TD5 turbo charger

RAVE said:

The Td5 engine utilises a Garrett GT20 turbocharger with an electronically controlled wastegate modulator to improve
engine performance. The turbocharger uses the engine's exhaust gas to spin a turbine at very high speed. This
causes inlet air on the other side of the turbine to be drawn in through the turbocharger intake for compression. The
inlet air is carried round by the vanes of the compressor and then thrown out under centrifugal force from the
turbocharger's outlet duct. This compression of air enables a greater quantity of air to be delivered to the inlet manifold
via an intercooler. Combustion is improved through better volumetric efficiency. The use of a turbocharger improves
fuel consumption and increases engine torque and power. Exhaust noise is also reduced due to the smoothing out of
exhaust pulsations.
The rear cast iron body of the turbocharger housing connects to a port on the exhaust manifold at the LH side of the
cylinder head by three studs and nuts. The interface between the exhaust manifold and the turbocharger housing is
separated by a metal gasket. The exhaust outlet of the turbocharger is located at the bottom of the turbocharger cast
iron housing; it is connected to the exhaust system front downpipe and is attached by three studs and nuts. The
interface between the turbocharger housing and the exhaust front pipe is separated by a metal gasket.
The front casing of the turbocharger is constructed from aluminium alloy and is connected to the air inlet duct by a
metal band clip. The compressed air outlet is connected to the intercooler by a metal pipe which has rubber hose
extensions at each end attached by metal band clips.The turbocharger is exposed to extremely high operating temperatures (up to 1,000 °C (1832 °F)) because of the hot
exhaust gases and the high speed revolution of the turbine (up to 150,000 rev/min). In order to resist wear of the
turbine bearings a flow of lubrication oil is supplied from the engine lubrication system to keep the bearings cool. Oil
is supplied from a tapping at the front of the full-flow filter adaptor housing via a metal pipe with banjo connections.
Oil is returned to the sump via a metal pipe which connects to the cylinder block at a port below the turbocharger
assembly.
A heatshield is attached to the left hand side of the engine to protect adjacent components from the heat generated
at the turbocharger. The heatshield is attached to the engine by two bolts an additional bolt attaches the heatshield
to the turbocharger casting.
The engine control module controls the amount of boost pressure the engine receives by way of the turbocharger.
When full boost is reached a control signal is sent to the wastegate modulator, and a vacuum is applied to the
wastegate valve. The wastegate valve opens, bypassing some of the exhaust gas away from the turbine to be output
to the exhaust system.
The engine should be allowed to idle for 15 seconds following engine start up and before the engine is switched off
to protect the turbocharger by maintaining oil supply to the turbine bearings.

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rbc872 said:

Hi

1. is the TD5 2002 Model Year turbo charger the Variable vane type ?

Re my intermittent power gain/loss I'm wondering if it is this type and have the vane's been sticking ?

2. Also does this vehicles ECU know what gear the car is in ? (manual transmission).

The disco pulls harder and faster than it's ever done in the 5.5 years of ownership but still looses it now and then as if the turbos been taken off, it can't sense load or it's starved of fuel ????
Cheers Nick.

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fanatic said:

yawn injector seals, oil in the loom, seized waste gate- isn't there a sticky for this yet.

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rbc872 said:

Many thanks for all the info,very much appreciated. I'm very much thinking the fuel pump is the problem. I've been warned about the cheap one's.
where is the best place to get a genuine one ?
I can't believe i've lived with this problem for 5.5 years !!!!! It's like owning a new car when it's on song now

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trooper32 said:

Modulator pipes perish, they are the same as the windscreen washer pipe but run in the engine heat. Check the one from the Modulator to the intercooler feed pipe. In my experience it can split, you can't see it and it makes acceleration intermittent. If it goes completely it's like driving with Kangaroo juice.

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