed this with quite a few of the slower competitors, but it didn’t happen to the fast people, like Haddock, Speed, Hartman or Burton’s karts. Apparently those people knew how to tune a carb.
No need to trust me on this one, but you should try it.
Comments, Compliments, Criticisms and Questions always welcome.
 
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