How does intake work ?

[Racer57]

Ok, I know its a dumb question. Older intakes air/fuel source is on top and goes straight down. Modern intakes air is at the front. How does it get evenly distributed from front to rear ?

[worthywads]

Ok, I know its a dumb question. Older intakes air/fuel source is on top and goes straight down. Modern intakes air is at the front. How does it get evenly distributed from front to rear ?

I assume port fuel injection so only air moving through new intakes.

[Filthy Filbert]

Yup.  Modern intakes are 'dry' and only move air—because fuel is sprayed right at each intake valve or even directly into the combustion chamber via fuel pressure/pump and injectors (50-ish psi)  No worry of fuel puddling in the plenum wheee air velocity may slow down.  So they can be designed to tune the air pulses according to the intended rpm power band.

Old carb intakes are 'wet' and need to reduce the possibility of fuel falling out of suspension and puddling in the intake.  Velocity must be kept high in order for Bernoulli's principal to work and pull the fuel into suspension in the air flow.

[Bullitt-]

 Engineering?   found these cutaway pics of a modern intake
https://www.jeepgarage.org/threads/6-4-hemi-intake-manifold-cutaway-photos.65679/

[Racer57]

Ok, I know its a dumb question. Older intakes air/fuel source is on top and goes straight down. Modern intakes air is at the front. How does it get evenly distributed from front to rear ?

I assume port fuel injection so only air moving through new intakes.

Sorry, air travel is what I'm asking about.

[MoparLeo]

The factory intake on the Gen III Hemi works like a short tunnel ram with long individual long runners coupled with port fuel injection. The throttle body is just one large intake air valve.

[HP2]

Ok, I know its a dumb question. Older intakes air/fuel source is on top and goes straight down. Modern intakes air is at the front. How does it get evenly distributed from front to rear ?

Sorry, air travel is what I'm asking about.

Despite the air entering at the front of the intake, pressure and flow at the front combined with the volume of the intake, the volume of the filling cylinders, and the vacuum create by the filling cylinders during the intake cycle, there is not a distribution problem  of air within a dry manifold.

This is because of  Isaac Newton's Second Law of Motion. If a small volume of fluid is flowing horizontally from a region of high pressure to a region of low pressure, then there is more pressure behind than in front. This gives a net force on the volume, accelerating it along the streamline, thus pushing it to the rear of the intake.

Atmospheric pressure seeks to fill voids, the throttle body creates a venturi, intake cycles create negative pressure, cylinders fill without have problems of less air at the rear than the front.

[blown motor]

I love this science.

[Racer57]

Ok, I know its a dumb question. Older intakes air/fuel source is on top and goes straight down. Modern intakes air is at the front. How does it get evenly distributed from front to rear ?

Sorry, air travel is what I'm asking about.

Despite the air entering at the front of the intake, pressure and flow at the front combined with the volume of the intake, the volume of the filling cylinders, and the vacuum create by the filling cylinders during the intake cycle, there is not a distribution problem  of air within a dry manifold.

This is because of  Isaac Newton's Second Law of Motion. If a small volume of fluid is flowing horizontally from a region of high pressure to a region of low pressure, then there is more pressure behind than in front. This gives a net force on the volume, accelerating it along the streamline, thus pushing it to the rear of the intake.

Atmospheric pressure seeks to fill voids, the throttle body creates a venturi, intake cycles create negative pressure, cylinders fill without have problems of less air at the rear than the front.

Thanks !! I wish my College Physics Professor had been as good as you for explaining things.