Horse Power Ratings
 

When looking at specs, I see nearly all the time a split rating. IE: 475/415

How is this supposed to be read. Is it a range... 415 to 475.. Is there some crazy mathematical knowledge to answer this???

What you have is an electronic engine that has 2 HP settings controlled by the computer.

When the truck is just puttering along and does not need the power the puter cuts back the HP to the lower rating, but when it does need it then it ups things to the higher.

My present motor started out life as a 325/350 = 325 normally but 350 when on cruise control. Depending on who you beleive, split ratings were "invented" to encourage company drivers to use cruise control to save the company fuel - or to save stress on the drivetrain as the cruise control is smoother on the throttle so the drivetrain can take more power when it is engaged.

ooooooooooooooooooo.....

I get it. I know most CAT motors can be turned up, is the same for all motors. Motor in question is Detroit 60 14L

The split HP method is pretty much the same for all engines. Though Cummins has split "torque" engines instead, called "SmartTorque". They boost the torque rating by 200lb/ft when needed.

I wonder how Cummins' smart torque impacts automatic transmissions' capacities. For example, top Fuller Ultrashifts™ post capacities of not more than 1750 lb.ft. This precludes their matching with engines with higher torque ratings. However, as smart torque occurs in the top gears, when cruising at about 55-65 mph, engine torque typically cranking lower than peak, thus saving the transmission from tearing down.

I've tried a few times to contact Fuller regarding this issue, and regrettably they only directed me to a friendly Fuller dealership. I did that, but the technicians there told me they're "not quite sure," only eager to sell me one and maybe expecting hefty fees after it being driven beyond its rating.

Moreover, Fuller should offer Ultrashifts™ with torque capacites of 1850 lb.ft. or higher. That would be nice.