I have the same problem I have a retired Prime truck 2016 model Cascadia evolution. I had mine turned up as high as they said it can be taken to 506. And it still will not climb Hills and it is just a dog.
Pittsburgh Power has a box you can add to increase hp and torque. Costs close to 3000 dollars though.
the DD15 torque curve is about 1000rpm to 1400. After that it starts dropping off significantly. Volvo has multiple torque curves you can program in it based on your operation. That torque number doesn’t mean much if it’s not available at the rpm you need it. You might sit down with a dealer to see what’s available on the DD15. Just using the torque may not be the right solution. They need to adjust the torque curve to match your cruise rpm. When they do that, it also changes the fuel mapping. It’s a lot more complicated than just a torque number.
Good to know I’m not crazy, had I known this I wouldn’t have shopped for this motor. This is unacceptable.
crazy part is that’s exactly where it feels weakest, 1k-1400. If I floor it at 1100 on flat ground, it’s flat and unresponsive until 1400 then it puts you in the seat but by that time it’s time to shift. Going up a grade, forget it, it drops speed like I’m trying to coast up the grade.
Yeah I won't argue with that one. It seems to be lacking power just does not want to pull Hills or get back up to speed if you're slow down for some reason.
Almost all diesels no matter the year or make will feel sluggish at 1100. They're not meant to run there contrary to popular opinion. 1600 is the sweet spot for *most engines. Some a tad higher some lower.