2008 isx how do they pull

Apparently you've never run one before? Even at 500, they are a very impressive engine, even with ours having problems. I used to run to PA and VA/WV nearly every weekend in during the summer. There are plenty of 8-13% grades out there. I very rarely ever got passed, same as with the Cat.

The ISX powered truck does have 3.70 gears.22.5 talls, so that does help for sure. If it had 3.55s/24.5LP like mine does, it wouldn't pull as good as mine, either. I ran with a guy that had a 550 ISX, but with much faster gears and a 10spd. I had to slow down and let him catch the whole time.

Last winter I ran with a guy that had a 500 N14 and 3.70 gears. I couldn't stay ahead of him for anything, but, I was needing a fuel filter bad, and had low fuel psi anyhow from a bad fuel bypass valve. Replaced the valve and filter and got the power back, and a bit more boost with a light puff of smoke on start up.

Have the fuel temp wire harness on order from Platnum, so we'll see what she'll do now.

 

a 13 spd with a .73 final drive, 3.55's on lo-pro 22.5's

 

movingstuff, I talked to my buddy earlier today and it turns out I was mistaken on a couple of things. For one, he has 22.5 low pros on there and secondly he's currently getting 5.6 mpg and has 18,500 miles on it.

 

If you have 525-600hp, 24.5LP and 3.55 gears would be fine at that weight. 500hp and 3.70's pull **** good! Stay away from the 3.36 gears that a lot of trucks get spec'd at. Will be too fast.

13 or 18spd trans only.

 

My dad had a 379 with a 525hp N14, it pulled good but was one sorry a-z-z excuse of an engine.

 

Ran a 485 ISX at 105,500lbs and does pull very good relatively speaking, too bad it was not my truck, was a leaser from the dealer!!!
My truck has a 435 Detroit 60 DDEC IV, and doen't pull worth of ##&% at 98,000lbs and you will be craaaaaawling at 105,500lbs on any kind of a positive incline.