SLP clutch kit on the 24 boost

[ryang85]

I like the SLP weights for their easy adjustability from the outside of the clutch. I only see options for the 22 boost with update and the trail sleds and I cant even find a full kit for the 24 RMK. Right now I have 155 2.75 track which will be swapped to a 300lx at some point so I'm trying to pick my most critical upgrades for this year, . I typically ride at 5k or 9k in elevation and switch back and fourth every week so not having to pull the entire clutch apart to add or remove a couple grams is a game changer. With the turbo it seems to compensate pretty good on the top end but the low end looses a lot of its snap above 8k and takes a while to build some boost, which is a pain in the technical stuff but still revs up to 8500 once it has time to get there. I haven't heard of anyone with the SLP kit on the 24 boost with the newer mapping and I wanted to see if anyone has ran it and if its worth spending the $600 there or saving it it for something like the 300lx track as the stock clutching gets the job done decently. The ibex kit has good reviews but the magnet weights are always a hug pain to adjust. Thought about just trying the slp weights on the stock primary and secondary setup as well but not sure if that's been done before or if it has enough benefits just to save a few hundred dollars.

 

[Teth-Air]

Try gearing down to 2.52:1. It made a huge improvement to my 24 Boost. Snappy in the bottom end.

 

[ryang85]

Try gearing down to 2.52:1. It made a huge improvement to my 24 Boost. Snappy in the bottom end.

Ill have to look into that. Used to gear down my pro ride and it helped a lot. Did you keep your stock helix or did you have to swap that out?



After looking the speedwerx kit looks to be fairly easy to adjust so that might be a better option than to deal with SLP.

 

[Teth-Air]

Ill have to look into that. Used to gear down my pro ride and it helped a lot. Did you keep your stock helix or did you have to swap that out?



After looking the speedwerx kit looks to be fairly easy to adjust so that might be a better option than to deal with SLP.

Only other change I found necessary was a 145/295 primary spring as it was over-revving once the break in was complete. Stock gearing is about 2.3:1 Doo has 2.52:1, has low end long stroke torque and the primary clutch starts out in a lower gear too. Polaris P-22 has the center clutch bearing that makes the it start in a higher gear than the P85 or the Doo clutch. These are the 3 main reasons people like the bottom end of the Doo.

 

[ryang85]

I assume you went with the TKI QD2 kit? Seems to be the only decent option from my 15 minutes of looking.

 

[Chadly]

Stock gearing is already low on the Boost. Gearing it down ruins the whole reason for having a Boost. You just have to learn how to ride the Boost like a man which is probably asking too much for you 97%ers.

 

[JH@CM]

Stock gearing is already low on the Boost. Gearing it down ruins the whole reason for having a Boost. You just have to learn how to ride the Boost like a man which is probably asking too much for you 97%ers.

While Chadly says this so Chadly, there is truth in his statement.

If you're an highly skilled and very fit rider who likes to ride fast, the boost shines. If you ride slower or with any hesitancy a boost is not as versatile. The low end is not its strength.

Doo turbos are much more versatile.

 

[CHarding]

While Chadly says this so Chadly, there is truth in his statement.

If you're an highly skilled and very fit rider who likes to ride fast, the boost shines. If you ride slower or with any hesitancy a boost is not as versatile. The low end is not its strength.

Doo turbos are much more versatile.

What Teth-Air is saying makes sense. The Doo IS geared lower, the primary clutch starts out in a lower gear... Sounds like good reasons that it might be snappier and more versatile on the bottom end...

Makes perfect sense that a gear down would help the Boost out in this area. It would still be geared the same as a Doo.

 

[Chadly]

What Teth-Air is saying makes sense. The Doo IS geared lower, the primary clutch starts out in a lower gear... Sounds like good reasons that it might be snappier and more versatile on the bottom end...

Makes perfect sense that a gear down would help the Boost out in this area. It would still be geared the same as a Doo.

I've argued with Rusty about this. Just like people who say you can fix lag with clutching. It's Newton's law. You rob Peter to pay Paul. Sure, gear down to make your Boost appear snappier but it will ruin this top end power in which it makes it better than the 9R. It's idiotic mentality. Buy a 9R if you don't like lag. If you want lots of power, you buy a boost. Or of you want to be retarded like a 97%er, you buy a Boost and try to make it into a 9R or vice versa buy a 9R and try to make it into a Boost so in the end you end up with something that is mediocre at everything.

 

[doudea]

I've argued with Rusty about this. Just like people who say you can fix lag with clutching. It's Newton's law. You rob Peter to pay Paul. Sure, gear down to make your Boost appear snappier but it will ruin this top end power in which it makes it better than the 9R. It's idiotic mentality. Buy a 9R if you don't like lag. If you want lots of power, you buy a boost. Or of you want to be retarded like a 97%er, you buy a Boost and try to make it into a 9R or vice versa buy a 9R and try to make it into a Boost so in the end you end up with something that is mediocre at everything.

I agree gearing down a boost makes no sense to me. The stock boost gearing is pretty low. The Boost engine responds well to load, and is why I’m looking to gear mine up. This year I did the Carls 900 with the 9R crank and 9R fly-wheel on my 24 Boost. It’s definitely ripper in the bottom end and mid range then the 850 Boost. However it’s still heavier then the 9R and not as nimble, but is more fun then the 850 Boost in technical situations with the lower inertia. Riding in the nose bleed elevations in Colorado a 9R simply will not compete with a Boost including most technical tree riding situations. At 11k - 12k in elevation the 9R is so far down on power in comparison, it just doesn’t have anywhere near the track speed of the Boost. If at lower elevations I can see why the 9R is so popular. Here the 9R is marginally better then an 850 N/A and the Boosts walk all over both.

Back to the topic of gearing, I’m going to experiment with trading some of the bottom end response of the 900 Boost for the higher gearing and track speed on pulls. Honestly I suspect I’ll land back on the stock gearing, to keep the ripper low end in technical terrain. I like playing with setups, so I’m curious and going to try gearing up. Also looking forward to turning up the boost on the 900, as the tuning from Carls….. has similar target boost tables as the 850 boost.

Screen shot of a pull this weekend at 11k ~30* ambient, on straight 91 non-ethanol and zero DET occurring. Carls….. 900 Boost tuning.

 

[ryang85]

I've argued with Rusty about this. Just like people who say you can fix lag with clutching. It's Newton's law. You rob Peter to pay Paul. Sure, gear down to make your Boost appear snappier but it will ruin this top end power in which it makes it better than the 9R. It's idiotic mentality. Buy a 9R if you don't like lag. If you want lots of power, you buy a boost. Or of you want to be retarded like a 97%er, you buy a Boost and try to make it into a 9R or vice versa buy a 9R and try to make it into a Boost so in the end you end up with something that is mediocre at everything.

Thats my fear of gearing down, I think there's a reason polaris has it geared the way it is. My theory behind screwing with clutching is just improving the engagemnt on the low end a touch or at least getting it the best I can do without loosing any top end which is my goal. I agree part of owning Boost is just learning to drive like hell, I see guys on khoas Boost every trip out who never have the ski get off the ground all day and complain about how the boost sucks. I'm not looking or expecting a miracle but Figured if I'm going to be screwing with different tracks it's probably going to require me to adjust the weights regardless so I minus well get some adjustable weights before hand.

 

[diamonddave]

Thats my fear of gearing down, I think there's a reason polaris has it geared the way it is. My theory behind screwing with clutching is just improving the engagemnt on the low end a touch or at least getting it the best I can do without loosing any top end which is my goal. I agree part of owning Boost is just learning to drive like hell, I see guys on khoas Boost every trip out who never have the ski get off the ground all day and complain about how the boost sucks. I'm not looking or expecting a miracle but Figured if I'm going to be screwing with different tracks it's probably going to require me to adjust the weights regardless so I minus well get some adjustable weights before hand.

I can tell you for a fact, Polaris doesn’t understand the first thing about properly gearing a mountain sled. Never has. QD2 was great in ‘21 but it was a BNG add to match Doo for an out of date chassis.

I can also tell you for a fact, some of the posts in this thread prove a zero understanding of the type and design of turbo systems in the Doo and the Poo. They are still hung up on old school thinking with aftermarket turbo system powertrain calibration and performance.

While I haven’t geared down a stock QD2 Boost, I can definitely see opportunity where there could be improvements in performance, response, and belt life depending on the CVT calibration being used.

 

[ryang85]

I can tell you for a fact, Polaris doesn’t understand the first thing about properly gearing a mountain sled. Never has. QD2 was great in ‘21 but it was a BNG add to match Doo for an out of date chassis.

I can also tell you for a fact, some of the posts in this thread prove a zero understanding of the type and design of turbo systems in the Doo and the Poo. They are still hung up on old school thinking with aftermarket turbo system powertrain calibration and performance.

While I haven’t geared down a stock QD2 Boost, I can definitely see opportunity where there could be improvements in performance, response, and belt life depending on the CVT calibration being used.

I'll be the first to admit gearing down vs clutching is over my head. I understand the basic physics of clutching and gearing but don't have a lot of expirence outside of fine tuning clutches to get top or engagement rpm. I messed with the gearing my pro ride and had it dialed for climbing straight up, but thats all it did. Doing a re entry on that sled was terrifying and nearly impossible. I was also very new to sledding and just wanted to climb hills, engagement was slow and steady and smooth. My axys was a rowdy sled and already clutched agressive to get rpm quicks when I bought it and really changed the style of my riding to doing wheelies everywhere in all terrain just for ****s and giggles even though my climbing ability wasn't the same as the pro ride. With the boost I want both, I want to climb out of sketchy areas but still party through the trees and do bowties as much as I can without killing myself.

I'm sure this isn't exactly right but this is my shot at what's going on.

From my very limited knowledge the benefit I see is that the p22 essentially is like starting out in high gear with the roller bearing, so the gearing down counter acts that and puts less resistance on the clutch so that can spool faster off the bottom. But potentially at the cost of shifting out too quickly and loosing a few mph of track speed on the top end? Potentially why the doo dosnt pull as hard in the top rpm along with the difference in the longer stroke. The main reason I got the boost is for that top rpm fun, so I'm not wanting to sacrifice anything at those top rpm.

To be honest I'm not sure if there's any huge difference to be gained by just clutching a 24 that I've heard of yet, maybe just weights to get that slightly harsher engagement and get the rpms up a touch faster. I've jumped on a few boost various clutch kits and wasn't blown away but they were all 23s or older so it's not a good example. Bikeman claims on their website these are very touchy machines and having the proper clutching is critical which I havnt heard a lot of evidence to back it up, but they may be referring to their tunes which are providing a bit more power.

Starting to think I should take Chadlys advice and just stop sucking and keep 8000rpm through the trees all day until polaris make a 900 lightweight turbo.

 

[polaris dude]

What is interesting to me is that I rode with a fella who does R&D for one of the aftermarket companies and he had a map setup for 2 extra lbs of boost. Those 20 extra ponies plus whatever gains were from the exhaust setup +clutching felt pretty incredible compared to my stock sled. Granted I was still in break-in mode so a grain of salt is needed of course., but I cannot fathom needing more power from the jump than what his sled was making. We were riding quite a bit of fluff, but on his sled I felt like I could climb out from any hole just punching it and holding on for dear life.

 

[Teth-Air]

I assume you went with the TKI QD2 kit? Seems to be the only decent option from my 15 minutes of looking.

Yes, replaced the QD2 with TKI.

 

[Teth-Air]

Stock gearing is already low on the Boost. Gearing it down ruins the whole reason for having a Boost. You just have to learn how to ride the Boost like a man which is probably asking too much for you 97%ers.

So 65 mph with a geardown is too slow for you? Maybe the stock gearing that can do 80 mph is more applicable to hill climbing in the trees? Your expertise is showing.

 

[Teth-Air]

I agree gearing down a boost makes no sense to me. The stock boost gearing is pretty low. The Boost engine responds well to load, and is why I’m looking to gear mine up. This year I did the Carls 900 with the 9R crank and 9R fly-wheel on my 24 Boost. It’s definitely ripper in the bottom end and mid range then the 850 Boost. However it’s still heavier then the 9R and not as nimble, but is more fun then the 850 Boost in technical situations with the lower inertia. Riding in the nose bleed elevations in Colorado a 9R simply will not compete with a Boost including most technical tree riding situations. At 11k - 12k in elevation the 9R is so far down on power in comparison, it just doesn’t have anywhere near the track speed of the Boost. If at lower elevations I can see why the 9R is so popular. Here the 9R is marginally better then an 850 N/A and the Boosts walk all over both.

Back to the topic of gearing, I’m going to experiment with trading some of the bottom end response of the 900 Boost for the higher gearing and track speed on pulls. Honestly I suspect I’ll land back on the stock gearing, to keep the ripper low end in technical terrain. I like playing with setups, so I’m curious and going to try gearing up. Also looking forward to turning up the boost on the 900, as the tuning from Carls….. has similar target boost tables as the 850 boost.

Screen shot of a pull this weekend at 11k ~30* ambient, on straight 91 non-ethanol and zero DET occurring. Carls….. 900 Boost tuning.

Go ahead and gear it up. I have done this for a long time. Some need to learn the hard way.

 

[Teth-Air]

You just showed your true colors. I mean you actually showed them when you invented worthless teth-air, which is as useful as flame less matches, submarine screen doors, and helicopter ejection seats. You obviously only pound icey trails because no Boost in the world is making 65 mph track speed on the hill let alone if it was geared down. Just admit you suck at snowmobiling and you don't know anything about riding off the trails and we'll let the teth-air thing slide.

I am replying for others reading this because I don't expect Chadly to understand. Who said 65 mph on the hill? Top speed with clutches shifted out all the way is what I was referring to, you will not get this climbing. Why would you not want to use more of the sheaves in your clutches rather than just the first 1/2? By gearing down you achieve more belt sheave contact in your primary clutch while climbing at 40-50 mph. With the stock gearing (or gearing up) you will have your belt ride much lower in the primary at that speed. Ideal is 1:1 clutch ratios at your heaviest load speed. (likely climbing) 1:1 ratio will have the least slipage in the sheaves if the clutching is correct. If you gear up a sled and you get more track speed while climbing your clutching was way off to start with an you just got lucky. It still won't be at it's best.

 

[Teth-Air]

I’ve been doing this a long time as well. What’s the point of this response, not productive at all. Same as me assuming the Teth-Air system is as worthless as it looks, but that would be an unproductive statement dont you think. You are a good reminder why I don’t post much anymore, you sir are a moron.

I am trying to give solid reasons why I believe gearing down is the right way to go. You have been lucky gearing up so why don't you explain how it improves your sled? This forum is a good source of knowledge and experience and others can learn before spending their money and not seeing the results they hope for.

 

[turboless terry]

I am replying for others reading this because I don't expect Chadly to understand. Who said 65 mph on the hill? Top speed with clutches shifted out all the way is what I was referring to, you will not get this climbing. Why would you not want to use more of the sheaves in your clutches rather than just the first 1/2? By gearing down you achieve more belt sheave contact in your primary clutch while climbing at 40-50 mph. With the stock gearing (or gearing up) you will have your belt ride much lower in the primary at that speed. Ideal is 1:1 clutch ratios at your heaviest load speed. (likely climbing) 1:1 ratio will have the least slipage in the sheaves if the clutching is correct. If you gear up a sled and you get more track speed while climbing your clutching was way off to start with an you just got lucky. It still won't be at it's best.

Seen this a few times years ago. One buddy was gearing down. Another buddy, with exact same sled and thought he knew everything and worked at a cat dealership, said he was crazy. The geared down sled blew his doors off. Those were na sleds. If anything can take advantage of being geared up it would be boosted since they shine under a load. Depends on where you're at to start with I'm guessing.