Selecting the Proper Injector
In order to select the correct size injector for your application, you might wish to use one of the following formulas.  
In most cases a naturally aspirated engine will have a B.S.F.C of .50. This means that the engine will use .50 lbs. of fuel per hour for each horsepower it produces. Turbocharged engines will want to be at .60 lbs. per hour or higher.  
Using these numbers as a guideline, you can select the approximate injector size in the following formula for a four cylinder, naturally aspirated engine at 200 bhp.  
Most injectors will max out at 80% duty cycle and this is the accepted industry standard.  
B.S.F.C is brake specific fuel consumption  How much fuel you are using per horsepower per hour  
The proper injector for this application would be 31 lbs. / hr. or 330 cc / min  
To find the HP value of the of the above mentioned injectors use this formula:  
___________________________________________________________ To convert cc / min to lbs. / hr.  Divide by 10.5 ___________________________________________________________ To convert lbs. / hr to gal. / hr  Divide by 6 ____________________________________________________________ To convert cc / min to gal. / hr.  Multiply by .015873 ____________________________________________________________  
To find the new FUEL FLOW rate after a fuel pressure change: Example 1: If a 240 CC injector tested at 43.5 PSI is run at 50 PSI. The result would be: Example 2: The horsepower value of this injector would increase by the same
rate
 

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