Traction Vs Boost and Clutch Set Up

[AAdavis]

35 helix from Dalton and a Black/Orange Dalton secondary spring, I'd set the spring at 80 or 90 wrap. Which is 2 & 6 = 80 degree wrap, or 3 & 6 = 90 degree wrap, just add the two numbers and thats what we talk about wrap. If you are using stock secondary rollers I'd start with the 80 wrap, just know that wrapped up higher will backshift quicker and make more RPM. It would/could also make more clutch and belt heat and blow a belt. The key is to only pinch the belt as much as you have to without slippage. I run the wrap up at 90, but I also use Hi-Torque rollers that roll easier and show less side pressure on the secondary on the scale than the stock sticky rollers that don't roll well or easily.

So what rollers should I buy?

 

[AAdavis]

MCX is out to lunch saying that, but of course altitude is going to lower the output. The Pro-Mods are up over 400HP using that turbo at mid 30's for boost, Trail sleds are getting around 300 at around 17.5-18 lbs. of boost with a header tune, of course its going to take more boost to get the same power at higher altitudes.


So you are using a stock secondary setup? There's the problem. You need something more like a straight 35 helix and say a Dalton Black/Orange setup at 80-90 wrap for the conditions you are running in. That stock 35-39 reverse helix is total garbage. It over revs bigtime down low and under revs up top. I've found in loose snow and spinning a straight 35 to be best all around to keep RPM consistent and keep RPM up. On hard packed trails, I run a 41-37 with the same B/O set on 90. Straight helix on hardpack the sled just slows a bit, the progressive helix is faster, but your running a bare un-studded 1" track I think anyways, so it's never going to hookup up well, its always spinning. Go to a straight 35 Dalton B/O at 80 or 90 and don't look back, tune the primary and RPM to this secondary setup. Shoot for around 9000 RPM and be done if thats all the boost you have and are running.

Take the reverse angle 35-39 and toss it in the garbage because it doesn't work in any conditions, unless you have an extremely weak tune on the bottom end. I can't stress this enough. Even the stock sled over revs on the bottom with it and under revs up top with that piece of crap reverse helix. It's total garbage, only good for a paperweight is all, you will never get good consistency from it in the snow or the trail... Stock sled hits 9300 on the bottom and drags down to around 8500 with it. Tuned sled is even worse over rev down low.

Ok so have done my homework on the secondary. My parts list is new rollers prim and sec, Dalton straight 35 helix, and black and orange sec spring? I already have dalton prim arms.

 

[Axelqvist]

Touch nothing in primary. Order from dalton straight 35 helix for secondary and dalton black/orange secondary spring.
If you want to upgrade secondary rollers to hi torque if i remenber they are from thunder products.

 

[KnappAttack]

Touch nothing in primary. Order from dalton straight 35 helix for secondary and dalton black/orange secondary spring.
If you want to upgrade secondary rollers to hi torque if i remenber they are from thunder products.

The best out there are the Hi-Torques hands down, they can be had thru Hurricane or direct thru Hi-Torque, they are not made by Thunder Products at all.

 

[Axelqvist]

Ok, my bad

 

[AAdavis]

Had a great hi speed ride this weekend. Smoked my brothers Polaris 850 modded trail sled even from a dig. That had never happen before. He would always get me out of the hole. Left him from the word go.

 

[AAdavis]

You know given that I am on only my second belt in 3600 miles I am afraid If I change the clutching I will blow more belts?

 

[AAdavis]

The key for consistency from deep snow spinning and hardpack hookup is in the secondary helix angle and spring settings. If clutched correctly for the both, you should not see more than a few hundred RPM difference with temps and pressures being the same. We'll need to know what the setup is prior to making suggestions. Myself, I'd be using a 35 helix with a Dalton B/O set at 90 and Hi-Torque rollers for those type of conditions. Hardback you can get by with more helix like a 39-35 or a 41-37 type of deal, but spinning in snow requires a different less aggressive setup because of the track spinning.

14.5 lbs isn't much for boost and why intake temps are easily in check, and it should boost the same wether hardback or loose snow, should be no difference there. Should you not be up at 17 lbs or more in the mountains. 14.5 would be a pretty low HP number at altitude even with a header.

17.5-18 lbs at sea level is 300 HP with a header setup. You need more boost at altitude to compensate for the lack of air. As I recall 14.5 at sea level is only 240 HP with a header and intake never gets warm at that little bit of boost level.

OK did all the clutch work. New rollers on the primary plus a 911 cover. Also discovered I did have some weight the arms so I took a little out of them. The 35 helix with the B/O spring at 80 and the high torque rollers. And it worked as you said it would. Yesterdays ride included everything in one day. Un tracked grippy groomed, loosed new snow on trails, 8 inches of powder on a firm smooth base(we call it cowboy powder) ,hill climbs in powder, long straight trails good for 100mph plus. In all of those conditions rpm only varied 8700 to 9000. 16lbs of boost, intake temps never go over 50 (30 degree day) and feeding in full throttle from 70mph its trying to rip my arms off. I feel it is a very safe tune and I am just fine with how it runs and am loving ridding it. Yesterday could not have been more fun. Wyoming is a great place to live!

 

[REDLINE 1]

I’m over in island park ID we rode to West Yellowstone then up to two top yesterday ! Beautiful out here ! Clear sky’s could see the Teton range.

 

[KnappAttack]

OK did all the clutch work. New rollers on the primary plus a 911 cover. Also discovered I did have some weight the arms so I took a little out of them. The 35 helix with the B/O spring at 80 and the high torque rollers. And it worked as you said it would. Yesterdays ride included everything in one day. Un tracked grippy groomed, loosed new snow on trails, 8 inches of powder on a firm smooth base(we call it cowboy powder) ,hill climbs in powder, long straight trails good for 100mph plus. In all of those conditions rpm only varied 8700 to 9000. 16lbs of boost, intake temps never go over 50 (30 degree day) and feeding in full throttle from 70mph its trying to rip my arms off. I feel it is a very safe tune and I am just fine with how it runs and am loving ridding it. Yesterday could not have been more fun. Wyoming is a great place to live!

Glad its working well now Art. I was afraid that reverse angle 35-39 helix and stock spring & rollers was giving you the trouble in those varying conditions. Hard to beat the straight 35 for those wildly varying snow conditions like that. I have no idea why Yamaha wanted to use that reverse 35-39 helix and old Apex short track secondary spring, but they belong in the garbage, they do nothing well in any certain condition IMO.The clutching engineers went backwards when they went to this setup after the first couple of seasons.

 

[AAdavis]

At sea level its closer to 300HP, at altitude I suspect you'd be up at 270 or so I suspect. The higher the boost of course the more intake heat as you know already.

The stock turbo has made 400 at mid 30's for boost on the pro-mods, but they only make 5 second blasts at that. Doesn't mean it efficient there, but max kackle is what you do when racing.

Just watched a Gale Banks you tube where he is measuring air density in a steel box. The box at room temp no boost and then again at 188 degrees and 3.8 pounds of boost. The air density for both is the same. Therefore the power level in both cases would be the same. So my sled stops gaining air temp at plus 20 degrees so I can make the same power all day no matter how hard I ride. For those of you running bigger boost numbers if you do not control the intake temps the longer you run and gain heat you are losing power. So a quote of 270 hp tune is at what intake temp? If you go above that temp you do not have that much power anymore. So the fact that I can maintain temps at 16 pounds of boost and it is a safe # for pump gas makes a lot of sense for me.