Don't take my word for it, there are plenty of Abstracts, studies, and write ups available online for reading concerning the:
Effects of Exhaust Back Pressure on the Performance of a Turbocharged Diesel Engine
Most turbocharged Diesel engines have no throttle valve, so there’s very little if any restriction on air coming into the engine. So why should there ever be a restriction on the exhaust gases leaving the turbo? That is why Diesels tend to perform better with larger free flowing exhaust systems.
Any exhaust system backpressure on a turbocharged diesel engine affects the flow rate of exhaust gases passing through the exhaust system at the optimum rate. As a result of any restriction, back pressure and exhaust gas temperatures (EGT’s) increases within the turbine housing.
Increased combustion chamber outlet exhaust gas temperatures due to increased back pressure affects the turbocharger in a number of negative ways and causes inefficiencies which can include problems with, oil leaks, carbonization of oil within the turbo bearing area, turbo response times and performance across its entire operating range.
With increases in exhaust back pressure, engine volumetric efficiency decreases. Volumetric efficiency, fuel economy and combustion efficiency can be improved by simply decreasing exhaust back pressure.
So simply getting rid of the EGR system and getting rid of the restrictive CAT and installing a free-flowing muffler can improve turbo efficiency, engine performance, and longevity.
Backpressure is never “necessary” for the operation of a diesel engine! If you are concerned about NOx, then install a water-MeOH fogging system, and you take care of the NOx and have the side effect of cleaning your combustion chambers and lowering EGT’s. The more air you can flow into a diesel engine and the faster and less restricted you can get the exhaust gases out, the better the performance and longevity your diesel engine and turbo will provide.
_________________
Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount98 Dodge Cummins 24 Valve