What boost level do you start using Meth?
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Joined: Nov 2003
Posts: 13,616
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From: Norn Iron
I am calculating the flow based on the nozzle rating flow at a given pressure. The nozzles I used were rated for 14gph@100psi, so given that you can figure out the flow at any pressure by bernoulli's principle. I did use methanol and not water when testing so the specific gravity is taken care of.
I accounted for sparying into a pressurized chamber by subtracting out the boost pressure from the nozzle pressure. If you look in the spreadsheet you see there are several tables of data, the "corrected pressure across nozzle" is subtracting out the boost. Secondly spraying atomized fuel into a pressurized chamber is generally a bad idea
What I essentially created was a pump flow map. Nobody seems to want to publish theirs so I made my own.
My main point of linking to the thread I made was to really double check the voltage the pump is getting so you can be sure its doing what its supposed to.
I accounted for sparying into a pressurized chamber by subtracting out the boost pressure from the nozzle pressure. If you look in the spreadsheet you see there are several tables of data, the "corrected pressure across nozzle" is subtracting out the boost. Secondly spraying atomized fuel into a pressurized chamber is generally a bad idea
What I essentially created was a pump flow map. Nobody seems to want to publish theirs so I made my own.
My main point of linking to the thread I made was to really double check the voltage the pump is getting so you can be sure its doing what its supposed to.
A brief flow test in open air that Richard/Aquamist done. It will be with the same base Aquatec pump nearly all the meth kit suppliers use.
I am at work so I did a quick test with our 160psi pump.
230psi (1 turn CW) for 1 minute ............. 985cc/min @158psi (72psi drop)
180psi (3/4 turn CW) for 1 minute .......... 950cc/min @145psi (35psi drop)
160psi (0 turn) for 1 minute................... 905cc/min @136psi (24psi drop)
Conclusion: turning up the pressure from 160 to 230 psi only yielded 80cc/min extra flow with a pressure drop of 72psi.
230psi (1 turn CW) for 1 minute ............. 985cc/min @158psi (72psi drop)
180psi (3/4 turn CW) for 1 minute .......... 950cc/min @145psi (35psi drop)
160psi (0 turn) for 1 minute................... 905cc/min @136psi (24psi drop)
Conclusion: turning up the pressure from 160 to 230 psi only yielded 80cc/min extra flow with a pressure drop of 72psi.
And as he also goes on to mention, asking higher base pressures of the pump, more work etc...this will also affect how fast the pump actually powers up which with rapid off/on throttle events could easily see the engine not receiving the meth flow you want it to when relying on pump speed as a method of flow control.
The pressures I recorded were at the nozzles, like this:
By open air test I assume you mean just a hose from the pump outlet and no nozzle? That is not a very useful test since the pump will be on the bottom right and right edge of its map. If you look at a compressor/pump map you will notice the right edge is nearly vertical, which means independent of pressure, hence why there wasnt much difference using the much higher pressure.
What I basically did was measure the pump output at multiple points so I could build a more complete map to know how the pump behaves over a range of pressures and flows.
By open air test I assume you mean just a hose from the pump outlet and no nozzle? That is not a very useful test since the pump will be on the bottom right and right edge of its map. If you look at a compressor/pump map you will notice the right edge is nearly vertical, which means independent of pressure, hence why there wasnt much difference using the much higher pressure.
What I basically did was measure the pump output at multiple points so I could build a more complete map to know how the pump behaves over a range of pressures and flows.
9 Second Club
Joined: Nov 2003
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From: Norn Iron
There was a nozzle as the test suggests, 900cc although I think Aquamist maybe size them by numbers
the test was more to show the nonsense claims of man about these 200psi, 300psi claims especially when using large jets.
The pumps simply cannot cope with that amount of flow and still maintain anywhere near the quoted pressures and as your test shows, flow improves very little even with trying to use higher pressures again because the pump just cant keep up.
Add boost into the equation and things deteriorate even more.
the test was more to show the nonsense claims of man about these 200psi, 300psi claims especially when using large jets.
The pumps simply cannot cope with that amount of flow and still maintain anywhere near the quoted pressures and as your test shows, flow improves very little even with trying to use higher pressures again because the pump just cant keep up.
Add boost into the equation and things deteriorate even more.
