Endcastings flow?

[Wreck]

when flowing the end casting , they would only flow one throat at a time , so that is 120cfm per throat . like ports . you don't flow both intake ports at the same time .

[Dusty1]

[Alstrup]

Dont know what the rules say, but as such that is not a problem
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[58 Plastic Tub]

Do you run FV, Dusty?

I've been looking very hard at it. It's the arcane rulebook and the lack of track time (20 minute races? Really?) that has kept me from it.
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[Dusty1]

[NJ John]

This is not my pic or end casting.

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[BFB]

[chrisflstf]

Most of the stock, if not all, have a small notch connecting both cylinders between them. Some people fill those (no plenum affect)

[modok]

Heads flow more at 25" than they do at 10"
And they flow more at 29 than they do at 25
right?
29" of water is right about 1 psi

Mass flow in the running engine levels off about when pressure drop is kissing 200 inches of water (2:1 pressure ratio; 7psi of suck)

Also the majority of flow into a cylinder happens in 120 crank degrees or less

So if you adjust your math with these factors, it will be closer to what actually happens in the engine.

The main point of flow testing things is to too see how efficiently they flow compared to how big they are.
Bigger holes flow more than smaller ones In case you hadn't already guessed that. You don't need a flowbench to measure a hole. But you do need a flow bench to measure how efficiently the hole flows for it's size.

[Wreck]

[BFB]

[Wreck]

Get 2 restrictor plates made that flow 55 CMF each port , put them under the manifolds of a 2.3lt with twin IDFs and see how high you can rev it .

or put stock valved (35in /32ex) heads on that 2.3 and limit the valve lift to 0.080" See how high it will rev .

[BFB]

[Alstrup]

Youre missing something here
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[Brian_e]

Just break it into a single cylinder engine for your software inputs.

Divide your displacement by 4, and use 110-130cfm for your calculations. That will get you close, but it will still need the rest of the intake system figured into the equation. The engine can't run with an open hole on the end of the manifold. Realistically you should be using the whole intake system if you want to get accurate numbers from your software.

Brian
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[BFB]

if im missing something on this then educate me, because maybe I am. but it seems pretty cut & dry to me, an engine that pumps 220 cfm doesn't pump 220 cfm per cylinder. if its a 220cfm 4 cylinder then you divide 220 by 4 to get per cylinder cfm, if its a 600 cfm V8 you divide 600 by 8. and we all know theres more factors involved in the complexity of the entire system and that the end castings are a paired runner so its not just as simple as " the end castings flow 110- 130 cfm", all that is a given.

but to say that opening a stock valve .080 as an equivalent of one cylinder flowing 55 cfm ( the 220 / 4 ) is just trying to be an ass about it vs just explaining how that conclusion was come to.
a single cylinder measuring 94mm w/ 82 mm stroke is 569cc or 34.7 Ci , we'll just call it 35. plug those numbers into the equation or an online calculator and you get the same results, 55cfm @ 100% VE, 85% VE is like 47 cfm. I have no idea why Wreck would think this same cylinder moves 220 cfm.

I havent boosted as many engines as I have by mis-calculating engine cfm and referencing a turbo maps to match things up. so I can't be off by much... not by 660 cfm...
but again, show me, if im wrong then im wrong.
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[EVfun]

[Wreck]

If you look at the chart on this

threadhttps://www.thesamba.com/vw/forum/viewtopic.php?t=573099

look for stock 1600 twin port flow numbers at 0.100" That is what they flow per port at the measured depression.

At the beginning you said that a 2.3lt needed 220cfm at 5500 to be at 100VE

That is just a theorised program that doesn't take into account port design and efficiency . It is a tool to work out what your intake needs to flow per cylinder to get 100% cylinder filling at that rpm .

I was pointing out that those numbers are per cylinder. People think you put twin twin throat carbs/itbs to get more air into the engine , that is not correct , it is to separate the reversion pulses and get the engine to run smoother at lower rpm . and more ability to fine tune it.

[BFB]

[BFB]