So with the mpg problems the 600s are having, would there be anyway that getting rid of the cat and the 3rd injection event would work? and if so would it be emissions legal and in which states? if it is an option then let me make the decision as to what I want, either emissions or mpg friendly. why punish all of us for the rules that apply to a few. BTW great board I'm learning alot.

 

All the common rail engine since 03 on up have the third injection from idle on up to approx. 1200 RPM , I just did a trip from Sacramento to Las Vegas last weekend and mostly at 75 to 80 mph and average 17 mpg hand calculated , for a 4X4 I dont think that is so bad and I had no problem staying with a bombed PSD thru the Tehachapi pass.

 

If I am not mistaken, I also think that I saw on the Cummins site that they made some other changes to the pistons and the head to become EPA compliant without the addition of an EGR valve. This may be the culprit somehow.

 

re: removing the CAT

I've read a few other threads where people have removed it and had no change in MPG. It's a federal emissions requirement now, I heard their even going into the big rigs.

 

That's new to me... what was your source for this info?

 

03 and 04 engines have only 2 injections per cycle. The only engine that has 3 injections per cycle is the 04½ "600". The added injection event with numerous other improvements are what made the ISBe 50 state compliant as far as emissions go.