Saturday, May 02, 2009 at 19:04
x2.
From what I've read on the patrol
forum, the blokes who seem to have beaten the 3 litres problems have done the following:
1. Fit EGT and Boost gauges
2. Block off the EGR valve (stops exhaust gases being recycled into the induction process).
3. Fit a Dawes Valve (I think this limits the amount of boost that can be developed by the turbo, but I'm no expert).
4. Fit an oil catch can to the PCV valve (Positive Crankcase Ventilation)
5. Fit an electric fan to the top of the intercooler (temperature or manually controlled)
There could be a couple of other mods, but these are the main ones I think.
The theory with the 3 litre blow-ups is along the lines of:
The MAF sensor (Mass Airflow Sensor) in the air intake area, gets a coating of dust or oil residue (from the EGR process and or the PCV valve?) on it's sensor.
This sensor then sends a "false" signal to the computer to the effect that the boost needs to be raised to overcome a lack of air (which it isn't really suffering from).
The variable vains on the turbo (controlled by the computer) are then angled to a different pitch (just like the propellers on a aeroplane), to increase the boost pressure.
The boost pressure increases, sometimes resulting in a Intercooler hose blowing off....but all too often it results in far too much BANG in the cylinder, with a subsequent holing of a piston.
The idea of the modifications are to limit the amount of boost (Dawes valve) and to stop the oily residue getting into the air intake and onto the MAF.
FollowupID:
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