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Discussion Starter #1
hi
Got my F7-snopro benched or dyno tested dont know what the name is.
I was a little disapointed :unsure: , 132hk on 98octan and 7500rpm . It was done in Sweden on Mc Express.
 

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how amny hours on the motor ? nic motors take a while to break in . im not talking milage but actual time. also was this a track dyno or a motor dyno? makes a big difference.
 

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Discussion Starter #3
Originally posted by f-5snopro@Dec 10 2002, 09:07 AM
how amny hours on the motor ? nic motors take a while to break in . im not talking milage but actual time. also was this a track dyno or a motor dyno? makes a big difference.
20hours, they pot the instrument right in the motor through the primary cluth, no track.
 

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did they give you the dyno sheet? there are so many variables that come into play when dynoing a motor . air temp,fuel temp , jetting, engine temp, pipe temp, the dyno itself, actual fuel octane not the pump rating, ect ect ect.................... i would not worry to much about it . i think you stated it made 132 hp and thats only 6 hp off the 138 mark. hp can be achieved with proper tuning and with changing other variables that come into play when dynoing an engine.
 

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There's probably less air up there in Sweden. Most of it hangs around the equater. . . lol.

Interesting. I wonder what others are dynoing in at. Perhaps the 98 octane is causing the sled to produce less power.
 

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Discussion Starter #6
Originally posted by f-5snopro@Dec 10 2002, 09:28 AM
did they give you the dyno sheet? there are so many variables that come into play when dynoing a motor . air temp,fuel temp , jetting, engine temp, pipe temp, the dyno itself, actual fuel octane not the pump rating, ect ect ect.................... i would not worry to much about it . i think you stated it made 132 hp and thats only 6 hp off the 138 mark. hp can be achieved with proper tuning and with changing other variables that come into play when dynoing an engine.
We did the test acouple of times. The temp were cheched many times. When it got 80C it started to lose power, I got 125hp, then we let it cool of and I got 132hp. The test was done 5 times. I think they were going to dyno another F7 this week, if that snowmobile get 138hp I`m going back to the dealer. To see if there is any problem with mine.
 

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Discussion Starter #8
around -7 Celsius not sure, it was -15C outside the port was open a bit i guese it sneked in some cold air.
 

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I'm probably gonna get flamed all to hell for saying this but in a stock motor that much octane is gonna cost you a few HP.......

Putting on flame suit now .....
 

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ZRT is right. Should run 87 octane for the dyno. That is what the engine was designed for. You would likely lose a couple to 3 horse that way.

Jester :) :blink:
 

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the higher octane will not fuly burn in the combuxtion chamber unless you have the compression to ignite the air fuel mixture , so the high octane fuel will cause it to lose some hp . like i said earlier there are a LOT of variables that can cause higher or lower numbers.
 
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The high octane will lower the HP and won't burn the fuel at the right time unless you have the right timing and compression. If you really have that much octane put a timing key in that bad boy.
You could try blowing cold air at the from of the sled, intake. Was that actual HP or corrected HP? What is your eleavation and was there a low pressure weather front? These are are other varibles that would effect the HP. <_<
 

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i' will lay money the horse power was down due to fact of high octane gas i have posted before that running high octane gas in anything you have to advance the timing and in some cases add more fuel,,
 

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OK folks here it is. same kinda test this guy did.

25 deg F , 89 octane 220 miles 140.3 HP @ 7750 ish rpm.
 

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Hey MC,

If the actual octane is 95. I would make sure your ethanol switch is not flipped up and add an offset flywheel key for sure. We are doing it here in MN. with 92 octane fuel and having pretty good luck. You may even be able to check your head volume.

Did you have a dyno sheet that showed your BSFC (how lean it is running)? You will have your answers with that number. lol
 

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Here in Sweden the gasoline octane rating is RON in the US. Gasoline is rated in PON. PON is achieved by: (MON+RON)/2 that means a typical comparable value for Swedish 98 octane is about 92,5 PON.

The different octane rating numbers is:

RON = Reasearch Octane Number

PON = Pump Octane Number

MON = Motor Octane Number
 
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