RPM's- What is considered bogging?

[Coolslice]

I just put some 35" tires on my truck which has the 48re and 3. 73's. I'm thinking that I may have made a mistake because at normal driving speeds my truck seems to be bogging down and the egt's are much higher. At about 60 mph, I think I'm running about 1300-1400 rpms. Am I asking for trouble?

Thanks.



Ryan

 

[JFinke]

Anything below 1600-1700 is pretty low. At 13-14 you don't make much boost and are heating things up pretty good. You probably should go to 4. 11 or 4. 56. Nothing else you could just run in drive. Jake

 

[nickleinonen]

Anything below 1600-1700 is pretty low

i guess it depends on who you talk to or what your opinions are...



i think lugging is below 1400rpm on my engine when in 6th... i'll putter around in 3rd, 4th & 5th turning 900-1400rpm, but in 6th i don't like driving with it lower than 1400

 

[klenger]

I think that to determine what's lugging, you need to consider RPM and load. I can run as low as 1000 RPM if I am sort of coasting, can accellerate at 1200 RPM if the load is light (slow accel), prefer to be above 1500 to keep up with traffic, and above 1800 (or higher) if I have my camper hooked up.

 

[Dane]

If you step on the go pedal and not much happens for a while, you're bogging it

 

[tpuig]

Yep, I did the same thing. Put my 18" Weld wheels and Toyo 35's on for a quick run to LA and Vegas. Did some playing in the dirt. On the highway, my GPS said I was doing 75 mph at 2000 rpm. But around town, say about 25mph it's only around 1000 rpm. I found myself manually downshifting out of OD and even into 2nd gear to keep the revs up a bit higher. No load, city streets. I've still got a lot of tread left on my original BFG's, so I usually run those on the street. Once the oems wear out, I may look into swapping gears.

TP

 

[Hohn]

This is one reason that I opted for the 6-speed. I have the 3. 54 gears so 35s would be too much with the auto.



However, with the 6-speed, it's almost ideal. 1st gear is no longer such a creeper, and 6th is a really tall OD, as it should be.



Isn't the 48re smart enough to compensate for larger tires if the revs/mile are changed in the ECM?

 

[Coolslice]

Isn't the 48re smart enough to compensate for larger tires if the revs/mile are changed in the ECM?

I sure hope so, I have yet to have the Revs/mile changed.

 

[jersey diesel]

Hahn 6th gear taller ?

Does the sixth gear now improve your mpg? tks

 

[Fred Swanson]

Even with 37's, at 80 I'm at 2200RPM. Mileage really hasn't changed for me, though.

Anything below 1700RPM for the auto is not desirable, thus I recommend guys keep it out of OD for anything below around 50-55MPH. Especially 3. 54's or 3. 73's with 35's(315's) or larger tire.



Pulling a load, absolutely keep the RPM's above 1700.