I know the bottom end of our trucks is rock solid, but at what horsepower level do you have to think about upgrading some of the parts, like rods, and pistons, or maybe the crank?

 

Somewhere north of 700hp I'd look into new pistons. Doubt I'd get them, but I'd look into them. These engines really are about as bullet proof as you can get.

 

The stock rotating assembly is strong enough for over 1000 hp.

 

See below for the Cummins medium duty ISB engines, which are governed to a lower rpm than the one in the Ram. You can obiously get more out of one with a box and other mods, but the one below are the ones that Cummins is willing to offer, provide a warranty for, and advertise as having an averge life of 350k miles.

http://www.everytime.cummins.com/eve...sb_ratings.jsp

HP - Torque - governed rpm

ISB275 660@1600 2600
ISB260 660@1600 2500
ISB260 550@1900 2600
ISB245 660@1600 2500
ISB230 520@1600 2500
ISB215 520@1600 2500
ISB200 520@1600 2500
ISB185 420@1600 2600

 

Interesting, I knew they were rock solid, but you here of the V8 crowd having to upgrade so that they can go with more power..

 

It won't be much longer until the 5.9 or its successor (the 6.7?) will be in the same boat as the V8 guys. Cost cutting will make rods weaker and decrease bottom end strength. Yes, I'm pessimistic.

The stock bottom end on these things is about as overbuilt as you will find in a production engine. At least for now.

 

i wouldnt worry about internals at all ..just keep an eye on EGTs, an dfuel pressures and dont be stupid running full throttle with a 800 hp cummins for an hour straight

 

Unless the EGT are below 1300* for the entire hour.

 

I know it doesnt make the rods and pistons any stronger, but keep in mind, our in line six cylinder has 7 main caps while a V8 has only 5
Something to think about.

 

still doubting the internals of a cummins?
here:

http://www.atsdiesel.com/Video/Munci...20040609_1.MOV

 

Eh? Aren't the common rail's cracked metal rods stronger than the ISB and 6BTA rods?

brandon.

 

I don't think the dodges will have a problem as long as they buy from cummins and detune for stock.
It all has to do with potentials. If what you have out of factory is 90% of possible then you could have a problem. They aren't going to design an engine that is stronger then it needs to be. It doesn't make $$ sense (ferd, chebby)
BUT>>>
if you buy an engine that is "factory" stock setup for heavier loads then detune it to keep the running gear in your application from turning into pretzels. Then you have much more room to play.

Either way a determined mod maniac can turn any engine into scrap, given enough money and a large enough lack of sense.