5.9L vs 6.7L Cummins ? I noticed an Edmunds review of HD 2006 dualie diesel trucks. Since the 5.9 is very close to the newer 6.7 for HP and torgue, what are the advantages (MPG, acceleration, etc) of the 6.7 ? I guess the 6.7 must have a very large untapped potential. I am of course ignoring the advantages of the 07 with the new 6spd auto vs the 4spd auto in the 06.

Also, upon review of a new 2008 3500 Cummins (auto), I noticed the air intake (appears to be a more efficient air intake plenum behind the front grill ------------ and blocking air flow to the tranny cooler, as compared to the 07 design) is considerably different from the 07 Cummins (air intake still inside the front fender). Do the 07 and 08 Cummins produce the same HP and torgue ?

Reason for asking, I can purchase a barely used (6K miles) 07 for more than $10K less than a comparably equipped 08.


FYI: I currently have a 2001 5.9 Cummins quad dualie (auto and 3.55 rear). Even though not very peppy, I regularly see 20MPG unloaded at 65 to 70 MPH cruising, and 12 to 14 when carrying a 4000 lb camper under the same conditions.


BTW: Any feedback regarding the new 6 spd auto would be appreciated as well ------------ I rarely buy a new major upgraded item (tranny) the first year it is offered to the public.

 

My opinion: keep what you got.

 

George,

You got a lot going on there!!!!!

I am assuming that the 07 that you can purchase is a 6.7? If it is a 5.9, I so go for it.

The 6.7 has a lot of required emissions equipment that hurts your mileage.

Performace numbers of a 07 and 08 6.7 are the same, difference will be between auto and manual, but they are the same year to year.

Now, the 6.7 is a good engine, but it will not ge the same mileage as a 5.9, period, all things being equal.

Stealth