2008 isx how do they pull

A bullhauler I know bought a new flattop '08 389 Pete with the 600 ISX a few months back. Said it pulls like you wouldn't believe. He's VERY impressed, and he's a Cat man. Said he's getting 5mpg, and the engine isn't even broke in yet.

Not sure on reliability directly (for the new ISX). When we were specing a new KW truck, even the big whig from the KW HQ said to stay away from the Cat. Said they've had MUCH lower warranty repairs on the ISX. The exhaust after-treatment crap is MUCH simpler as well.

We have a pre-EGR ISX500, and it pulls like a freakin' train. I can still outpull it on big hills with my non-ACERT 525hp C15, but it pulls HARD! The ISX fuels a lot harder as well. The ISX can out run me on the lower 5 gears because of it. I get better mileage with my Cat, though. 5.5-6 runing OTR, and 1mpg better than the ISX locally. Can't break 5.3 with the ISX.

 

Soooooooo if you are beating a ISX with a 525hp MBN CAT, then why brag about the isx so much?

 

My Dad has a 08 isx 600 and it pulls very well. The fuel mileage is decent too. The warranty work has been really minimal with it.

 

A buddy of mine has a 550 ISX in his '09 389 Pete with an 18 spd and loves it. He pulls a grain hopper with it and is always 80,000 or more and is still managing to get 6.5 mpg in a truck with less than 20,000 miles on it.

 

I have got nothing to compare it to as I have not driven a truck with an engine made by another manufacture with 600 hp. The difference between a 500hp cummins isx and a 600 hp isx is unbeleiveable. It was a 20 mph difference going up I-70 to the Eisenhower tunnel system in Colorado. Instead of going up it at 19-21 mph fully loaded with the 500 hp I was going up it at 43 mph fully loaded with the 600 hp. As for fuel mileage I never check it as I do not pay for it and I do not get fuel bonuses or anything like that. They tell me to drive from point A to point B and that is what I do.

I would like to add that I talked to a driver of a flatbed last week while he was unloading with a 550 isx 07 and newer style engine. He said that he is getting 7 mpg. He also said that he does not drive the truck over 1400 rpm.

 

My buddy's truck has 3.55's in his and I think he runs 24.5 low pros.

 

I know that both those trucks I was talking about were running 24.5 tires. I do not know about the gear ratios. I will check on the gear ratio tomorrow on the one truck if I remember. The other truck is out of state right not so I cannot check on it.