C15 what motor Serial numbers can you upgrade?

Yes, thank you osokusmc some one finally gets it, it applies to all engines Cat, Cummins, Detroit any of them. The wiring harness is more prevalent in the Acert because of the extra heat, caused by the extra turbo, caused by the retarded timing, caused by...well you get the picture. But it is just good basic maintenance practice to keep everything top shelf. Putting a performance tune on your "average" enter your favorite engine here compares to putting someone with C.O.P.D. in the Boston Marathon, not going to end well. A performance tuned ECM will not "fix" anything, in fact usually the opposite happens, it will point out most of the maintenance short comings, usually in pretty short order. This is when everyone wants to point their finger at the tuner, in my opinion (and just my opinion) the Acert from the head gasket down is the strongest engine they(Cat) ever built, from the head gasket up not so much. Sub-par electronic settings (to please the EPA) and a few sub-par materials above the head gasket cause most of the problems, but they must be addressed first then you can "tune it up".

 

I can upgrade my dad's c-15 mbn. Right now avg 5.23 mpg. Planning to plug performance harness into the engine. Another 40 HP and .5-more mpg. Estimating 5.73 or more mpg. Hopefully.

 

You will only get 40 hp in winter when fuel stays cold and mpg won't change. Mpg will change in ecmbecause harness tricks ecm to think fuel is hot but in real world pen and paper pump to pump it won't change. On a hot summer day the power harness will give you maybe 5-10 hp as the fuel will be almost as hot as tricked reading

 

Still I'll have some power and more mpg to.

 

You will have a bit more power but mpg won't increase

 

My truck is kw t600, there could be some little difference.

 

Truck model wont make a bit of difference, an engine mod on an aero truck or non aero truck will be relative, simple fact that the power harness doesnt give you any real world mpg savings, there are some on here who will say they gained .5mpg or better, they get this info from the on-board computer display whichgets its reading from the ecm which is tricked by the harness... do a pump to pump pen and paper and you will see no difference, Aero truck wont see an increase because its aerodynamic, the power harness is an engine mod not a body mod

 

If an Aero truck would see an MPG increase with that harness so would a classic truck

 

6nz are different compare to mbn. MBN may have bad mpg but better jakes than 6nz.

 

Because of the high compression, you then have head gasket problems.