Like I said, I'm running 200+ hp with a 32° ramp. Makes more track speed than the 50° ramp that was in there before. So comparing sled HP or track speed based on what helix it has doesn't make sense. Take a few hours and read AAEN Clutching handbook and then tell me I'm wrong.
Prolaris 850
- Thread starter i'llDooit
- Start date
Like I said, I'm running 200+ hp with a 32° ramp. Makes more track speed than the 50° ramp that was in there before. So comparing sled HP or track speed based on what helix it has doesn't make sense. Take a few hours and read AAEN Clutching handbook and then tell me I'm wrong.
Ok, you are wrong. If you really read and understood his book, you would have acknowledged that primary, secondary, gearing etc., all have to work together. Can you make a 32 deg. helix work better then a 50? Absolutely, but you need the other parts that compliment that part. As well your 32 will take longer to get to faster ground speed vs. a 50. Would you like a dyno graph to show your elapsed time for both?
Besides who cares what your track speed is; what I want is more or better control of ground speed. In the end faster ground speed will outperform anyone focusing on track speed. ( Have someone identify what their track speed is as they are turning out of a climb because their snowmobile is becoming a very expensive snow blower!
Looked at the Polaris website - sure it is a nice sled but the 850 Patriot engine is still "throttle body injected" and therefore no way as precise as "direct injection". Polaris will need to step up the R&D if they want to be taken seriously.
Agreed, but we are not debating how clutching works. I simply was making a comment in response to Fred saying, "with a 40’degree helix, how fast can it actually be.. 860/880 in the past Are pilling 46 plus helixes"
It is not simply that taller helix = faster.
BTW, thanks for being so pleasant to a potential customer. Cheers
I am currently in the market to spring check something this year. Have no brand loyalty so to speak . Had raced Doos in Sno-X & currently have been on a Axys RMK since 2016. Love the handling, slim design & the track. Dislike the build quality, fuel mapping at elevation & electrical issues like relays. That said I am either going with 850 Axys, Summit SP 165 with Shot or keep my current sled one more year. Both manufactures have great sleds with a 4 year warranty. I have some seat time on a 17 Summit X 154 & it was good. Was not a fan of the wide tunnel with the brake/chaincase in the way though. Engine was very smooth with good power. Going to dealer that carries both brands & maybe deciding factor will be OTD price.
J
Having ridden the Axys extensively and the Gen4 I will say they are entirely different rides. Not saying a good rider can't adapt to either, but I personally feel the Axys is a far better sled when it comes to holding an edge, the Doo has (had?) the better powerplant - at least in non-boosted form. I also held the belief that Doo had a higher quality sled but after a season on mine I do not find this to be the case. They have more technology in their motor, but this is a double edged sword.
Overall you can get either to work well no matter the application, but all things considered I think the Ski-Doo is a super fun package out the crate whereas the current Axys a more capable package out the crate. With the addition of a better motor, it'll be hard for a guy like me to *not* go back to Polaris, even though my Doo has been built to address all the shortcomings.
Both are awesome. You'll have fun either way.
In the sled world, what is the DI really accomplishing that the TBI isn't? Yes it's more high tech....but in the mountains it's using the same amount of oil and fuel, throttle response is every bit as crisp on the Pol. 850 Doo is not seeing anything spectacular for longevity so far. So what's left....smoother idle? Not trying to be smart....just realistic.
I’m not sold on di either. It seems that the only way to get good throttle response is to have injectors either in the case or in the port.
N
Fuel is injected in the transfer port, not throttle body injected.. same as previous Polaris SDIs. Fuel doesn't enter the case.
ETEC doesn't achieve better fuel economy other than at light loads. Low pressure DI systems have little to no advantage in a 2 stroke application as far as power output since the charge will be homogeneous at high load / speeds. Combustion takes place in <0.006s in a 2 stroke at 8000 RPM - far too fast for stratified injection/combustion. Idle quality and low load cruise is where the gains are made. Ski-Doo and Polaris guys who ride together in the mountains consistently use similar amounts fuel. ETEC is low-tech as far as DI technology.. Not saying it doesn't work well, just reality.
Last edited:
This is very well put. Due to unfortunate circumstances I was stuck on an Axys for a day in McCall. The Polaris is very stable and takes half the input than the Doo. However, what most say they don't like about a Doo is exactly why I do like it. The Polaris is definitely easier to ride than Doo and I was struggling until Cody told me I was way over riding the Polaris. If Polaris truly is matching the power that the Doo 850 is putting out I don't think I would argue the fact that the Axys is a better sled out of the box than the Doo. However, I won't be buying one or switching brands.
M
Cats?
Arctic cat is worth a look or better yet a ride! Independent riders have a lot of good things to say about the '17s, '18s & '19s! :juggle:
Arctic cat is worth a look or better yet a ride! Independent riders have a lot of good things to say about the '17s, '18s & '19s! :juggle:
D
Weird my cousin who rides an Axys's says the exact opposite when he rides my Ski Doo. Or I guess says the same thing....
J
I do think a few factors play into this assessment.
Riding style - If you play in terrain more akin to high alpine riding in BC (bigger, open areas) I think the Ski-Doo is a formidable choice. Easy. Fun. Great in deep snow. In this type of terrain I could understand someone saying the Ski-Doo is an easier ride.
On the contrary if you are often in steeper more technical terrain, I feel the Axys holds an edge better. No two ways about it. I've spent a lot of time getting my Ski-Doo to hold an edge as well as an Axys but at the end of the day *it is more effort* in steeper technical terrian. Partly because of the wider track. Partly because of T-Motion (even locked out - flex edge still fights you) and mostly becauase of static weight distribution/overall weight (sled rides a lot heavier at slow speeds).
Boost or No Boost - The Axys is a far easier sled to ride without further modification when boosted. This is due to static weight distribution (more 50/50 out of the box) and how the skid works. The Doo relies more on the motor to transfer weight and make the skis feel lighter, which is fine, until you realize a boosted sled is going to transfer load later in the powerband and then transfer a lot more when it does transfer. (hence how big of a deal my Tom's kit is for me - total game changer). With boost, I think there is little question the Axys is an easier ride unless you want to throw money at the skid.
My $0.02
My opinion
Heres my Opinion... FWIW.
Two completely different animals.
The Rotax-850 has a much larger stroke and smaller bore than the Polaris 840 mill.
Rotax 82mm x 80mm bore/stroke 849cc
Polaris 85mm x 74mm bore/stroke 839cc (in contrast, the 866cc '900 liberty' had 83mm x 80mm)
Polaris had an 80mm stroke sled in their stable in 05/06... and I'm glad that they opted for the shorter stroke at 74mm.
One is Semi Direct Injected, SDI aka port-injected (Polaris) the other is Direct injected.(Rotax)
We'll see next season, when the actual production sleds are in the hands of consumer what the REAL numbers are.
I can say this though, just from a physics perspective, the engine with lower rotational mass will have less influence over the chassis in directional changes.
Rotax had to go with large bolt on bob-weights in the crank and an active vibration cancellation system built into the clutches to deal with the vibrations inherent in the big stroke engines without needing the extra heft of a counterbalance like they did in the 1000 SDI.
Polaris, on the other hand, did not have any of this on the 866cc '900' with the 80mm stroke, and it was a real buzz-box.
In contrast... the 800 ETEC, with it's 75.7mm stroke, did not need a counterweighted crank nor vibration cancelling system... and was a pretty smooth runner.
Leads me to believe that the 'sweet spot" is better served in more moderate strokes.
The 840cc Patriot Mill is definitely not throttle body injected though.
It is a Semi Direct [port] Injected (SDI)
I agree, that the Rotax/Ficht Direct injection is a more advanced system.... it is still not a closed loop system however.
Both are running, from the control end of things, as a speed-density injection system.
Though, when building a sled... you have to factor in if you actually need Direct Injection.
For BRP, that answer was yes, and they worked with Rotax and Ficht to make it happen in a quality way.
If you can get the fuel economy and power that is needed from a simpler SDI system ... makes sense.
Polaris has had Direct injection in their stable before in PWC.
DI is more complicated, and has more expensive components.
It has proven to be a reliable system however for Rotax and SkiDoo.
Again, we'll see if the new 840 from Polaris is what it claims to be in the hands of the consumers... around this time next year. Polaris is monitoring even more engine parameters than before, getting as close as a non-closed-loop injection system can get to a closed control type of performance, IMO.
I also will admit, that Rotax/Doo has shown better quality in the components and engines.
After working on both following crashes or engine issues. I tip the scales in favor of the Polaris for ease/speed of repairs. It just seems that you have to take less apart 'to get to things' on the Poo compared to the Doo.
.
Heres my Opinion... FWIW.
Two completely different animals.
The Rotax-850 has a much larger stroke and smaller bore than the Polaris 840 mill.
Rotax 82mm x 80mm bore/stroke 849cc
Polaris 85mm x 74mm bore/stroke 839cc (in contrast, the 866cc '900 liberty' had 83mm x 80mm)
Polaris had an 80mm stroke sled in their stable in 05/06... and I'm glad that they opted for the shorter stroke at 74mm.
One is Semi Direct Injected, SDI aka port-injected (Polaris) the other is Direct injected.(Rotax)
We'll see next season, when the actual production sleds are in the hands of consumer what the REAL numbers are.
I can say this though, just from a physics perspective, the engine with lower rotational mass will have less influence over the chassis in directional changes.
Rotax had to go with large bolt on bob-weights in the crank and an active vibration cancellation system built into the clutches to deal with the vibrations inherent in the big stroke engines without needing the extra heft of a counterbalance like they did in the 1000 SDI.
Polaris, on the other hand, did not have any of this on the 866cc '900' with the 80mm stroke, and it was a real buzz-box.
In contrast... the 800 ETEC, with it's 75.7mm stroke, did not need a counterweighted crank nor vibration cancelling system... and was a pretty smooth runner.
Leads me to believe that the 'sweet spot" is better served in more moderate strokes.
The 840cc Patriot Mill is definitely not throttle body injected though.
It is a Semi Direct [port] Injected (SDI)
I agree, that the Rotax/Ficht Direct injection is a more advanced system.... it is still not a closed loop system however.
Both are running, from the control end of things, as a speed-density injection system.
Though, when building a sled... you have to factor in if you actually need Direct Injection.
For BRP, that answer was yes, and they worked with Rotax and Ficht to make it happen in a quality way.
If you can get the fuel economy and power that is needed from a simpler SDI system ... makes sense.
Polaris has had Direct injection in their stable before in PWC.
DI is more complicated, and has more expensive components.
It has proven to be a reliable system however for Rotax and SkiDoo.
Again, we'll see if the new 840 from Polaris is what it claims to be in the hands of the consumers... around this time next year. Polaris is monitoring even more engine parameters than before, getting as close as a non-closed-loop injection system can get to a closed control type of performance, IMO.
I also will admit, that Rotax/Doo has shown better quality in the components and engines.
After working on both following crashes or engine issues. I tip the scales in favor of the Polaris for ease/speed of repairs. It just seems that you have to take less apart 'to get to things' on the Poo compared to the Doo.
.
Last edited:
Some good information here, the 2019 axys is a great looking package from Polaris. Would not mind trying one, most of my riding is exploring through steeper trees and creeks.
Similar threads
