BENDIX TCH-001-026 User Manual

Technical Bulletin

Bulletin No.: PRO-01-26 Effective Date: 12/15/86 Cancels: PRO-01-26 Dated 11/28/83 Page: 1 of 5

Subject: Compressor Turbocharging

Traditionally, Bendix has permitted compressor turbocharging with certain exceptions
and limitations. Generally, original equipment installations of turbocharged compressors
have prior Bendix approval. Factors affecting approval of a specific installation include
the engine, turbocharger and compressor combination.

Compressor turbocharging becomes a concern in the Aftermarket when one of the
components of the originally approved combination is changed or when turbocharging is
considered for a previously unturbocharged compressor. For example, when a
turbocharged TuFlo 501 is changed over to a TuFlo 700.

The following can be used as a guide to determine if it is acceptable to turbocharge a
Bendix compressor in a specific application.

TURBOCHARGING

Definition
A turbocharger is a turbine driven compressor unit where the turbine is driven by the hot

gases of the engine exhaust. Its function is to increase engine efficiency and power
output by compressing air drawn through the vehicle air cleaner and directing the
compressed air into the engine intake manifold. The air pressure generated can
typically fluctuate between 30 psi and a slight vacuum, depending upon engine load.
Turbocharger outlet pressure increases as engine load increases.

A vehicle brake system compressor is turbocharged when its inlet is connected to the
outlet or PRESSURE side of the turbocharger. For example; a compressor would be
turbocharged if its inlet is connected to the intake manifold of a turbocharged engine.

Advantages of Compressor Turbocharging

1. Convenience of installation – Often the location of the compressor relative to the
engine manifold allows a short connecting line to be used.

2. Enhanced oil control – The elimination of inlet vacuum reduces the possibility of
excessive oil passing.

3. Increased compressor capacity – Under some circumstances compressor capacity is
increased. The following chart illustrates some vehicle and road conditions as related
to the turbocharger output.

Disadvantages of Compressor Turbocharging
The primary disadvantage is reduced compressor durability when Bendix turbocharging

guidelines are not followed.

TURBOCHARGING GUIDELINES

General

1. Particular attention must be given to the specified minimum inlet, discharge and
coolant line sizes along with coolant flow requirements for the compressor model
being turbocharged. Turbocharging of FULLY air cooled compressors is not
recommended.