Without a
wastegate, the amount of boost that a turbocharger creates varies with
the pressure of the engine's exhaust. This happens because exhaust pressure
varies with relation to the engine's speed (measured in RPM's). This implies
that as an engine reaches higher RPM's, increasing amounts of boost will
be created by the turbocharger. The problem with this is that an engine
can only accomodate a given amount of boost.
Most stock engines are only meant to take about 10 PSI if not less. In
order to regulate the amount of boost that comes into the engine, a wastegate
acts as a door only allowing a given amount of exhaust to hit the turbocharger's
exhaust turbine. Once the engine starts producing more exhaust pressure
then the wastegate system will allow, a flap is opened to redirect excess
exhaust away from the turbine blades. In turn, this is where a wastegate
gets it's name. It's a gate to carry away waste .
There
are two types of wastegates.
The first one is an internal wastegate.
An internal wastegate is a component on the turbo unit itself. The gate
is opened via an actuator which is a diaphram type system. Excess exhaust
is then fed directly into the exhaust system.
We also have what is called an external wastegate
Unlike an internal wastegate, it is seperate from the turbo unit and does
not require an actuator. Excess exhaust can either be fed into the exhaust
system or it can be vented straight out and into the atmosphere. High
performance set-ups typically follow the latter alternative.
Most stock systems come with an internal wastegate as this set-up is better
suited for low boost applications. However most aftermarket systems perform
better with an seperate external wastegate assembly making it an ideal
choice for those generating boost in the range of 20-30 PSI.
SPECIFICATIONS:
46MM PISTON
AL606I TOP
304 STAINLESS STEEL BASE
ADJUSTABLE PRESSURE
14.5 PSI SPRING PRE-SET
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