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Old 02-19-2009, 02:55 AM   #1
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Default Clutch tuning questions

I have a basic understanding of a centax, tighten it down if you want engagement in a higher RPM and vice versa for the opposite.

So why would I ever want to run a softer/harder clutch spring if I can just adjust the clutch nut? Does this go hand in had with weighing down the flyweights?

Also, when and why would I run with a harder clutch shoe?

Thanks.
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Old 02-19-2009, 06:11 AM   #2
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The hardness of the spring in combination with the flyweights wil have influence on how the clutch engage (hard. soft, slippery etc) and the type of shoe has also influence on the grip and so slip...
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Old 02-19-2009, 06:52 AM   #3
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Also, when and why would I run with a harder clutch shoe


at VRC you can use the red shoe to allow alittle slip at engagement so when you pull the trigger coming out of the tight corners the car dosen't swing out the ass end do to over power...
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Old 02-19-2009, 07:41 AM   #4
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I think you should try and test yourself because the difference between a tighter spring and a harder clutch shoe is hard to explain here.
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Old 02-19-2009, 10:11 AM   #5
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We landed on a clutch set-up for the Kyosho that is excellent. We haven't changed the set up in 4 years. What type of chassis are you running? If it's a Kyosho M3, NovaRossi powered, I can share, by PM, our clutch setup. As a comment - our (Empire's) clutch set up doesn't work with other chassis or motor combos -

It is best to see what the "fast" guys are running at your local track and ask them. Also, each chassis manufacturer will have set up sheets posted so you can review what the "best of the best" are doing. All of the components work together - it's not a "one" item (such as a shoe) proposal - Shoe, flyweights, spring, gap - all must work together.
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Old 02-19-2009, 10:35 AM   #6
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All of these points are correct. You just have do your own testing. It took me a better part of 2 years to fully understand the correct way to set-up a centax clutch and I still have more to learn.

Pass you soon...
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Old 02-19-2009, 10:47 AM   #7
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spring: change tension to tune engines optimal engagement rpm, but you could stack a soft spring trying to get it to engage later. So you switch t a harder spring.


clutch shoe: use this to fine tune for traction. A hard shoe will slip alittle more but last longer, a soft shoe will hit hard and wear fast.

You might have a perfect shoe for qual's but it won't last the hour main so you go one harder......

These are very general/generic...

Talk to me next race at speedworld and I will give you all the knowledge you need/want
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Old 02-19-2009, 03:54 PM   #8
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this helped me..
http://www.rctek.com/technical/clutc...they_work.html
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Old 02-19-2009, 04:17 PM   #9
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To translate what Jay was saying, If you keep cranking down on a soft spring it can coil bind to where it can't compress any more. A harder spring can eliminate this problem.

In addition, spring rate has another effect. Imagine two springs, a soft one and a stiff one. If you could actually put a strain gauge under the spring you could tighten down on the nut until both were putting the exact same amount of pressure on the shoe. This way, the rpm at which the shoe would start to move toward the clutchbell would be exactly the same. However, the shoe has to move a certain distance before it actually begins to touch the clutchbell. Despite both springs having the same pressure at rest, it will take more time and rpm to get there with the harder spring.

There are many other things that affect clutch engagement. Weight of the flyweights and gap between the shoe and clutchbell for instance. I've spent years getting the Mugen clutch down and then they went and changed it . Fortunately I've found the new one even better for me.
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Old 02-19-2009, 06:34 PM   #10
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Quote:
Originally Posted by wingracer View Post
To translate what Jay was saying, If you keep cranking down on a soft spring it can coil bind to where it can't compress any more. A harder spring can eliminate this problem.

In addition, spring rate has another effect. Imagine two springs, a soft one and a stiff one. If you could actually put a strain gauge under the spring you could tighten down on the nut until both were putting the exact same amount of pressure on the shoe. This way, the rpm at which the shoe would start to move toward the clutchbell would be exactly the same. However, the shoe has to move a certain distance before it actually begins to touch the clutchbell. Despite both springs having the same pressure at rest, it will take more time and rpm to get there with the harder spring.

There are many other things that affect clutch engagement. Weight of the flyweights and gap between the shoe and clutchbell for instance. I've spent years getting the Mugen clutch down and then they went and changed it . Fortunately I've found the new one even better for me.

Hi Sean, it's Mike Keely. Do you think that it is better overall for any certain reason or because you just found the sweet spot. I worked with it but kept feeling like I was doing something wrong with the new clutch. It always seemed like the engine would overheat.
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Old 02-19-2009, 08:49 PM   #11
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I like the new one because I seem to be able to use larger gaps without problem. I love how the clutch works with .7-.8mm gap but the old one would do weird things with that much gap. The new one seems to take it Ok.

My 301 3 shoe Mugen clutch set-up:

Flyweights lightened slightly by trimming a small amount of plastic off the back side of the trailing edge.

Yellow shoe.

Orion CRF spring set to about .8-.9mm when new. May need to go a bit tighter after a few runs.

Clutch gap at around .6mm. May go slightly higher if I need more snap.

Then I space the back of the clutchbell to eliminate most of the endplay.
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Old 02-19-2009, 09:45 PM   #12
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Thanks for the replies!
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