HKS GT Extension Kit Evo 10
[14019-AM002]

HKS GT Extension Kit CZ4A Lancer Evolution X

A key item in controlling exhaust gas pressure is born using knowhow gained from the HKS SZ200S (CZ4A)

Designed to extract maximum performance from the stock turbo.

A flexible joint used for the extension elbow and front pipe in order to increase durability.

The stock turbo is small, giving good low speed response but at higher rpm, exhaust gas flow resistance increases and hinders performance and feel.

An uncompromising design improves boost spooling at lower speeds whilst delivering more power and torque at high rpm.

The extension elbow piece is CAD designed to maximise exhaust efficiency in the limited space available due to the size of the stock turbo outlet. The complicated design was realised by using lost wax casting methods which carries other benefits such as the absence of welding, where cracking can occur due to high temperatures. Lost wax casting also benefits from a smooth surface finish which further enhances efficiency.

Turbo outlet design separates the exhaust gases from the turbo blades and the swing valve in order to reduce the resistance generated when the two streams interfere with each other.

In order to maintain the kits compliance for road use, the extension elbow and front pipe are attached with a flexible joint so that engine vibration can be absorbed increasing durability. In the event of exhaust collision with the ground or similar, damage to the engine and turbo are minimised.

Extension elbow volume is increased by 25% whilst cross sectional area of the outlet is increased 10%. Exhaust gas back pressure is reduced by approximately 20% with improved power and torque throughout the rev range.

About HKS Extension

The extension pipe combines thee exhaust gas from the turbo and the bypassed gas from the actuator. When the actuator is activated and the gases are forced into one chamber, a secondary pocket of high exhaust gas pressure is created causing boost levels to fall and reduce power. HKS Extension kits have been designed to minimise power loss and extract the most from the turbo.

By separating the main and bypass pipes, exhaust gas flow disruption is minimised. Turbochargers which combine main and bypass gasses within the exhaust housing can still benefit from an extension kit as the kit contains a boss which separates main and bypass gasses in the exhaust housing using a bossed flange. The joining point for the two pipes is placed further down the exhaust where exhaust gas pressure is lower to maximise efficiency. Moreover, the main pipe diameter increases soon after the turbo. The expanded area minimises exhaust gas rotation which can cause exhaust gas pressure increase and reduce power. All these areas reduce exhaust gas pressure build up and provide more power with stable boost levels. Flanges are made from Stainless steel grade which is highly resistant to heat, whilst the pipes are made from SUS304 grade stainless steel for durability, heat resistance and attractive appearance.



The purpose of the extension on swing valve type turbo systems is to smoothly flow exhaust gas from the turbo to the front pipe. This prevents exhaust gas build up reducing load on the turbo to allow the turbo to respond and boost at full capacity. HKS GT Extension kits combine a specially designed extension and front pipe to maximise exhaust gas flow after the turbo. In some applications, the flange between the extension and front pipe is enlarged to allow great gas flow which is only possible through a kit which was specifically designed for this purpose.

HKS GT Extension kits for Lancer Evolution models replace exhaust piping between the stock turbo and catalyser. The extension section has 60mm diameter main pipe with 58mm bypass pipe which is kept independent from the main pipe to reduce exhaust gas pressure build up close to the turbo. The gases will flow through to a 70mm diameter front pipe. This configuration will make power outputs of approximately 300kW (400PS) possible. Boost response is also improved by approximately 15% over the stock exhaust parts.

• HKS GT Extension kit gives a wider range of performance options on your Silvia/180SX/200SX. Whether you are using stock turbo, GT-SS or GT-RS, maximum performance can be extracted from your turbo with the GT Extension kit

• Extension pipe diameters have been increased for both the main and bypass pipes. Boost response is improved by up to 10% and mid/high RPM power and torque is substantially increased over competitors products during tests at HKS Headquarters in Japan.

• A specially designed dual layout is used for the front pipe. This allows for larger pipe cross sectional area and therefore increased exhaust efficiency. Compared with conventional front pipe designs, the dual layout gives an additional 15-20mm of ground clearance for lowered vehicles.



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Whether it is engine, suspension, or drive-train systems, there is no substitute for the performance, quality and reliability of HKS.