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Discussion Starter #1
I read with great interest this thread which unfortunately went dormant last week.

http://www.yellowbullet.com/forum/showthread.php?t=317768&page=5

It got me to thinking......

Considering some of the opinions on valve size, port size, choke diameter & location - does this only apply to N/A engines or is there any % change made for N2O or alcohol fueled engines?

First, let me say I know VERY little about any of these principles, just enough to get me in over my head. Next, I am coming on the N/A forum since it looks like most engine builders also build boosted or N2O combo's as well & hopefully have some input on this question. I love the technical discussions that take place on the bullet!

Now my question:

If there is a particular valve size (if not bore limited), runner cc, or choke diameter for a N/A engine, would there be benefit or necessity of an increase in any of these measurements (since with the kits turned on or with alcohol being run almost 2:1 stoichiometrically by volume richer) due to the added volume of "stuff" passing through the runner?

When I think about it, it seems logical that the runner should be larger to support the greater volume, however, part of me feels that if the runner has great velocity or "the right" velocity, then the runner should easily pass the added volume accurately. Just curious about the added fuel from N2O or volume of alcohol becoming "stopped up" in a small port and becoming bottlenecked.

I hope you guys understand the question since I feel like I kind of got lost on my explanation.

Please let me know your opinions! :D

Thank you,

Paul Langlie
 

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Discussion Starter #3
Bringing this up from the dead. Still looking for information from someone with way more knowledge than me. I have my ideas, just looking for everyone elses thoughts.

Paul Langlie
 

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I think with boosted apps the port still needs to "perform". Areas and velocity profiles need to be increased as VE goes up with forced induction, but I'm not a believer in automatically throwing a big head at something just because it's boosted. As far as NOs, Mike Orbon's RES powered Camaro is certainly "pioneering" some new information on how small a port can be and still provide some outstanding performance, even with considerable Nos added. How all that gets quantified is another story, with all the variables.
 

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I have always thought on a boosted app you would keep right on your numbers for a good n/a port since its basically seeing the same pressure drop to fill the cylinder its just operating in a pressurized atmosphere. Now with nos I would think the exhaust side needs to flow like crazy to get the heat out of the cylinders so the nos coming in behind it or a second kit has a fighting chance to make more power. I would think the intake side could stand maybe 5-10% volume increase sine the nos cools the charge making it denser as long as you keep enough signal up to the Carb as not to lose your incoming fuel. As always these are my own theories and I'm not a pro. Thanks.
 

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Boosted with what fuel? It's all about speed! Meth Boosted cars seem to like alittle more volume, but speed is where we have seen improvment in track and Dyno performance.
 

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Well I think n/a cars on method need volume also, but unlike the op suggests I don't think they like the extra volume because of the very small amounts of extra fuel but because of the increased expansion rates of the highly evaporative fuels. They are turning into larger amount of vapor than gasoline. But you might be onto something with the extra speed maybe your getting the fuel to the cylinder and letting it expand there. Hmm got me thinking, well that and my wife keeps feeding me beer.
 

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Well I think n/a cars on method need volume also, but unlike the op suggests I don't think they like the extra volume because of the very small amounts of extra fuel but because of the increased expansion rates of the highly evaporative fuels. They are turning into larger amount of vapor than gasoline. But you might be onto something with the extra speed maybe your getting the fuel to the cylinder and letting it expand there. Hmm got me thinking, well that and my wife keeps feeding me beer.
(Proper) port speed = VE
 

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I have always thought on a boosted app you would keep right on your numbers for a good n/a port since its basically seeing the same pressure drop to fill the cylinder its just operating in a pressurized atmosphere.
Most guys who do FI for a living don't give a rats ass about the head. Whatever is a good head for NA will work for FI.
 

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IDK what he'd say. I know what the professionals we have worked with tell us. Many just don't care as long as they're "close enough".
I 'd Have to say Alan Johnson IS the Best professional there is....

You have Just shown your true colors........ go to speed talk to sell your s$$t.......... we're all full here...............
 

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My experience is the "professionals" don't leave any stone un-turned.

The heads I build for turbo and blower apps, .. as well as the NOS combos,..
ALL get adjustments in area depending on the application,. ..
I realize my specialty is custom work, ..

curtis
 

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My experience is the "professionals" don't leave any stone un-turned.

The heads I build for turbo and blower apps, .. as well as the NOS combos,..
ALL get adjustments in area depending on the application,. ..
I realize my specialty is custom work, ..

curtis
That's pretty much it. Adjustments are one thing, a completely new head is another. Guys like you can tweak, but to say you need a completely different head is stupid.
 

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I 'd Have to say Alan Johnson IS the Best professional there is....

You have Just shown your true colors........ go to speed talk to sell your s$$t.......... we're all full here...............
Shut the fuck up. WTF is "true colors" anyway.

You almost earned a little respect in the block thread, where you actually know how to deal with seating sleeves. Then you go say something stupid.
 

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Hmmm. I wonder if Alan Johnson would agree.
Aren't you the guy who was charging a customer to port an exhaust port when in the second post I said it wouldn't matter? And then pages later, we came to the conclusion it wouldn't matter? The experienced people said they don't even consider exhaust flow? Pay attention and get your head out of catalogs, maybe you'll learn something.
 

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Pressure will take any way out...but always prefers the easiest way. ;)
That, once you put pressure behind it everything else becomes less relevant.

Do you agree? There's a huge difference between sucking and forcing..(just leave it alone)...:D
 

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Aren't you the guy who was charging a customer to port an exhaust port when in the second post I said it wouldn't matter? And then pages later, we came to the conclusion it wouldn't matter? The experienced people said they don't even consider exhaust flow? Pay attention and get your head out of catalogs, maybe you'll learn something.
I want to say here that I think the exhaust port and how it moves air is very important. My point was that exhaust flow bench numbers are useless for exhaust lobe design. That's two different things entirely.
 
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