I would like to know how to accurately calculate this.... As Datamaster is very very ackward with it... Thanks

 

Well, take the flow rate equation:

hp*bsfc/#of cylinders*duty cycle = flow rate lb/hr

hp*bsfc/#of cylinders*flow rate lbs/hr = duty cycle

eg,

500*.50/8x39= .8

-Mindgame

 

I always thought it was pretty straight foward. Make a few WOT runs and check the log, but the math is nice to know

 

How is it possible to have 150% then???

 

100% duty cycle as I understand it, means that the injector is open all the time. So, anything over 100% doesn't really matter cause "open all the time" is rather self explanatory.

You generally want to stay at 80-90% but no higher. If your demands go beyond that rate, then you need a bigger injector.

-Mindgame

 

Duty cycle is calculated by dividing actual pulsewidth by the amount of time available in two crank revolutions (the time for a 4-stroke cycle) at any particular RPM. Some available times for 2 crank revs at various RPM:

4000 - 30mS
5000 - 24mS
5500 - 22mS
6000 - 20mS
6500 - 18mS

If you were running at 6000rpm, and DataMaster showed a 17mS pulse width, your duty cycle would be:

17/20 = 0.85 = 85%

I have seen some DataMaster logs where the "duty cycle" numbers don't make any sense. I have suggested to people that they go back to TTS and ask why, but no on has done that.