Clutches for Clutchless Transmissions

[SPARKY]

I am doing research on clutches for clutch less transmissions ---is there anyway to soften the shift

[Crackerman]

If ibam not mistaken. Its all mechanical interaction, no slipping, no physical way to soften the shift in the driveline due to intertia of mass changing relative speeds.

However, careful timing control/retard during and directly after shift ought to keep the spike down some.

[Interested Observer]

You can always consider putting a “soft” or compliant member in the driveline.

[SPARKY]

Compliant is good I am thinking of a silicon coupling like GM used on some of there AWD vechicles

[Ron Gibson]

I read on one of the clutchless sites that a clutch that slips a bit at shift was absolutly necessesary to prevent breakage of parts. That would be a fine line at drag racing traction but I don't think at the salt that would be a problem unless you're like some that weigh 7000 pounds.

Ron

[Ron Gibson]

On Jerico's site, one the second page of the "break in procedures", it talks about clutch slippage on shifts.

Ron

[jl222]

 
 We back off the throttle some when we shift, sometimes Less air in tires might help.
 We can soften the shocks and springs and have a longer instant center to soften the hit. But were sprung.

             JL222

[Mr. Schimstock]

Could you increase the stroke of the springs on the friction plate?  These are really designed to smooth out the pulses from the engine..... or add another set of them?

[kiwi belly tank]

I am doing research on clutches for clutch less transmissions ---is there anyway to soften the shift

What's the story here Sparky, are you trying to complicate the tank more than it is now or are you going drag racing with the Firechicken?
  Sid.

[rouse]

Hey I'm just throwing something up against the wall here Sparky, so don't laugh before you think about it.

The motorcycle folks use an ignition kill for just a few Milli seconds to shift. If you set something like that up on your shifter, that should soften the hit. Simple to do and shouldn't cost to much. All providing your engine combination will stand such a thing.

Rouse 

[Eddieschopshop]

I read on one of the clutchless sites that a clutch that slips a bit at shift was absolutly necessesary to prevent breakage of parts. That would be a fine line at drag racing traction but I don't think at the salt that would be a problem unless you're like some that weigh 7000 pounds.

Ron

The problem isn't weight or traction,  something has to absorb the energy from the sudden change in rpm,  with big power it will usually snap something before it has a chance to try to spin the tires. 

[SPARKY]

Well we are making some progress---thanks to PMs--- from some pretty fast guys---lots of phone calls---and the very beginning to grasp the ways to change the clutch induced shock loads.

this is what I think is a way to help the problem---
a multi disc clutch that has adjustable springs and 6 adjustable or changeable levers to be able to change the static clamp for coming off the line and getting up to eng speeds where the centrifical clamp load starts to apply

The trick is now going to be how to figure out the rpm the eng will live and thrive with a rpm adjustment of clutch where the drive train can handle the recp. mass  inertia loads on the drive train with the instaneous up shift.

So does anyone know where there may be some old BBC pro-stock clutches laying around? 

[Eddieschopshop]

Racing Junk  Sparky,  plenty of clutches/trans stuff on there

[Interested Observer]

Sparky,
I think you need to sit down and think about what you are trying to do.
A drag racing clutch is generally set up to slip coming off the line with centrifugal weights to effect lockup of the clutch at high rpm.
This is almost the inverse of what you want.
You want a clutch that slips at a torque level above your maximum nominal output torque but below a level that would damage the driveline.  This is not rpm dependant.  Centrifugal control is not workable.  You are asking the clutch to pass your maximum torque, and then at a shift point, magically slip at any marginally higher torque (which would be induced by inertial effects at essentially the same, or lower, rpm). 
All you need is an adjustable preload clutch that behaves very well.  And, once slipping doesn’t just keep on slipping and overheating and wearing out and becoming an adjustment/maintenance headache.

[SPARKY]

I O  you are spot on---

But I THINK the secret is going to be to set the max clamp above the RPM shift point of my shift range so that I am not using near what the centrifical clamp range is capable of at what ever the Max clamp is set at:  ie use only as much as is needed

Again thanks to all who posted---every little bit helps stimulate the evaluation process---what a great resource we have with this website