Do you mash the pedal climbing mountain roads in the west

[Coached]

I just leave it on cruise control, always have. I understand that if tranny starts to overheat I select lower gear or pull over - hasn't happened yet. Side rad fan is hydraulic and speeds up by thermostat input. Been through the Rockies (40 and 70) several times and Smokies lots - works great.

[Rick Long]

I try to keep the tach between 3400 rpm and 4200 rpm so I'm at the top of the torque band.

[RVsteve]

With my deisel, I watch the RPMs and the turbo boost guage, and try to find a gear that keeps the RPMs around 2000, and the boost in the middle range. I don't worry about my speed. Both gas and deisel engines have a "comfort zone", usually around 2000 RPM where they are the most efficient.

Going DOWN hill is my challenge, trying to keep all that weight (41K) under control without burning out my brakes. I use a low gear and watch that the RPM are not at the redline all the time, backing off as needed by lightly pumping the brakes. Those long 10% grades get my attention. Going over Wolf Creek Pass, I had a CHP pull me over and TELL me which gear and what speed I should use on the downgrade.

RVsteve
08 Holiday Rambler Ambassador
2003 Suburban

[JimM68]

Just to hit this again....
The drivetrain i.n my 08 monaco is pretty sweet and pretty smart. Niether the engine nor the trans ever gets hot, never. Same temps on level ground at forty farenhiet as pulling a 10% grade at 100!

I've played with different throttle settings, and manually selecting gears. WOT = max boost, and max boost = max torque. Anything less, the boost drops, and she falls on her face. She will hold and pull at 2200 rpm... If she is able to accelerate, i punch the mode button on the trans pad which forcesz an upshift. Lifting is no good, i lose boost, and that is always bad.

Again, I'm not talking interstates here.....
And the modern diesel is smart enough not to overfuel....

[SteveSkinner]

Originally Posted by Robert L

So as I understand this correctly, I need to find the peak torque or peak HP RPM's and stay in THAT range, down shifting if necessary?

Regards

Only addition to the above for me would be keep an eye on the temps and lift the throttle a little as it reaches your personal limits. That way you should never be parked on the side of the road waiting for the tow truck.

[jauguston]

Forget about torque you need horsepower to go up a hill. I just got a ScanGauge D and one of the gauges available is horsepower. There is not a lot of horsepower at the rpm of maximum torque. Horsepower goes up with RPM. Maximum horsepower is at a much higher rpm than maximum torque. Higher rpm also turns the fan faster for more cooling.

Jim

[Mr_D]

Originally Posted by jauguston

Higher rpm also turns the fan faster for more cooling.

Jim

Not if you have a hydraulic fan like most of us with side radiators.

[jauguston]

OK --- Except for the very small number that have side radiators. Happy now?

Jim

[Davdeb1]

I have a 2000, and the owners manual says DO NOT GIVE FULL THROTTLE FOR EXTENDED PERIODS. The engine will overheat, probably because of over fueling.
Down shifting to keep rpms at about 2200 seems to make the engine happy, and gives it plenty of power to hold speed. Going up a long grade in AZ, I had my foot down to the floor, the temp gauge started climbing pretty fast , I backed off, down shifted, everything went back to normal.

So, it all depends on the coach. You'll find out soon enough.

[RickO]

Originally Posted by jauguston

OK --- Except for the very small number that have side radiators. Happy now?

Jim

I'm not sure that side radiators comprise only a "very small number" though.

It's important to remember that threads like this are widely educational. The OP asked about what different driving habits exist out there for getting over mountains. There's no "one right answer" and it's helpful to explain the nuances our different rigs and driving habits bring to the party.

I envy those who can just leave the cruise control on and not have to give a second thought to the fact that they're hauling >16 tons over an 11,000' mountain pass in the heat of summer. My rig won't do that without getting a bit hot under the collar. I need to keep a close eye on the temp (VMSpc) when climbing in hot weather and downshift to keep the rear radiator fan working hard but clearly others don't.

Rick

[jauguston]

It is a strange thing to hear a RV manufacturer admit that with the 330 Cat engine they installed in Davedeb1's motorhome he cannot use all the power the engine is designed to make on a continuous basis because the cooling system they installed won't cool it. Unbelievable!

Jim

[Barlow46]

Originally Posted by Mr_D

Not if you have a hydraulic fan like most of us with side radiators.

I believe that higher RPM does turn the water pump faster and does help with the cooling even though the hydraulic fan may not be affected by RPM. But, thinking that through, if the hydraulic fan is not coming on then you would not need the higher RPM to move the water pump along. If the fan is on and temps are rising, then the higher RPM would help pump the water though the system a little faster and should improve the temps.

[frankdamp]

I set cruise control for somewhere around 35-40 mph and let the various computers figure things out. We've climbed Washington Pass (Washington SR20), which tops out at around 5200 ft., in both directions several times using this philosophy, without a problem.

Radiator temps stayed in the green, transmission behaved well, changing between o/d and 3rd as required. If it can handle that, I don't sweat any other mountain crossings we're likely to encounter.

My philosophy is "trust but verify". I'll let the computer gremlins do their thing unless observation shows they're screwing up. Then I'll do somethong manual to over-ride them.

[RottenRalph]

Eisenhower Tunnel, Class A gas burner, Workhorse chassis, 4300RPM 25MPH, foot to the floor for a while.