Author Topic: bsfc vs. rpm  (Read 172 times)

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Offline 1manband

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bsfc vs. rpm
« on: December 22, 2014, 08:02:44 pm »
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Offline Cut4fun .

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Re: bsfc vs. rpm
« Reply #1 on: December 22, 2014, 08:08:48 pm »
I had to look up bsfc.  http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption 

Not a term I have seen before. But trying to learn new stuff. Thanks for sharing.

I'm so lost. http://ecomodder.com/wiki/index.php/Brake_Specific_Fuel_Consumption_%28BSFC%29_Maps




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Offline farmboy

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Re: bsfc vs. rpm
« Reply #2 on: December 22, 2014, 09:23:59 pm »
Me TOO!
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Offline 1manband

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Re: bsfc vs. rpm
« Reply #3 on: December 23, 2014, 05:15:55 pm »
if motor was held on a dyno at a steady XXXX rpm, under load...  the bsfc at that particular rpm, represents the fuel used/necessary to do so.

the lowest bsfc shown on the actual graph line, is still pig rich.  (this is average graph of 30+ motors i had data for.  some are quite a bit higher, some quite a bit lower of course).

as motor performance is optimized, a lesser safe bsfc is usually shot for on a dyno.

this graph does not have anything to do with "gas mileage"  (ie.  cuts per gallon).

usually a bsfc graph looks like an oyster.  will post one up of this type.



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Offline 1manband

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Re: bsfc vs. rpm
« Reply #4 on: December 23, 2014, 07:58:13 pm »
some notes on the photo....


......the best "cuts per gallon" is the range of rpms within 300 circle in the middle....  at 1/2 load, ~4200 rpm.





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Offline 1manband

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Re: bsfc vs. rpm
« Reply #5 on: December 23, 2014, 08:13:25 pm »
forgot to add one more thing.

the top arc on the graph labled WOT, just means the carby throttle butterfly was held wfo for that test line.

that arc also represents the torque curve of the motor.
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Offline aclarke

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Re: bsfc vs. rpm
« Reply #6 on: December 23, 2014, 09:31:20 pm »
Joe, cool stuff!
Amazing the fuel use down low and above the torque peak.  I know you used some strato motors for the average, any idea what the strato motors  bsfc is Compared to traditional piston ports? 


Offline 1manband

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Re: bsfc vs. rpm
« Reply #7 on: December 24, 2014, 05:15:33 am »
believe the husqvarna site lists numbers there?
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Offline 1manband

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Re: bsfc vs. rpm
« Reply #8 on: December 24, 2014, 12:36:16 pm »
numbers lead to more numbers and eventually lead into a model of something like this.  (just a toy right now).

old 066.
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Offline 1manband

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Re: bsfc vs. rpm
« Reply #9 on: December 25, 2014, 06:01:52 pm »
double post
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