Twin Charger Turbos


A twin charger turbo system is the combination of a supercharger and a turbocharger. This arrangement is actually complementary, so that supercharger and turbocharger can balance each other. Both the supercharger and holset hx40 have some disadvantage. This arrangement is to compensate each other’s cons.

Parallel and series are the two types of system with twin chargers.


In parallel arrangements, one basically needs to use a diverter valve which permits both the compressors to work for the engine. In case there is no valve and both the compressors are routed straight to intake, then the supercharger will certainly try to choose the less resistant path rather than pressurizing the intake and in most cases it will start to blow in a backward direction. This is why a diverter or bypass valve needs to be used in such a way that the turbocharger emits the air till it achieves the pressure to intake the manifold. Electronic controls, which are usually costly or complex, are needed for easy delivery of the power.


It can be described as one of the common arrangement in twin charger. It is set up in such a way so that any one of the compressors, either the supercharger or turbocharger’s output device supply the inlet of another. The supercharger is connected to the turbocharger. Once the supercharger gets connected it gives pressure to the immediate manifold. But this can be done by eliminating the turbo lag. If not, then the holset hx50 cannot reach to its working speed. Once it reaches the speed, start to pressurize the air to its inlet. This actually enhances the efficiency of the induction. The pressure can also get bypassed.

Twin turbochargers are mostly used in the vehicles that go for many fashionable performances. They are mostly used in luxury cars. It actually offers a large amount of power and great acceleration.

Parallel twin turbocharger

The parallel twin turbocharger is mostly found in v designed engine which use the turbo for each reservoir of the cylinder. It actually reduces the turbo lag. The size of the parallel twin turbocharger is also smaller than that is found in the engine with a single turbo. This is due to the less exhaust gas.

Twin sequential turbocharger

A twin charger is meant for the combination of a large holset hx60 with the small turbocharger. To prevent turbo lag problems, the smaller turbocharger keeps quick response at the speed of lower engine and also helps to reel the larger turbocharger by increasing flow of the exhaust gas. But both the small and the big turbocharger needs to match each other.

There are many disadvantages of the twin turbocharger. The biggest negative of the twin turbocharger is that it has high RPM power. On the other hand, sequential twin turbos are very complex due to their design.

One thing needs to be remembered. Don’t get confused with the twin turbo charger and twin charging. Twin chargers are made of a combination of turbochargers and superchargers but that is not what is implied by twin charging.

Turbocharger Wastegate – Internal and External


The internal and external wastegate is boosting controlling device that operates by restricting the exhaust gases that pass through the turbocharger, thereby controlling the pressure generated by the device itself. A wastegate includes an outlet and inlet port, a pressure actuator and a valve. Read more from Turbocharger Review.

How a wastegate functions?

The pressure actuator is controlled by means of the boost pressure and figures out if the wastegate is closed or open. When it is at rest, a wastegate remains closed, with the increase of the boost pressure, the actuator is impacted with the force. At the point, when the threshold value of the spring is exceeded by the boost pressure, the actuator starts to open the wastegate gradually, bypassing a percentage of the exhaust gases, this way keeping up the boost pressure to a fixed level. Essentially, a holset hx30 prevents the unrestricted increase of boost pressure that may eventually blow up the engine.

When to use an external wastegate?

Most of the manufactured turbo systems include an interior wastegate in order to manage the stock support levels. The most well-known purpose of adding an external wastegate is better boost control and hence the force yields of your motor. Moreover, turbochargers that are quite huge in size are not fitted with internal wastegates.

For any motor delivering over 400hp, it would be best to use an external wastegate as using high boost only via the internal wastegate provided by the manufacturer can overwhelm the actuator spring, thereby lowering the boost level. And hence, external wastegates include bigger outlet and inlet ports, high performing pressure springs and larger actuator diaphragms than can successfully control higher boost pressure. There are

  • Manual booster control
  • Electronic booster control


In case of holset hx35, the flapper might start getting sticky and as a result it might not give you the same performance it should give. This is why it is your duty to check whether the flappers are working rightly. If the flapper starts getting stuck it will cause a lag in the building boost.

You might also need to inspect the vacuum lines as well and check whether you need to replace it or not.

You can also check the datalog file in order to make sure you are aware of the boost control stability and this way you will be able to maintain your wastegate in such a way that your turbo engine will give you a better and long lusting performance.

Things you must consider

Internal wastegates are perfect for maximum of the motorists but always remember that you can use this only as a performance enhancer of the turbochargers.

In case you are really thinking to modify the engine and get a higher performance, it is better that you use a proper wastegate so that the turbocharger is not damaged.

In case of aftermarket turbo, you might need to use the external wastgate so that you can control the extra power and boost with ease. So, be careful, research a bit and get the best possible performance from your engine.