On the exhaust side, a Wastegates provides us a means to control the
boost pressure of the engine. Some commercial diesel applications do
not use a Wastegates at all. This type of system is called a
free-floating turbocharger.
However,
the vast majority of gasoline performance applications require a
Wastegates. There are two (2) configurations of Wastegates, internal or external.
Both internal and external Wastegates provide a means to bypass exhaust
flow from the turbine wheel. Bypassing this energy (e.g. exhaust flow)
reduces the power driving the turbine wheel to match the power required
for a given boost level. Similar to the BOV, the Wastegates uses boost
pressure and spring force to regulate the flow bypassing the turbine.
Internal Wastegates are built into the turbine housing
and consist of a “flapper” valve, crank arm, rod end, and pneumatic
actuator. It is important to connect this actuator only to boost
pressure; i.e. it is not designed to handle vacuum and as such should
not be referenced to an intake manifold.
External Wastegates are added to the exhaust plumbing
on the exhaust manifold or header. The advantage of external Wastegates
is that the bypassed flow can be reintroduced into the exhaust stream
further downstream of the turbine. This tends to
improve the
turbine’s performance. On racing applications, this Wastegated exhaust
flow can be vented directly to atmosphere.
boost pressure of the engine. Some commercial diesel applications do
not use a Wastegates at all. This type of system is called a
free-floating turbocharger.
However,
the vast majority of gasoline performance applications require a
Wastegates. There are two (2) configurations of Wastegates, internal or external.
Both internal and external Wastegates provide a means to bypass exhaust
flow from the turbine wheel. Bypassing this energy (e.g. exhaust flow)
reduces the power driving the turbine wheel to match the power required
for a given boost level. Similar to the BOV, the Wastegates uses boost
pressure and spring force to regulate the flow bypassing the turbine.
Internal Wastegates are built into the turbine housing
and consist of a “flapper” valve, crank arm, rod end, and pneumatic
actuator. It is important to connect this actuator only to boost
pressure; i.e. it is not designed to handle vacuum and as such should
not be referenced to an intake manifold.
External Wastegates are added to the exhaust plumbing
on the exhaust manifold or header. The advantage of external Wastegates
is that the bypassed flow can be reintroduced into the exhaust stream
further downstream of the turbine. This tends to
improve the
turbine’s performance. On racing applications, this Wastegated exhaust
flow can be vented directly to atmosphere.