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Old 05-17-2017, 11:21 PM   #16
 
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Going to look at the configuration of our sterilizers tomorrow. They use water to pull, up to a 28", vacuum on the steam chamber. The black/white diagram appears to be correct...for what's used on a steam sterilizer at work. I've got Inlet gas at 45 stuck in my brain for some reason. Been a while since I've worked on them.

All good points.



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Old 05-18-2017, 02:38 AM   #17
 
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@chengny; just finished my final on monday for my fluid mechanics class.

Some super interesting stuff, by maaan its a lot.


I feel like as long as you could direct the airflow purely downwind in the exhaust, there would be an improvement. But only if the ambient air was building a higher pressure than the exhaust gases themselves.


So if you had a scoop set, it probably wouldn't have any effect on the piping until you hit at least highway speeds. Driving around town probably wouldn't do much for it, and more likely hinder the flow.


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Old 05-18-2017, 04:54 AM   #18
 
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Wasn't this idea explored back in the 70's and 80's? I seem to recall a certain system on these vehicles that everyone wanted to delete. It was usually belt driven, pumped air into the manifolds and such. If only I could remember the name of this system.


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Old 05-18-2017, 06:46 AM   #19
 
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Originally Posted by 87ChevyR10 View Post
Wasn't this idea explored back in the 70's and 80's? I seem to recall a certain system on these vehicles that everyone wanted to delete. It was usually belt driven, pumped air into the manifolds and such. If only I could remember the name of this system.
That was for emissions at start up. It's called secondary air injection no a days. It pipes in fresh air to the exhaust to clean up tail pipe emissions when the engine is cold......smoke and mirrors for the tree huggers.


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Old 05-18-2017, 05:09 PM   #20
 
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Originally Posted by Honky Kong jr View Post
It's a good read with real world documentation. http://www.headersbyed.com/hc_ventext.htm
nice read. Kinda want them now lol, thanks.


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Old 05-18-2017, 05:15 PM   #21
 
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Originally Posted by Camar068 View Post
nice read. Kinda want them now lol, thanks.
Hey others said it was useless and would work I found that they aren't and do.😏


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Old 05-19-2017, 04:25 AM   #22
 
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Originally Posted by Honky Kong jr View Post
That was for emissions at start up. It's called secondary air injection no a days. It pipes in fresh air to the exhaust to clean up tail pipe emissions when the engine is cold......smoke and mirrors for the tree huggers.
I was being sarcastic. However, whether the air is being pumped in or venturi'd out, it's still doing the same thing: pushing the exhaust gasses faster through the exhaust system. Why not take that smog pump, reroute the air line near the end of the exhaust and see what happens. At least this way, the scavenging effect would be present no matter how fast you're moving.


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Old 05-19-2017, 07:23 AM   #23
 
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I think in the end headers, an X-pipe, free flowing mufflers and properly sized pipes do a pretty good job of scavenging. I believe the venturi works because the outlet is near the end of the pipe and open to atmosphere but still very close to the engine since it is installed in the header collector. Would it be true to say that increased back pressure from more pipe length, the accumulation of bends and the addition of mufflers would reduce or eliminate any gains the venturi could provide? I believe time spent on induction and ignition after the above mentioned exhaust system would be more beneficial than trying to create a "vacuum scoop" under the truck where turbulent air flow abounds.
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Old 05-20-2017, 08:31 AM   #24
 
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Right, but the heat, man. Voted no because not enough consideration is given to the exhaust gas temperature, which is really high!
Wouldn't the incoming cooler, fresh air be stifled by the rapidly expanding, escaping hotter exhaust?


And what Jerry said.


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