Boost Pistons or NA pistons?

[FlynHigh]

So for model year 2025 Polaris is using the same piston "casting" for NA that is used for the Boost. Notice it says same "casting" not same piston. Wondering if anyone knows what the other difference is? I have heard the boost pistons have a thermal coating on top that NA's don't. Anyone know if that's true?

Getting ready to put new pistons in my 2020 850 NA and looking at part numbers on the Polaris website it isn't updated yet for the 2020 model year show the new 2025 NA pistons. But if I look at the 2025 part numbers it cross references back to my 2020 so I should be good to go with the newer 2025 pistons. But I was thinking why not put Boost pistons in it? Wouldn't those be better if they have a thermal coating on top? Interestingly enough cost is the same for a Boost or NA pistons.

 

[Sheetmetalfab]

So for model year 2025 Polaris is using the same piston "casting" for NA that is used for the Boost. Notice it says same "casting" not same piston. Wondering if anyone knows what the other difference is? I have heard the boost pistons have a thermal coating on top that NA's don't. Anyone know if that's true?

Getting ready to put new pistons in my 2020 850 NA and looking at part numbers on the Polaris website it isn't updated yet for the 2020 model year show the new 2025 NA pistons. But if I look at the 2025 part numbers it cross references back to my 2020 so I should be good to go with the newer 2025 pistons. But I was thinking why not put Boost pistons in it? Wouldn't those be better if they have a thermal coating on top? Interestingly enough cost is the same for a Boost or NA pistons.

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I thought the boost pistons were lower compression ratio.

 

[underpressure]

I believe they are changing compression with the head.

 

[live2beel]

My understanding is, no difference in head or piston crown. Both the N/A and Boost run the same compression ratio. The difference is in the ring land. TRS where are you? Can you confirm this?

 

[User Name]

Prob in Afton - Seems hes confused on his priorities.

#1 Snowest Gospel
#2 RMSHA stuff

 

[FlynHigh]

live2beel you got me thinking maybe boost and NA use different rings. Mainly I thought they might be gapped different. Seems like in the automotive 4 stroke boosted world rings have a little more gap to compensate for the higher temps when boosted. Looking at Polaris part numbers from what I saw boost and NA use the same rings. When you say "ring land", I assume that is the distance from the top of the piston to the ring groove? or is "ring land" some other geometry? If it is the distance it must be the same for NA and boost at least according to the 2025 product improvement bulletin that says the same casting is used between boost and NA now.

 

[TRS]

The pin boss is different between NA and Boost pistons.
Heads are the same except for…..
The head on the boost has a larger port for cooling the turbo which sends coolant through the throttle bodies. This also increases boost and fuel temps, another not so good of an idea.