No no and no I'm afraid Steve
Don't worry about it though. I'll go over some basics so I hope this isnt making you suck eggs but I'll cover it all to be safe
These run a cool EGR system (the tube itself acts as an 'intercooler' or sorts for the gases) and don't affect cylinder temps very much. The intercooler upgrade I have in place anyway allows more air into the engine so using my Exhaust Gas Temperature guage I can see that I'm running very cool anyway, about 300 degC bellow safe levels (this just shows how light a tune Nissan gave this 2.2 beast of an engine). So yeah by blanking the EGR and allowing more clean fresh air into the cylinders will in fact either cancel out not having the exhaust gases any more or even make the cylinder temps even cooler.
The reason for the EGR on a Diesel is to burn any No2 gases. It's an emissions thing, but doesnt effect the MOT as Diesels are only judged by a Smoke Test.
Ok for one, Diesels are REALLY flexible when it comes to Air/Fuel ratios, so for a Diesel to actually be 'overfueling' you'd need a silly amount of fuel to be going in against very little air (
see video). Fuel is what gives Diesel engines their power, and air is less important unlike in Petrol tuning. The more air you put in to a diesel though the more fuel you can put in which is the same as a petrol, the difference in that running
rich gives more power to a Diesel engine. More fuel = hotter exhaust gases and cylinder temps but this only becomes dangerous levels with LOTS of fuel. For exmaple I can get away with a smokey tune to gain more power. Upping the boost and/or upgrading the turbo provides more air to reduce the smoke, which in turn allows for more fuel to be dumped in!
For my engine the hybrid turbo will be able to provide lots of air. The bottle neck could be in the fuel pump and/or injectors. Upshot is that because this engine is to be tuned and I've got my eye on EGR temps, any changes to the setup is fine.
Sorry it's that's a bit of mess but I was just typing what was dribbling out of my brain :thumb: