I'm trying to educate myself on general diesel engine operation here, as well as get specific info on the box I want...

I plan to get a TST powermax for my 04.5 dually. If I understand right, this box improves mileage. Does it do this because of advanced injection timing?

Another question: How much real-world mileage gain can I expect (assuming I continue to drive for fuel efficiency)? Of course, I will use the power, but as I get used to it, that will die down so that I only do it occasionally.

Is advanced injection timing the ONLY change boxes make that improves fuel economy?

 

Real world gain at 65-75mph I see .75-1.25 extra. City driving with back and forth to work gain is zero. I like the tst but, do not expect any box to make your fuel mileage jump through the roof, no matter what you read or hear. 5% increase is a good guidline with timing alone. I only use my box on long trips,or to pass a chevy or ford. The knock from the advanced timing is why I don't run it all the time. Tst said timing knock is harmless, I just have not programmed my brain to accept it yet.