BorgWarner 76mm S400SX3 105/87 Turbo 

Part Number 178781 – AirWerks S400SX3 Performance Turbocharger

• 76.00mm / 2.99” Compressor Inducer Dia.
• 4.13” Compressor Wheel O.D.
• 81.74mm / 3.220” Turbine Exducer Dia.
• 87.37mm / 3.44” Turbine Wheel O.D.
• 550-1100 HP Turbo

Airwerks turbochargers are designed for the competitive motorsports market as well as drivers retrofitting a naturally aspirated engine or looking for a little more performance from a factory turbocharged car. Engineered specifically for drag racing, pulling and road racing, AirWerks turbochargers have earned a reputation as robust, brute-force induction systems. Looking for a no-frills replacement? Want to upgrade your turbocharger? Working with limited space? BorgWarner’s AirWerks turbochargers are the perfect go-to product for many applications. With a twin hydrodynamic journal bearing design, AirWerks turbochargers feature an effective high-pressure ratio compressor stage, extended-tip technology and a high-efficiency turbine stage. The configuration provides ultra-fast response and more than 70 PSI of boost.

Extended Tip Technology

Select BorgWarner turbochargers employ BorgWarner ”S” generation compressor wheels that incorporate extended tip technology. This compressor wheel design feature promotes greater airflow using a low inertia wheel that performs like a wheel of greater size and mass. Extended tip technology enables you to have faster spool-up at lower engine speeds while providing the boost for the powerful top-end performance that most turbocharger enthusiasts have come to desire. Turbochargers have to meet different requirements with regard to map height, map width, efficiency characteristics, moment of inertia of the rotor and conditions of use. New compressor and turbine types are continually being developed for various engine applications with compressor wheels having an increased influence on the engine’s operational characteristics. These wheels are designed using computer programs that develop a three-dimensional calculation of the airflow and pressure.

Twin Scroll (Twin Flow) Turbocharger Generates Higher Boost Pressure at Low Revs

Twin-scroll housings are becoming very popular for performance use, and for good reason. By dividing the manifold and turbine housing into two flow paths, the engine firing order can be made to ”alternate” the flow all the way to the turbine wheel inlet. Twin scroll technology produces results similar to twin-turbo applications, but in a smaller package with lower weight and cost. In turbochargers of this type, the channels between the exhaust manifold and turbocharger of the first and fourth as well as the second and third cylinders are separated from each other. The exhaust gas streams are directed into so-called scrolls (spirals) and then reunited again directly at the turbine wheel. Separating the streams in this way offers improved performance. The engine blow-down pulse is generated when the exhaust valve opens. During the blow-down, the engine power cylinder is still at very high pressure as a residual of combustion and the power stroke. This initial ”pop” of energy travels at very high speed down the manifold runner, through the volute, and impacts the wheel. For this reason, the stream is very much a ”pulsed flow” and the divided nature of the system simply amplifies and arranges those pulses. The engine firing order creates a “one-two” (alternating) punch on the wheel, keeping the pulses evenly spaced and in rapid succession. As the engine speed increases, this becomes a blur and the alternating nature loses its value. Hence, twin-scroll housings only benefit the low and medium speed operation of an engine. Within this range, it is a very effective way to improve turbine effectiveness. The wheel loves the high velocity evenly-spaced pulses of gas, and as long as they are ”slow” enough in succession and duration, the wheel can make good reaction usage of the energy. What results is an improvement in ”effective” efficiency, and at lower engine speeds more turbine power can be generated. The obvious result is quicker spool and better low-end boost response. As mentioned, the top-end operation is not improved, everything else being equal. Put into practice, a single-scroll housing of sufficiently large size is the recipe for a user that is seeking only top-end power optimization. That said, a very potent combination is a twin-scroll divided system that works to retain good low speed boost response, while sizing it large (aerodynamically) for the best top-end power. It’s the best of both worlds, in many cases. With this type of charging, spontaneous boost pressure can be built up 1000 RPMs earlier, which significantly improves response in the low rev band. The engineers at BorgWarner have also mastered the problem of high exhaust gas temperature in gasoline engine turbocharging despite the genuine challenge presented by such a compact turbine casing with two scrolls. One approach employed by engineers was to develop a new downsizing method of casting turbine housings to improve their temperature resistance and guarantee the quality needed. The benefits of the twin scroll turbocharging technology and other market-leading technologies by BorgWarner Turbo Systems offer passenger vehicles, dynamic performance, low fuel consumption and lower C02 emissions.