Ramps in the TRA, how they work and how they effect performance.

[tollen77]

It's the other way around it's the heat making the rpm bounce around......

As for 2 much weight you need weight to run at the motors factory calibrations. If the 800R is calibrated to peak at 8150 rpm your going to need the weight to acheive those rpm's. Weight is not an option

The addition of adding or subtracting clutch weight in the TRA primary should only be used for acheiving and maintaining peak rpm as you tune your sled. If i want to grab the belt harder im not going to add or subtract weight in the primary nor do i advise anyone else to do so.

2 thing could occur either you have 2 much finish on the primary spring or your ramp profile is to steep. When useing a steep profile ramp you slow the shift becuase it's harder for the roller to go up the steep ramp into higher shift ratios thus causing added friction in the process. Or you could also have a combination of both.

The TRA need weight between the ramps, roller/arms X 3 = 300 grams approx. to operate add 16 grams of pinweight to each roller and your near 340 grams of weight plus or minus.

each ramp 63 grams
each roller/ arm 34 grams



OT

I think we've covered this in previous threads. Suffice it to say, I agree with some of this and disagree with a fair amount (specifically your opinion on how ramps work). No need to get into the details again though.



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[Original Tetonice]

I think we've covered this in previous threads. Suffice it to say, I agree with some of this and disagree with a fair amount (specifically your opinion on how ramps work). No need to get into the details again though.



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The more you squeeze the throttle the more the roller/arm shift into higher ratios on any ramp profile, the less you squeeze the throttle once at higher ratios the /arm will falls to lower shift ratios of the ramp profile..... If the roller/arms work any differant as they contact the ramp, than explain..

Ramps do not work without the arm/roller & and arms/rollers do not work without ramps. And neither the ramps or the arms/roller work until the throttle is squeezed.... It's just that simple

OT

 

[tollen77]

The more you squeeze the throttle the more the roller/arm shift into higher ratios on any ramp profile, the less you squeeze the throttle once at higher ratios the /arm will falls to lower shift ratios of the ramp profile..... If the roller/arms work any differant as they contact the ramp, than explain..

Ramps do not work without the arm/roller & and arms/rollers do not work without ramps. And neither the ramps or the arms/roller work until the throttle is squeezed.... It's just that simple

OT

OT, of course I don't disagree with that.

 

[Teth-Air]

By looking at the ramp profiles in the race manual, it starts getting more clear how they will effect performance. You can't generally state anything about the ramp angles as the angles can change from bottom to top. It's at least three points on the ramp that you need to consider and the relationship between. e.g. if the ramp starts really high and then drops deep into a curve, this will make the clutch shift up easily and at lower rpm as the ramp could effectively be going down hill. Now being deep in the curve, if the upper part of the ramp is steep, the engine rpm will tend to be held longer until it can get enough momentum to move farther up this steep section of the ramp. I personally did not like the buzzy feeling of my 800 xp on the trail. It was sitting at near 6000 rpm when I was only going slow. I change to a ramp that started higher and the mid section and the top was the same as the 413. (410 I think it was) This helped the clutch shift up earlier and now at the same track speed, the rpm is near 5000. This was a great improvement for me but the sled may be a little slower off the line. Just look at your ramps and think about your sleds performance and consider at which rpm you would like to make changes, thats where the ramp should differ from yours. IMHO

OOPS,
It was a long summer, I actually have the 414 ramps right now. They are a fair bit taller on the starting end then the 413 stockers but 1/2 way and up are the same. This helps move the gearing up at lower engine speeds (under 5500 rpm) and greatly helps the coasting feel after letting off the throttle. Some might say, reducing the backshift? Any feedback from the clutching gurus is appreciated.

 

[YamaDoo PolCat]

I could see where if you had the belt in the same spot for minutes at a time it would create some excessive heat but I can't see there being any hardly measurable difference over a short time, say 10 seconds or so. I think what Joe is getting at is no matter how good your clutching is, there's going to be some amount of slip(although minimal) no matter where the belt is riding in the clutches. None of us are that good of tuners to ever get truely "perfect clutching". If you ride with the belt contacting the same areas of the sheave over time it will generate heat and slip, which generates more heat and slip. The belt slip and heat would sort of keep exponentially increasing, whereas if the belt keeps moving in the clutches you are giving that heat a chance to dissipate from that area of the clutch sheaves.

Why not experiment. Just try installing a couple of belt pulleys off your old washing machine. One on the engine - one on the jackshaft, and see how much heat they generate by leaving the belt in one spot. Probably about as much heat as it did on the washing machine. It is just a belt drive - nothing different.

While you are at it this might be a good time to "increase the clamping force" of the pulleys by tightening the belt up until the jackshaft starts to bend a little. Then run it again and see if that makes heat... Got hot and broke the belt, didn't it. Do you still think "slippage" makes killer heat?

You can leave a belt loose and "slipping" on a pulley forever and not cause the heat you will cause when you over tension a belt.

So much for slippage, look someplace else for heat.

 

[YamaDoo PolCat]

I least the kids got enough common sense not to bye into the hype of a Polar

Heehee! Oops that is a Polaris OT is pushing not a Polar! Heehee! Get a Polar clutch OT and stop pushing so hard, heehee! Looks like you are carrying an extra brown spring in the pants... Too funny!

 

[tollen77]

Why not experiment. Just try installing a couple of belt pulleys off your old washing machine. One on the engine - one on the jackshaft, and see how much heat they generate by leaving the belt in one spot. Probably about as much heat as it did on the washing machine. It is just a belt drive - nothing different.

While you are at it this might be a good time to "increase the clamping force" of the pulleys by tightening the belt up until the jackshaft starts to bend a little. Then run it again and see if that makes heat... Got hot and broke the belt, didn't it. Do you still think "slippage" makes killer heat?

You can leave a belt loose and "slipping" on a pulley forever and not cause the heat you will cause when you over tension a belt.

So much for slippage, look someplace else for heat.

YDPC, you're completely taking 'slippage' out of context. When a belt is loose, like at idle, of course the heat created is next to nothing. But when the belt is under tension (as the clutches are trying to grab onto the belt to move it) and then the belt slips, signifigant heat is generated.

When the driver of a F1 car pops the clutch, a lot of heat is generated while the two plates spin against each other trying to grab on. Same thing in a sled clutch... heat is generated as the clutch faces spin against the belt trying to get a good grip.



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[Original Tetonice]

Heehee! Oops that is a Polaris OT is pushing not a Polar! Heehee! Get a Polar clutch OT and stop pushing so hard, heehee! Looks like you are carrying an extra brown spring in the pants... Too funny!

Why buy a a primary at triple the price when you can just buy a P85.
Plus the TRA primary work just fine as long as your not assuming any false hopes & understand the Doo's & Don't of the TRA primary.......SHHHHH don't tell anyone about secret spring in kids diaper. He want to install in the Polar but the Polar broke before he had a chance. to test it.

When the Polar makes its way to the podium at any race events is when i might pay attention.. The P85, TRA and Artco still dominate the podium.

OT

 

[Original Tetonice]

YDPC, you're completely taking 'slippage' out of context. When a belt is loose, like at idle, of course the heat created is next to nothing. But when the belt is under tension (as the clutches are trying to grab onto the belt to move it) and then the belt slips, signifigant heat is generated.

When the driver of a F1 car pops the clutch, a lot of heat is generated while the two plates spin against each other trying to grab on. Same thing in a sled clutch... heat is generated as the clutch faces spin against the belt trying to get a good grip.



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Some folks need to learn how manage the TRA heat. 1st of all talking about idle is a mute point.....At 6500rpm to 8150 rpm (where we ride at least most of us) the belt is always under tension, the belt is always being grabbed and the friction is always generated between 6500 rpm and 8150 and will alway generate heat. GET OVER IT !!!!!

And NO the transmission in a F1 and the TRA transmission is not the same. If the TRA were liqued cooled we wouldn't be having this discussion. PERIOD.

OT

 

[banditpowdercoat]

It's the other way around it's the heat making the rpm bounce around......

As for 2 much weight you need weight to run at the motors factory calibrations. If the 800R is calibrated to peak at 8150 rpm your going to need the weight to acheive those rpm's. Weight is not an option

The addition of adding or subtracting clutch weight in the TRA primary should only be used for acheiving and maintaining peak rpm as you tune your sled. If i want to grab the belt harder im not going to add or subtract weight in the primary nor do i advise anyone else to do so.

2 thing could occur either you have 2 much finish on the primary spring or your ramp profile is to steep. When useing a steep profile ramp you slow the shift becuase it's harder for the roller to go up the steep ramp into higher shift ratios thus causing added friction in the process. Or you could also have a combination of both.

The TRA need weight between the ramps, roller/arms X 3 = 300 grams approx. to operate add 16 grams of pinweight to each roller and your near 340 grams of weight plus or minus.

each ramp 63 grams
each roller/ arm 34 grams



OT

OT, WHO CARES how much the ramps weighs. It's weight does NOTHING. It could be 100Lbs for all it matters. It is STATIONARY and does not move. All it is is a surface for the ramp to roll on. Do you care how much the ground weighs when you drive on it???

Quit confusing yourself

 

[tollen77]

And NO the transmission in a F1 and the TRA transmission is not the same. If the TRA were liqued cooled we wouldn't be having this discussion. PERIOD.

OT

oohhh-kaaaaaayyyy! ummmmm , riiiiight.

 

[Dock]

Belt Heat

As I understand it Dock, the friction in the system when the belt stops moving up or down in the clutch is due to the motion of the belt moving over the sheaves (think of the heat your tires generate as they roll down the highway. They`re not slipping, but they still generate heat.) and the clamping forces of the two sheaves on the belt (a heavy truck generates more tire heat than a light car, even if the tires aren`t slipping).

As for too much clutch weight, the additional weight would clamp that belt harder the same way the heavier truck pushes harder (due to gravity) on its tires than the light car. Too much squeeze will generate more heat, though it`s a clearly better alternative that the heat generated from the belt slipping in the clutch. At least this way most of the RPM generated by the engine is being transferred to the secondary.

The other problem with too much weight, which I`m sure you already knew, is that additional weight makes the engine work harder and so becomes less responsive. Nothing new there.

I still don`t understand what about RPM fluctuation causes heat though. I`ve been racking my brain trying to understand how it works. Please, if anyone has a little clearer explanation of how this works, please feel free to share.



.

I understand what you are saying. My thing is that i can drive my car around all day long and my tires might heat up a few degrees until i start skidding my tires, then they heat up real quick.I drive my sled around, even just going up on a nice trial, by clutches get scorching hot. I have noticed that my primary usually get hotter then the secondary...???

 

[tollen77]

I understand what you are saying. My thing is that i can drive my car around all day long and my tires might heat up a few degrees until i start skidding my tires, then they heat up real quick.I drive my sled around, even just going up on a nice trial, by clutches get scorching hot. I have noticed that my primary usually get hotter then the secondary...???

Just like you were skidding your tires, you're now skidding your primary clutch.

The secondary has a good grip on the belt but the primary isn't gripping the belt hard enough. The belt slips against the faces of the primary and this friction is generating heat.

You need to increase the clamping force of the primary by doing one or a combination of the following:

1) change the ramp to one with a flatter angle or a thinner profile (thinner at either the top, the middle, the bottom, or all the way through. The thinner the ramp at a given point (top effects high RPMs, bottom effects lower RPMs) the more force the arms can provide to the clutch face.

2) change the spring to one that has less finishing force (the final number) This will provide less resistance to the forces applied by the swing arms.

3) adjust the clickers down to flatten the ramp. (This effectively makes the top of the ramp thinner and flattens the angle of the ramp. Thinner ramp so the arms are further from the centre of the crank. The further the mass is from the centreline, the more force it can transmit. The flatter ramp angle the more of the force vector pushes toward rather than perpendicular to the clutch face.)

4) add more weight (ensuring you can get to and hold 8,150 RPM at WOT)



Sorry if I'm providing more info than you need. Just trying to make sure I'm crystal clear.

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[Wheel House Motorsports]

One point i would like to make that doesnt really add to the clutch discussion, just relating to the heat option, managing heat by adding vents doesnt make any more power, just means the belt stays a few degrees cooler..... the problem is the mechanical engergy has been transfered into heat, therefor IS NOT going to your track.... you could water cool a TRA for all I care, it WOULD run cool, but it doesnt mean your sled is gonna be any more effecient, the energy is still being lost, but now its disipated into the cooling system....

I will admit, cooling the clutches does help with the affects of the heat, but doesnt really deal with the TRUE problem, more or less a bandaid for the heat soaking issue. The TRA has a LOT of opportunitys to transfer mechanical energy into heat, we are just trying to turn the most mechanical we can into track motion not heat.

As for ramps and all this jazz, its pretty interesting discussion to read, I have learned good bit from this discussion and the other one you gentelmen had, now i need some snow to test out my clutching and work on a setup for my sled.

 

[tollen77]

One point i would like to make that doesnt really add to the clutch discussion, just relating to the heat option, managing heat by adding vents doesnt make any more power, just means the belt stays a few degrees cooler..... the problem is the mechanical engergy has been transfered into heat, therefor IS NOT going to your track.... you could water cool a TRA for all I care, it WOULD run cool, but it doesnt mean your sled is gonna be any more effecient, the energy is still being lost, but now its disipated into the cooling system....

I will admit, cooling the clutches does help with the affects of the heat, but doesnt really deal with the TRUE problem, more or less a bandaid for the heat soaking issue. The TRA has a LOT of opportunitys to transfer mechanical energy into heat, we are just trying to turn the most mechanical we can into track motion not heat.

As for ramps and all this jazz, its pretty interesting discussion to read, I have learned good bit from this discussion and the other one you gentelmen had, now i need some snow to test out my clutching and work on a setup for my sled.

Very, very good points! Completely agree with everything you said.



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[banditpowdercoat]

Just like you were skidding your tires, you're now skidding your primary clutch.

The secondary has a good grip on the belt but the primary isn't gripping the belt hard enough. The belt slips against the faces of the primary and this friction is generating heat.

You need to increase the clamping force of the primary by doing one or a combination of the following:

1) change the ramp to one with a flatter angle or a thinner profile (thinner at either the top, the middle, the bottom, or all the way through. The thinner the ramp at a given point (top effects high RPMs, bottom effects lower RPMs) the more force the arms can provide to the clutch face.

2) change the spring to one that has less finishing force (the final number) This will provide less resistance to the forces applied by the swing arms.

3) adjust the clickers down to flatten the ramp. (This effectively makes the top of the ramp thinner and flattens the angle of the ramp. Thinner ramp so the arms are further from the centre of the crank. The further the mass is from the centreline, the more force it can transmit. The flatter ramp angle the more of the force vector pushes toward rather than perpendicular to the clutch face.)

4) add more weight (ensuring you can get to and hold 8,150 RPM at WOT)



Sorry if I'm providing more info than you need. Just trying to make sure I'm crystal clear.

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I would like to add,
If your slippiing the belt trail running, Mid throttle. But not at WOT. Then IMO you need a ramp with a different profile.

Yes, like Tollen said, changing weight,s or springs will help it shift more. BUT, it will also change the WOT characteristics. WHat good is adding weight, to cure a midrange slipping problem, if it now is to heavy fro you to pull your Peak RPM's.

Now, changing ramp profile, MAY now need a weight/spring change to keep the Peak RPM's happy, depending on how/where the ramp profile was changed

 

[tollen77]

One more point to add regarding clutch heat and vents. I'm still in favour of providing as much cool air to your sled as possible. As has been discussed, a clutch is going to make heat no matter how good the set-up. The more you can do to keep your belt from getting heat soaked, the better (and the more consistent) your clutching will be.


Vents don't fix anything, but they help to keep things from getting worse.



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[banditpowdercoat]

One point i would like to make that doesnt really add to the clutch discussion, just relating to the heat option, managing heat by adding vents doesnt make any more power, just means the belt stays a few degrees cooler..... the problem is the mechanical engergy has been transfered into heat, therefor IS NOT going to your track.... you could water cool a TRA for all I care, it WOULD run cool, but it doesnt mean your sled is gonna be any more effecient, the energy is still being lost, but now its disipated into the cooling system....

I will admit, cooling the clutches does help with the affects of the heat, but doesnt really deal with the TRUE problem, more or less a bandaid for the heat soaking issue. The TRA has a LOT of opportunitys to transfer mechanical energy into heat, we are just trying to turn the most mechanical we can into track motion not heat.

As for ramps and all this jazz, its pretty interesting discussion to read, I have learned good bit from this discussion and the other one you gentelmen had, now i need some snow to test out my clutching and work on a setup for my sled.

GENTELMEN?? WHOAA Im speshul

 

[tollen77]

I would like to add,
If your slippiing the belt trail running, Mid throttle. But not at WOT. Then IMO you need a ramp with a different profile.

Yes, like Tollen said, changing weight,s or springs will help it shift more. BUT, it will also change the WOT characteristics. WHat good is adding weight, to cure a midrange slipping problem, if it now is to heavy fro you to pull your Peak RPM's.

Now, changing ramp profile, MAY now need a weight/spring change to keep the Peak RPM's happy, depending on how/where the ramp profile was changed

Good point Bandit. If Dock is generating a lot of heat in the mid range RPM's but not at WOT he needs a ramp that is thinner in the middle.

If only there was a way to measure how much your belt was slipping throughout your ride.... ie: how much is it slipping at 5,000 RPM, 6,000 RPM, etc...

if we had such a way of measuring belt slippage we could do a better job of clutching than anything we have right now. Hopefully there is some electronics genius reading this thread right now who can develop such a sensor system.... one day people, one day.



Note: edited to say thinner in the middle, not taller. my mistake.
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[Wheel House Motorsports]

GENTELMEN?? WHOAA Im speshul

Well, i have learned a lot from you guys, and trying to pay some respects to those who definately get these things way more then I do. Or those who are helping this discussion stay positive and constructive, helps out a lot for the Novice TRA guys like me who want to learn.

As for what we are tunning for, its really hard to have this discussion with half throttle trail riding, and WOT over the hood climbing being compared, i really think that most of us dont give a hoot about the trail running, a good mountain setup should do fine on the trail, and 1 long hard pull in deep snow will do more wear then 10 miles of trail will, so lets tune to the one that works harder.

I need some snow again to get a better feal for the clutches on my RT, i like the way things work, just the primary seems to slip a little on WOT on climps. I need to be able to see how far out its shifting, but i think a little less finish on the primary spring is in order, otherwise she pulls my arms lik i havent seen in a while.