older cat vs. newer paccar engines

This subject is very hard to explain easily. The way l understood it is that torque stops you from slowing down but hp makes you accelerate. Understand that? Meaning on a hill its fine to be above the peak torque when you start climbing. Just like you are at 1700 rpm. As you get into the hill the rpm will drop into the range where the torque rises. Thats why you would hear old guys say torque rise. Thats what made believers out of Mack R model guys And Cat 3406 guys. These engines had higher torque rises than others so on hills they would keep pulling and the rpm would stop falling. If you just don't have enough torque for your weight and hills your in it'll just go right through the torque range and stall the engine. Unless you downshift to get it back into the meat of the torque range.Thats why some guys didn't like old Detroit's and old style Cummins for heavy work bitd. A good rule of thumb for pulling on a hill is to always be in a gear that you can accelerate in and that you dont have to use full throttle to maintain speed at. If you are at full throttle and barely holding road speed than drop a gear. That will put you just above the torque rise and keep you from losing road speed and when the hill gets less steep hp will accelerate the truck over the crest. Simple as mud right? Have fun and experiment to find the engine's sweet spot.

 

Naw don't worry about that shifting wise. You'll find that when you are lugging the engine generally you have low boost and higher egt. Another reason to keep the rpm's a little higher when in a hard pull. Some guys call it running free. They'll say keep the engine running free when pulling. Meaning don't lug it. This is all during hard pulls once its on level ground or gentle rolling hills you can let it poke along at low rpm. Where you are you guys seem to have a lot of short steep hills that can sneak up on you. Especially running around 100g with milk in the tank. Sometimes the slosh alone can make you have to downshift on a short steep climb lol