It
is quite common for people to blank off the Exhaust Gas Recirculation
system on diesel cars. The benefits of blanking the EGR system are
to prevent dirty
exhaust gasses entering the inlet manifold, and to reduce air inlet
temperatures.
Most
people tend to just fit a blanking plate between the exhaust manifold
and the EGR recirc pipe. This will ensure the inlet system stays
clean, and the engine will get plenty of cool air, which of course
is good for performance.
However,
this blanking method can be improved upon, as the actual EGR valve
assembly causes quite a restriction to inlet airflow which will
have an adverse effect on performance, as you can see in the pictures
below. The picture on the left shows the early EGR valve assembly,
as used on 1998 - 2001 models. The middle picture shows the EGR
valve assemby used on 2001 - 2004 models, which has an additional
butterfly valve, causing an even greater restriction!
Our
solution to this issue was to produce our own EGR bypass kit which
has a straight through design, as can be seen on the right, above.
This results in improved engine torque, giving a smoother, more
flexible engine.
This
kit is a direct replacement for the original EGR valve, and bolts
neatly between the intercooler outlet and inlet manifold.
The
egr valve body replacement is made from high quality, laser cut
aluminium, with a rolled edge for secure fixing of the intercooler
hose.
The
exhaust manifold blanking plate is made from robust 6mm
thick mild steel, so will not distort under high exhaust
temperatures. Both items are made from the same materials
as original parts, so will give a perfect fit under all
engine conditions.

Early Type
|

Later Type |
The
illustrations above show both inlet, and exhaust manifolds on an
early and late type Td5 engine, with the EGR components to be removed,
highlighted in yellow.
Later type Td5 engines had a slightly different arrangement to early
engines, often fitted with an additional water/air heat exchanger
(not shown) on the EGR recirc pipe, and a twin diaphragm EGR valve
assembly, with integral throttle butterfly.