quick and easy cat question

try to drive in "green zone" of tacho, from 1150 to 1400 rpm, but really the optimal engine speed depends on engine load and road conditions

 

I run mine at 1400, and 1700 on a pull/hill.

 

my old 3406E i ran at 1400 to 1700 my acert runs real good at 1300 to 1500 rpm

 

What kinda rear end gear ratio and tire size are you running?

 

I say one more time, everething depends on roiad conditions... Driving up a hill, rev up engine over 1500, driving at crusing speed drive 1200-1400. Fuel efficiantly mathematical functions are not so simple, yeah, electronics help on new trucks, becouse there are built in ECM program troque limiters that make you shift when engine runs in non optimal regime, but you drive old rig so use your experience, eyes and ears. You can see hill before you drive up a hill, so you can prepare to downshift before any autoshift can do it. On new ZF autos there are gyros built in to let tranny ECM know about hills, you be smarter any electronics. Experienced drivers here may get more MPG driving old, fully mechanical trucks

 

The maximum torque on that engine and most CATS is at 1200-1250 RPM's, the preferred cruising speed is between 1400-1500 by CAT specs. Most operators that come from another engine to CAT find it hard to run it that low. If you run at higher end of RPM range you won't have any torque.