They had a factory spec of 505 HP on a C12 for a motorhome application. I have a T600 w/ a C12 n it has 46000 hrs on it n doesnt use oil. Rated for 430/1650. I would buy another in a flash!! Good engines!!
I haven't had mine dyno'd but it should make decent power for a c12. It was night and day over the stock tune
What is your average fuel mileage in miles per american gallon ? What type of trailer and percentage of miles loaded ?
I pull a 5 axle flat,,,,I do local runs,,,longest haul is 90kms (56 miles) one way,,,most trips are 70 kms (43 miles) and I also do real short stuff 14 kms (9 miles),,,,so its a LOT of stop and go,,,especially running into toronto area!!! I once kept track for 1000 kms,,(620 miles) I shifted 1616 times,,,and shut off and started the truck 64 times!!! I'm loaded 50%,,,,my fuel mileage this past summer has been between 6.9 and 7.70 hand calculated (imperial) I know my speedo runs about 4% slow, my odometer is likely out the same,,,I figure out my mpg by the #'s on the odometer!!! Guys doing the same job with c-15's are getting 6 imperial in summer,,,5 in the winter!!! A C12 is about 900 lbs lighter than a c-15!!!
Yeah, I'm as light as most of the daycabs at my work and I have a sleeper too. i run air mile work and got a 6.3 mpg and I idle all day long with half of the day in yards and doing very small moves.
I run a stock 3406e set at 550/1850, our neighbors run c12s set at 435 HP. They run the fuel temp wires as well. My truck has 3.42 rears, they run 3.90 I think. I can tell you on a short pull they can almost push me up the hills. But on the long hard pulls I run away from them pretty easily. Last place I worked we ran c13s set at 430 HP with 3.55 rears, they performed well.