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NAVIGATION
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Phase 1 and Phase 2 pre '99 Turbo Diesel 306 came with two different
types of fuel pump, the Lucas Pump or Bosch Pump, and two different
types of Turbo, the KKK turbo and the Garret T2 Turbo. With a couple of
simple modifications to these components, the power of a standard Dturbo
could be raised from 92bhp to around 115bhp. Many companies will charge
stupid amounts of money for these modifications, when it is very simple
to do yourself.
The guide
given here is designed mainly to help those with a Lucas Pump and a
Garret turbo on their Phase 1 306. There are however various references
to the Bosch Fuel pump. |
| Boost
compensator Fuelling |
| The procedure to increase the boost compensator fuelling is
similar on both the Lucas and Bosch pumps. The boost compensator unit
can be recognised by a brass coloured diaphragm assembly connected to
the intercooler by a vacuum hose. |
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The Red Arrow points at the Vacuum hose, which
you can see connecting to the Intercooler. This then leads down to where
the Blue Arrow is pointing which is
the Brass coloured diaphragm Assembly.
A closer
look at this assembly shows that there is a cap covering the Lock Nut
and the Adjustment Screw. This is a warranty seal and needs to be
broken off in order to access the Screw. |
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Unscrew the external 14mm lock nut and turn the
adjuster anti-clockwise. The adjustment range is about 1.5 to 2.5 turns
(adjustment can be made in half turns). The setting is not so critical;
running the car rich from the compensator does not make a great
performance difference. |
| Maximum Fuel
Settings |
| A large plastic plug is found on the front of the pump. |
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This must
be unscrewed in order to access the maximum fuel screw. In order to
unscrew this plug you will need a Large flat headed screwdriver. Press
the screwdriver hard into the plug to make indents, this is then the
leverage to unscrew the plug. As soon as the plug is removed the pump
will empty its contents of diesel.Using a small mirror look inside the
pump and you may see a hole with an allen key type bolt. I think it's
about a 5mm size Allen key. If this can not be seen put the engine in
gear and slowly push the car backward. |
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You will see a cylinder assembly rotate in the
pump. It will need to rotate about 180 degrees to reveal the maximum
fuel screw. The screw will need to be turned clockwise. To access the
screw you will need to insert the long part of the Allen key. Do not use
a ball type driver, as the ball may break-off in the pump. The screw is
quite tight and so a spanner will need to be used on the end of the
key. The range of adjustment is a relative 20 to 40 degrees (40 degrees
is rich, make adjustments in about 10 degree increments). Replace the
plug; prime the pump and test drive. Look for evidence of smoke. Repeat
the procedure until the desired performance, smoke level and economy
compromise is reached. |
| With the Bosch Pump the procedure is much easier.
The maximum fuel screw is located on the top right side of the pump. It
will have a tamper proof fitting on it, which will need to be removed.
This screw is adjusted clockwise up to about 90 degrees (again use about
10 to 20 degree increments). |
| Turbo Pressure
Increase |
This is rough guide for those with a Garret T2 turbo
The
wastegate arm is accessible from underneath the car. Positioning
yourself with your legs pointing out from underneath the front bumper,
you should be able to spot the wastegate arm as seen in the picture
below: |
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The Blue Arrow points to the Wastegate arm. Notice
that there appears to be two sections of the arm. A rod (rusty looking
bar) and then a sleeve over it. The sleeve is actually threaded, and
must be screwed onto the bar - this effectively making the arm shorter.
In order to screw this sleeve further onto the bar, the arm must be
released from the other section (the flat plate). This is done by
removing the spring clip, as pointed to by the Red Arrow - try not to
lose it, you'll need it later! The Wastegate arm can then slide off, and
the flat plate can be moved out of the way: |
Red Arrow = The Flat Plate
Blue Arrow = Wastegate Arm |
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You now should be able to turn the Wastegate arm
(sleeve part) shortening the arm, in relation to the flat plate. On most
cars every full turn is 1psi higher, this may not be the case for
all cars, and therefore I would not recommend measuring your pressure by
this method.
The KKK
turbo has a small lock nut on the end of the turbo, the actuator is
enclosed. But you can sort of make it out, its on the drivers side.
Unlock the 8mm nut and tighten the small allen screw, try 2 turns at
first. |
| Pressure Gauge |
In order to see what pressure your turbo is actually running,
you will need a pressure gauge. This is easy to temporarily set up,
simply while you are measuring the adjustments made above.
The
pressure gauge can be connected up along the Vacuum hose indicated when
you look at adjusting the Boost compensator. |
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Red Arrow = This is where a T-Piece must be inserted for the
Pressure Gauge. Another long piece of tube must be connected onto the
T-Piece which will connect up to the Pressure Gauge, the gauge will be
read while driving and therefore the tube used here will need to be long
enough to reach inside the car. The tube should be able to handle the
pressures being dealt with here, and so can be fed through the door seal
without being crushed.
Green Arrow = Using another piece of tube, this is where the
third end of the T-Piece should connect up to. This is the original
connection used by the Vacuum Hose on the intercooler.
Blue Arrow = A pressure gauge |
As standard the pressure being produced should be
around 1 bar = 14.7psi. The peak pressure the turbo will produce should
be when it is under full load, so when testing the pressure of your
turbo, find a straight road, preferably a dual carriageway or motorway,
and slip it into 5th, foot right down, around 3000rpm the max pressure
will be produced.
The performance gains above 15 PSI boost diminish
quite quickly as the charge temperature raises rapidly. However, if the
car produces less than 15PSI boost the increase in boost to standard
will yield a relatively higher gain in performance than above. I would
not recommend raising the boost above say 18 PSI (peak boost) unless
uprated intercooling was used. Remember, the boost pressures and
fuelling are not independent on a diesel engine. The waste gate is a
final mechanical pressure blow-off, if the fuelling is the limiting
factor, additional boost will not be gained. Hence, when tuning the car
check the boost as the fuel increments are made. |
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© 2006 All Rights Reserved.
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