WARNING: This
procedure requires the use of an after-market boost gauge. If one is
not available it is recommended that the fuel cut defenser, if you have
one, be removed or disabled so that the ECU can control over boost accordingly.
Failure to take adequate care during the adjustment phase could result
in serious engine damage. Please also read the other sections in this
document particularly the “Cautionary note” disclaimer at the beginning
of these instructions aswell as the section on “How do I know if I have
hit the factory bost limit ?” for advice on the effects of the factory
boost limit.
THESE
INSTRUCTIONS ASSUME THE VSV HAS BEEN DISCONNECTED. IF THE VSV IS CONNECTED
DURING THE ADJUSTMENT PROCEDURE ENSURE THE VSV IS OPERATING NORMALLY
AND BE AWARE THAT THE ECU CAN INDISCRIMINANTLY REDUCE BOOST BY AROUND
4PSI. IF THE ECU DOES THIS DURING ADJUSTMENT BE CAREFUL NOT TO OVER
COMPENSATE OTHERWISE OVER-BOOST WILL OCCURR WHEN THE ECU RESTORES FULL
BOOST – YOU HAVE BEEN ADVISED.
NOTE:
These adjustments can be performed with the pipes connected to the relief
valve providing the hose clips are not too tight – simply twist/rotate
the knurled end of the relief valve inside the pipe as required.
Preparation
Drive carefully
to a suitable straight road or dual carriageway where the car can be accelerated
with no danger to you or other road users.
Ensure the
engine is at normal operating temperature.
If you haven’t
done so already, adjust the relief valve so approximately half of the
adjuster threads are showing – be careful not to completely undo the relief
valve as the ball and spring may drop out.
Perform
a reference run to determine the current boost pressure – it is unlikely,
with the valve half way, that boost will be above the factory limit however
…
If the boost
limit is reached proceed to Resetting the ECU
If you want
to raise the boost higher proceed to Increasing the
Boost
Increasing
the Boost
Shorten
the valve by 1 full turn or ½ turn for a smaller increase.
Perform
a power run and determine the current boost pressure.
If the boost
limit is reached proceed to Resetting the ECU
If more
boost is required (DON’T BE GREEDY) carry on Increasing
the Boost
If you have
found a happy balance between improved power and the boost limit - stop
increasing the boost and see how things go before performing further adjustments
!
Decreasing
the Boost
Lengthen
the valve ½ a turn or 1 full turn for a larger reduction.
Perform
a power run and determine the current boost pressure. If the boost limit
is still reached proceed to Resetting the ECU
If more
boost is required (DONT'T BE GREEDY) proceed to Increasing
the Boost
If you have
found a happy balance between improved power and the boost limit - stop
increasing the boost and see how things go before performing further adjustments
!
Resetting
the ECU
Pull the car over to the side of the road.
Switch off the engine.
Remove the 15 amp EFI fuse from the fuse box under the bonnet near the
battery.
Wait at least 30 seconds.
Refit the 15 amp EFI fuse in the fuse box.
Restart the engine.
Proceed to Decreasing the Boost
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