4x4ord wrote:
Shiner I really don't think we are that different in how we understand things. For one thing I am giving the Ram/Cummins engineers a bit more respect than you do. I believe with today's technology it is not that difficult for an engineer to program a transmission to select the right gear for the load being towed. The truck computer has a lot more information to base things on than you do. Based on what you have posted I would likely lock out 6th gear with your truck if I was towing 13k at 60 mph. If I was towing at 65 mph I would definitely be in 6th unless the terrain, wind or traffic conditions were such that the tranny was shifting back and forth. Between 60 and 65 I really doubt it would make much difference what I did.... According to the BSFC map that you posted the fuel economy would be the same.... Likely about 9.5 mpg.
It is not about giving them credit or respect. It is about knowing what they have to work with, how the tuning is done, and what parameters determine shift points. Making shift points for an unloaded vehicle with a known weight is easy. Making shift points for a vehicle towing an unknown amount of weight, unknown grade, unknown drag, and for an unknown speed is not so easy.
Then you have the factor that you will not satisfy everyone. Just look at the trans tuning section in the diesel forums. You will have a third of the people who will want to be in the highest gear possible, another third that wants it at higher rpms for power, and another third that want it somewhere in between because they all use their trucks differently.
This is why my tuner stopped charging for transmission tuning after three years and just offered one trans tune for everyone. He was constantly getting emails from people wanting to change it for different purposes, and it was hard to please everyone with his trans tuning updates. The only way he will change now is if you go to his shop, put it on the dyno, and be right there with him as he adjust the parameters.
This is likely why the makes just offered the select shift, different rear gear options, and in the case of Ram different engine options for power or efficiency because it is easier and more cost effective to offer these options than spend all this money on something that will not please everyone. You are close on my mileage. In 6th it was always below 10 mpg and in 5th it was always above 10 mpg with cruise set to 65 mph.
