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Interesting (low) vacuum readings on 1982 W150 truck & 1
https://slantsix.org/forum/viewtopic.php?t=56981		 Page 2 of 2
Author:  wjajr [ Thu Jan 29, 2015 1:31 pm ]
Post subject: 
Dan:
Quote:
Welll, god promised America endless cheap gas forever; it's right there in the bible, so don't you fret about it none, y'hear?
New or old testament?

The price may go up & may go down, and we may have recently seen a dead cat bounce in crude, but paying with worthless greenbacks makes it cheap.
Author:  spacecommander [ Sat Feb 14, 2015 8:29 pm ]
Post subject:  New results with 4bbl Carter 400CFM & Offy manifold
The new Offenhauser manifold and Carter 400CFM AFB have brought the truck's 65 MPH vacuum numbers up to about 9" from 5". Could it be possible that because of altitude the 1bbl carb had to have the throttle plate open further during 65mph cruise than the throttle position of the 2 primarys on the 400CFM Carter, causing a loss in ported vacuum pressure? The truck just seems to work better all around with the 4bbl - smoother running, with the only issue a tiny hesitation when the throttle is mashed and the accelerator pump squirt runs out - could alter the pump pivot point, but it's good enough now.
Author:  NEVjr [ Sun Feb 15, 2015 8:17 pm ]
Post subject:  Re: Interesting (low) vacuum readings on 1982 W150 truck &am
Quote:
Been cold here in New Mexico

BUAHAHAHAHAHAHAHA!!!!!!!!

I'll bet you didnt know this, but water, like what falls out of the sky when it rains, will become solid when it gets cold, infact, it sometimes falls out of the sky as a solid. Here, I often have to shovel it off of my sidewalk, sort of like sand that falls from the sky in a foot deep layer.

You see, it must be potentially fatal before it is cold.
Author:  SlantSixDan [ Sun Feb 15, 2015 8:22 pm ]
Post subject:  Re: New results with 4bbl Carter 400CFM & Offy manifold
Quote:
Could it be possible that because of altitude the 1bbl carb had to have the throttle plate open further during 65mph cruise than the throttle position of the 2 primarys on the 400CFM Carter, causing a loss in ported vacuum pressure?
Well, the altitude and the fact you're pushing a big brick through the wind with a low-power engine, yes. But there's nothing such as "vacuum pressure".

You'd probably have at least as good a "better all around" result with a thoughtfully-picked 2bbl.
Author:  spacecommander [ Mon Feb 16, 2015 12:27 pm ]
Post subject:  Re: New results with 4bbl Carter 400CFM & Offy manifold
Quote:
Quote:
Could it be possible that because of altitude the 1bbl carb had to have the throttle plate open further during 65mph cruise than the throttle position of the 2 primarys on the 400CFM Carter, causing a loss in ported vacuum pressure?
Well, the altitude and the fact you're pushing a big brick through the wind with a low-power engine, yes. But there's nothing such as "vacuum pressure".

You'd probably have at least as good a "better all around" result with a thoughtfully-picked 2bbl.
Woops - I know there's either vacuum or pressure. Well there's really just an absolute pressure - vacuum is a lower pressure relative to a higher pressure. ;-) Had the carbs and offy manifold, didn't want to spend the $ for a 2bbl as eventually the 2 x 2bbl carter/webers will go on once the linkage is fixed.
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