2020 CTEC Clutching at High Elevation

[dgibbons]

What's everyone running for clutching on stock setup above 10k feet? Loving my 20 HC, but it's not pulling RPM under load in deep snow. Noticed it happening both on climbs and even mildly flat areas. Dealer said he's been installing 68g weights in all the sleds at this elevation and guys are not having issues pulling rpm. I can hit 8050 on the trail but am not seeing over 7900 in the deep stuff. Typically 77-7800 fading to as low as 7500 rpm - the sled is bone stock. I'm planning to throw 66g weights in, just concerned because he claims others are pulling rpm with 68g weights in. I'm 210 without gear on a bone stock powered 2020. Let me know if anyone has any insight on this issue.

 

[dgibbons]

To further the conversation, I'm out of break-in (over 200 miles on sled) and wear marks on primary are showing almost a full inch from full shift out.

 

[slyrydr]

to maintain rpm above 9-9.5k altitude, you'll need to shallow your helix to 44-46 degrees depending on how high and how deep/heavy the snow is....remember you're losing about 3% of your horsepower for every 1k feet of altitude....you can't drive a vehicle over a mountain pass in high gear, you have to shift to a lower gear...on a snowmobile that is accomplished with helix/weights/springs....i use a 48/44 helix with 68 gr weights and a driven spring that is a little stiffer, but not a lot, than stock...anyway, this is the direction you have to go....and if you're not up at altitude that much, maybe don't have to change anything....i regularly go high, and to do so i made the changes noted above....i pull about 8100 rpm and will hold that up through 11k...good luck.

 

[ranger12]

I would get yourself a Mountain Series Pro Shift Clutch Kit from SSI. I have installed one of these in all of my sleds for the last several years and also installed them in a lot of other sleds for people. You won't be disappointed. You get a new Helix, Both primary and secondary springs and a set of adjustable weights. If you have any questions send me a personal message or just ask on here. 15-TM108H is the kit you would need.

 

[J-Dog]

I would also try a 44 or 46 degree helix

 

[dgibbons]

I would get yourself a Mountain Series Pro Shift Clutch Kit from SSI. I have installed one of these in all of my sleds for the last several years and also installed them in a lot of other sleds for people. You won't be disappointed. You get a new Helix, Both primary and secondary springs and a set of adjustable weights. If you have any questions send me a personal message or just ask on here. 15-TM108H is the kit you would need.

Thanks for the feedback. I don't think I'm going to spend any more money on SSI clutching stuff as every helix I've seen has a bushing that disintegrates over time and every time I've reached out to try to get a new one (not asking for a freebie), I get ignored. This was for a friend's 2016 cat that I worked on for him. Also found broken mag weights in the sled as well when he got it, but that may have been user error. Another friend with identical sled had same issue and was also ignored when he reached out. Not sure if they don't have a solution for it or don't want to deal with it, but it's annoying and doesn't make me want to buy any more of their products. I'll most likely grab a Dalton with the replaceable bushing in that range of cut and go from there with clutching.

Thanks for the other feedback. Totally understand the benefits of a shallower helix and am glad to here others are having good luck with a switch. I think I will end up grabbing one after I ride this weekend (hopefully in deep snow) and report back. CO2.0 mentioned he's running a 45 deg Dalton and is seeing good results above 10k feet, which is the altitude where most of my riding is (9.5-12k ft)

What spring rates are you guys liking in the aftermarket at elevation? What stiffer secondary spring rate are you having success with?

 

[kanedog]

In my experience, once Bdx/Ssi has your money it’s game over.

 

[dgibbons]

In my experience, once Bdx/Ssi has your money it’s game over.

Yeah, the disappointing thing again is that I wasn't even looking for a warranty claim or anything. Just wondering if they had a replacement bushing for it that I could pay for. Sucks not to get a response.

 

[Rinker]

I'm running the Speedwerx high elevation kit and it is money. It's a progressive helix- i believe 50/48/46. I'm at 10k+ feet in Colorado and it has not missed a beat 8150-8200 in the deep or steep. Pretty impressed with the kit. Track speed is really good too. Amazing how well these Alpha's get on top of snow though. I'm actually selling the kit so if you're interested, let me know. I put a Silber on this week so using the CNS clutching for the turbo.

 

[rr715]

Really interested to hear what you think of the cns clutching. And the turbo as well. I’m trying hard to talk myself into the CNS set up.

 

[dgibbons]

After this weekend, I have even more questions on clutching. Need to order a shallower helix still but I dropped to 66g weights and am still fighting a serious RPM drop issue. In more setup snow on a climb, I could pull 8100-8200 and wasn't dropping significant RPM (78-7900), but in the light, deep pow, I am now seeing the tach drop to as low as 7400, lower than it was with the 68g weights the last few weekends. I haven't had a chance to check valve cable length compared to spec, but am checking tonight, I hope that's part of my problem. Also, switched from stock can to a Diamond S Stainless quiet can and now have approx 250 miles on the sled. If I can't get this figured out with valve adjustment and new helix, I'm going to go to bone stock and start over again. Really annoyed. Hopped on Goinboardin's new-to-him 18 MC with Silber tune, BMP Y, stock helix, stock springs, stock can with 68g weights and it was pulling 8050 to 8100 with no RPM drop and felt really strong.

I love the Alpha's hookup and even with low rpm I can still pull skis while climbing but it sounds and feels like a dog comparatively.

I've been seeing some guys saying the 20's fuel mapping sucks and the more they're ridden the worse they are, and I'm starting to wonder the same thing. I feel like I'm chasing a moving target because the issues keep changing by the day (and getting worse).

 

[CO 2.0]

Something is wrong with your sled Austin. No way it should be bogging down RPM that much. My old 18 my buddy now owns has the stock helix in and it never drops below 8000 with 66g. I have a feeling that stock tune could be an issue. But I haven't heard Matt say other 20's around here having that issue either. I wouldn't want you to just throw money at it and get a Silber tune if that's not the issue. I'm running a 46 helix in both mine, just checked. But 2 deg in helix shouldn't cause a drop in rpm that much. Talk to Matt and see what he thinks. Maybe the exhaust temp sensor, throttle safety switch, broken secondary clutch spring, PV cable length, compression. Also seal up the can exit. Mine had a good gap around it.

 

[dgibbons]

Something is wrong with your sled Austin. No way it should be bogging down RPM that much. My old 18 my buddy now owns has the stock helix in and it never drops below 8000 with 66g. I have a feeling that stock tune could be an issue. But I haven't heard Matt say other 20's around here having that issue either. I wouldn't want you to just throw money at it and get a Silber tune if that's not the issue. I'm running a 46 helix in both mine, just checked. But 2 deg in helix shouldn't cause a drop in rpm that much. Talk to Matt and see what he thinks. Maybe the exhaust temp sensor, throttle safety switch, broken secondary clutch spring, PV cable length, compression. Also seal up the can exit. Mine had a good gap around it.

Yeah, that's what I'm afraid of. I'm not throwing anything at it as far as a tune until I get it figured out or if it turns out to be a mapping issue and Cat comes out with an updated map under warranty. The 18 I hopped on yesterday was having small RPM drop issues on Saturday with 70g weights (his first ride on the sled) and he threw in 68g that another buddy had laying around yesterday before we rode and it was ripping. I hopped on and pulled way harder than my sled and held rpm. All but confirmed that my helix isn't my issue as the silber tune isn't going to make up that much power loss with 2g more weight.

I texted Matt this morning as well with my symptoms and asked him the same question if he's hearing any bitching from anyone else with 20's. Thanks for the ideas, I'll pull compression tonight, check and adjust PV cable length, pull secondary (primary clutch spring was fine last week when I checked after I started having the issue) to see how far out of spec it is and go from there. Would it be TSS if it's hitting 8100-8200 and then dropping? Seems like it would kill power before that but maybe not. I installed the Diamond S Stainless quiet can before this weekend (had RPM issues before as well) and there's definitely a big gap at the belly pan exit. Didn't think that would be a cause of an issue this big. And again, had issue with stock can as well.

The thing I can't figure out is the symptoms keep changing. Like the ride home yesterday not being able to barely pull 7850 rpm and it was a climb to even get there. That was brand new at the end of the day. I always have my coolant temp showing and I haven't seen over 135-140 banging a trail hard back to the truck and that's only on really thin snow on pavement but normally 125-130. Stays at 100-110 typically in the deep as well.

 

[dgibbons]

Also, I have been reading about the mid range bog issue from other guys, specifically Kevin H, and i seemed to notice a couple burbles on the trail in that range Saturday on and off the throttle, but nothing that affected my riding off trail. Just the WOT issue. I read today that Kevin flashed his sled and cleaned that up, but different symptoms than I'm having it seems.

 

[76crosscountrycat]

I'm running the Speedwerx high elevation kit and it is money. It's a progressive helix- i believe 50/48/46. I'm at 10k+ feet in Colorado and it has not missed a beat 8150-8200 in the deep or steep. Pretty impressed with the kit. Track speed is really good too. Amazing how well these Alpha's get on top of snow though. I'm actually selling the kit so if you're interested, let me know. I put a Silber on this week so using the CNS clutching for the turbo.

What are you looking to get for that speedwerx kit? PM me.

 

[Dam Dave]

I just weighed some 70 G OEM Cat weights and they weighed 71.5 G

 

[Old & slow]

I just weighed some 70 G OEM Cat weights and they weighed 71.5 G

Did all the weights at least weight the same?

 

[Old & slow]

Also, I have been reading about the mid range bog issue from other guys, specifically Kevin H, and i seemed to notice a couple burbles on the trail in that range Saturday on and off the throttle, but nothing that affected my riding off trail. Just the WOT issue. I read today that Kevin flashed his sled and cleaned that up, but different symptoms than I'm having it seems.

Just an FYI for everyone about break in. After reading some of the service manual the break in period of 6 hours is tied the the TPS. The TPS has to meet a certain criteria before the time is counted against the 6 hours. Of course it doesn't give that info, most likely similar to Polaris where the RPM has to be over 5500 to count as break in.

 

[dgibbons]

Just an FYI for everyone about break in. After reading some of the service manual the break in period of 6 hours is tied the the TPS. The TPS has to meet a certain criteria before the time is counted against the 6 hours. Of course it doesn't give that info, most likely similar to Polaris where the RPM has to be over 5500 to count as break in.

That wasn’t the issue. I was way past break-in with my issue. The issue ended up being a bad bushing in aftermarket clutch cover. It popped out on the clutch shaft and was blocking the cover/moveable sheave from making full shift and the catastrophic failure was a broken primary spring late in the day. Company rectified the issue immediately and said it was a QA/QC issue with a former employee assembling them. They were great to work with and as soon as I replaced stock spring and put stock cover back on (before getting new aftermarket cover), sled was back to pulling like a freight train.


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