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Hey guys, i'm new to this forum. I have a 1991 440 f/c Polaris Sport, that i'm suping the shit out of. I'm getting a single pipe for it that will add 8 HP. What is the stock HP on a 440 f/c engine?
 

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Take the compression of both cylinders add them and devide by 2, multiply that by the motors max rpm and multiply that by the actual cc's, and then devide that by 6400000 and you should have your approximate HP (very close)
 

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^ that is really cool, ill have to try that now..
 

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Heres what I got when I tried that

86 indy 400 60hp
95xcr 600 stock 136hp "a little overated on that one I think"
 

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I tried the formula for my Vmax4, came up with over 200hp. I don't think a formula like this can work.

An older 440 fan cooled probably makes in the neighbourhood of 40-50 hp, a performance liquid cooled 440 can make upwards of 100 hp.
 

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Welcome to the forum man. Should be around 50-60 somewhere in there.

I think that formula only works on twin sleds or divide the compression numbers added together by the number of cylinders perhaps, well atleast that is what I am thinking...
 

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ya, that formula sounds about right for my sled, but it's a 440 liquid with a little higher compression than stock... Got me about 75HP...
 

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It works on singles/Twins/and tripples if done correctly - with a single just use the compression - with a twin and a tripple use the average compression. I got this formula from one of my snomobile magazines...... When I use it on my 91 Formula 470, I get 85.2 hp before adding the UFO's into it - so somewhere between 85 and 91hp.
 

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I get 93 hp for my XLT SP using the formula. Sounds like its in the ball park to me. Cool.
 

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mine seems a little off altho im not sure of the true hp of my sled. (was told 130-135) its almost/is the same spec. as a spx it has 135 psi in all cyls. the formula says it has 123 hp.
 

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Hmm, i get 68.5 for my 440 liquid, but I know it's got a heck of lot more than that.
Maybe it works better on bigger CC sleds?
 

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Formula does not work for the 1997+ xcr 440's they had 98 hp.
 
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