Cruising RPM

zig80toy · Nov 26, 2007

Whats a good healthy RPM to cruise at on the highway? I went to Yakima and back this last weekend in the 05 dodge diesel. I set the cruise control at 71mph and was at 2000rpms. The thing redlines at 3200rpm. Is this a little too fast, just fine, etc...?
I was empty on the way over and carried back a couple boxes of wine, so weight was no big deal. Ooh yeah, the little computer thingy said i was getting 21.6miles per gallon...

Boomer · Nov 26, 2007

Probably not a cruising RPM ideal for fuel economy, but it doesn't sound too high to me. With the 4.10 gears and 35" tires, I usually cruise along the highway at 2,000-2,200 RPM in my old 12 valve. From what I have heard, the 24 valve and CR CTDs are a good bit friendlier to higher RPM ranges, too. Seems that 1700-1800 RPM is the CTD's "sweet spot" for fuel economy.

Nuzzy · Nov 26, 2007

With my 4.10s and stock tires, I cruise at about 23-2400 rpms @ 75mph. Not ideal for mileage, but oh well...

Lucky Jeff · Nov 26, 2007

2k seems to be the breakover point for mileage. It literally dropped mine about 3 mpg. 19-2200 for power/mileage. No one revs higher then a 12 valve though. But unless you're doing any sledpulling, you don't need to worry about that.....

bite me · Nov 26, 2007

Nuzzy said:
With my 4.10s and stock tires, I cruise at about 23-2400 rpms @ 75mph. Not ideal for mileage, but oh well...

mines about the same, glad I'm not the only one running that high of an rpm.:redneck:

GRNTACO · Nov 26, 2007

My 06 with 4.10s is the same.

Jay W · Nov 26, 2007

07 6spd, all stock, about 2200-2300 at 73.

Not Jobless · Nov 26, 2007

2000 24V 3.54's does 70 @2k

Anything over 75 and the mpg goes way down...

skinny_pedal · Nov 26, 2007

anything over 2k in my 04 duramax starts to suck fuel. but i can cruise at 70 at 1900

leadfoot067 · Nov 26, 2007

67MPH @ 2000 rpms= 20ish MPG

Lucky Jeff · Nov 27, 2007

Just checked on the way home. 65 mph at 2300 RPM........ In 4th gear :fawkdancesmiley:

Fullywrecked · Nov 27, 2007

My old 2wd dually 12 valve would only get 17.5mpg at 2900 rpms in 5th gear (95MPH) all the way across new mexico and Arizona and it only had 245K miles when I did it. It still running fine at 280K. I drove it as much as I could over 2500 rpms and it never got less than 17mpg. Although it would get 19-20 around 2000rpms. My 4wd won't do it, I have never seen over 17.5???????? You won't kill the lower end of these 5.9's you'll just spend more $$$ on fuel.:beer: