1ml/min is equivalent to 0.0158503 gal/hr (GHR) thus the rating on devils own is 440 ml/min is equivalent to 6.97414 GPH @ 200psi
This would also mean that 375 ml/min @ 280 PSI for the Snow nozzle equates to 5.94387 GPH.
This would be approx 17% flow increase at 80 PSI less from the Devils own nozzle vs. the Snow nozzle.
Some math from a forum post that came from devils own:
Standard nozzle pressure per devils own is 100psi (
http://www.alcohol-injection.com/forum/nozzle-size-calculator/2210-nozzle-flow-rate.html)
Here is the formula to calculate flow rate vs pressure.
1. Divide new pressure by 100 psi (standard nozzle pressure)
Example: 140 divided 100 = 1.4
2. Obtain square root with calculator
Example 1.4 sq-root = 1.1832159
3. Multiply result by nozzle size at 100 psi
Example: 1.1832159 x 1.00 = 1.18 GPH
This is your new flow rate @ 140 psi of pressure.
hope this helps you.
So in your case @ 280 PSI we get the below for the Devils Own #4
280/100 = 2.8 ^ (1/2) = 1.67332005307 * 1 (I do NOT know the flow rate of the DO4 at 100PSI, thus this calculation becomes invalid unless this is correct) = 1.67332005307 GPH @ 100PSI.
@ 200PSI per the Devils own poster within the same thread you would be at DO4 @ 200PSI 5.66GPH (working backwards from this we could assume that the flow rate at 100 PSI becomes the following:
200/100 = 2 ^ (1/2) = 1.41421356237
5.66 GPH @ 200 PSI = 1.41421356237 * Flow Rate @ 100 PSI => Flow Rate @ 100 PSI = (5.66 GPH / 1.41421356237) = 4.00222438152
If we put this back in our previous equation, where we had a differential value of 1.67332005307, we get Flow Rate @ 280 PSI = 1.67332005307 * 4.00222438152 =
6.69700231448 GPH, this seems like a proper GPH @ 280 PSI given what we know at 200 PSI.
Since Snow gives you ml/min of 375 ml/min @ 280 PSI, we can use the direct conversion we did earlier, giving 5.94387 GPH for the snow nozzle.
This means the increase in flow, assuming my math is correct, is equivalent to [(Devils Own Flow in GPH)/(Snow Flow in GPH)] = ( 6.69700231448 GPH / 5.94387 GPH) = 1.12670740014
To get this as an actual percent, we do (1.12670740014 - 1)*100 = 12.670740014 percent flow increase with the new nozzle.
I am not a meth guru, and the equations/math came from that general devils own equation and using google for unit conversions so feel free to double check.
Snow has this on their site, though I am sure you have seen it (
https://www.snowperformance.net/category-s/191.htm)
You may want to call devils own and talk to them as they would be able to either confirm my math or provide you with the answer or the constants needed to do it ourselves with their equation (ie. the flow rate at 100 psi).
Note that snow lists the nozzels as being rated at 40 PSIG (PSI gauge) on that chart above, which could change things drastically if the snow nozzle is actually rates 375 ml/min @ 40 PSI rather than 280 PSI.
