Ideal rpms?

[Dkoeberle]

I have a 2000 2500 auto with 3:54s.

At 55 mph in 4th gear I am at 1500 rpms.

At 55 mph in 3rd gear I am at 2100 rpms.



In either gear with or without my 12,000 lb trailer the truck and engine seem to be running fine. But some people have led me to believe I may be lugging the engine at 1500 rpms.



At 60 mph the rpms increase by about 100.



1600 rpms should not be lugging this engine.

Am I right?



Dave K

 

[rubberneck]

the engine loves 1500 rpm, the transmission on the other hand may be another story. i dont know i have a manual.

 

[Whitmore]

Dave , the ideal rpm range is from 1700 to 2300, but on the lower rpm I would not be concerened if you are lugging not so much as if you are causing high EGT, I did some over the road trucking for a while and our mechanic told me that rpm ment nothing but he wanted a downshift when egt got to 1500 degrees, I think 1500 is to high for a prolonged period but I wouldnt be scard to climb to that and then downshift. IMHO... ... ... ... ..... Kevin



Dave , I see you have an auto, I would deffinatly drop it out of overdrive

 

[LSMITH]

Dave, I am in the same situation with my truck. I think that as long as you are not using heavy throttle that 1500 in OD is fine. I try not to exceed 15 PSI of boost in OD below 1750 or so, After that I will let the hammer down. These are numbers that I came up with, they may or may not work for you. Get this, I routinely drive my truck with the TC locked in OD at 1150-1250 RPM for up to ten miles at a crack. In that situation I don't go over 4 PSI and 650 degrees. If I need power I punch the button to get it in Drive, otherwise I just cruise along. I really don't think it will hurt anything at all to run these rigs at low RPM if it is done responsibly. Start hammering the go pedal at low RPM and trouble will find you, just use the power wisely.