(04-26-2020 )Rawze Wrote: (04-26-2020 )amermextrucker Wrote: Rawze,
I drive @ 1450 MT. Would you consider that lugging it?
I don't like pushing mine at 1400-1450 for sustained periods much at all. I try to stay at 1500+ when I need power and below 1400 when barely on the pedal. This is because the ISX is known for having harmonics in the crank and bottom end in the 1400-1450 rpm range. It shows up prominently with bad custom tuning programs/bad-deletes or when the power is at 800HP+ and steps to mitigate it are not taken, so I know it is there, even though it is not likely an issue at all under normal power levels. - Some guys drive them there, I just choose to avoid it out of personal piece of mind/opinion only though. I personally consider the 1450 or so range at the point where you grab your next gear and bring the rpm back up when your foot has to be most the way to the floor to climb that hill.
just my own thoughts on it.
NOrmal power levels and decent programming ... not likely an actual issue... However i have seen plenty of times that had bad programming .. or bad programming and 700+ or 800+ horsepower, literally beat the crank bearings out from around the crankshaft at 1400-1450 rpm becasue of that harmonic on competition engines where a bunch of idiot tuning dips#$its tried to put the screws to them. here is what that looks like ...
(photo borrowed from elsewhere...)
Yep I would agree
I have a mixture of Cat, Cummins and Detroit, I don't care what colour the engine is. When your in a pull shift it before 1500 rpm and get the revs back up in the top of the rev band. Any of my drivers that are lazy with the gear stick don't last very long. I tell them I would rather they hit 2000 rpm at gear changes with three trailers on than lug them. It really suprises me that drivers cannot hear the engine protesting loudly when asked to make maximum torque in the 12 - 1400 rev range. And why do the manufactures allow the torque to be available in that rev range. I would personally like to limit the torque available below 1500.
