If you do not have factory compatible connectors for a Diesel Tuning Module designed for a Bosch CR system then I'd be a bit warey! Its a oain to install & de-install.
FLASH programmers are easy, but the fact its a non-standard program is immeiately visible to the dealer, and could be over-written with an updated version to address issues when the car is serviced (& perhaps you wont know until you wonder why its lost its edge after the service). At that point you have adecision, 1. stay with the new factory program (but less power), or undo the fixes supplied in the new factory program and re-install the after market program (if the programmer will let you).
Properly set up external diesel tuning modules will not generate ECU codes. If you try to go beyond the safe design limits you run the risk of engine damage & / or ECU codes.
How ever be very careful trying to bump the boost without appropriate precautions, or you will generate ECU codes from over boost. The over boost is an artifact of the VGT having limited resolution for its adjustment, and hunting between the two positions (on modified fuel system). This over boost could be up to additrional 10PSI. Thats not a good thing.
Also consider that adding fuel can only add heat (after all its the conversion of energy from fuel to heat that generates the power). Those are the laws of physics - sum total energy can only be converted, not added or lost. Improved tiiming may cause some of this fuel to be burnt in the cylinder. But add more fuel and it will also generate more heat, and that has to go somewhere - some usually goes out the exhaust. That causes EGT to go up under load.
We have found that fitting a complete 2.75"-3" exhaust system (from back of turbo to exhaust tip) assist in spooling up the turbo and reducing EGT.
Any power gains over about 30HP (on Jeep 2.8L) should also be accompanied by EGT gauge to ensure that the operator maintains EGT in the same zone. Any other control will need to determine the operating conditions at the time and take those into consideration to adjust the fuel load if EGT become excessive (strange that trucks used to have EGT gauges for this very reason at one time when drivers understood their truck). Typilcallly high EGT are because the operator has selected the wrong gear for the task at hand, and held WOT to try and solve the problem. Drop a gear and increase airflow is the proper action.
Remember that highway cruising in winter and operations under high load in the mid summer heat of the mountainous areas will produce very differnt operating conditions. The first can be tuned for more power with the same reliabiity. Anybody expecting to get much more than 40HP and long term engine reliablity by module alone need to reconsider their goals. If its a race engine then reliabiity is not required (other than to finish the race).
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DaveO
ENG-TEK Diesel Performance Centre
Australia