Bongo Fury

Hi folks haven't posted on this forum for a while but very interested in this EGR mod. Your thoughts on this snippet from the motoring section of the Telegraph.
Quote " My Nissan X-Trail 2.2 dielsel is little more than two years old and is already on it's third turbo charger. On the last occasion the intercooler was also replaced. If I keep the car after the manufacturer warrenty expires, can I expect some hefty bills?"

Keep reading, this get interesting.

Reply Quote "In a different context, another reader explained why diesel turbo chargers sometimes fail: ..... The Exhaust Gas Recirculation valve should open to allow carbon dioxide (which is a cooling gas) into the combustion chambers when the engine is under load (more than 30 per cent boost). This allows the combustion chamber temperature to drop and thus the temperature of the exhaust gases. If it sticks in the closed position the exhaust gas temperature will rise, causing the turbo bearings to fail and eventually allowing engine oil into the induction system. This can cause the engine to run on its crankcase oil until it is either stalled or goes bang. Problems with the EGR valves are also often the cause of rough running when the valve is stuck in the open position as well. In several cases turbos have blown but the EGR valve has not been replaced. Inevitably the new turbo unit will not last long.
The most common cause of the EGR valve sticking is dirty, sludged or otherwise contaminated oil." Unquote.

I guess this applies to Bongos as well. So my question is:- if you block the EGR pipe (like many are doing) does the above apply?

One of the main functions of the EGR valve is the recirculation of the exhaust gas in order to lower the combustion chamber tempertures which in turn lowers the production of Oxides of Nitrogen emissions. This a bad emission both for us and plant life

By allowing a controlled amount of exhaust gas to re-circulate back to the combustion chamber, the next combustion process is far cooler. This is because the exhaust gas contains water vapor, which brings about a cooling effect, and the presence of the exhaust gas means lower combustion pressures (less space for air and fuel). This is why your bongo engine will give you an improved performance when you block the EGR valve. But as stated above your Oxides of Nitrogen emissions will go up.
To get back to your question, I would guess that with EGR valve blocked the combustion chamber tempertures will also increase and the extra heat therefore produced must go somewhere and it is very possible that the increase in exhaust gas tempertures could well cause problems to the turbo bearings in time.
Hope this helps
Steve

Shouldn't be a problem even with the small intercooler used on the Bongo the charge is reasonably cooled. Even with the boost pressure considerably increased I never had any problems in 80,000kms+ only other mods aside the boost controller are K&N filter on turbo snout and second similar size intercooler in series with the original.