pDrive CLUTCH... DISCUSSION... TUNING, CLICKERS, FLYWEIGHTS... PHOTOS AND VIDEOS.

mountainhorse · Feb 26, 2016

Xeiscountyduke said:
i asked the rotax guys about the new pdrive clutch. I thought you could only Change the engage rpm of the clutch by changing the Primary spring?! The said yes, but on the new clutch, as you can see it in the Video, you Change the whole Position of the ramps out and in and additionally the inclination.
So the wole rpm range moves up and down. If you cange the top rpm up or down, you also Change the engange rpm the same up and down......
Thats what the rotax guys told me......

here is the Video. look at time 3:18 and you can see the movement of the clicker.

https://www.youtube.com/watch?v=c1LoVKaC8Ds

rulonjj said:
We won't really know until we begin fussing around with this clutch. I can see why you'd think the whole rpm range moves but with the shape of the ramps they could minimalize how much the engagement rpm changes

Xeiscountyduke said:
it's not my thinking about the function. i asked the rotax engineers about the function of the new clutch, because i was really impressed of the new design.
But one of them told me, he is also a former snowcross racer here in Austria, that he is not satisfied with the new clickers because of the Change of the whole rpm range especially the Change of the Engagement......

this is only Information directly out of the rotax facility.......

Ski-doo#1 said:
He is right. Watch the video closely you can see it change the position of the ramp where the ramp pivots.

It won't change the weight but will change the distance the weight of the ramp is away from the clutch. This will change the centripetal forces within the clutch. Therefore, changing engagement. Also it changes the ramp angle so yes, it will change top engine RPM as well.

My question is if 300 engagement equals 300 top engine RPM?

Deep Powder Guy said:
The clickers on all skidoo's have always changed ramp position on every TRA clutch ever built .... There are 2 ways to change engagement either by changing primary spring or ramp profile or both .... Clicker position does not effect engagement.

DPG

Looking at this clutch... and trying to wrap my head around it.

This is a discussion... a work in progress if you will to discuss and adapt our understanding of this new clutch.... so please bear with me and participate in the discussion.

The ramp...which now looks convex rather than concave.

So the tilt of the flywieght changes.

If the roller of the arm is in contact with the flyweight at rest... and holds clutch open to that point... and the arm cannot move at all... then, yes you would also change the engagement speed...

But... if the arm/roller can 'flop' a bit, like on a TRA, before it contacts the ramp...then it will not affect the engagement speed.
Edit:See post #16 below... I now believe that Xeiscountyduke's info from his Rotax contact IS, in fact, correct... and that engagement RPM will also be affected.

So my questions are...
Why is the flyweight convex now? (or do I need to change my brand of crack??)
Does the arm/roller have any free movement before it hits the ramp?

.

mountainhorse · Feb 26, 2016

Ahh...

NO arm... Just the roller mounted to the top of the 'spider'

The ramp IS the ARM... like on a P85... Now I'm getting it.

The clicker then acts as a max travel stop for the flyweight??

diamonddave · Feb 26, 2016

Not sure it acts as a stop necessarily but it appears to me that the clicker moving will change the profile of the arm/ramp. This would take the place of the 1/8" allen weight pins that hold the weight/ramp in a P-85.

This roller design (to me) serves as the button and roller in a P-85.

This thing looks cool. It really looks like a better P-85.

hoov165x · Feb 26, 2016

mountainhorse said:
Ahh...

NO arm... Just the roller mounted to the top of the 'spider'

The ramp IS the ARM... like on a P85... Now I'm getting it.

The clicker then acts as a max travel stop for the ramp (cam) ??

The clicker changes the pivot position of the 'ramp', effectively changing the position of the 'ramp' in relation to the roller. The ramp is actually like the flyweight on a P85, in simplistic terms.

That's the way I see it anyway.....

mountainhorse · Feb 27, 2016

To me... so far... yea... this pDrive seems closer in function to a P85 than the TRA of the past.

The clicker is an ingenious field adjustment... WAY COOL TECH!!

The clicker adjusts both the start position and and final position of the cam... I'll call it a flyweight..because it is no longer a 'ramp' to me.

:laser:This would only affect the engagement speed of the clutch IF... IF... the flyweight were in contact with the roller with engine at rest.

This seems unlikely to me that the flyweight would be in contact with the roller at rest... or you would have to open the clutch slightly to adjust the clicker... which does not seem like is the situation.

I've started the video at the part with the clutch motion and the clicker operation
<iframe width="900" height="506" src="https://www.youtube.com/embed/7-kf9KxiR54?start=267" frameborder="0" allowfullscreen></iframe>

.

mountainhorse · Feb 27, 2016

So... looks like you unscrew the the clicker plate cap-screw to move the toothed-plate to the right... spin the internal toothed ring and then retighten the cap-screw.

I wonder if someone will come out with a good 'quick clicker' for this??

nuttyn01 · Feb 27, 2016

engagement

I was talking with Tom (Tom's snowmobile). He didn't get into great detail, but he did indicate that you no longer have to swap out springs to increase or decrease engagement rpm but rather add or take away shims.

mountainhorse · Feb 27, 2016

ADDING WEIGHT TO THE HEEL OF THE pDrive CAM.

Further tuning of the pDrive has you remove this bolt and you add a weight bushing under the head of the bolt and screw it back in.

Not long before adjustable flyweights like the Team Rooster or SLP lightning weights get released for these pDrive clutches.

This will allow you to tune to the engine power band well... by placing a weight, within the flyweight, at the tip, mid or heel.

This Clutch is VERY easy to understand now for me... very similar to a P85 in function... with some great new features.:face-icon-small-ton

.

mountainhorse · Feb 27, 2016

xteam.SkiDoo.com

Posted on September, 12 2015

New pDrive Clutch

To make the most of the additional power, the Valcourt Race Shop matched the engine with a completely new high performance pDrive primary clutch.

This new pDrive is designed to reduce friction, reduce weight, tighten tolerances, allow for more consistent RPM delivery, require less maintenance and last longer.

To accomplish this the specialty racing pDrive clutch features unique elements like fast and friction free dual rollers to transfer torque in place of traditional sliding buttons, the renowned BRP exclusive adjustable clickers – only this time applied to flyweights, needle bearings in oversize rollers and a compact open design that’s also 11mm narrower.

The new clutch and new clutch cover combine to reduce belt operating temperature by 68° F (20° C).

mountainhorse · Feb 27, 2016

Goodwin Racing

http://goodwinperformance.com/product/ski-doo-tra-puller-2016-600rs-models-only

pDrive puller

mountainhorse · Feb 27, 2016

Other tools for pDrive maintenance.

there is a grease injector for the rollers (529 036 376), roller axle removal tool (529 036 372)... Spring compressor (529 038 373) and other pDrive specific tools.

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mountainhorse · Feb 27, 2016

Shimming of the spring

Yes, just like on other brands... you can shim the primary spring to raise engagement rpm.

If there are already shims under the spring, you can also remove them to LOWER the engagement RPM.

This will also have an effect on clutch performance at other RPM and sheave positions as well.

.

Deep Powder Guy · Feb 28, 2016

mountainhorse said:
Further tuning of the pDrive has you remove this bolt and you add a weight bushing under the head of the bolt and screw it back in.

Not long before adjustable cam-weights like the Team Rooster or SLP lightning weights get released for these pDrive Cams.

This will allow you to tune to the engine power band well... by placing the weight, within the cam, at the tip, mid or heel.

This Clutch is VERY easy to understand now for me... very similar to a P85 in function... with some great new features.:face-icon-small-ton

.

I don't see a huge advantage to having adjustable flyweights since the Doo offers clickers which adjust rpm .... With that in mind adjustable flyweights can also change the engagement, up shift and back shift pattern as well, but I'm sure skidoo will have an assortment of ramps to choose from which do the same.

I'm not sure about the grease fittings grease in the clutch gives me the ebbie gebbies.

DPG

snowmobiler · Feb 28, 2016

fill with grease after 100k miles.LOL

mountainhorse · Feb 28, 2016

Closer to a P85 than a TRA.

Deep Powder Guy said:
I don't see a huge advantage to having adjustable flyweights since the Doo offers clickers which adjust rpm .... With that in mind adjustable flyweights can also change the engagement, up shift and back shift pattern as well, but I'm sure skidoo will have an assortment of ramps to choose from which do the same.

I'm not sure about the grease fittings grease in the clutch gives me the ebbie gebbies.

DPG

The clickers will help with altitude compensation.... but just like adding pin weight to a TRA there are other dimensions besides flyweight inclination.
I'm fairly confident that the clicker on the flyweight will not have the same exact effect as the clicker on a TRA.... the function is not the same.

The pDrive is closer in function to a Polaris P85, IMO, than it is to a TRA.

Adding weight at different locations on the flyweight will give different fine tuning capabilities.....synonymous to lightweight TRA arms that have different weight locations.... Plus, I'll bet that there are different flyweight curves that will be available.... just like there are for the other brands.

Exciting design... tuners will have a lot to ponder.

The grease injector is for roller maintenance... but I hear ya on grease in a primary.

.

mountainhorse · Feb 28, 2016

Wrapping my head more around this... a learning process for sure... and some fine crow eating as well.

But hey...
It's a discussion...so roll with me. For the clutch guru's out there... please chime in and help with the discussion.

What Xeiscountyduke had to say from the Rotax guys seems to bear fruit... as I work to understand this clutches function.

The clicker controls the inclination of the flyweight compared to a plane perpendicular to the centerline of the crank/clutch.

If the flyweight is inclined out more from the centerline of the clutch.. then engagement will be affected as a lower RPM WILL will push more on the roller at a lower RPM...thus moving the clutch to close sooner (lower RPM).

Starting sooner will also load the clutch more towards the end of the flyweight's travel... the more outward tilt will provide more centrifugal force that the weight can push against the roller... making the engine work harder for a given RPM. Tilting it back down in angle will have the opposite effect.... pushing against the roller with less centrifugal force against the roller... making the engine work less hard for a given RPM.

Of course, the weight of the flyweight, where that weight is placed on the flyweights length and the shape of the flyweight itself will all still affect the character of the clutch performance in addition to the inclination of the flyweight... related in analogy to the use of lighter/heavier TRA arms, TRA pin weight, ramp Profile etc.... More controllable by the user and faster to change in the field with no special tool for those tuning sessions. You can now pull a flyweight in the field without special tools it would seem.

How this cooperates with the secondary... and it's state of tune for backshift performance is just as important as ever... some are fans of the QRS... others prefer to float the QRS... while others prefer the floating Team Secondary.

.

.

Deep Powder Guy · Feb 28, 2016

mountainhorse said:
The clickers will help with altitude compensation.... but just like adding pin weight to a TRA there are other dimensions besides flyweight inclination.
I'm fairly confident that the clicker on the flyweight will not have the same exact effect as the clicker on a TRA.... the function is not the same.

The pDrive is closer in function to a Polaris P85, IMO, than it is to a TRA.

Adding weight at different locations on the flyweight will give different fine tuning capabilities.....synonymous to lightweight TRA arms that have different weight locations.... Plus, I'll bet that there are different flyweight curves that will be available.... just like there are for the other brands.

Exciting design... tuners will have a lot to ponder.

The grease injector is for roller maintenance... but I hear ya on grease in a primary.

.

The pin weight in the TRA has everything to do with rpm and the pin weights is to set the TRA rpm baseline and control the shift of the bouncing Betty's ... While the TRA clickers are for fine tuning your rpm depending on elevation .... The reason Poo, Cat & Yamaha do not require pin weight is because the flyweight (ramp ) is the weight and can be purchased in the correct amount of grams needed for your riding elevation. Or for a more precise tune you can purchase flyweights with a baseline weight for your elevation which comes with set screws you insert into the flyweight to fine tune.

DPG

rulonjj · Feb 28, 2016

I'd be surprised if the clickers on this new clutch changes engagement rpm (if it does at all) as much as it changes peak rpm. So let's say you change peak rpm 300 rpm with the clicker, I would think that the engagement rpm would only change 100-150 rpm.

I just don't see how it could change the engagement rpm. The arms still take the same rpm to push the rollers and overcome the spring. If the spring start rate stays the same, how could that change engagement rpm? If the clickers change clutch engagement rpm then adding or taking off weight would also?? I'm not sure but just trying to understand how this thing works.

Edit: I got looking at this a little more. I may sound a little nuts here but I wonder if changing rpm with the clickers will have the opposite effect on engagement rpm. So making peak rpm higher would lower engagement rpm. ??

Deep Powder Guy · Feb 28, 2016

I found this on goggle the photo illustrates where the arm/roller from the older TRA primary begins engagement on 3 different ramp profiles.

DPG

mountainhorse · Feb 28, 2016

Deep Powder Guy said:
The pin weight in the TRA has everything to do with rpm and the pin weights is to set the TRA rpm baseline and control the shift of the bouncing Betty's ... While the TRA clickers are for fine tuning your rpm depending on elevation .... The reason Poo, Cat & Yamaha do not require pin weight is because the flyweight (ramp ) is the weight and can be purchased in the correct amount of grams needed for your riding elevation. Or for a more precise tune you can purchase flyweights with a baseline weight for your elevation which comes with set screws you insert into the flyweight to fine tune.

DPG

The 'adjustable' aspect is not just for total weight of the flyweight, but WHERE that weight is added within the flyweight.

A weight with the same profile and same overall weight, but more weight at at the tip will run differently than one that is the same but carries more of that weight at the heel. Adding more weight on the clicker adjuster bolt will have different effects than adding it just at the tip of the flyweight for the pDrive.

As I mentioned above... in the TRA designs... many tuners were using different weight arms... in addition to adjustable pin weights to add different parameters to the tuning...an adjustable flyweight with multiple weight positions would add this dimensionality to the tuning of the pDrive as well... and be SUPER EASY to tune as it looks like you wouldn't even need to remove the flyweight from the pDrive to add/subtract weight....

I've seen Tundershift arms, LW Dalton arms and quite a few others for the TRA... We'll see if this this concept is offered in a flyweight from for the pDrive as well.

Ski Doo has a system to load the heal of the weight for the pDrive for the mountain sleds.

Of note...(many will have already known this)... The pDrive was released last season on the 600RS sleds... but, it did not include 'clickers' on any of the models that I saw.

.

pDrive CLUTCH... DISCUSSION... TUNING, CLICKERS, FLYWEIGHTS... PHOTOS AND VIDEOS.

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