Any one ran both ISX & C-15 ?

I'v never driven an isx but I don't need to in order to answer that question. you are looking at a smaller cummins in a MUCH more aerodynamic truck with a lower rear gear. It would be much better on fuel than the cat but I'v heard lots of problems on the ISX so you may want to look into that. I don't pay too much attention to them since I'm not in the market for anything that new.

 

Maybe I can help.........We run both of these engines in our fleet. But I have one question you said the T600 is a 2003, does this cummins isx have an EGR? Also where do you plan on running this truck, city or highway?

 

Hey 2hellandback, keep in mind that the aerodynamics of the T600 may not be much help on saving fuel at lower speeds......40, 45 mph.At 50 mph and above aerodynamics start paying off...... The C15 CAT and the CUMMINS ISX are both 15 liter engines and in most cases the HP rating can be turned up through the ECM. But getting back to your question which engine gets better fuel mpg.......In our fleet the CUMMINS ISX with out EGR seems to have the edge in better fuel milage than our C15 CATS.........on the other hand our CUMMINS ISX with EGR have there own set of problems....BE SAFE!!!!!!

 

ya I believe it's the egr's I've heard about. Basicly he is saying if the cummins has an egr then go for the cat, if it doesn't have an egr then go for the cummins

 

This is what I am saying..........

 

needing frequent replacement, rough running and poor fuel economy.