How a Compound Turbocharger System works - Aurora Plus - 4000, 03-07 Dodge 5.9L, Compound system, uses factory HY35 to HE351 turbocharger

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Aurora compound turbocharger
Compound Turbo Charging (One turbo compressor wheel feeding the other) Compound turbocharging is not the same as twin turbo charging. A compound turbo utilizes different sized turbos feeding off one another to do the job of one turbo.

Air enters the low-pressure turbo (the larger of the two) and is fed into the high-pressure turbo (the smaller of the two), then directed into the engine or intercooler. This is why this type of turbo charger arrangement is referred to as Compound Turbo System. Compound Turbo Chargers work in series.

Multiple turbo chargers are also commonly referred to as twin turbo chargers; twin turbos are just that "twins". The two identical sized turbo chargers are the same in nature or identical is size and work in parallel. Typically each turbo is used to do one half of the work and is not in a compound configuration. The air that is compressed into the engine is not fed from one turbo compressor to the other; the air that goes to the engine is simply split between the two of them.

The compound turbo charger set up offers all of the attributes of a small and large turbo charger with out the negative effect of ether one of them. There is a small turbo charger and a large turbo charger plumbed in series to one another. The small turbo charger is referred to as the high-pressure turbo charger and the large turbo charger is referred to as the low-pressure turbo charger or the atmosphere turbo charger. In a "Compound" turbo charger set up the small turbo is responsible for generating quick turbo response and rapid air flow right off idle. As the engine is accelerated from idle the small turbo begins to produce boost immediately wile the large turbo slowly starts to produce a positive pressure to the small turbo. The large turbo when matched properly should be supplying boost pressure to feed the small turbo shortly after the small turbo is making boost in to the engine or intercooler. If the large turbo charger is not matched properly it will cause the small turbo charger to stall and the low-end performance will suffer.

Turbo charger balance is a fine art; the exact balance must be achieved to produce the desirable results or the turbo charger design will not perform efficiently. In order to design a compound turbo charger package, the exact pressure ratios must be matched between all of the stages of the turbo chargers. This balance is only achieved by sizing the turbine housings, turbine wheels, compressor wheels, diameters and an array of other calculations.

The ATS Aurora(tm) Compound Turbo Charger System provides the utopia in the turbo charger world. Quick spool up off idle, extreme midrange torque and incredible top end performance is what you can expect from the ATS Aurora(tm) Compound Turbo Charger System. The Aurora 2000 and 5000 turbo chargers are placed in specifically designed turbine and compressor housings to provide a positive boost ratio through out the entire engine operation range. A positive pressure ratio means there is more boost pressure feeding the intake side of the engine than there is exhaust pressure exiting the engine. Maintaining a positive boost pressure is a major step in maximum performance and economy. This means the engine is always operating near maximum efficiency, burning all of the diesel fuel during the combustion process and reducing exhaust temperature. 100 percent of the exhaust energy is passed through the turbine wheel maximizing the available wasted exhaust energy.

The secret to power and economy is airflow; increased airflow is the lack of resistance along with a positive intake charge. The ATS Aurora(tm) Compound Turbo Charger System is designed for power levels up to 600-rear wheel HP; exhaust temperatures remain low and drivability is responsive and enjoyable.

During the design and layout of the turbo system we were sensitive to the needs of the every day requirements such as heavy haulers and RV-ers. Unlike many other turbo systems currently available the ATS engineers elected a more reliable method of manufacturing the complex components that create this system. All of the high stress and high temperature exhaust sections of the system are specially designed and made from high temperature iron with an internal exhaust diverter valve mechanism to maximize reliability and performance. There are no welded joints or "pipes" used in the construction of the turbos or the mounting of the system. All of the high stress/heat areas are designed to be self-sealing requiring no problematic gaskets that are common to fatigue and blow out after severe heat cycles. The low-pressure turbo has been placed in the exact position of the factory turbo charger requiring no exhaust modifications to be performed during the retrofit and allowing adequate room for the over sized intake system.

The ATS Compound Turbo Kit comes completely assembled with all of the necessary mounting hardware, a new ATS Exhaust Manifold, Turbos, and Intake for an easy bolt on installation.