Pete 379 with Cat C-15 mpg?

Yes they do I drove a w900L that we took to 625 and 1850 torque and got 5.8-6.0 all day long. Pittsburgh power mufflers, twin turbo delete go to a single big turbo, Acert delete if you want to get spendy.

 

What tires do you have? Also are your mufflers the factory mufflers? What year is the truck and do you still have the factory fuel lines on the truck or have they been replaced?

 

you're not going to get decent fuel milage out of an acert cat. I ran my dads acert 67 at 1425 hooked to a pot last week, over 2000 miles I averaged 3.5mpg. I get the same milage out of my E model running 80. That acert is designed to cruise at 1350 at 65 and they're know to be a fuel sucking motor. I know pulling a hopper however my dad drives that truck he can manage to get almost 6 out of it but he's also not bucking much wind dragging a hopper around. If you want to get milage out of that truck you'll need to get it breathing a lot better (get rid of them catalitc mufflers!!!!) do an ECM tune (.5mpg-1mpg) and quite possibly delete the twins and go to a single turbo. Cat's have always guzzled a little more fuel than the other motors, but those acerts are ridiculous about drinking fuel and they're gutless IMO. Our cat god is no longer giving advise on the forum. Do a search on for Mr. Haney and PM him, get his contact info and talk to him about your goals with that motor. He can tell you what to do to turn that CAT inside out.

FYI i've talked to a couple guys that have done the single turbo conversion it turns that 475 horse kitty into a raped ape.

 

Delete everything that makes it environment friendly. Mr.Haney would know he might suggest some other things though.

 

Tuning the Ecm will probably provide the most bang for the buck. But be sure to start out with an engine performing at its peak first. Things such as overhead set just right, absolutely no CAC leaks, Exhaust leaks etc. I have seen guys tune an engine that wasn't running at its potential level but it ran so good they couldn't really tell it had a minor issue. They say the tune helped but sound a little unhappy with it. Then the small issue is resolved and they really get a grin about the whole deal. It really amounts to how much you want to spend. Or if you can keep your foot out of it after in a case like one of ours. I have read about guys spending a bunch and gaining face changing HP but still unhappy with millage, from what I read they seemed to done every thing right. So expect better response and hope for millage. It seems every outcome is different there.

 

I had an 05 379 70" that had an accert twin turbo C15 in it, and I got 6.2mpg with it pulling a tanker. I'm thinking maybe a good tuneup is in order before a bunch of mods are done.