Running high RPMs for long periods

[Wellibe]

Originally Posted by Gary Miller

There is no law that you have to maintain highway speed, especially when towing a trailer. Sometimes it is best to place the transmission into the lower gear and slow down so you're not rapping the engine up so much. Your transmission trying to shift back and forth between 3rd and 4th is a good clue that it is one of those times to place it in third and back off on the fuel so your not rapping out the engine.

If I was o.k. with doing 50 mph on the interstate, I would not have a problem. Might be alright for a weekend trip within a day's drive of home, but ain't gonna happen on a cross country trip.

And in some places, there actually is a law that you have to maintain highway speed. Driving more than 10-15 mph under the speed limit can be dangerous.

[deserteagle5]

Originally Posted by Wellibe

And in some places, there actually is a law that you have to maintain highway speed. Driving more than 10-15 mph under the speed limit can be dangerous.

^This.

Out here where we have mountain passes to climb we have many accidents with people running into the back of big rigs that cannot maintain the speed limit going up the pass. When general traffic is moving 80 mph and more, closing speeds with the slower vehicle can exceed 30 mph. Not a good scenario for inattentive drivers

[1320Fastback]

I believe the RPM of peak torque was mentioned above and that is where I would hold it while towing on hills. For me it's 1,900 RPM.

[Boris spider]

Originally Posted by MCCOHENS

I did an oil analysis this year and got excellent numbers, no metal or any signs of oil breakdown even after going 10K on the oil when normal is 5K.

What oil and filter are your using? How many miles are on the motor?

[MCCOHENS]

2004 silverado, 4.8 LS with 170K miles. Using the little purolator filter and mobil 1 10W30. We bought this truck about 4 years ago from a farmer. It was his go to town truck, not his work truck.

[Dave Pelletier]

Originally Posted by deserteagle5

^This.

Out here where we have mountain passes to climb we have many accidents with people running into the back of big rigs that cannot maintain the speed limit going up the pass. When general traffic is moving 80 mph and more, closing speeds with the slower vehicle can exceed 30 mph. Not a good scenario for inattentive drivers

Ever watch "Highway Thru Hell"? .....that's a local route for me; 8+% grade. No trucks can maintain the speed limit and many are down to 20mph or so. They stick to the far right lane and put their flashers on.....and it's not just semi's; most vehicles towing or hauling stuff can't maintain the speed limit up that hill....a half dozen of them typically burn up on the side of the road each year.

Dave

[twinboat]

Originally Posted by 1320Fastback

I believe the RPM of peak torque was mentioned above and that is where I would hold it while towing on hills. For me it's 1,900 RPM.

If Peak torque is listed at 1900 RPMs, that's measured at full throttle.

If your backing off the throttle to hold that RPM, your not reaching peak torque.

[Gary Miller]

Originally Posted by Wellibe

If I was o.k. with doing 50 mph on the interstate, I would not have a problem. Might be alright for a weekend trip within a day's drive of home, but ain't gonna happen on a cross country trip.

And in some places, there actually is a law that you have to maintain highway speed. Driving more than 10-15 mph under the speed limit can be dangerous.

Then it's time to get a vehicle that can handle the load at the speeds you want to drive.

[Wellibe]

Originally Posted by Gary Miller

Then it's time to get a vehicle that can handle the load at the speeds you want to drive.

Yeah, despite my budget constraints, I think that's the conclusion that I'm coming around to.

[kdauto]

Originally Posted by deserteagle5

^This.

Out here where we have mountain passes to climb we have many accidents with people running into the back of big rigs that cannot maintain the speed limit going up the pass. When general traffic is moving 80 mph and more, closing speeds with the slower vehicle can exceed 30 mph. Not a good scenario for inattentive drivers

If people are racing uphill at 80 MPH and cannot see a 13' tall and 8.5' wide truck, then they deserve to crash and free up the roadway for safer people. I am growing real tired of us having to protect the "freedoms" of the careless and dangerous crowd.

I'm starting to think of installing a I-beam bumper with 6" spikes at the rear of the 5th wheel now.

[Wellibe]

Where I'm from, mountain passes like that usually have an extra climbing lane for slow vehicles.

[Argosy]

Originally Posted by Wellibe

The engine temp gauge stayed well within the normal range, though I could feel lots of heat coming out of the engine/trans compartment when we stopped.

One thing you should do before stopping any engine after working it hard is let it idle and continue to cool. There’s a huge amount of heat inside the engine, if you shut it off a condition called heat soak occurs, engine temperature begins to spike, oil cokes, seals and gaskets are affected.

[propchef]

Originally Posted by Wellibe

Where I'm from, mountain passes like that usually have an extra climbing lane for slow vehicles.

And speed limits well below 80.

[Steve Rankin]

For us, it depends on whether we feel like we have a need to go faster or slower. While I normally cruise at 60-62 (about 1500 RPM) taking the grades in 5th at 1850 RPM, last Fall we had a need to get from Billings, Montana to south of Albuquerque, New Mexico in a day. Set the cruise at 85 and let the Cummins handle the rest. We found a couple of grades that slowed us to around 80.

Originally Posted by 1320Fastback

I believe the RPM of peak torque was mentioned above and that is where I would hold it while towing on hills. For me it's 1,900 RPM.