Engine/Transmission (1998.5 - 2002) RPM Limits

[GCULP]

ok, I searched the forum but didn't find the answer, what kind of RPM's are people running, I have an 01 HO six speed with 3:55 rearend. Curious as to what people are running empty, shift points, and towing. My truck seems to really come alive about 1900 up to 2500 but some of my old school buddies say never above 2200.

 

[Boondocker]

There isn't one answer. So here's a bunch.

Lower the RPM, better the MPG.

Peak torque about 1600 RPM

Peak HP about 2700 RPM

Defuel starts about 2700, redline 3200.



Cruising empty, I like 1700-1800, that's about 65 MPH in 6th.

Towing (gross 17K-18K), with any kind of grade or headwind, I like about 2200 RPM in 5th, room to accelerate, lower EGT. It'll pull hard at 2400 for hours, but that'll get on your nerves and push the water temp if it's hot and you're heavy.



Regular driving shift point, about 2400 RPM. Hard acceleration shift point, no higher than the tach goes. Defueling is no longer an issue

The sweet spot on my engine is about 2100 RPM, it feels real strong and responsive at that point. That's about 75 MPH in 6th, not towing of course.



With the CTD, you're more apt to do harm lugging than overrevving. It's too annoying to run high RPM, easy to lug, especially with a stick and clutch.



Cheers,

Neil

 

[GCULP]

Thanks Neil,

that sounds about how I drive, shift empty about 2400, pull long hills in 4th or 5th at 2400 to 2500, cruise the freeway empty at 70 mph.

 

[JKinney]

as boondocker said, but I have a 410 re so about 60 or so im at 2000 rpm so when I run 70 im up to 2350 or so the good news is when you get the smarty, theres no more defueling at 2700 Oo.

 

[Hohn]

For safety, you really only need to worry about lugging it. Don't load it hard below 1600rpm or so.

These things can handle 2700rpm all day without blinking. Above that, you should probably not sustain operation.

I shift ~2k rpm with my 3. 54s and get decent mpg and plenty of getup.

 

[Vaughn MacKenzie]

These things can handle 2700rpm all day without blinking. Above that, you should probably not sustain operation.

I would agree with that, 2700 is about the RPM ceiling where you can run sustained indefinitely without any significant consequences. This is probably why in most applications the B-series is governed at 2600-2700 RPM (and can be run there day in and day out). I know some say you can run against the 3400 RPM governor on the Ram indefinitely but I think at that RPM it would take a toll pretty fast. In reality there is no need to operate it like that anyway . . . unless you have a 4. 10 geared dually 5-speed trying to set a new speed record crossing Montana :-laf

 

[NoSeeUm]

For safety, you really only need to worry about lugging it. Don't load it hard below 1600rpm or so.



These things can handle 2700rpm all day without blinking. Above that, you should probably not sustain operation.



I shift ~2k rpm with my 3. 54s and get decent mpg and plenty of getup.

What RPM do you think that it starts to float the valves with a stock cam?



Jim

 

[GCULP]

thanks everyone, I'll be turnin her a little tighter this summer, RPM's help keep the egt's lower anyway.