The intake manifold may have a design that allows you to work in a certain range of engine speeds. A two-plane design is preferred for operation at medium and low revs (approximately two and a half to four and a half thousand revolutions per minute). However, due to the fact that fuel comes from only one part of the carburetor into each cylinder, at low speeds, as a rule, low power develops.
The intake manifold with an open chamber usually gives a low torque. At low speeds, this is usually associated with problems in the carburetor itself (for example, the fuel supply is poor and it is sprayed with a low air flow). At the same time, the intake system works well at medium and high speeds.
The two-plane design provides a rigid transmission of pulses to the carburetor diffuser. This contributes to an increase in air velocity and, consequently, increases the accuracy of the dosage and improves atomization.
Considering the inlet manifold with one plane, it should be noted that due to the larger volume in the chamber, the majority of the pulse intensity decreases. The fact that each impulse reaches completely the entire carburetor also affects the decrease in intensity. These differences affect the reaction of the motor, speed, power, gas pedal, torque.
Before installing the intake manifold, it is necessary to determine the number of revolutions at which the motor must reach the highest power. Each space, contour, each turn in the design affects the operation of the carburetor, as well as the properties of the flow of the mixture of fuel and air.
The intake manifold, which has a double-plane design, is endowed with a significantly smaller volume of the channel (line) compared to the single-plane model. This volume between the valve and the carburetor is very important when moving the mixture flow towards the cylinder. Due to the pulse generated in the intake tract during valve opening and piston movement downward in the cylinder, the flow movement is uneven. With a hard pulse supply at some moment, the acceleration of the movement of gases through the diffuser occurs.
When the throttles are closed , due to the influence of a pulse in the inlet channel, a sharp increase in pressure occurs in the line in the idle system and the transition system. This causes a positive reaction to the idle fuel flow. This direct relationship between the carburetor and the opening of the valve increases the power at low revs and the partially open throttle.
A single-cavity collector operates on a slightly different principle. When the process of moving the pulse in the incoming stream is carried out towards the carburetor, most of the pulse intensity is reduced. A subsequent decrease will occur when the impulse reaches the carburetor. In this case, it (impulse) will transfer its energy to all four chambers, and not to two, as occurs in the construction of a collector with a double plane. At low engine speeds due to this difference, the pulse intensity is significantly reduced. In addition, spraying and fuel flow are affected. Thus, the sensitivity of the engine to the movement of the throttle valve is reduced, as well as a decrease in power at low speeds.
With an increase in speed, the problems characteristic of a single-cavity collector are reduced. At a certain indicator of engine revolutions, the gas velocity reaches a level at which stabilization of the dosage of the atomization and the flow of fuel by means of an amplified signal occurs. At high fuel flow rates, a single-plane collector with an open chamber outperforms the two-plane design with a separate chamber.