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how to figure out volume increase
#819422
10/01/10 09:55 PM
10/01/10 09:55 PM
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Joined: Sep 2005
Posts: 2,442
LOWELL IN
QWK_ENUF
OP
top fuel
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OP
top fuel
Joined: Sep 2005
Posts: 2,442
LOWELL IN
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say from a .140 orifice to a .160
how much more volume can it flow
thanks
WAXER
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Re: how to figure out volume increase
[Re: QWK_ENUF]
#819425
10/01/10 10:12 PM
10/01/10 10:12 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
quicktree you slay me but i am looking for a formula
Ok you asked - .160-.140=.020  sorry 
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Re: how to figure out volume increase
[Re: QWK_ENUF]
#819426
10/01/10 11:50 PM
10/01/10 11:50 PM
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Joined: Oct 2007
Posts: 4,209
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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The easy math:
New^2 ÷ old^2
.160^2 ÷ .140^2 = +36%
But it's not that simple. The Poiseville effect increases it slightly, but the pressure differential is slightly lower - and even that's if your pump can always supply the same pressure.
Holley probably has a comparison somewhere.
Boffin Emeritus
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Re: how to figure out volume increase
[Re: QWK_ENUF]
#819427
10/02/10 12:05 AM
10/02/10 12:05 AM
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Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar
master
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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It will flow the same volume, it will just take longer  The increase in area is PI*(0.160/2)^2 - PI*(0.140/2)^2 = ? 0.0201062 - 0.0153938 = 0.0047124 The increase in area is about 30.6% (If I did the math right?)
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Re: how to figure out volume increase
[Re: QWK_ENUF]
#819428
10/02/10 01:20 AM
10/02/10 01:20 AM
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Joined: Aug 2003
Posts: 684
Milwaukee
ToddP
super street
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super street
Joined: Aug 2003
Posts: 684
Milwaukee
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On the Barry Grant website, they publish a jet flow chart . It only goes up to a holley 100 size jet.
The chart shows jet dia. to flow curve is steeper than cross sectional areas would indicate.
Years ago someone posted a formula. I think it was b1Ken?
dia.^2.2 x 142200 = jet flow
The barry grant curve however is not exactly inline with this formula.
Using this formula shows a 34.1 % flow increase as opposed to a 30.6% increase for just cross sectional area. (.160" dia over .140" dia)
Last edited by ToddP; 10/02/10 01:26 AM.
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Re: how to figure out volume increase
[Re: ToddP]
#819429
10/02/10 11:13 AM
10/02/10 11:13 AM
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Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar
master
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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Quote:
On the Barry Grant website, they publish a jet flow chart . It only goes up to a holley 100 size jet.
The chart shows jet dia. to flow curve is steeper than cross sectional areas would indicate.
Years ago someone posted a formula. I think it was b1Ken?
dia.^2.2 x 142200 = jet flow
The barry grant curve however is not exactly inline with this formula.
Using this formula shows a 34.1 % flow increase as opposed to a 30.6% increase for just cross sectional area. (.160" dia over .140" dia)
Good info. I searched around and found a few other posts with the jet flow calculation. Seems it may relate closer to actual flow taking things like surface tension of the fuel and flow friction into account?
either way I think comparing the change as percent difference seems to be more useful to me than the actual area or flow numbers.
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