I ran tankers since I bought my truck new in 1999, until last year, NEVER ever came close to 7-8 MPG empty, and NEVER much more than 6 loaded It is the one in my avatar, I would bet those guys are stretching the truth, just a bit, or not figuring it out correctly.

The Cat is very reliable and strong and will last a long time, BUT are very thirsty motors, all of them, big and small.

Ooops, I missed the part where it was a c13.

It is possiable they were fibbing a tad LOL..... the main guy I talk with has a W9 with a 475hp C15. He has the donaldsons, bully dog programmer and the aftermarket manifold with a few other mods I guess. he claims 7.5-8mpg on his round trip from Chicago to Savanah and back (40k loaded and empty tank back)

Like I said, if i can drop the resionator and get a some free-flows on the back, then I should gain .3-.5mpg easily (I now have a resionator under the cab, then 2 mufflers on the back) plus maybe a Bully Dog down the road if I can get even .2mpg out of it, it will pay for itself and then I can also run some of these Ontario loads we got here at $5 a mile

I agree, they aren't mileage engines, but still, as one who works for one of the big fleets who DO run Cats, I am still baffled that my '06 Classic got better mileage (with lots of idling at night) than my '07 387 (with TriPac APU and 1% idle time) with the same kinds of freight, same running area, and same driveline specs (9-speed tranny with top-2 auto-shift, 3.55 rears).

Well I have a chance to get a 04 WS Lowmax with a pre-emission C15. I believe the pre-emission motor would be a bit better than this ACERT motor now. The star is also a flat-top with 13spd and 3.55 rears. What do u guys think?

Why??

DOW decided to put in a new overhead rack and my current condo won't fit. I don't want to lose my gig so it's either get the WS or my old FLD back. I found all this out today and thankfully the dealer is willing to help out.

On a side note, I'll also be getting new trailers as these J&Ls won't clear either

Well, the Pete is gone this coming friday and I will be getting into a 2004 WS with a pre-acert CAT. Hopefully it will do better with the flat-top and single turbo. I already have it lined up to get a PDI tune as well

its too bad you had to get rid of the pete after you put so much time and money into making it fuel efficent. Hopefully you like the star.

I was admiring the looks of a Western Star just the other day. Good looking truck. I liked the color, a deep rich maroon.