Perhaps more knowledgeable will reply but I believe ECM stands for Electronic Control Module.

The Detroit Diesel has a DDEC brain, which is programmed with certain operating parameters. I purchased a DDEC code reader on Ebay, and it's very interesting what kind of information is in that computer. There is indications that there are several "governor" settings which limit performance.

Some of boosting horsepower is simply a change in programming of the DDEC, while others require actual hardware changes. For example, I actually downgraded my engine from 500HP to 450 at the suggestion of a good friend who is regional tech specialist with DD. That change required no hardware, but DD did indicate if I wanted to go lower, it would require injector changes to match.


Ray