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02-20-2019, 10:26 AM | #41 | |
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Re: Both 94s sinked at 20kg/h at idle
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02-20-2019, 10:32 AM | #42 |
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Re: Both 94s sinked at 20kg/h at idle
Actually air flow is caused by atmospheric pressure.
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02-20-2019, 07:12 PM | #43 | |
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Re: Both 94s sinked at 20kg/h at idle
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The uni-syn is measuring mass air flow and giving you the result in kg/hr. You can convert that to "cfm" and that also tells you how much air is going into the engine while idling. I found a formula that converts kg/hr to cfm by multiplying your flow number by 2.08. 2.08 x 40 (carbs combined) tells you that the engine is getting 83.2 cfm at that engine speed. Or 41.6 cfm per carb. I would guess that having that "balance" makes for better volumetric efficiency of the engine by maximizing the likelihood that you'll get the same amount of air into each cylinder (in a perfect world). Just my two cents. Very interesting discussion too. Mike |
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02-21-2019, 08:00 PM | #44 | |
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Re: Both 94s sinked at 20kg/h at idle
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Yes. When vacuum is below 7.5" the pv opens on a single holley94. 2 carbs split the number or close. My understanding. More nonsense to add... https://www.jalopyjournal.com/forum/...-valve.798600/ Last edited by Tinker; 02-21-2019 at 08:42 PM. |
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02-21-2019, 08:02 PM | #45 |
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Re: Both 94s sinked at 20kg/h at idle
A flathead sitting has no atmospheric pressure on it, till it runs creating flow/pressure. But like blowing through a straw if you don't put your finger over the end then no pressure is made either. I do have a barometer in my house though. . Last edited by Tinker; 02-21-2019 at 08:32 PM. |
02-21-2019, 09:39 PM | #46 | |
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Re: Both 94s sinked at 20kg/h at idle
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02-21-2019, 09:41 PM | #47 |
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Re: Both 94s sinked at 20kg/h at idle
This must be a new science. What does that barometer measure?
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02-21-2019, 09:44 PM | #48 |
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Re: Both 94s sinked at 20kg/h at idle
Your sarcasm is not lost.
but just encase. https://www.youtube.com/watch?v=i2UKTpIQG6M https://www.youtube.com/watch?v=4K_XJGuRy88 neat version https://www.youtube.com/watch?v=EkDhlzA-lwI Last edited by Tinker; 02-22-2019 at 12:28 AM. |
02-21-2019, 10:09 PM | #49 | |
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Re: Both 94s sinked at 20kg/h at idle
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Yes, being there is twice the air flow, 2 carbs vs 1. Like having two holes in a dam. So vacuum decreases quite quickly. Needing pv's that open at lower vacuum. An engine that is working well at 18-20" vacuum at idle. Once you accelerate, it decreases engine vacuum. One carburetor only lets so much air flow through the engine. Two carburetors add more flow, etc. More flow less and less vacuum. Vacuum shared by each pv or carb. pv's on 94s are reverse thinking. They close under vacuum and open under low vacuum conditions. Not a fan. . Last edited by Tinker; 02-21-2019 at 11:59 PM. |
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02-22-2019, 10:13 AM | #50 |
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Re: Both 94s sinked at 20kg/h at idle
neat version
https://www.youtube.com/watch?v=EkDhlzA-lwI Now I see why so many hot rodders lower their cars. The pressure pushing down into the carbs will be higher at lower elevation. Fascinating! |
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