Rawze.com: Rawze's ISX Technical Discussion and more

So I’m wondering what is the max safe rpm for an ISX 15 during acceleration?

you could run it at 2100RPM all day for the next 10 years and it would have less wear in it than if it was run below 1400 its whole life.

the ISX will last its absolute longest at 1650-1700RPM.. that is its center-point.

for whats its worth mine has been pushed in the high rpms alot and the jake brake seems to work best at 1900-2100 rpm bought my truck new and had to inframe at 687K but that was due to broken piston rings on #5&6 due to carbon packing. I didnt see any excessive bearing wear and the truck still idled at 30 psi of oil pressure. im not telling you to run it that way just stating my experience

I run mine 1800 loaded and even 1800 MT. Been running it that way for 2.5 yrs now. NO ISSUES. Oil samples are good, no metal.

BTW I picked up that info here on this forum.