Cummins ISL 9 with Alison 4000 6 speed.
2014 Providence 42p pulling a toad. Combined total weight about 42000. Traveling on 70 through Utah. This rig really seams doggy. With cruse set on 65 it will pull down to 40 on evan the moderate gra...
Forum Discussion
Brett, I'm curious what speed you have at 1500 rpm? At 65 I'm turning 1750 so if we have the same axle ratio... that's about 55?
OP, are you saying you got down to 24 MPH on 70 before the Eisenhower tunnel? What boost pressure were you showing and what rpm? It does not take much of a hill for mine to downshift into 5th and 2000 rpm with the mode on to try and stay at 65.
In rolling hills like on I-75 north of Macon GA I've found it's better to turn the cruise off and at the bottom of the next hill be at 70+ and accelerating. This gets me over the next one at a little less than 65 and usually still in 6th. If I leave the cruise on and wait for it to start accelerating I lug down and at the top I'm at less than 60 in 5th.
OP, are you saying you got down to 24 MPH on 70 before the Eisenhower tunnel? What boost pressure were you showing and what rpm? It does not take much of a hill for mine to downshift into 5th and 2000 rpm with the mode on to try and stay at 65.
In rolling hills like on I-75 north of Macon GA I've found it's better to turn the cruise off and at the bottom of the next hill be at 70+ and accelerating. This gets me over the next one at a little less than 65 and usually still in 6th. If I leave the cruise on and wait for it to start accelerating I lug down and at the top I'm at less than 60 in 5th.
