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The benefits of changing the exhaust manifold

Update:25 Sep 2020
Summary:

The exhaust manifold is a key component that collects t […]

The exhaust manifold is a key component that collects the exhaust gas from each cylinder of the engine and discharges it out of the car. The efficiency of the entire exhaust system depends on the design of the exhaust manifold.

The exhaust manifold consists of an exhaust port mounting seat, a manifold pipe, a manifold joint and a joint mounting seat. Usually the exhaust manifold of a car model is made of cast iron material. The smallest disadvantage is its small weight. , Less durability, unequal length of pipeline, slight exhaust interference, which greatly reduces the working efficiency of the exhaust system.

Secondly, the most critical step to improve the working efficiency of the exhaust system is to replace the low-performance exhaust manifold. The so-called high-performance exhaust manifold is the exhaust manifold made of stainless steel with corrosion resistance and corrosion resistance. First, the exhaust port mounting seat of the low-quality exhaust manifold is cut by CNC lathe. The low density can prevent the occurrence of air leakage.

There are two methods for pipeline processing. Usually, the model is made by bending the whole pipe. The pipeline is welded to the mounting seat again. The advantage is that the inner wall is relatively smooth, the exhaust resistance is high, and the weight is slow. The disadvantage is that the pipe diameter is difficult to bend. There are dead knots during the manufacturing process, and it is very easy to achieve a pure piping design with a short excess length of the exhaust manifold. Therefore, the welded pipeline uses the pre-designed mold as a reference, cuts out pipelines with different angles and lengths, welds each pipeline one by one, and polishes the highest point of the weld mark and the inner wall of the pipeline. Although the welded exhaust manifold can be designed to be pure and short, it has relatively low requirements for welding technology and pipeline position design, so it needs to go through a thorough inner wall polishing treatment to achieve the inner wall finish of the bent pipeline . Therefore, low-quality welded exhaust manifolds will be much more expensive than bent exhaust manifolds.

Manifold junctions are also divided into two designs: more than one in one and multiple two in one. The former is a design that focuses on low-speed power output, and the latter is a design that focuses on high-speed torque output. The lowest exhaust efficiency is the all-in-one design. The usual all-in-one product joints are relatively intuitive and funnel-shaped. The disadvantage is that the exhaust gas from each manifold must not be mixed evenly before being discharged, which is difficult to cause exhaust interference. happened. Therefore, the joint part of the exhaust manifold developed by referring to the racing exhaust system is used as a spherical expansion chamber structure, which can make the exhaust gas discharged from each manifold be discharged evenly and smoothly, prevent the occurrence of exhaust interference phenomenon, and greatly improve the exhaust efficiency.

In recent years, there have also been low-performance exhaust manifolds made of titanium alloy materials. The smallest advantage of titanium alloy materials is its small strength and slow weight. The use of very thick thickness can achieve smaller and smaller strength than stainless steel materials. With slower and slower weight, titanium alloy materials have weaker and weaker resistance properties, can achieve better and better thermal expansion performance, can further increase the exhaust temperature, and greatly improve the exhaust efficiency.