My single turbo Cat is set on Soft Cruise and it seems to mimic what a driver should do in hills etc. quite well. Bought another truck 2013 with Cummins. WOW. I thought the C15 had power but the Cummins pulls like a train! Only thing I don't care for is the "hard cruise" where it keeps the throttle in it for any drop in speed at all. Seems it would get even better mileage on soft if Cummins has such a thing. There is darn near 1 mpg better on the Cummins. However the Cummins cruises at 1400 and can pull like a train but as soon as much rpm drop falls off in power fast where as the Cat has tremendous torque or holding power down to 1200. Perhaps if that is the case I should leave the cruise on the Cummins set how it is ? Drivers hate that soft cruise but they aren't buying the fuel either though. Any advice?
I love the soft cruise on cats.... Got my Detroit and just hated the cruise because was used to soft cruise of the cat I had before... Needless to say I use cruise less now . No need to peg the boost quage on every little incline on the hwy...
Whats your HP rating, took mine to PP Power and got the 600 tune putting 550 to the ground, I don't use cruise much just because it sucks to much fuel. I just came out of a C-15 Acert and it ran good but this cummins is Awesome, especialy with the tune.
Cummins (at least on ISX) uses droop to achieve more or less the same thing. Images below are for EPA201 ISX: If you have Insite or have access to it, you can check these parameters and try and play with them to see what you like best.
I have one and have the upper and lower droop both set to 3mph. It works well for most terrain. Also need to change the amount over cruise set speed to enable engine brake to be greater than the lower droop setting. Think mine is at 6, so if I leave cruise and jake on at set speed 63 in 65 zone it will keep the fuel rate pretty steady between 60 and 66 and will put engine brake on at 69. It does make it similar to driving using the pedal with an egg under it. I like it. You can still beat the system mpg wise using your foot, but if you ask a driver to do that he will want some form of accessorial pay.