FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: wideopen231 on January 26, 2019, 05:15:18 PM
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Would 16 nozzles totally same area as 8 have same or greater atomization pressure? Smaller nozzles should mean more pressure to get same fuel to engine. Having 16 and area being equal to 8 larger ones it would seem pressure would be same .Since pump has no idea how many openings just how much resistance to pushing x amount of fuel. Have run 16 nozzle setup before on injected motor and had some luck but always too much fuel mainly due to too much total area. Was very main jet sensitive. Just looking at ideas and wondering about better atomization of fuel.
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It would be unlikely that you could match your 8 nozzle area exactly when using 16 nozzle out of the box. eg 8 x .032 = .006434, .006434/16 = .000402.
.022 = .0003801, .023 = .0004155. Using .022 will see a bigger increase in nozzle pressure and decrease in main pill.
I would think more nozzles with the increased pressure would result in better atomization but the placement of the nozzles would be more important to see any improvement.
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exact probably not,but how far down do you need to go in total area. I am thinking anything past.000_ is just numbers of very little significant's. Plus would have almost no effective change in main. Maybe I am wrong about how much it would actually mean.
My 16 nozzle systems have all been similar to blower set up.8 small(.020 or so) in hat and 8 larger like .030 or so in port right at intake flange. I use larger ones to adjust cylinder to cylinder.Just numbers not exact set up.
Guess only true way to know would be ABA test. Make one shot with single,maybe 8 .037 .come back connect top set and swap out ports with say .029 to .031(again just number have not ran totals) and make a pass w/o touching main jet. As long as all temps where pretty much same and conditions,then get answer. Heck thats all?Gain would probably be small,but a gain is a gain and small steps make for bigger leaps.
Thanks for reply.
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Pressure is determined by total area of nozzles and bypasses (or leaks) in the system and the specific gravity of the fuel.
16 nozzles of the same area as 8 would be identical pressure. Atomization would be better as the droplets/streams would be smaller. Might not be a noticeable gain in performance however. It usually isn't.
One thing that can get you is that different orifice types that are the same size don't flow the same. The lead-in on the hole, the length of the hole, the surface finish of the hole - all determine actual flow. So, you might have an Enderle .032, a Hilborn #16 and a Kinsler 620...all should be pretty much the same area calculation-wise, but they don't flow the same...close, but not the same. Flow testing them would be one way to get good numbers for them.
For example, some place (like FIE) could test your 8 @ 100 PSI/.792 SG and conclude that they flow 1.51 GPM.
The 16 you chose to replace them with might flow 1.63 GPM. Among other things, that would tell you that the main pill size for the new nozzles will need to be slightly larger to drop the system pressure a few pounds to make the GPM output equal to the original 8.
Spud
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Same TOTAL area will have same pressure. Thing is with 16 smaller nozzles they will clog easier than 8 larger ones. I would say stay with 8 nozzles until you get to 1750 or more Horsepower to feed.
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The only other thing to keep in mind is smaller holes are more easily plugged.