8DN Belt thoughts and results - Heat issues

[Snowaddict]

When you over clamp the belt it causes premature wear due to the belt getting stuck in the sheaves. Like I said it was not rotational slipping, you proved that by reducing belt clamping force by reducing spring wrap.( you usually wrap the secondary more if your slipping). As the belt rotates it needs to be pulled out of the secondary & primary sheaves, if it’s wedged in to tight it takes a large amount of force to pull it out. Clutches will run very hot because of this and it sounds like it was sticking so bad that you rpm’s went up with reducing the twist on the spring it’s usually the opposite.M2C

I'm confused. Will you have higher Rpm wrapped at 2-3 or 3-3 (theoretically) with TP orange secondary spring? I'm hoping for a few more on top from last year (was running stock secondary wrapped at 6-1.)

 

[ClutchMaster]

2-3 wrap should reduce your RPM compared to a 3-3 wrap. His setup did the opposite, inefficient clutching too much belt clamping.

 

[ClutchMaster]

If he was running an 8dn hard belt clamping force would have been more optimum.

 

[ClutchMaster]

Ask NOSpro I’m sure he can verify they found the clutches to be more efficient with less tension/wrap. It is somewhat belt specific due to how soft/hard the belt your running is. I would not doubt that with the Gates he could take even more wrap out and loose some tip weight.......keep changing till you find the lowest belt temps and best rpm.

 

[ROCKERDAN]

Higher degrees = more backpressure =more rpms.

But in general you control RPMS with primary weights,not secondary. While the secondary pressure and helix angles will change RPMS some, you want to set the rpms via primary weights.

More backpressure more belt squeeze, LESS slip, more heat.

Less backpressure MAY cause more slip and in turn also cause heat.

Its a tight-rope walk of balance.....to get the best setup.

Gates and other softer belts can use less backpressure, as they dont slip as easy.

Im going to try 8DN again as I have had good luck with them.

 

[jonlafon1]

I'm confused. Will you have higher Rpm wrapped at 2-3 or 3-3 (theoretically) with TP orange secondary spring? I'm hoping for a few more on top from last year (was running stock secondary wrapped at 6-1.)

You have to realize your putting a WAY STIFFER spring in also. So if you ran the stock secondary at 6/1 and went to the orange TP at 3/3 its way different because the tension is ALOT higher.. Takes more force to open the clutch sheaves in secondary. I would guess you will pull a little more RPM somewhere along the shift pattern. Not always on top. Dan said it > you control engine RPM with primary weights.. that being said it even more so when you have adjustable primary weights.. Now you have three areas(maybe 4) to put weight on the weight itself(tuning holes).. And they control your shift pattern in areas .. Hole shot. mid. top end..

 

[ClutchMaster]

Yes rpm with the primary and belt tension with the secondary.

 

[jonlafon1]

I also mentioned belt compounds in another post and have concerns. Most guys do not realize by going with a soft belt(sticky) that the clutching is alot less forgiving. I described it by saying your clutching better be SPOT on. Not saying you should only run a 8DN.. But the HP numbers even on a stocker make this clutching even LESS forgiving. I believe we are seeing so much discussion and maybe even argument on the subject here because one little difference between guys set ups and bang goes the belt. And lets face it most are boosted to different levels of HP. The 8DN is my choice on "MY set up". This stuff is very subjective. And are we not are all(most) looking to pound alot of miles and stay with a durable belt, and avoid breaks? If your blowing 8dn's i would say your set up is very off. IMO

 

[chaleurphantom]

Higher degrees = more backpressure =more rpms.

But in general you control RPMS with primary weights,not secondary. While the secondary pressure and helix angles will change RPMS some, you want to set the rpms via primary weights.

More backpressure more belt squeeze, LESS slip, more heat.

Less backpressure MAY cause more slip and in turn also cause heat.

Its a tight-rope walk of balance.....to get the best setup.

Gates and other softer belts can use less backpressure, as they dont slip as easy.

Im going to try 8DN again as I have had good luck with them.

I agree with everything you have to say except for the SLIP part. The Secondary spring being set so stiff doesn't allow Secondary to open. The Primary is trying like hell to open the Secondary but it won't. The result is the belt SLIPS on the Secondary. I know this because I could smell the belt, there was a ridiculous amount of belt dust and there is a black streak from belt on the Secondary face.

I think you may be correct about more wrap increasing RPM's. But I believe that is when the spring is soft enough to allow cimpression no matter what the wrap is?
Not sure. Yes/No.

 

[ROCKERDAN]

I agree with everything you have to say except for the SLIP part. The Secondary spring being set so stiff doesn't allow Secondary to open. The Primary is trying like hell to open the Secondary but it won't. The result is the belt SLIPS on the Secondary. I know this because I could smell the belt, there was a ridiculous amount of belt dust and there is a black streak from belt on the Secondary face.

I think you may be correct about more wrap increasing RPM's. But I believe that is when the spring is soft enough to allow cimpression no matter what the wrap is?
Not sure. Yes/No.

With high backpressure its near impossible to slip a belt....But not gonna argue with ya.

 

[chaleurphantom]

With high backpressure its near impossible to slip a belt....But not gonna argue with ya.

No sir,

Definitely not trying to argue. I respect everything you do for the love of snowmobiling. Just trying to have a conversation and learn. I have'nt felt like learning in awhile and this stuff has peaked my interest. I am sure you can respect that.

That being said, what would cause the ridiculous, excessive belt dust from a belt not known for being dusty? Gates Carbon belts are not dusty, at least on a Viper that was modded. That I know.

 

[ClutchMaster]

I agree with everything you have to say except for the SLIP part. The Secondary spring being set so stiff doesn't allow Secondary to open. The Primary is trying like hell to open the Secondary but it won't. The result is the belt SLIPS on the Secondary. I know this because I could smell the belt, there was a ridiculous amount of belt dust and there is a black streak from belt on the Secondary face.

I think you may be correct about more wrap increasing RPM's. But I believe that is when the spring is soft enough to allow cimpression no matter what the wrap is?
Not sure. Yes/No.

It’s from your clutches/belt getting to hot melted the belt .....yea warm is good it helps the belt grip better.....smoking hot from sticking in the sheave and I’m sure it was slipping when it was 250 degrees. Yea that hot it’s gonna leave a mark. If your RPM’s went up with less twist it was sticking very bad. That’s why I say take even more twist out and weight out if you insist on running that belt. M2C
I agree with Jon 8dn is more forgiving ... you can’t over clamp it, squeeze it as much as you want it won’t stick in the sheave.
You know what they say about horses and water?

 

[ClutchMaster]

Switching to an 8dn from softer belts can tell you a lot about your clutch setup.
If the clutches get hotter you don’t have low enough helix angle and/or your secondary spring isn’t strong enough you need to grab the belt harder.
If clutches get a lot cooler you need less spring force/more helix angle to reduce belt clamping on the softer belt.
For example cat guys are running soft belts with 50 degree helixes and hard belt gets a 42 degree. Cat offers belts of varying compounds. Yamaha did it to back in the day. Anybody remember the 8ch belt..POS. Lol

 

[ClutchMaster]

Well Phantom you’ve gotten a lot of responses on this and that’s all good. When you say things like “you may be correct about more wrap increasing rpm” it shows your experience level. Not trying to bash at all, it just gets frustrating for me personally.

 

[ROCKERDAN]

No sir,

Definitely not trying to argue. I respect everything you do for the love of snowmobiling. Just trying to have a conversation and learn. I have'nt felt like learning in awhile and this stuff has peaked my interest. I am sure you can respect that.

That being said, what would cause the ridiculous, excessive belt dust from a belt not known for being dusty? Gates Carbon belts are not dusty, at least on a Viper that was modded. That I know.

My guess...its BRAKE PAD dust.