Intake Manifold Porting Show ‘n Tell

[juuhanaa]

When you tell a 4-cylinder guy (with half the cylinders in use) that he needs a spacer.


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-juhana

Maybe a nice radius would help

Yea, i think so. Im not sure how many spacers or radiuses i need, so to play it safe, im thinking to doubling up.

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-juhana

[1980RS]

I did this coz I'm stupid & couldn't buy the required manifold.
440 Chrysler victor intake chopped up & welded back together to fit an AMC 401:

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Now that's talent right there. Fantastic work.

[Bigchief632]

Think this one is big enough?

[Lloyd klem]

Nice to use billet runners and leave a nice bell radius in plenum around each port.

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[Erland Cox]

Dry flow?

Erland

[Lloyd klem]

Dry flow?

Erland

Mfi,
Runner nozzles

[juuhanaa]

The secondary ramming wave cancels out the higher cylinder pressure before TDC and both prevents reversion, lets the intake cycle start
a little earlier and cleans the combustion chamber of residuals which means that som loss out the exhaust is necessary. .
It is a positive wave, next we need a negative so it is more or less canceled out during overlap.
Next big depression comes from exhaust before EVC and piston after that.
Not earlier waves.

Erland

Now that we got to the dry flow manifolds...

What earlier waves? You said it yourself that a wave is reflected by the change in area, so its the same thing that goes back and forth between the runner entry and the valve, that we can calculate the frequency for, and that makes a difference between IVO and IVC.



-juhana

[Erland Cox]

No. There is no frequency for it during valve open.
Outgoing wave velocity is the local speed of sound minus the flow velocity.
Ingoing wave velocity is the local speed of sound plus the flow velocity.
Forget the earlier waves, everything starts with the energy from the exhaust and the piston, IVO to IVC.
That energy will be used up during valve closed, IVC to IVO and then it starts over again.
If you look in the diagram you can see the difference in degrees from top to bottom of the waves between
what happens during valve open and valve closed.
That is because of the flow velocity during valve open and no flow velocity during valve closed.
There are a lot of residual waves but they are weaker and thinking about them clouds everything and makes it even harder to understand.

Erland

[juuhanaa]

How much value would it give to show an example using a simple calculation for the thing vs pressure trace from various rpm using a simulation software vs chassis dyno?

When the calculator is from USA, simulation software from South Africa, and engine from Finland?



-juhana

[Erland Cox]

Vanniks software would show the curves and what happens with different tapers and lengths.
The dyno would show what the result was.

Erland

[Lloyd klem]

Vanniks software would show the curves and what happens with different tapers and lengths.
The dyno would show what the result was.

Erland

There we go ,the more we do the math the less we know! Experience,r&d is everything.I have read so much expert knowledge that is no where near what goes on.People think they find something,and that's cool.Most things do not duplicate enough for us to understand.Thats why I only do what intrigued me ,I will never work on anything again that someone thinks they figured out.What happens at one rpm does not at another.The only guys that impress me have general knowledge of race engines,can produce a decent Dyno sheet and bring that to life at the track etc!!

[juuhanaa]

Vanniks software would show the curves and what happens with different tapers and lengths.
The dyno would show what the result was.

Erland

You miss the point when we disagree about the thing and wether the thing has a frequency during valve open. Doing a calculus for the thing and finding it using the tools i suggested, would then not give you value.



-juhana

[hoffman900]

Nice to use billet runners and leave a nice bell radius in plenum around each port.IMG_20221127_191150943.jpgIMG_20221127_190651537.jpg

Ever play with a divider down the middle?

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It takes some correlation, but EngMod4t is fantastic for this stuff, but mostly is looking at dry flow. However, I put one of the virtual pressure sensors at the booster location and that’s revealing. Remember, carbs work off of pressure differentials and will work both ways as well… people who work with individual runner carburetors know this well.

[JES]

Wow, those pictures are great. Thanks Chad, I can see to some degree how you are making the runner length more equal. You and others have shown me much by pictures and dialogue that I can understand.

[Tom68]

Ever play with a divider down the middle?

Which picked up 7kw on the V10 but didn't work on the V8, it says they divided the front cylinders on the V8 and encouraged interference on the rear, or something to that effect. Flat plane crank anyways no doubt.

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf