Different ISX power levels

[hotrodder_101]

Hello everyone. I'm considering purchasing a truck to tow my camper. I have no intention as of right now to use it for commercial transport. I've been doing a ton of looking and reading. The question I have is about the different power levels of the ISX. I'm focusing on the ISX15. I have seen trucks with this engine have to levels from 425 to 550. What are the differences? Is it as simple as having it tuned to jump from the 425 to the 500 how range? It seems that the ISX15 is a 15 liter engine?
Thanks in advance.

[Rawze]

The ISX15 engines generally seen from the factory within 2 tiers. Mid-tier 400 - 515 hp and above 525HP+. At 485 and below, definitely tier-2. At 500 - 525hp, it may have to be looked up by engine ser#, and above 525hp is tier-3. The 2 different tiers have different injectors, cams, and slightly different compression (but same size) pistons. Everything else inside them is the same like crank, bearings, etc.etc.etc. - I am also told that some of 2250 and 2350 ISX's have different exhaust impellers in the 451 turbo that comes with them, though I have not confirmed this myself.

There are no factory programs to put a 400 all the way up to say, 600HP, but even the 400 ISX can be set easily enough to 600-HP with a custom made program.

Adding power to a mid-tier engine is not the same as adding power to the higher tier engine. Sure the smaller engine can do it with no troubles, but it takes a bit longer for the fuel to get into the cylinders, they have a bit less valve opening time (they did this for for improved emissions), etc. making them build heat more quickly at high HP levels as an engine with the parts designed for this in them. Does not hurt them one bit as long as they don;t have to use that extra HP for extended periods. I know of guys with 800+HP on their mid-tier engines that have no issues at all, simply because they don't drive them that hard very often + they made the HP higher, not the torque.

The higher the HP by increasing torque though, the shorter the engine life on any engine. This is especially true of the the ISX due to its short piston rod design. This higher torque abuse of them mostly comes form truck owners these days who are hell bent on driving them with higher torque settings down in the engines lower rpm ranges (below 1500). It is this ridiculous mentality of high geared rear ends, etc. making it hard on the engine, requiring high torque to get the truck moving. It is the hardest on the liners due to the high internal friction that it creates (short rods + high volatility) by making that much torque at low RPM's. I.E.> It is not the increased HP that shortens their life, but the extra torque added into them on the lower end. The 600HP is a fine example of abuse right from the factory. It has 2050 ft-lbs torque in it, but only in the 1100-1300 rpm range where it is very hard on the engine. Those 550+ hp engines life a shortened life when driven hard in the lower rpm ranges because of this.

[hotrodder_101]

Thanks for the in depth reply. I am thinking about being somewhere around the 550hp range. I do know that I will have a 13 speed. I found the information about using high torque while using low rpms. I'll definitely downshift to extend the life of the engine.

[Waterloo]

Why do you think you need 500+ hp to pull a camper? I had an 97 Volvo VN, had the little Cummins M-11 in it, about the same size as what you will find in a Dodge pu. The HP on that little guy was 390, I forget the torque. I pulled a 53' step deck van with that truck for a couple of years, it preformed flawlessly and returned 8 mpg without breaking a sweat with the 3:90 gears. I was hauling windshield wiper cowls on steel racks for GM, Belleville MI to Fort Wayne Assembly in Roanoke Indiana. The racks and parts weighed roughly 15,000 pounds, not including the weight of the trailer, figure another 14,000 lbs. I was round trip, parts down, racks back, the parts combined did not weight as much as one of the racks. So the mpg was consistent.

I sold the truck to my neighbor, he still uses it to pull his horse trailer, darn thing is still running to this day.

My point, you will pay a bit more for a higher hp tractor, HP you really do not need. Myself, I would be looking more for fuel economy and the proper gearing. As far as transmission, maybe an automatic, so that the wife or someone else could drive it if need be, like in an emergency. Just my .02

And you are in the right place to ask these questions. Just be very careful if you pull the trigger. That old Volvo of mine never saw a shop other than for routine maintenance. These new trucks, they can drain your bank account in a matter of seconds. More than a few of us here have enough money invested in these newer trucks to own an entire fleet of those old Volvo VN's. The ones that just worked, I miss those days.

[the missing link]

You need to do some reading on here , if you want it to live , low rpms is NOT the answer!