How does a variable runner intake function?

A variable intake can create two or more pressurized “hot spots”, increasing engine output. When the intake air speed is higher, the dynamic pressure pushing the air (and/or mixture) inside the engine is increased.

What is intake runner length?

Intake manifold runner length is the linear distance from the inlet port (the face of the head) to a common point shared by all cylinders. Depending on the throttle position this could be the open atmosphere (if each cylinder has its own throttle butterfly) or a plenum (if they share a throttle body).

How does intake length affect performance?

Since the waves must travel up and back the intake tract length, the length of the tract determines how much time it takes to arrive. It takes longer for the waves to travel in long runners, so they are most effective at lower engine speeds (where sufficient time is allowed to cover the distance).

What is intake runners?

Intake runners are the actual tubes that channel intake air from a reservoir, known as a “plenum” to the intake ports. The image above shows a typical intake manifold, on which the runners connect to the plenum individually, as opposed to branching off from a single exit point as was usual on older manifolds.

What happens when you increase length of intake runner?

The length of the intake runners have certain affects on the engine operation. For example, longer intake runners are used to improve the bottom end torque (torque at low RPMs) while shorter intake runners will improve top end power (horsepower at high RPMs).

What are the benefits of using variable intake runners?

A longer intake runner setup is designed to provide greater power at the bottom end of the rev range. If you have shorter runners, you’ll see greater horsepower numbers when the engine is up in the rev range. The best of both worlds happens when you have a variable intake manifold.

Is longer or shorter intake better?

Longer intake runners are usually associated with better top end performance at higher rpms. Those longer runners as shown may deliver benefits from being able to perhaps take in more and cooler air than if closer to the engine as opposed to better flow.

Do longer intake runners make more torque?

So we all know long intake pipe means better low end torque-hp & short intake pipe means better torque-hp at high RPM’s. 1) During the suction stroke of an cylinder the first place to generate vacuum is the runner because the air filled in the runner gets sucked inside the cylinder.

How is intake runner volume measured?

Intake runner volume is a popular way to compare cylinder heads. It tells you the size of the passage leading to the intake valve. It is expressed in cubic centimeters (cc)….How does it affect performance?

How do I calculate my running length?

. The current design correlates with this equation and performs well.