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Benefits of retrofitting the exhaust manifold

Update:10 Jun 2020

The exhaust manifold is an important component that col […]

The exhaust manifold is an important component that collects the exhaust gas discharged from each cylinder of the engine and discharges it outside the vehicle. The working efficiency of the entire exhaust system depends on the design of the exhaust manifold.

The exhaust manifold is composed of an exhaust port mounting seat, a manifold pipe, a manifold joint, and a joint seat. The exhaust manifold of a general model is made of cast iron. The biggest disadvantage is its heavy weight and poor durability. , The unequal length of pipeline exhaust interference phenomenon is serious, greatly reducing the efficiency of the exhaust system.

Secondly, the most important step to improve the efficiency of the exhaust system is to replace the high-performance exhaust manifold. The so-called high-performance exhaust manifold is an exhaust manifold made of stainless steel with good heat resistance and corrosion resistance. The exhaust port mounting seat of the quality exhaust manifold is cut by CNC numerical control lathe, and the precision is extremely high to prevent the occurrence of air leakage.

There are two methods in the pipeline processing. The general vehicle model is made by bending the whole tube, and then the pipeline is welded to the mounting seat. The advantage is that the inner wall is smoother, the exhaust resistance is low, the weight is light, and the disadvantage is that the pipe diameter is easy Dead knots are produced during the bending process, and it is difficult to achieve the design of pure equal length exhaust manifolds with multiple lengths and bends. Welded pipelines are based on pre-designed molds, cut out pipelines with different angles and different lengths, weld each pipeline one by one, and highly polish the weld marks and the inner wall of the pipeline. Although the welded exhaust manifold can be designed with pure and equal length, it has high requirements on welding technology and pipe position design, and it needs a comprehensive inner wall polishing treatment to achieve the inner wall light junction of the bent pipe. Therefore, high-quality welded pipe exhaust manifolds are much more expensive than bent exhaust manifolds.

Manifold junction is divided into two-in-one and two-in-one designs. The former is a design that focuses on high-speed power output, and the latter is a design that focuses on low-speed torque output. The highest exhaust efficiency is the all-in-one design. The joint of the general all-in-one product is a simple funnel shape. The disadvantage is that the exhaust gas discharged from each manifold cannot be uniformly mixed and discharged, which is likely to cause exhaust interference. The joint part of the exhaust manifold developed from the exhaust system of the racing car is a spherical expansion chamber structure, which can make the exhaust gas discharged from each manifold uniformly and stably discharged, prevent the occurrence of exhaust interference, and greatly improve the exhaust efficiency.

In recent years, there are also high-performance exhaust manifolds made of titanium alloy materials. The biggest advantage of titanium alloy materials is their high strength and light weight. With a thin thickness, they can achieve greater strength and lighter weight than stainless steel materials. Moreover, the titanium alloy material has stronger heat resistance, can achieve better thermal expansion performance, can further increase the exhaust temperature, and can greatly improve the exhaust efficiency.

The intake manifold should not be modified as much as possible, which is too damaging to the car.