Hill climbing

[Rick A]

Any engine that’s “under reviving” under load is being stressed. Torque is, the load transmission feeding back into the engine and this stress should be answered with revs.  Under-reving is blowing fuel out the exhaust not to mention other damaged being caused. Revs are the response to the torque being applied to the engine.  
The way to deal with the torque which is “power demanded by the load” is revs. If the revs are not responding then down shift to increase revs. This maintains the speed and keeps the torque rev ratio in sync. 
Revs are your friend. 
Torque is your enemy, if left unchecked it will stress the engine and the result is the rev counter drop even when the peddle is being depressed. 
I have an ISL 400 with the Allison 3000 and I can depress the pedal quickly and it will down change on its own but I prefer to force a down gear manually. I often pass other units because their drivers haven’t figured out the “happy zone”.

Tell me if I’m wrong please. 

 

 

[John Haggard]

4 minutes ago, Rick A said:

Any engine that’s “under reviving” under load is being stressed. Torque is, the load transmission feeding back into the engine and this stress should be answered with revs.  Under-reving is blowing fuel out the exhaust not to mention other damaged being caused. Revs are the response to the torque being applied to the engine.  
The way to deal with the torque which is “power demanded by the load” is revs. If the revs are not responding then down shift to increase revs. This maintains the speed and keeps the torque rev ratio in sync. 
Revs are your friend. 
Torque is your enemy, if left unchecked it will stress the engine and the result is the rev counter drop even when the peddle is being depressed. 
I have an ISL 400 with the Allison 3000 and I can depress the pedal quickly and it will down change on its own but I prefer to force a down gear manually. I often pass other units because their drivers haven’t figured out the “happy zone”.

Tell me if I’m wrong please. 

 

 

Your correct

And a Peddle to the metal not only throws fuel out the exhaust 🤫

It ( can ) under certain conditions destroy the proper lubing of the cylinder s and rings. 

We are not driving gas powered car's. 

[Rick A]

2 minutes ago, John Haggard said:

Your correct

And a Peddle to the metal not only throws fuel out the exhaust 🤫

It ( can ) under certain conditions destroy the proper lubing of the cylinder s and rings. 

We are not driving gas powered car's. 

I agree let’s not baby the engine, (thinking revs are harmful) and kill the entire power train with uncontrolled torque. When speed and load demand attention answer with engine power! 
 

[Ivylog]

“It ( can ) under certain conditions destroy the proper lubing of the cylinder s and rings.” Not even on your 99 Sig which will not puff black smoke because of modern electric controls. 

[Gary Cole]

An engineer for Mack Truck wrote an interesting article regarding the development of Mack's Maxidyne engine some years ago. The Maxidyne was the forerunner of today's modern high torque rise diesel engines. Mack used a reliable low torque rise 6 cylinder engine as a test block for the new engine. The Maxidyne operated at 1200 rpm on the low end with a torque rise of nearly 40% at that low rpm as I recall from the article. I was lucky  enough to have driven one of the earlier trucks. Very impressive experience.  He said that the failures, some of which occurred in minutes, included stretched head bolts, broken/bent  crankshafts, bent rods, fractures in the engine block, and transmission housings which split down the middle. Mack was forced to develop a new triple shaft transmission as no single shaft transmission of the day  was capable of handling the low rpm torque. This was before engine computer control and when engineers were required to do very complicated stress analysis calculations with slide rules, pencil, and paper. Today's stress analysis software based on finite elements and graphical representations would have been considered from another world at the time.

[Nevada Rob]

Engine torque gets a vehicle moving, engine horsepower keeps it moving. That is why the power torque band is low on the rpm scale. Low rpm torque gets the coach moving. Once up to speed the HP is what keeps the coach at speed. Since the majority of HP band is in the 1750 to 2100 rpm range it is best to keep that range of RPM when climbing hills. Take control of your vehicle and do not depend on the trans or ECM or any other device to drive your coach. There is no substitute for human input and control. At least not yet. Climbing a grade is only half the battle. Whatever goes up must come down. As a general rule, use the same gear you climbed the hill in to descend the hill. Not always the case but a good place to start as it is better to upshift on a down grade than trying to slow down. 

[John Haggard]

My signature likes 👍1600 to 2000 rpm. 

Only one hill  do I get down to first gear and run 2200 rpm

 

Rt. 111 North of Soddy Daisy.

South of Static. 

[FishAR]

51 minutes ago, John Haggard said:

My signature likes 👍1600 to 2000 rpm. 

Only one hill  do I get down to first gear and run 2200 rpm

 

Rt. 111 North of Soddy Daisy.

South of Static. 

Is that a steeper grade than Monteagle?

[John Haggard]

24 minutes ago, FishAR said:

Is that a steeper grade than Monteagle?

The climb on the old road 

North of the river valley is 8 %

South of Sparta  

Edited July 10, 2021 by John Haggard

[Chuck B 2004 Windsor]

I see nothing is being said about a exhaust or true engine Jake Brake.  On my 2004 Windsor, when I reach the top of a long high grade, I slow down to 15 MPG, engage my 2 stage Jake brake, and start down the hill in the low setting.  If the lower stage slows me down lower than 15 MPG, I switch to high.  When my speed reaches 30 MPH, I switch to the low setting.  I toggle back and forth all the way down not having to use the brake peddle.  That worked every time for me.  Chuck B 2004 Windsor

[Dr4Film]

Chuck, I didn't want to interject posts on how to descend a grade on this thread just so people wouldn't get confused.

I was hoping that someone would start a NEW thread in regards to descending a grade.

Big differences whether one has an Exhaust Brake or an Engine Brake.