Cummins ISX 400HP up to 475HP

I think an ISX 400 can go up to 500 with an ECM flash alone provided the transmission is rated for additional torque.

 

YES YES you can. But Why ? Just cost mo $$ to operate.Unless Heavy haul.

 

That's news to everyone that's had HP uprated and gotten better fuel mileage.

 

I have vnl 780,2007 when I bought it last year,it was 400hp.I upgrade it to500hp immediately with only ecm no other job,so far no problem at all.

 

Completely false. Adding hp will improve fuel mileage. An engine that is cut back will constantly work. When its turned up and driven correctly it doesn't have to work as hard to perform and burns less fuel. That was told to me by a Cummins tech.

 

On a side note I wouldn't pay Cummins, Cat or any other dealer/engine mfg to uprate an engine. Been down that disappointing road countless times. Aftermarket is by far the best bang for the buck for both HP or fuel mileage.

 

When I worked at Stevens, there were a few T600's that had been delivered with 460hp N14's installed by mistake rather than the 410hp N14's the fleet used at the time. The Stevens mechanics derated them to 410's and it caused all sorts of problems, more gutless than a straight 410, poorer fuel economy until Cummins advised them that derating the engine did more harm than good. They were reset and had to be pried out of the drivers hands when it came time to trade them in.

 

Used to be a shop in Westmont, near the school bus barn.

That guy turned them up, and cheap........

 

Derating kills an engine. The 444, 460, and 525 IMO are some of the best engines Cummins ever made. I run an IH 9200 daycab when I'm home on my days off of my regular job. I surprise alot of drivers with that little truck. They never expect it to have a 525 Redtop in it.