I have an early 03 with the standard output cummins 250hp with the 47RE tranny. I was told just about the only difference between the 250hp and 305hp is the injectors. So if I want to make an extra 55hp and maybe a little better gas mileage can I just change out the injectors? What is the real difference between the 3rd gen engines?

 

CP3 is different (lower capacity), ecm has a different fuel map, and the piston crowns are not oil cooled. I've heard the injectors are the same as the 305 but hey, I don't have the parts book in hand either. But I do plan to find out. I sure like mine. (though it does seem to have a lflat spot in the fuel map in 4th gear between 1800 and 2200. The pyro hits a flat spot @ about 900 degrees F and it dosen't pull as hard as it does outside of this zone. This is while towing of course.)

 

The difference between a 250hp (S.O.) engine and a 305hp (H.O.) engine is an EZ on level 2 w/ boost elbow.

 

i had 50 hp injectors put in mine and it made areal difference and now i dont even run my box unless i want to mess with someone seems to get better mileageby about 1 to 1.5. got agood deal from micheal at hotroddiesels.com

 

Once you do everything in my sig there is hardly any difference at all as compared to an HO doing the exact same mods...

The injectors are the same or all of us SO owners would be trying to buy HO injectors....

 

on the SO's, they are oil cooled, but the method is different. the SO's have saddle jets that spray the bottom of the piston. the HO's have a J jet spraying the bottom of the piston. it is a more tuned spraying that is more efficent at cooling the piston