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Conversion from sequential to full
time twin turbochargers.
Toyota 2JZ-GTE engine
We modified the standard sequential turbo system (one
turbo at low rpm and two at high rpm) so that both turbochargers operate
at all times.
This was done so they operated as two separate turbochargers
with their own internal wastegates. The original setup had only one
wastegate on the first turbo. What looked like a wastegate on the second
turbo is used to control the initial spin up of the second turbo, and
it operated totally different to a normal wastegate.
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Standard turbine housing off second stage turbocharger.
(A) Points to what looks like a normal internal wastegate, but
the area under the flap valve is not connected to the exhaust
inlet of the housing but has a passage (B) that connects to the
exhaust outlet of the housing.
To turn this housing into a normal operating internal wastgate,
we need to drill the hole (A) through to the inlet side of the
housing, and block the passage (B).
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Block passage and drill wastegate hole.
Wastegate hole has been drilled (A).
The outlet area (B) has been bored out to take a stepped sleeve
(C) we machined from steel.
This sleeve will be pressed into the outlet to block the passage.
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Press sleeve into housing.
(A) The sleeve has been pressed into the housing blocking the
passage.
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The finished housing.
Two holes (A) are drilled at a angle into the wastegate outlet
area. This is required so exhaust gas from the wastegate valve
can exit into the turbine outlet area.
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Manifold Modifications.
The exhaust manifold was cut and welded so there was no connection
between the fount and rear turbochargers.
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Other Turbocharger Modifications.
The turbochargers had their carbon face seals removed and replaced
with dynamic seals. The seal plate and oil shield from a Mitsubishi
TD06 turbocharger were used.
This was done for two reasons,
1. We could not get new carbon seals.
2. The dynamic seals will have less drag, and should help turbocharger
response..
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