t300/mpg

[mdscott]

We have a 04 t300 with a ISC315 cummins, 433 rear end and a 6 speed allison tranny.
we get an avg 8.5 mpg running 65 mph. is that about avg with other trucks set up the same way? thx

 

[P51bombay]

Sounds a bit low, what is your rpm at that speed? Tire size?

I have an 03, 3126, 4.63RE, 10spd Eaton, with 11R22.5's. It is overgeared and only turns 1750 and 60 and still gets 9.25 with a combination city/highway

 

[mdscott]

Tire size is 295/75R22.5. RPM is 1625. This mpg avg is over several mos. thx

 

[gotta go]

I have a 2005, T300, with the ISC 315 engine, 3.90 rearend, and Eaton Fuller 10 speed. Running at 60-61 mph, I'm at 1500 rpm and get 9.91 mpg. If I run 65 the rpm is at 1650 and mpg is down to 8.4. That's just not worth it.

 

[P51bombay]

RPM sounds low, if you plug in your data on Cummins power spec it will tell you where you should be and how variables will change things

Cummins PowerSpec

 

[SKIDROCK]

I average about 10mpg in a 2003 Sterling 3126 230hp Cat, 6spd, not sure what rears I have, 11R22.5 tires, no muffler, running at about 2350 rpms at 65mph. Its not a T300 but just trying to give an idea of what kind of mpg I get.