Does the 850 STOCK ski doo motor on the turbo really only have 125 hp

o zone guy

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So if 1 pound of boosT produces 8 hp ... Does that mean that the boost is set at 5 lbs ... 8 hp times 5 ponds of boost = 40 Hp from 0 to 8000 ft ... So the 850 motor only needs 125 hp ... Put stock hp 125 plus 40 turbo hp = 165 ... Now because the air box has a bypass valve from 0 to 6100 rpm and high ratio stock gearing 21/53 =2.52 it gives u the false sense of 165 hp ... But once the automatic electronics of the turbo kick in at 6200 u then have 165 Hp ... So does the 850 stock Ski doo motor really only have 125 ... ( could it be a 650 motor which has 125 hp ) All the turbo setting u can't adjust they r set... Please debate this ... I'm just Learning ... Thanks ... BRP states that a stock 850 has 125 hp at 8000 ft and the stock turbo has 165 hp at 8000 ft 40 hp differance ... Hmmm
 
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Teth-Air

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So why is it that when you go to 8000 ft and ride the 850T back to back with a N/A 850 it only feels like maybe 10 HP difference and not 40 HP?
 

jcjc1

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if you're suggesting that the 850 is really a 650cc engine then think critically for a sec about how that would not be possible.
n/a engines lose roughly 5hp for every 1k rise in altitude so the turbo is there to make up for that power loss as needed which is dependent on elevation. it's not always providing a 40hp power increase.
the motor makes 165hp at sea level. the turbo kicks in to maintain that 165 as altitude increases up to 8k feet. above that, the turbo loses power as well.
 

canuck5

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Here it is in the simplest terms your stock sled makes 165hp at 0 feet with density at 1.0 now go to 8000 feet your air density drops and goes to .786 so your hp would be 129hp now add your 4 psi creating 32 more hp and your back to 161 ish.
 

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I kinda hate to even step foot in this thread...

Is everyone clear that the 850t raises and lowers boost pressure with density altitude? It’s elevation compensation. At sea level it adds very very minimal boost of roughly .5 psi. As density altitude decreases, meaning you gain altitude, it adds boost to compensate for reduced atmospheric pressure and the corresponding decrease in horsepower. It’s aircraft technology that has been used for years and years and years. So yes, it is a 165hp base engine that maintains power to altitude.

I do agree they seem to run better than 165hp.

And to anyone who doesn’t think they run better than a non turbo 850 at altitude...LOL
 

o zone guy

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Lots of Brain ceLLs: .. But I has a bet with a guy named RoB for $500,000.00 that the guYs on snow n mud could answer this question properly and professionally and see look at the knowledge they passed on ... So now I don't have to seLL my waYne Gretzky rooKie CarD (someone just bought a 10/10 at auction for 1 million ) mY card it's a 9.5 out a ten.... DoN CHeRRy would be proud ... Any Who guess my brain cells were working fine back then ... While pow powpowpow was playing wiT his CaP gun and riding his hot wheels 3 wheeler with his Gretzky rookie card attached to the spokes of 3 wheeler with a close peg ... K-pow !! k-pow !! pow pow pow ... Guess I just shoot this guy wiT my bow n plastic arrow ... LMAO... IndiaNa JoNES would be ProuD... thanks snow n mudders have a merry Xmas and stay safe in the mountains .... beeP !! beeP !! ... O I think pow pow POWs 3 wheeler came wiT a horn ... HoTSaucE ... LMAO
 
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canuck5

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Lots of Brain ceLLs: .. But I has a bet with a guy named RoB for $500,000.00 that the guYs on snow n mud could answer this question properly and professionally and see look at the knowledge they passed on ... So now I don't have to seLL my waYne Gretzky rooKie CarD (someone just bought a 10/10 at auction for 1 million ) mY card it's a 9.5 out a ten.... DoN CHeRRy would be proud ... Any Who guess my brain cells were working fine back then ... While pow powpowpow was playing wiT his CaP gun and riding his hot wheels 3 wheeler with his Gretzky rookie card attached to the spokes of 3 wheeler with a close peg ... K-pow !! k-pow !! pow pow pow ... Guess I just shoot this guy wiT my bow n plastic arrow ... LMAO thanks snow n mudders have a merry Xmas and stay safe in the mountains .... beeP !! beeP !! ... O I think pow pow POWs 3 wheeler came wiT a horn ... HoTSaucE ... LMAO

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o zone guy

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Here it is in the simplest terms your stock sled makes 165hp at 0 feet with density at 1.0 now go to 8000 feet your air density drops and goes to .786 so your hp would be 129hp now add your 4 psi creating 32 more hp and your back to 161 ish.
So iT would Be SaFE to say that the 2021 850 sTocK TuRBoo would have 5 PounDs of BoosT...5 pounds times 8 hp = 40 HP to compensate 8000ft eleVaTioN thanks for the confirmation ... Cause some peoples said the 850 ski doo stock turbo was SeT at 3 pounds of boosT...so thaT would be 13 hp per pound which is unrealistic...when 8 hp per 1 pound of BooST is the average ... beeP !! beeP !!! .. KooLBeaNS
 
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canuck5

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It would be dependant on elevation your riding if someone threw a boost gauge on and was only at 6000feet maybe 3 psi is possible. As stated above they are elevation compensation kits I believe trying to maintain the same manifold absolute pressure. There’s no doubt an aftermarket kit at lower altitude will feel crazy strong in comparison and so would a stock sled at lower elevation too.
 

o zone guy

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It would be dependant on elevation your riding if someone threw a boost gauge on and was only at 6000feet maybe 3 psi is possible. As stated above they are elevation compensation kits I believe trying to maintain the same manifold absolute pressure. There’s no doubt an aftermarket kit at lower altitude will feel crazy strong in comparison and so would a stock sled at lower elevation too.
would the SiZE of the turbo also determine the Maximum horse power that 1 pound of boosT would produce ... The facTorY stock ski doo turbo is very small would this produce only to maximum of 8 hp per 1 pound of boost on pump gas
 
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o zone guy

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So a stock 850 ski doo can handLE 185 of reliable HP... So this would mean 850ski doo factory turbo could add 2 more pounds of boosT 16 hp.. 8 hp for 1 pound of boost... 125 hp at 8000ft add 56 boosted hp = 181HP .... BelieVe in the FuTuRE ... beeP !! beeP !!!
 
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cattechsummitrider

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Pound ( Pounds) of boost is pounds of boost, turbo size would not make a difference unless it is so small it cant supply the volume of air needed, Volumetric efficiency would go down and it would create more heat in compressing the amount of air required
To big of turbo would would spool up slower and be slower to react ( lag ) but the volumetric efficiency would be better and it would create less heat
It is a balancing act
Its like an air compressor hose or a furnace duct both can deliver the same volume of air, one just reacts slower to inputs than the other
 

o zone guy

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Pound ( Pounds) of boost is pounds of boost, turbo size would not make a difference unless it is so small it cant supply the volume of air needed, Volumetric efficiency would go down and it would create more heat in compressing the amount of air required
To big of turbo would would spool up slower and be slower to react ( lag ) but the volumetric efficiency would be better and it would create less heat
It is a balancing act
Its like an air compressor hose or a furnace duct both can deliver the same volume of air, one just reacts slower to inputs than the other
so ideally BRP should go from a 8 hp turbo to a 5 hp turbo... 55hp/11psi 5/1 horse power to boosT at 8000 ft... BRP could set the setting s for.. 8psi times 5hp=40 +125 =165hp ..... 9psi times 5hp=45+125=170hp... 10psi times 5hp = 50hp +125 =175... 11psi times 5hp =55+125 =180hp... 12psi times 5 hp = 60hp + 125 =185hp... but all this would only be possible if the smaller turbo can supply the volume of air needed and maintain volumetric efficiency with minimum compressed air that is required... I like the way u think.. now I understand 100% much appreciated, thanks... BeLieVe in the FuTuRE !!! Thinking (upsTream) 6hp and 7hp size turbos also
 
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Teth-Air

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Just spit out my coffee lmao. Come ride some real snow

How does "real snow" increase HP? Are you really down on the N/A 850 Ski-Doo that it couldn't run in "real snow" compared to the 850T? I find the 850 N/A really good in the torque dept at any elevation and in any snow conditions. In fact I think it feels torquier than the 850T. Can you post some comparative H.P. torque curves?
 
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