Questions for the C12 & C13 Cat guys.

Yeah I've got a question for you c12 guys. I drive a 2013 Peterbilt day cab. And it's got the 355hp c12 in it. Yeah the truck couldn't pull a hot knife through melted butter. But anyways. I'm wanting to know about the RPM' s at 60mph. I'm turning around 1375. I can't help to think that's to low of RPMs. So should the truck be turning a higher rpm at 60mph or is 1375rpm's right ?

 

How is it you have a c12 in a 2013 peterbilt? If its a glider, why didnt they go with c15?
And a low hp c12 at that. Cat stopped building motors for highway trucks somewhere around 2007. I find it hard to believe someone ordered a glider with c12 instead of c15. but anythings possible and a c12 with 350hp at that.
I have an 2002 379 with 425 hp c12 tuned to 525 and also have detroit turbo and pdi manifold. Pulls like a raped ape. With that aside, I see a lot of threads people talking about engine rpm and road speed. You arent the first person to post that is out in the dark about simple motor and gear ratio speeds.
Road speed has nothing to do with the operation of a motor. If your motoe is turning 1375 rpm in 60 mph and someone elses motor is turning a higher rpm at the same speed and same motor , that means they have different gear ratios in the transmission or rears. The motor hp and setup has absolutely nothing to do with it.

 

Yeah I don't understand why someone would put that motor in the truck. I'm just trying to figure this truck out. I don't know a lot about diesel engines. But since I've been driving this truck with this poor excuse of a motor. I've been trying to learn what I can. And from what little knowledge I have and after driving this truck. Compared to the other semis I've drove I just thought maybe there was a gear ratio issue. My opinion is that to big of a gear ratio. But I don't know. The truck runs like a scalded dog. When I'm bobtailing. But when I hook a trailer to it. Loaded or empty. The truck struggles to run 55/60 mph.. And can't pull a hill for nothin. And if I'm in a head wind. It's over. I've had to run 9th gear just to maintain 55mph. Super10 transmission. But anyways. Thanks for your feedback.

 

geez man. sorry to hear that. Get the cat tune on it. IT will wake up