HKS Super Header, which offered ideal exhaust efficiency, has now returned as a further improved type II model. This new version takes the basic concepts of efficient exhaust construction one step further. New billet flanges are used to get high precision build quality which is only achievable through billet construction.

HKS conducted tests on many different engine types and found that 4-2-1 construction ideal for street use. 4-1 designs work well in racing applications as the short pipe before the join allows maximum power to be extracted at high revs. For street use, a longer pipe is required before joining into one. A 4-2-1 design allows this to be achieved and thus gives more torque at lower revs which is more suited to street driving. By making the joins of the individual ports as straight as possible, exhaust gas is accelerated and thus pulls exhaust gas from the engine improving efficiency..

In order to achieve maximum efficiency, the flange is shaped in the port to make the change in shape from oval to round as smooth as possible. This is enhanced by careful tig welding on the inside of the joints which aims to make the joint smoother and achieve the best results.

HKS Racing Header is the culmination of many years of development into exhaust systems. An exhaust manifold has been created to improve high speed power whilst maintain mid range torque. In order to achieve this, each application is designed and treated individually to achieve the maximum possible from each engine.

The merits of naturally aspirated engines lie in its sharp high rpm response. However, in street use, the overall balance across all rpm ranges is just as important. In order to achieve optimum balance between high rpm response and mid range torque, HKS have introduced a separating plate where the ports join. This separating plate fine tunes the length of pipe from each port to the point where they join with the other pipes. This adjustment allows the balance between mid range and high rpm characteristics and creates a 4-2-1 structure which creates strong vacuums to pull exhaust gas out from the engine.

In order to achieve maximum efficiency, the flange is shaped in the port to make the change in shape from oval to round as smooth as possible. This is enhanced by careful tig welding on the inside of the joints which aims to make the joint smoother and achieve the best results.

When creating a vacuum or area with low pressure, areas with high pressure are created also. HKS have overcome this issue by designing bypass pipes and reducing the pressure through the pipes and control the rhythm of high and low pressure through each port. The number of bypass pipes and their routing is different for every engine type allowing the benefits of low pressure to be harnessed whilst eliminating the demerits of high pressure. Power can drop off at certain rev ranges in NA powered