Forum Discussion
4x4ord wrote:
Is that dyno sheet from the actual truck that they used in the towing test? It seems as though it's not just an isolated truck. I thought the reason the Duramax they put up against the Ram failed to perform better might have been on account of the shift points programmed into the Alison transmission, but,after seeing the high rpms used in this run up the mountain I recognize that the Alison is tuned to aggressively use the high end of the power curve. It seems strange to tune the transmission to run high engine rpm if there is no additional power to be has there.
Not the actual truck for this test, but a previous one in 2017, where the 445hp Duramax failed to beat a 385hp rated Cummins.
The reason I feel this is elevation choked, is because Gale Banks has a nice series of video "killing a duramax", which he showed the turbo parameters being nearly maxed out to produce the rated 445 hp.
Therefore at elevation, the turbo has nothing left, and power output suffers starting at such an early RPM. Tuners often push the turbo way past its efficient zones on the compressor map, shortening the life.
I bet at sea level the engine hp will keep climbing after 2500 rpm.
About Travel Trailer Group
44,027 PostsLatest Activity: Apr 19, 2019